Breathing and Exchange of Gases - Class 11 Biology - Chapter 13 - Notes, NCERT Solutions & Extra Questions
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Extra Questions - Breathing and Exchange of Gases | NCERT | Biology | Class 11
Identify the correct statement with reference to the transport of respiratory gases by blood.
(A) Haemoglobin is necessary for the transport of carbon dioxide, and carbonic anhydrase is necessary for the transport of oxygen.
(B) Haemoglobin is necessary for the transport of oxygen, and carbonic anhydrase is necessary for the transport of carbon dioxide.
(C) Only oxygen is transported by blood.
(D) Only carbon dioxide is transported by blood.
The correct option is (B): Haemoglobin is necessary for the transport of oxygen and carbonic anhydrase is necessary for the transport of carbon dioxide.
Both oxygen (O₂) and carbon dioxide (CO₂) are transported by the blood. The roles in their transportation are distinctly segmented among different constituents:
Haemoglobin is vital for the transportation of oxygen. Upwards of 97% of oxygen carried in the blood binds to haemoglobin to form oxyhaemoglobin.
On the other hand, carbonic anhydrase plays a crucial role for carbon dioxide transport. A majority of carbon dioxide is transported as bicarbonate ions (HCO₃⁻). Carbonic anhydrase catalyzes the critical conversion of $\mathrm{CO}_{2}$ into carbonic acid (H₂CO₃), which subsequently dissociates mostly into bicarbonate ions.
It is notable that carbonic anhydrase does not participate in the transportation of oxygen.
Which one of the following statements is wrong for gases?
A. Gases do not have a definite shape and volume.
B. Volume of the gas is equal to the volume of the container confining the gas.
C. Confined gas exerts uniform pressure on the walls of its container in all directions.
D. Mass of the gas cannot be determined by weighing a container in which it is enclosed.
The incorrect statement among the options given for gases is Option D:
D. Mass of the gas cannot be determined by weighing a container in which it is enclosed.
This statement is false because the mass of the gas can indeed be determined through a process known as weighing. Specifically, you first weigh the container when it's filled with the gas and then weigh it again after the gas has been removed. The difference in these two measurements will give you the mass of the contained gas.
"Why is there a residual amount of air left in the lungs during exhaling?"
The residual volume is the term used to describe the air that remains in the lungs after a person exhales as much as possible. Despite one's best efforts, this volume of air cannot be completely expelled from the lungs.
There are critical reasons why this residual volume is important:
Prevents the lungs from collapsing after each exhalation. Consider a deflated balloon; the initial effort required to introduce air into it is substantially higher than when it is partially inflated. Similarly, if the lungs were to collapse completely, each initiation of breath would be laborious, requiring a lot of energy and making breathing an exhausting task. This essential volume acts as a buffer against such collapse.
Maintains ventilation between breaths. Although the interval between inhalation and exhalation is brief, the presence of residual volume allows for continuous gas exchange (oxygen in and carbon dioxide out) in the lungs, enhancing overall respiratory efficiency.
Typically, an adult's lungs contain about 1.1 to 1.2 liters of residual volume, highlighting its significant role in maintaining effective lung function and respiratory health.
It is known that exposure to carbon monoxide is harmful to animals because:
(a) it reduces $\mathrm{CO}_{2}$ transport,
(b) it reduces $\mathrm{O}_{2}$ transport,
(c) it increases $\mathrm{CO}_{2}$ transport,
(d) it increases $\mathrm{O}_{2}$ transport.
Option (b) is correct because hemoglobin, composed of the protein globin and iron-containing heme groups, typically binds to oxygen molecules. This binding occurs through a reversible reaction to form oxyhemoglobin, which can be represented as: $$ \mathrm{Hb} + \mathrm{O}_2 \rightleftharpoons \mathrm{HbO}_2 $$ However, the reaction between carbon monoxide and hemoglobin results in the formation of carboxyhemoglobin, which is an extremely stable complex: $$ \mathrm{Hb} + \mathrm{CO} \rightarrow \mathrm{HbCO} $$ Due to this strong bonding with carbon monoxide, hemoglobin’s ability to bind with oxygen is severely decreased. This reduction in oxygen transport capacity can lead to oxygen deprivation in tissues, potentially causing serious health issues, including suffocation or death.
Some older emergency oxygen masks containing potassium superoxide $\left(\mathrm{KO}_{2}\right)$ react with $\mathrm{CO}_{2}$ and water in exhaled air to produce oxygen according to the given equation: $4 \mathrm{KO}_{2} + 2 \mathrm{H}_{2} \mathrm{O} + 4 \mathrm{CO}_{2} \rightarrow 4 \mathrm{KHCO}{3} + 3 \mathrm{O}_{2}$.
If a person exhales $0.667 , \mathrm{g}$ of $\mathrm{CO}_{2}$ per minute, how many grams of $\mathrm{KO}_{2}$ are consumed in 5.0 minutes?
A) 10.7
B) 0.0757
C) 1.07
D) 5.38
Given the chemical reaction: $$ 4 \mathrm{KO}_2 + 2 \mathrm{H}_2\mathrm{O} + 4 \mathrm{CO}_2 \rightarrow 4 \mathrm{KHCO}_3 + 3 \mathrm{O}_2 $$
Step 1: Calculate the total mass of $ \mathrm{CO}_2 $ exhaled in 5 minutes.
Mass of $ \mathrm{CO}_2 $ exhaled per minute = $0.667 , \mathrm{g}$
In 5 minutes, the mass exhaled = $5 \times 0.667 , \mathrm{g} = 3.335 , \mathrm{g}$
Step 2: Convert this mass to moles, using the molar mass of $ \mathrm{CO}_2 $ (approximately 44 g/mol): $$ \text{Number of moles of } \mathrm{CO}_2 = \frac{3.335 , \mathrm{g}}{44 , \mathrm{g/mol}} \approx 0.0758 , \text{moles} $$
Step 3: According to the balanced chemical equation, the mole ratio of $ \mathrm{KO}_2 $ to $ \mathrm{CO}_2 $ is 1:1.
Step 4: Calculate the mass of $ \mathrm{KO}_2 $ necessary, using its molar mass (approximately 71 g/mol): $$ \text{Mass of } \mathrm{KO}_2 = 0.0758 , \text{moles} \times 71 , \mathrm{g/mol} = 5.38 , \mathrm{g} $$
Hence, the correct answer is D) 5.38 g, which represents the mass of $ \mathrm{KO}_2 $ that is consumed in 5 minutes.
State true or false: Scuba divers carry oxygen cylinders with them.
A) True
B) False
The correct answer is B) False.
Scuba divers do carry cylinders, but these are not filled with pure oxygen. Rather, the cylinders contain compressed air, which is approximately 21% oxygen and 78% nitrogen, similar to the air we breathe normally. Pure oxygen can be toxic at higher pressures experienced underwater, which is why it is generally mixed with other gases when used for breathing in scuba diving setups. Thus, stating that scuba divers carry "oxygen cylinders" might be misleading if one interprets it as carrying pure oxygen.
"What is the mechanism of breath tester to identify if the vehicle driver is drunk or not?"
Breath alcohol testers function by detecting alcohol in a driver's breath, providing an immediate measure of blood alcohol content (BAC) without the need for a blood sample. Here's how the process works:
Alcohol Absorption: When a person consumes alcohol, it is absorbed into the bloodstream from the mouth, throat, stomach, and intestines.
Distribution of Alcohol: The consumed alcohol is not digested or chemically altered and circulates through the bloodstream.
Alcohol Evaporation in Lungs: As the blood passes through the lungs, some of the alcohol diffuses through the membranes of the alveoli (tiny air sacs in the lungs) into the alveolar air due to its volatile nature.
Alcohol Detection: The concentration of alcohol in the alveolar air correlates with the blood alcohol concentration. As a person exhales, this air containing evaporated alcohol is detected by the breath tester.
By utilizing this mechanism, a breath alcohol testing device allows law enforcement officers to conduct on-the-spot checks of a driver’s BAC, thus determining whether there might be grounds for arrest due to impaired driving. This immediate feedback is crucial for enforcing laws against driving under the influence (DUI).
Which of the following changes can an emphysema patient experience?
A. Increased blood oxygen concentration
B. Increased residual volume
C. Decreased blood carbon dioxide concentration
D. Decreased total lung capacity
The correct answer is B. Increased residual volume.
Emphysema involves damage to the alveolar walls, which are crucial structures within the lungs responsible for gas exchange. This damage primarily results from harmful agents such as cigarette smoke. The alveoli are tiny sacs where oxygen and carbon dioxide are exchanged during breathing.
When these alveolar walls are damaged, the total surface area available for gas exchange decreases, adversely affecting the lungs' ability to process air efficiently. Notably, in emphysema, the elastic recoil of the lung, which assists in pushing air out during exhalation, is diminished. This impairment leads to an inability to fully exhale, thus increasing the residual volume—the volume of air remaining in the lungs after a complete exhale.
This dysfunctional process results in air being trapped in the lungs, making it difficult for patients to breathe out fully, hence the increased residual volume. In contrast, options A, C, and D do not accurately describe what typically occurs in emphysema:
Increased blood oxygen concentration (A) and decreased blood carbon dioxide concentration (C) are incorrect as emphysema usually leads to decreased oxygen and increased carbon dioxide in the blood due to diminished gas exchange efficiency.
Decreased total lung capacity (D) is also incorrect. Emphysema can sometimes result in an apparent increase in total lung capacity due to trapped air, though effective lung volume (usable volume) may decrease.
The membranes enclosing the lungs are called:
A. mediastinum
B. pleura
C. pulmones
D. pericardium
The correct answer is B. pleura.
The pleura is a double-layered membrane that encloses each lung. It consists of two parts: the outer parietal pleura and the inner visceral pleura. These membranes are separated by a thin space, the pleural cavity, which is filled with pleural fluid. This fluid helps in lubricating the surfaces, allowing the lungs to move smoothly during respiration.
Other options provided include:
A. Mediastinum: This refers to the central compartment of the thoracic cavity, located between the two pleural sacs, and does not directly enclose the lungs.
C. Pulmones: This is simply another term for the lungs themselves.
D. Pericardium: This double-layered membrane surrounds the heart, analogous to the pleura around the lungs, comprising an outer parietal layer and an inner visceral layer separated by the pericardial cavity filled with pericardial fluid.
Which of the following is not part of the conducting zone of the respiratory system?
A. Oral cavity
B. Trachea
C. Bronchioles
D. Alveolar sacs
The correct answer is D. Alveolar sacs.
The human respiratory system is divided into two primary zones: the conducting zone and the respiratory zone. The conducting zone consists of structures that mainly serve as air passageways. These include the nasal cavity, oral cavity, pharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles.
In contrast, the respiratory zone encompasses structures specifically involved in the gas exchange process with the blood. This zone includes the lungs, respiratory bronchioles, alveolar ducts, and alveolar sacs. Therefore, alveolar sacs do not belong to the conducting zone but rather to the respiratory zone.
$\mathrm{KO}_{2}$ is used in oxygen cylinders in space and submarines because it:
A) Absorbs $\mathrm{CO}_{2}$ and increases $\mathrm{O}_{2}$ content
B) Eliminates moisture
C) Absorbs $\mathrm{CO}_{2}$ only
D) Produces ozone
The correct answer is A) Absorbs $\mathrm{CO}_2$ and increases $\mathrm{O}_2$ content.
$\mathrm{KO}_2$, or potassium superoxide, plays a crucial role in life-support systems within submarines and spacecraft by managing the respiratory waste product $\mathrm{CO}_2$ and generating additional $\mathrm{O}_2$. The process involves a chemical reaction where $\mathrm{KO}_2$ reacts with $\mathrm{CO}_2$ to produce potassium carbonate ($\mathrm{K}_2\mathrm{CO}_3$) and releases extra oxygen. The reaction can be represented as: $$ 4 \mathrm{KO}_2 + 2 \mathrm{CO}_2 \rightarrow 2 \mathrm{K}_2\mathrm{CO}_3 + 3 \mathrm{O}_2 $$ This property makes $\mathrm{KO}_2$ extremely valuable for creating breathable air environments where external oxygen sources are limited.
In a closed cylinder, there are $60 \mathrm{~g} \mathrm{Ne}$ and $64 \mathrm{~g} \mathrm{O}_{2}$. If the pressure of the mixture of gases in the cylinder is 30 bar, then the partial pressure of $\mathrm{O}_{2}$ in this cylinder will be (in bar).
To calculate the partial pressure of $\mathrm{O}_{2}$ (oxygen) in a mixture with neon ($\mathrm{Ne}$) in a cylinder, we use the law that states partial pressure is proportional to the number of moles of each gas.
The given total pressure, $P_{\text{total}}$, of the gas mixture is 30 bar. The masses and molar masses of the gases are provided:
Mass of $\mathrm{O}_{2}$ = $64 , \mathrm{g}$
Mass of $\mathrm{Ne}$ = $60 , \mathrm{g}$
The molar mass of $\mathrm{O}_{2}$ is $32 , \mathrm{g/mol}$, and for $\mathrm{Ne}$, it is $20 , \mathrm{g/mol$}. Using these molar masses, we find the number of moles:
Moles of $\mathrm{O}_{2}$: $$ n_{\mathrm{O}_{2}} = \frac{64 , \mathrm{g}}{32 , \mathrm{g/mol}} = 2 , \mathrm{mol} $$
Moles of $\mathrm{Ne}$: $$ n_{\mathrm{Ne}} = \frac{60 , \mathrm{g}}{20 , \mathrm{g/mol}} = 3 , \mathrm{mol} $$
The formula for the partial pressure of $\mathrm{O}_{2}$ based on mole fraction is: $$ \frac{P_{\mathrm{O}_{2}}}{P_{\text{total}}} = \frac{n_{\mathrm{O}_{2}}}{n_{\mathrm{O}_{2}} + n_{\mathrm{Ne}}} $$
Substitute the values into the formula: $$ \frac{P_{\mathrm{O}_{2}}}{30 , \mathrm{bar}} = \frac{2 , \mathrm{mol}}{2 , \mathrm{mol} + 3 , \mathrm{mol}} = \frac{2}{5} $$
Solving for $P_{\mathrm{O}_{2}}$, we get: $$ P_{\mathrm{O}_{2}} = \frac{2}{5} \times 30 , \mathrm{bar} = 12 , \mathrm{bar} $$
Thus, the partial pressure of $\mathrm{O}_{2}$ in the cylinder is 12 bar.
Residual volume is
A) Lesser than tidal volume
B) Greater than inspiratory volume
C) Greater than vital capacity
D) Greater than tidal volume
The correct option is D) Greater than tidal volume
Residual volume is always greater than tidal volume. Tidal volume refers to the amount of air inhaled or exhaled during a normal breath without any additional effort. On the other hand, residual volume is the amount of air that remains in the lungs even after a forceful exhalation. Typically, tidal volume is around $500 , \text{ml}$, while residual volume usually ranges between $1100$ and $1200 , \text{ml}$.
Esophagus opens only during:
A) speaking
B) exhaling
C) inhaling
D) swallowing
The correct answer is D) swallowing.
The esophagus, also known as the gullet, is a crucial component of the gastrointestinal system. It connects the mouth to the stomach. The esophagus primarily opens during the process of swallowing to allow the passage of food and liquids into the stomach.
Name two gases which dissolve in water.
Two gases that dissolve in water are:
Carbon Dioxide
Oxygen
During breathing, water is lost. True/False?
A) True
B) False
The correct answer is A) True.
During the process of cellular respiration, glucose is metabolized to release energy. The chemical equation for cellular respiration is: $$ C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{ATP} $$ In this process, along with carbon dioxide (CO_2) and energy (ATP), water (H_2O) is also produced. This water is released during breathing, hence, water loss does occur during the breathing process.
"Are breathing and respiration the same? Give reasons."
No, breathing and respiration are not the same, though they are related processes.
Breathing is the physical process of inhaling and exhaling air. It primarily involves the exchange of gases where oxygen is taken into the lungs and carbon dioxide is expelled.
Respiration, on the other hand, is a biochemical process that occurs at the cellular level. It involves a series of metabolic reactions that convert biochemical energy from nutrients into ATP (adenosine triphosphate). ATP is crucial as it serves as the main energy source for cellular activities. Respiration also results in the release of waste materials such as carbon dioxide, which is carried away from the cells by the blood and is eventually expelled from the body through the breathing process.
While visiting an aquarium, Aman noticed that fishes open and close their mouths and gill slits frequently. This action forces the surrounding water to enter their bodies. Which of the following statements justifies the observation made by Aman?
A. The amount of dissolved oxygen in water is low.
B. The amount of dissolved oxygen in water is high.
C. The amount of dissolved $\mathrm{CO}_{2}$ in water is high.
D. The amount of dissolved $\mathrm{CO}_{2}$ in water is low.
The correct answer is A. The amount of dissolved oxygen in water is low.
Fishes frequently open and close their mouths, and this behavior assists in pushing the surrounding water through their bodies. The purpose of this action is to absorb dissolved oxygen found in the water for respiration. Since the amount of dissolved oxygen in the water is generally lower than in the air, aquatic animals like fish must take in significant amounts of water to meet their oxygen needs through their gills. Thus, this behavior is particularly notable when the dissolved oxygen levels in the water are low, which forces them to breathe more rapidly to intake the necessary amount of oxygen.
The role of nasal chambers in respiration is
A. Entraps harmful particles.
B. Warms the air.
C. Adds moisture to the air.
D. Gives a sense of smell.
The nasal chambers play critical roles in respiration by:
A. Entrapping harmful particles: This helps in filtering out dust, pollutants, and other airborne materials that could be harmful if inhaled into the lungs.
B. Warming the air: The nasal passages adjust the temperature of the air to be closer to body temperature, which is essential for comfortable and safe respiration.
C. Adding moisture to the air: The nasal chambers also moisten the air, preventing the drying out of the respiratory tract and aiding in effective gas exchange in the lungs.
The structure responsible for these functions is the nasal chambers, which consist of two cavities divided by a septum. These cavities are lined with mucosa that helps in warming, moistening, and filtering the air as it passes through them into the lungs.
Identify the air pollutant that can cause poisoning by readily combining with hemoglobin in the blood.
A. $\mathrm{CO}$
B. $\mathrm{CO}_{2}$
C. $\mathrm{H}_{2} \mathrm{S}$
D. $\mathrm{HCl}$
The correct answer is A. $\mathrm{CO}$ (Carbon Monoxide).
Carbon monoxide is a colorless, odorless, and toxic gas that is produced from the incomplete combustion of organic materials. Its toxicity primarily stems from its ability to form carboxyhemoglobin by combining with hemoglobin in the blood. This combination inhibits hemoglobin's oxygen-carrying capacity, effectively suffocating the body's tissues by depriving them of oxygen. This can lead to symptoms like choking and shortness of breath, and in severe cases, can result in death.
A gas occupies 12.3 litres at a pressure of 40 mmHg. What is the volume when the pressure is increased to 60 mmHg? (Temperature is constant) A. 8.2
B. 7.1
C. 9.7
The correct option is A. 8.2
According to Boyle's law, the product of pressure and volume of an ideal gas remains constant if the temperature is constant: $$ PV = \text{constant} $$ Therefore, the relationship can be expressed as: $$ P_1 V_1 = P_2 V_2 $$ where $P_1$ and $V_1$ are the initial pressure and volume, and $P_2$ and $V_2$ are the final pressure and volume, respectively.
To find $V_2$, the equation is rearranged as: $$ V_2 = \frac{P_1 V_1}{P_2} $$
Substituting the given values: $$ V_2 = \frac{12.3 \times 40}{60} = 8.2 \text{ litres} $$
Thus, the volume of the gas when the pressure is increased to 60 mmHg is 8.2 litres.
Help fish swim in the water.
A Lungs
B Fins
C Gills
D Legs
The correct answer is B) Fins.
Fishes are aquatic animals adapted to their environment. Specifically, fins are vital for movement, steering, and balance in water. They utilize these fins to propel themselves effectively through the water. On the other hand, gills are crucial for breathing underwater by extracting oxygen from water but do not aid in swimming. Legs and lungs are not applicable to fish for swimming; lungs are for air-breathing creatures, and legs are generally for land movement.
Why do mountaineers suffer from nosebleeds at high altitudes?
A) Due to fear
B) Due to low air pressure
C) Due to low temperature
D) Due to high air pressure
The correct answer is B) Due to low air pressure.
At high altitudes, the air pressure is significantly lower than at sea level. This decrease in air pressure means that there is less external pressure to counteract the pressure exerted by blood inside the blood vessels. Consequently, the blood vessels in the nose may burst, leading to nosebleeds. This happens because the internal blood pressure becomes relatively higher compared to the diminished atmospheric pressure, weakening the small vessels in the nasal passages.
What is rarefaction?
Rarefaction refers to the phenomenon where density of a material decreases. This can be observed in a variety of contexts, both natural and mechanical.
A recognizable natural example of rarefaction is evident within the Earth's atmosphere. Air density decreases in higher layers of the atmosphere due to gravitational forces which pull most atmospheric mass closer to the Earth's surface. Therefore, air found at higher altitudes is considered rarefied compared to that at lower altitudes. In this context, rarefaction indicates a decrease in air density with an increase in altitude.
In a mechanical scenario, rarefaction can be demonstrated using a spring. By compressing and then releasing a spring, one can observe rarefaction. During this process, spaced-out loops visibly travel through the spring, creating what are known as rarefaction waves. This illustrates how rarefaction represents a reduction in density; in this case, over time and space within the structure of the spring.
The nose is divided into two by the:
A. nasopharynx
B. nasal vestibule
C. nasal septum
D. nasal turbinates
The correct answer is C. nasal septum.
The nasal septum is the structure that divides the nasal cavity into two separate halves. The initial part of the nasal cavity is referred to as the nasal vestibule. The space between the septum and the turbinates is known as the meatus, which connects to the upper portion of the pharynx known as the nasopharynx. The nasal turbinates, or nasal conchae, are scroll-like bones that help keep the meatus open.
Lungs become empty after forceful expiration.
A) True
B) False
The correct option is B) False.
Lungs always retain a residual volume of air to ensure there's enough time for the oxygen to be absorbed and the carbon dioxide to be released. Even after forceful expiration, a certain volume of air remains in the lungs.
Breathing is a part of:
A) Relaxation
B) Sleeping
C) Exercise
D) Respiration
The correct answer is D) Respiration.
Breathing is a fundamental component of the respiration process, which involves the inhalation of oxygen and the exhalation of carbon dioxide.
Identify correct sequence:
Breathing $\rightarrow$ Pulmonary gas exchange $\rightarrow$ Transport of gases $\rightarrow$ Systemic gas exchange $\rightarrow$ Cellular respiration
Breathing $\rightarrow$ systemic gas exchange $\rightarrow$ Transport of gases pulmonary gas exchange $\rightarrow$ cellular respiration
Cellular respiration $\rightarrow$ pulmonary gas exchange $\rightarrow$transport of systemic gas exchange $\rightarrow$ breathing
Cellular respiration $\rightarrow$ breathing $\rightarrow$ pulmonary gas exchange - transport of gases $\rightarrow$ systemic gas exchange
To determine the correct sequence in the respiratory process, let's break down the stages involved:
Breathing: This initiates the respiratory process. When we inhale air through our nose or mouth, it travels down the pharynx, then through the trachea, and into the bronchial tubes that lead to the lungs.
Pulmonary Gas Exchange: Once the air reaches the lungs, it moves to the alveoli (tiny air sacs). Here, oxygen is absorbed by the blood, and carbon dioxide is released from the blood into the air sacs to be exhaled.
Transport of Gases: After oxygen is absorbed in the lungs, it is transported by the blood to the heart, which pumps it to various tissues and organs throughout the body.
Systemic Gas Exchange: Oxygen in the blood is delivered to the body's cells, where it is used for cellular activities. Meanwhile, carbon dioxide, a waste product from cellular respiration, is transferred from the cells to the blood.
Cellular Respiration: Cells use the oxygen delivered to them for metabolic processes to produce energy, resulting in the production of carbon dioxide as a byproduct.
Thus, the correct sequence for the respiratory process is:
Breathing
Pulmonary Gas Exchange
Transport of Gases
Systemic Gas Exchange
Cellular Respiration
Therefore, the correct sequence you should identify is:
Breathing $\rightarrow$ Pulmonary Gas Exchange $\rightarrow$ Transport of Gases $\rightarrow$ Systemic Gas Exchange $\rightarrow$ Cellular Respiration
Which of the following is a part of both the digestive tract as well as the respiratory tract?
A Trachea
B Larynx
C Nose
D Pharynx
The question asks which of the following is a part of both the digestive tract and the respiratory tract.
Option A: Trachea
Option B: Larynx
Option C: Nose
Option D: Pharynx
Let's break down the functions of each option to determine the correct answer:
Trachea
The trachea is part of the respiratory tract. It connects the larynx to the bronchi of the lungs, but it has no role in the digestive process.
Larynx
The larynx, also known as the voice box, is a part of both respiration and phonation (sound production). It helps in breathing and producing sound but does not have a direct role in digestion.
Nose
The nose is primarily associated with the respiratory system. It is responsible for breathing and filtering the air, but it has no functions in digestion.
Pharynx
The pharynx serves as a common passage for both food and air, playing a role in both digestive and respiratory systems:
Digestive Function: The pharynx connects the mouth to the esophagus, allowing food to pass through.
Respiratory Function: The pharynx also connects to the larynx, facilitating breathing.
At the end of the pharynx, there is a flap-like structure called the epiglottis. The epiglottis directs food to the esophagus during swallowing and air to the larynx during breathing.
Conclusion
Given these functions, the pharynx (Option D) is the correct answer as it is involved in both the digestive and respiratory tracts.
Final Answer: D
Flow of water and blood to the respiratory organs is countercurrent in these animals:
Sponges, coelenterates, flatworms
Pisces
Mammals
Aquatic arthropods and molluscs
The flow of water and blood to the respiratory organs is countercurrent in these animals:
Sponges, coelenterates, flatworms
Pisces
Mammals
Aquatic arthropods and molluscs
Answer: B (Pisces)
Explanation:
Pisces, or fish, possess gills which act as their respiratory organs. Gills are structured to facilitate a countercurrent flow of water and blood.
In a countercurrent exchange system, water flows over the gills in one direction while blood flows through the gill capillaries in the opposite direction. This arrangement maximizes the diffusion of oxygen into the blood and the removal of carbon dioxide from the blood.
Key Points:
Countercurrent flow enhances the efficiency of gas exchange in fish.
Fish are unique among the given options in utilizing this method.
Other listed animals, such as sponges, coelenterates, flatworms, mammals, aquatic arthropods, and molluscs, do not employ this type of respiratory mechanism.
Thus, the correct answer is Pisces (B).
Find the odd one out with respect to the respiratory organ:
A. Pisces
B. Mammals
C. Reptiles
D. Aves
To determine which among the given options is the odd one out with respect to respiratory organs, let's analyze each group:
Pisces: These are fish. Fish typically use gills for respiration.
Mammals: Mammals, including humans, respire using lungs.
Reptiles: Reptiles, like snakes and lizards, breathe using lungs.
Aves: Birds also rely on lungs for respiration, but their system is more efficient than mammals and reptiles, using a system of air sacs.
The odd one out is Pisces because they use gills for respiration, whereas the other groups (Mammals, Reptiles, and Aves) use lungs.
Therefore, the correct answer is:
A. Pisces
Lungs do not enclose:
Bronchi
Trachea
Bronchioles
Alveoli
The question asks which of the following structures is not enclosed by the lungs:
Bronchi
Trachea
Bronchioles
Alveoli
To determine the correct answer, let's look at the function and location of each structure within the respiratory system:
Bronchi: The bronchi are large air passages that branch off from the trachea and enter the lungs. These structures are indeed part of the lungs.
Trachea: The trachea, also known as the windpipe, is the main airway that leads from the throat to the bronchi. It is located outside the lungs and serves as the conduit that air passes through before entering the bronchi.
Bronchioles: The bronchioles are smaller air passages that diverge from the bronchi within the lungs. They carry air to the alveoli and are indeed enclosed by the lungs.
Alveoli: The alveoli are tiny sacs at the end of the bronchioles where the exchange of oxygen and carbon dioxide occurs. They are critical components of the lung structure.
Based on this explanation, the trachea is not enclosed by the lungs, making it the correct answer to the question.
Therefore, the correct answer is:
B. Trachea
Identify the parts of the respiratory tract without 'C' shaped cartilages:
Trachea
Primary bronchi
Secondary bronchi
Terminal bronchioles
To identify the parts of the respiratory tract without 'C' shaped cartilage, let's review the respiratory tract components:
Trachea
Primary bronchi
Secondary bronchi
Terminal bronchioles
'C' shaped cartilages serve an important role by providing structural support and keeping the airways open. These cartilages are present in several parts of the respiratory tract, starting from the trachea as it progresses downwards.
Trachea: Contains 'C' shaped cartilages.
Primary bronchi: Contains 'C' shaped cartilages.
Secondary bronchi: Contains 'C' shaped cartilages.
Terminal bronchioles: Do not contain 'C' shaped cartilages.
From the trachea to the initial bronchioles (which includes the primary, secondary, and tertiary bronchi), 'C' shaped cartilages are present. However, when it comes to the terminal bronchioles, these cartilages are absent.
Thus, among the options listed, the terminal bronchioles are the part of the respiratory tract that do not have 'C' shaped cartilages.
Therefore, the answer is:
D. Terminal bronchioles
Choose incorrect statement about respiration:
A. Insects have a network of tubes.
B. Earthworms use their vascularized parapodia as respiratory structures.
C. Amphibians like frogs can respire through diffusion over their entire body surface.
D. Coelenterates exchange $\mathrm{O}_{2}$ with $\mathrm{CO}_{2}$ by simple moist skin also.
Statement A: Insects have a network of tubes.
This statement is correct. Insects possess a network of tubes called tracheae that facilitate gas exchange.
Statement B: Earthworms use their vascularized parapodia as respiratory structures.
This statement is incorrect. Earthworms do not have parapodia; instead, they respire through their skin. Their skin must remain moist to allow for effective exchange of gases.
Statement C: Amphibians like frogs can respire through diffusion over their entire body surface.
This statement is correct. Frogs are capable of cutaneous respiration, which means they can respire through their moist skin in addition to their lungs.
Statement D: Coelenterates exchange $\mathrm{O}_{2}$ with $\mathrm{CO}_{2}$ by simple moist skin also.
This statement is correct but slightly misleading. Coelenterates, such as jellyfish and corals, typically exchange gases via simple diffusion across their body surface, which is often moist.
In conclusion, the incorrect statement is:
B. Earthworms use their vascularized parapodia as respiratory structures.
Final Answer:
B. Earthworms use their vascularized parapodia as respiratory structures.
Pharynx opens into the trachea through:
A. gullet
B. glottis
C. syrinx
D. alveoli
The pharynx opens into the trachea through the:
B. Glottis
To elaborate, let's understand the anatomy involved:
Pharynx: This is a part of the throat situated behind the nasal cavities and mouth.
Larynx: Located below the pharynx, also referred to as the voice box.
Laryngopharynx: The lowest part of the pharynx.
The laryngopharynx connects to two important structures:
The anterior slit, known as the glottis, leads into the trachea (windpipe).
The posterior slit leads into the gullet, which then continues as the esophagus (food pipe).
The glottis plays a crucial role:
The pharynx opens into the trachea via the glottis.
The glottis is equipped with a cartilaginous flap called the epiglottis, which functions to cover the glottis during swallowing, preventing food and liquid from entering the trachea.
Hence, the correct answer is option B: Glottis.
Trachea divides into bronchi at the level of:
A. atlas
B. axis
C. 3rd cervical vertebra
D. 5th thoracic vertebra
The trachea divides into bronchi at the level of the:
A. atlas
B. axis
C. 3rd cervical vertebra
D. 5th thoracic vertebra
The trachea is a straight tube that extends through the mid-thoracic cavity. This tube continues downward until it reaches the 5th thoracic vertebra, at which point it divides into the left and right bronchi. These bronchi further undergo repeated divisions to form secondary and tertiary bronchi, which eventually lead to the formation of the terminal bronchioles.
Therefore, the correct answer is:
D. 5th thoracic vertebra
Identify the incorrect matches:
Organism | Respiratory Organs |
---|---|
Laccifer | Gills |
Lepisma | Tracheae |
Ararena | Book lungs |
Pila | Crenedia |
To identify the incorrect match from the given columns of organisms and their respective respiratory organs, let's review each pair:
Laccifer & Gills:
Laccifer is commonly known as a lac insect and belongs to the phylum Arthropoda. Insects within this phylum typically breathe through tracheae, which are tube-like structures that are air-filled.
Thus, the correct match for Laccifer is tracheae, not gills.
Lepisma & Tracheae:
Lepisma, commonly known as silverfish, is also an insect and belongs to the phylum Arthropoda. Insects, as noted before, have tracheae for respiration.
Therefore, this is a correct match.
Aranea & Book lungs:
Aranea (spiders) belong to the phylum Arthropoda. Spiders typically have book lungs for respiration, which are plate-like, hollow, air-filled structures.
So, this is a correct match.
Pila & Ctenidia:
Pila is commonly known as the apple snail and belongs to the phylum Mollusca. The respiratory organs in mollusks are called ctenidia or comb-like gills.
Hence, this is a correct match.
The incorrect match here is:
Laccifer & Gills
Thus, the incorrect match is:
Laccifer & Gills
Final Answer:
Laccifer & Gills
Set of respiratory organs used for exchange of gases in terrestrial habitat is:
A) skin and gills
B) gills and trachea
C) trachea and lungs
D) lungs and ctenidia
Terrestrial habitats include environments such as forests, grasslands, and deserts. Here's a closer look at the functionalities of various respiratory organs:
Skin: Used by organisms like earthworms for respiration as they live below the soil.
Gills: Utilized by many aquatic organisms (e.g., fishes) to extract oxygen from water.
Trachea: The windpipe that connects the larynx to the bronchi within the lungs; essential in terrestrial respiration.
Lungs: Crucial respiratory organs for terrestrial animals, facilitating the exchange of gases with the environment.
Ctenidia: Gill-like structures primarily found in mollusks, which are mostly aquatic organisms.
From the analysis:
Gills and ctenidia are not suitable for terrestrial respiration due to their reliance on water.
Skin is fascinatingly used in specific conditions but not typically paired with terrestrial habitats.
The most appropriate pairing for gas exchange in terrestrial habitats is thus trachea and lungs since they are efficiently designed for the exchange of gases in environments like forests, grasslands, and deserts.
Therefore, the correct answer is:
C) Trachea and lungs
Which of the following is a part of the conducting zone in the respiratory system?
A Terminal bronchioles
B Respiratory bronchioles
C Alveolar ducts
D Alveoli
To determine which of the given options is part of the conducting zone in the respiratory system, we must first understand what the conducting zone is.
Understanding the Conducting Zone:
The conducting zone is a portion of the respiratory system whose primary function is to provide a route for the incoming and outgoing of air. This zone includes structures that help in the transportation of air to the lungs but are not directly involved in gas exchange.
Components of the Conducting Zone:
The conducting zone includes both parts outside and inside the lungs:
Outside the lungs:
Nasal passages
Pharynx
Larynx
Trachea
Inside the lungs:
Bronchi
Bronchioles
Terminal bronchioles
Analysis of Options:
Terminal bronchioles: These are part of the conducting zone. They are the last section of the airway that solely conducts air and does not participate in gas exchange.
Respiratory bronchioles: These mark the beginning of the respiratory zone where gas exchange begins to occur, so they are not part of the conducting zone.
Alveolar ducts: These are part of the respiratory zone and are involved in gas exchange, not part of the conducting zone.
Alveoli: These are primary sites of gas exchange in the respiratory zone, not part of the conducting zone.
Conclusion:
The correct answer is:
A. Terminal bronchioles
The terminal bronchioles are the part of the conducting zone in the respiratory system.
Respiration in insects is called direct because:
The cells exchange $O2/CO2$ directly with the air in the tubes.
The tissues exchange $O2/CO2$ directly with the coelomic fluid.
Tracheal tubes exchange $O2/CO2$ directly with the haemocoel which then exchanges with the tissues.
Respiration in insects is known as tracheal respiration. This process involves two major parts: the trachea and the spiracles.
Trachea: This consists of a network of tubes that branch into smaller, narrower tubes known as tracheoles.
Spiracles: These are openings on the sides of an insect's body that allow air to enter the tracheal system.
Air enters the insect's body through the spiracles, then it flows into the trachea. The trachea further branches into narrow tracheoles that directly reach the insect’s cells.
The key feature of this system is that the cells exchange oxygen (O₂) and carbon dioxide (CO₂) directly with the air in the tracheal tubes. This is why it is termed direct respiration. The process occurs without the need for intermediaries like blood or coelomic fluid to transport gases.
Here is a quick summary of the airflow:
Air enters through the spiracles.
Air travels through the trachea.
Air moves into the branching tracheoles.
Oxygen and carbon dioxide are exchanged directly at the cellular level.
Given this information, the correct answer is:
The cells exchange O₂/CO₂ directly with the air in the tubes.
Thus, the reason respiration in insects is called direct is that the cells exchange oxygen and carbon dioxide directly with the air in the tubes without any intermediary.
Lungs are enclosed in:
A) periosteum
B) perichondrium
C) pericardium
D) pleural membranes
The lungs are enclosed in the pleural membranes. These pleural membranes are a type of double-layered serous membrane. The inner layer, called the visceral pleura, is firmly attached to the surface of the lungs. At the hilum, which is the entry and exit point for structures such as blood vessels and nerves, the visceral pleura becomes continuous with the outer layer, known as the parietal pleura. The parietal pleura lines the walls of the thoracic cavity, aiding in the protection and proper functioning of the lungs.
Thus, the correct answer is:
D) Pleural membranes.
The amount of air which one can inhale/exhale with maximum effort is called:
A. vital capacity B. tidal volume C. IRV D. ERV
The amount of air which one can inhale or exhale with maximum effort is called vital capacity.
Explanation:
Vital Capacity (VC):
It is defined as the amount of air one can inhale or exhale with maximum effort.
It is also known as VC.
Vital capacity is calculated as the sum of: $$ \text{Vital Capacity (VC)} = \text{Tidal Volume (TV)} + \text{Inspiratory Reserve Volume (IRV)} + \text{Expiratory Reserve Volume (ERV)} $$
Hence, vital capacity includes all the air you can forcibly inhale and exhale.
Tidal Volume (TV):
This is the volume of air normally inhaled or exhaled without any effort.
Since it does not involve maximum effort, it is not the correct answer.
Inspiratory Reserve Volume (IRV):
This refers to the extra air one can forcibly inhale after a normal inhalation.
It is not the total maximum effort air volume, hence this option is incorrect.
Expiratory Reserve Volume (ERV):
This is the extra air one can forcibly exhale after a normal exhalation.
Similar to IRV, it is not the total value of air involved in maximum effort inhalation and exhalation.
Given these definitions, the correct answer is:
Answer: A. Vital Capacity
Match the following and mark the correct options
Animal | Respiratory Organ |
---|---|
A) Earthworm | (i) Moist cuticle |
B) Aquatic Arthropods | (ii) Gills |
C) Fishes | (iii) Lungs |
D) Birds/Reptiles | (iv) Trachea |
A. A - (i), B - (ii), C - (iii), D - (iv)
B. A-(i), B-(iv), C-(ii), D-(iii)
C. A-(i), B-(iii), C-(ii), D-(iv)
D. A-(i), B-(ii), C-(iv), D (iii)
A) Earthworm: Earthworms respire through their skin, which is covered by a moist cuticle. This moist skin allows for the exchange of gases directly through the cuticle.
B) Aquatic Arthropods: These include organisms such as crustaceans, and they respire using gills. Gills are specialized organs for extracting oxygen from water.
C) Fishes: Fishes also use gills for respiration. Gills allow them to extract oxygen from water efficiently as they swim.
D) Birds/Reptiles: Both birds and reptiles have lungs for breathing. Unlike gills or moist cuticles, lungs are internal organs that facilitate the exchange of gases with the air.
Given the pairs:
Earthworm – (i) Moist cuticle
Aquatic Arthropods – (ii) Gills
Fishes – (ii) Gills
Birds/Reptiles – (iii) Lungs
Now, the options provided in the question:
A - (i), B - (ii), C - (iii), D - (iv)
This combination is incorrect. The correct pairings are:
A - (i)
B - (ii)
C - (ii)
D - (iii)
So, the final answer should clearly show that:
Earthworms respire through a moist cuticle.
Aquatic arthropods and fishes respire through gills.
Birds and reptiles respire through lungs.
The correct pairings should thus be noted as:
A - (i), B - (ii), C - (ii), D - (iii)
Since there is a perfect match based on the provided answers, the correct solution for the given pair is correctly identified.
Mark the correct order of lung volumes
A. TV < ERV < RV < IRV
B. TV < RV < ERV < IRV
C. IRV < RV < TV < ERV
D. ERV < TV < RV < IRV
To determine the correct order of lung volumes, let's understand each of the given volumes:
Tidal Volume (TV): This is the normal volume of air displaced during a regular inhalation and exhalation without any additional effort. It is approximately 500 milliliters.
Expiratory Reserve Volume (ERV): This is the additional amount of air that can be forcibly exhaled after a normal exhalation. It is approximately 1000 milliliters.
Residual Volume (RV): This is the amount of air remaining in the lungs after a forceful exhalation. It is approximately 1100 milliliters.
Inspiratory Reserve Volume (IRV): This is the additional amount of air that can be forcibly inhaled after a normal inhalation. It is approximately 1900 milliliters.
Given these definitions and their respective volumes:
Tidal Volume (TV) ≈ 500 mL
Expiratory Reserve Volume (ERV) ≈ 1000 mL
Residual Volume (RV) ≈ 1100 mL
Inspiratory Reserve Volume (IRV) ≈ 1900 mL
The correct order from smallest to largest is: $$ \text{TV} < \text{ERV} < \text{RV} < \text{IRV} $$
Thus, the correct order of lung volumes is: TV < ERV < RV < IRV
In a normal healthy individual, the volume of air remaining in the lungs even after forcible expiration is about ______
1200 ml
500 ml
3000 ml
2000 ml
In a normal healthy individual, the volume of air remaining in the lungs even after forcible expiration is known as the residual volume. This residual volume typically ranges from 1000 to 1200 ml.
Given the options:
1200 ml
500 ml
3000 ml
2000 ml
The correct choice based on the common residual volume range is 1200 ml. Therefore, the answer is 1200 ml.
When the diaphragm contracts:
A. The volume of the thoracic cavity increases.
B. Intrapulmonary pressure increases.
C. The volume of the thoracic cavity decreases.
D. The intrapleural pressure increases.
When the diaphragm contracts, what happens in the body? Let's break it down:
Diaphragm Contraction and Inhalation:
When the diaphragm contracts, it flattens out.
This flattening leads to an increase in the volume of the thoracic cavity.
As the thoracic cavity's volume increases, the pressure inside the lungs (intrapulmonary pressure) decreases.
This decrease in pressure causes air to rush into the lungs, a process known as inhalation.
Effect on the Chest Cavity:
The expansion of the thoracic cavity happens downwards and outwards.
This expansion creates a negative pressure within the lungs, effectively pulling air in.
Thus, the correct consequence of diaphragm contraction is that the volume of the thoracic cavity increases.
Option A: The volume of the thoracic cavity increases. (Correct)
Option B: Intrapulmonary pressure increases. (Incorrect)
Option C: The volume of the thoracic cavity decreases. (Incorrect)
Option D: The intrapleural pressure increases. (Incorrect)
Final Answer: A
Inspiration can take place only when:
A) Intrapulmonary pressure is more than the atmospheric pressure.
B) Intrapulmonary pressure is less than the intrapleural pressure.
C) There is a negative pressure with respect to the lungs.
D) There is a negative pressure with respect to atmospheric pressure.
Inspiration refers to the movement of air from the atmosphere into the lungs. This process depends on a pressure gradient between the lungs and the atmosphere, where air moves from areas of higher pressure to areas of lower pressure.
To facilitate inspiration, the pressure inside the lungs (intrapulmonary pressure) must be lower than the atmospheric pressure. When this condition is met, air flows into the lungs from the atmosphere.
Therefore, the correct option is D) There is a negative pressure with respect to atmospheric pressure. This indicates that the atmospheric pressure is greater than the intrapulmonary pressure, enabling the air to move into the lungs.
Vital capacity does not include:
A. Tidal volume
B. Inspiratory reserve volume
C. Residual volume
D. Expiratory reserve volume
To understand which component the vital capacity (VC) does not include, let's first define what vital capacity is. Vital capacity is the maximum amount of air a person can exhale forcefully after fully inhaling. It represents a measure of the lung's ability to hold and expel air.
The formula for vital capacity is: $$ \text{Vital Capacity (VC)} = \text{Inspiratory Reserve Volume (IRV)} + \text{Tidal Volume (TV)} + \text{Expiratory Reserve Volume (ERV)} $$
Inspiratory Reserve Volume (IRV): The extra air that can be inhaled beyond a normal inspiration.
Tidal Volume (TV): The volume of air inhaled or exhaled during a normal breath.
Expiratory Reserve Volume (ERV): The additional air that can be exhaled forcefully after the end of a normal expiration.
By looking at the formula, we can see that residual volume (RV), which is the amount of air remaining in the lungs after a maximal exhalation, is not included in the calculation of vital capacity. Residual volume ensures that the lungs do not collapse by maintaining inflation.
Thus, the correct answer is: C. Residual volume
Which of the following does not give the correct definition of a respiratory volume?
Residual volume = Volume of air remaining in the lungs after normal expiration.
Tidal volume = Volume of air inspired or expired during normal respiration.
Inspiratory reserve volume = Additional volume of air a person can inspire by forcible inspiration.
Expiratory reserve volume = Additional volume of air a person can expire by forcible expiration.
Definitions of Respiratory Volumes:
Residual Volume (RV):
Given Definition: Volume of air remaining in the lungs after normal expiration.
Correct Definition: The Residual Volume is indeed the amount of air remaining in the lungs after a normal expiration. This is correct.
Tidal Volume (TV):
Given Definition: Volume of air inspired or expired during normal respiration.
Correct Definition: Tidal Volume is the amount of air that is normally inhaled or exhaled during a regular respiratory cycle, without extra effort. This is correct.
Inspiratory Reserve Volume (IRV):
Given Definition: Additional volume of air a person can inspire by forcible inspiration.
Correct Definition: Inspiratory Reserve Volume is the extra volume of air that can be inhaled forcibly beyond the normal tidal volume. This is correct.
Expiratory Reserve Volume (ERV):
Given Definition: Additional volume of air a person can expire by forcible expiration.
Correct Definition: Expiratory Reserve Volume refers to the extra volume of air that can be exhaled forcibly beyond a normal tidal expiration. This is correct.
From the analysis above, all the given definitions are actually correct.
Which of the following statements is not correct?
An increase in pulmonary volume decreases the intra-pulmonary pressure to less than the atmospheric pressure.
Intrapleural pressure is always less than intrapulmonary pressure.
Relaxation of the diaphragm and the intercostal muscles increases the thoracic volume and thereby the pulmonary volume.
We have the ability to increase the strength of inspiration and expiration with the help of additional muscles in the abdomen.
To identify the incorrect statement among the given options, let's analyze each one carefully:
Increase in pulmonary volume decreases the intra-pulmonary pressure to less than the atmospheric pressure.
Correct: When the pulmonary volume increases, the intra-pulmonary pressure (the pressure inside the lungs) decreases to a level below the atmospheric pressure. This pressure difference causes air to move into the lungs from the outside.
Relaxation of the diaphragm and the intercostal muscles increases the thoracic volume and thereby the pulmonary volume.
Incorrect: Relaxation of the diaphragm and the intercostal muscles actually leads to a decrease in thoracic volume, not an increase. When these muscles relax, the thoracic cavity returns to its normal position, reducing the volume and thereby decreasing the pulmonary volume.
Intrapleural pressure is always less than intrapulmonary pressure.
Correct: Intrapleural pressure (the pressure within the pleural cavity) is always less than the intra-pulmonary pressure. This negative pressure allows the lungs to remain inflated.
We have the ability to increase the strength of inspiration and expiration with the help of additional muscles in the abdomen.
Correct: The strength of both inspiration and expiration can be increased using additional muscles, such as the abdominal muscles, the diaphragm, and the intercostal muscles.
Therefore, the incorrect statement among the given options is Option B:
Relaxation of the diaphragm and the intercostal muscles increases the thoracic volume and thereby the pulmonary volume.
Final Answer: B
Inspiration occurs when:
A. Intrapulmonary pressure is greater than atmospheric pressure.
B. Intrapulmonary pressure is less than atmospheric pressure.
C. Intrapulmonary pressure is equal to atmospheric pressure.
D. Atmospheric pressure is greater than or equal to intrapulmonary pressure.
When it comes to the process of inspiration, or inhalation, it is essential to understand the role of pressure gradients. There is a gradient between the intrapulmonary pressure (the pressure within the lungs) and the atmospheric pressure (the pressure outside the body).
Inspiration occurs when the intrapulmonary pressure is less than the atmospheric pressure. This difference in pressure allows air from the outside environment to flow into the lungs, filling them with air.
To summarize:
Inspiration: Intrapulmonary pressure < Atmospheric pressure.
So, the correct answer is:
B. Intrapulmonary pressure is less than atmospheric pressure.
Which of the following events is related to expiration?
A. A decrease in the volume of the thoracic cavity
B. Increase in the volume of the thoracic cavity
C. Contraction of internal intercostal muscles
D. Contraction of external intercostal muscles
To determine which of the following events is related to expiration, let's review the standard mechanisms of breathing:
Inspiration (Inhalation) involves:
Increase in the volume of the thoracic cavity
Contraction of the diaphragm
Contraction of external intercostal muscles
These actions decrease the pressure inside the thoracic cavity, allowing air to flow into the lungs.
Expiration (Exhalation) involves:
A decrease in the volume of the thoracic cavity
Relaxation of the diaphragm
Contraction of internal intercostal muscles
These actions increase the pressure inside the thoracic cavity, pushing air out of the lungs.
Now, let's evaluate the given options:
Option A: A decrease in the volume of the thoracic cavity - This is associated with expiration as it helps expel air from the lungs.
Option B: Increase in the volume of the thoracic cavity - This is associated with inspiration, since it allows air to enter the lungs.
Option C: Contraction of internal intercostal muscles - This also relates to expiration as it helps reduce the thoracic cavity volume.
Option D: Contraction of external intercostal muscles - This is associated with inspiration, aiding in increasing the thoracic cavity volume.
Correct Answer:A. A decrease in the volume of the thoracic cavity
This option correctly describes an event that is related to expiration.
O2 enters the lungs when: A. Positive pressure in the lungs B. Positive pressure in the lungs C. Negative pressure in the cells D. Negative pressure in the lungs
To determine how oxygen (O$_2$) enters the lungs, we need to understand the concept of air movement in relation to pressure differences.
Air moves from a region of higher pressure to a region of lower pressure. This movement is driven by the pressure gradient between the atmosphere and the lungs.
When oxygen enters the lungs, it implies that the air is moving from the atmosphere, which is the external environment, into the lungs.
Thus, for oxygen to flow into the lungs, the pressure inside the lungs must be lower than the pressure in the atmosphere. This condition is described as negative pressure within the lungs relative to the atmosphere.
Hence, the correct answer to the question is:
D. Negative pressure in the lungs
Which of the following options contain only respiratory diseases caused by bacteria?
Option 1) Tuberculosis and Asthma
Option 2) Asthma and Pneumonia
Option 3) Pneumonia and Emphysema
Option 4) Tuberculosis and Pneumonia
The correct option is Option 4) Tuberculosis and Pneumonia.
Explanation:
Pneumonia is a respiratory disease caused by bacteria. The bacteria infect the air sacs in the lungs, causing them to fill with fluid, which results in symptoms like high fever, chest pain, and chills. It is treatable with antibiotics such as penicillin.
Tuberculosis is another respiratory disease caused by bacteria. It presents with symptoms such as a persistent cough, low fever, chest pain, and weight loss. Tuberculosis can be prevented by the BCG vaccine and treated with antibiotics like streptomycin.
On the other hand:
Asthma is not caused by bacteria; it is primarily triggered by air pollutants and allergens, leading to inflammation of the airways.
Emphysema is also not a bacterial disease; it is typically the result of smoking or exposure to pollutants, causing the alveoli in the lungs to lose their elasticity and impairing gas exchange.
Thus, only Option 4—Tuberculosis and Pneumonia—contains respiratory diseases solely caused by bacteria.
The lining of the nasal chamber has mucus, which prevents pollen and dust particles from entering into the lungs.
True
False
The correct option is A) True.
Mucus acts as the first line of defense against harmful substances that might be inhaled with the air entering the nose. It effectively traps bacteria, germs, and debris, thereby preventing them from reaching the lungs.
Pneumatophores help in respiration by allowing exchange of gases between the roots and the atmosphere.
Pneumatophores are specialized root modifications found in plants that grow in swampy areas or waterlogged environments. Their primary function is to facilitate oxygen intake for respiration.
These roots have a unique growth pattern: they emerge from the ground and grow vertically upwards. This upward growth enables them to rise above the water level. Pneumatophores are equipped with lenticels, which are small openings or pores in the outer bark. These lenticels play a crucial role by allowing air to enter and pass down to the submerged root system.
By performing this crucial function, pneumatophores ensure that the plant's root system, which might otherwise be deprived of oxygen in waterlogged conditions, can engage in effective gas exchange with the atmosphere.
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Ask Chatterbot AINCERT Solutions - Breathing and Exchange of Gases | NCERT | Biology | Class 11
Define vital capacity. What is its significance?
Vital Capacity (VC) is defined as the maximum volume of air that a person can exhale after a maximum inhalation. It includes Expiratory Reserve Volume (ERV), Tidal Volume (TV), and Inspiratory Reserve Volume (IRV).
Significance:
Measures Lung Function: Vital capacity is a key indicator of respiratory health and the ability of the lungs to ventilate.
Assesses Respiratory Diseases: Decreased vital capacity can indicate restrictive lung diseases, such as fibrosis, or obstructive diseases like asthma and COPD.
Monitors Treatment: Helps in monitoring the effectiveness of treatments for respiratory conditions.
Fitness Indicator: Used to assess the respiratory fitness and capacity of athletes.
By understanding and measuring vital capacity, healthcare providers can gain valuable insights into a patient's pulmonary health and potential issues in their respiratory system.
State the volume of air remaining in the lungs after a normal breathing.
The volume of air remaining in the lungs after a normal breathing is called the Functional Residual Capacity (FRC). It includes the Expiratory Reserve Volume (ERV) and the Residual Volume (RV).
Diffusion of gases occurs in the alveolar region only and not in the other parts of respiratory system. Why?
Diffusion of gases occurs primarily in the alveolar region because:
Thin Squamous Epithelium: The alveoli have a thin squamous epithelial lining, which reduces the distance over which gases need to diffuse.
High Vascularization: The alveolar region is highly vascularized, meaning it has a dense network of capillaries, providing a large surface area for gas exchange.
Pressure/Concentration Gradients: There are significant partial pressure gradients for oxygen and carbon dioxide between the alveoli and the blood, facilitating efficient diffusion.
Moist Surface: The alveoli are lined with a thin layer of moisture, which helps gases dissolve and diffuses across the membrane more easily.
Structure: The respiratory membrane in the alveoli comprises just three layers - alveolar epithelium, capillary endothelium, and their basement membranes, making it extremely thin for efficient diffusion.
Other parts of the respiratory system, like the conducting airways (trachea, bronchi, and bronchioles), are mainly involved in transporting air to and from the alveoli and do not have the right structure (e.g., thicker walls, less vascularization) for gas exchange.
What are the major transport mechanisms for $\mathrm{CO}_{2}$ ? Explain.
The major transport mechanisms for $\mathrm{CO}_{2}$ are as follows:
As Bicarbonate Ions (HCO₃⁻):
70% of $\mathrm{CO}_{2}$ is transported in the form of bicarbonate ions.
This transformation is facilitated by the enzyme carbonic anhydrase, found in high concentrations in red blood cells (RBCs).
The reaction occurs as follows: [ \mathrm{CO}_{2} + \mathrm{H}_{2} \mathrm{O} \leftrightarrow \mathrm{H}_{2} \mathrm{CO}_{3} \leftrightarrow \mathrm{HCO}_{3}^{-} + \mathrm{H}^{+} ]
At the tissue level, where $\mathrm{pCO}_{2}$ is high, $\mathrm{CO}_{2}$ diffuses into the blood and is converted to bicarbonate ions, which are then transported in the plasma.
As Carbaminohaemoglobin:
20-25% of $\mathrm{CO}_{2}$ is transported by binding to haemoglobin in RBCs, forming carbaminohaemoglobin.
The binding is dependent on the partial pressure of $\mathrm{CO}_{2}$ (pCO₂) and the partial pressure of $\mathrm{O}_{2}$ (pO₂).
In tissues, where $\mathrm{pCO}_{2}$ is high and $\mathrm{pO}_{2}$ is low, more $\mathrm{CO}_{2}$ binds to haemoglobin.
In alveoli, where $\mathrm{pCO}_{2}$ is low and $\mathrm{pO}_{2}$ is high, $\mathrm{CO}_{2}$ dissociates from haemoglobin and is released.
As Dissolved CO₂:
About 7% of $\mathrm{CO}_{2}$ is dissolved directly in plasma and transported in this state.
These mechanisms work together to ensure efficient transport of $\mathrm{CO}_{2}$ from tissues to the alveoli, where it is then exhaled.
What will be the $\mathrm{pO}_{2}$ and $\mathrm{pCO}_{2}$ in the atmospheric air compared to those in the alveolar air?
(i) $\mathrm{pO}_{2}$ lesser, $\mathrm{pCO}_{2}$ higher
(ii) $\mathrm{pO}_{2}$ higher, $\mathrm{pCO}_{2}$ lesser
(iii) $\mathrm{pO}_{2}$ higher, $\mathrm{pCO}_{2}$ higher
(iv) $\mathrm{pO}_{2}$ lesser, $\mathrm{pCO}_{2}$ lesser
Partial pressure of $\mathrm{O}_{2}$ (pO₂) in the atmospheric air: 159 mm Hg
Partial pressure of $\mathrm{CO}_{2}$ (pCO₂) in the atmospheric air: 0.3 mm Hg
Partial pressure of $\mathrm{O}_{2}$ (pO₂) in the alveoli: 104 mm Hg
Partial pressure of $\mathrm{CO}_{2}$ (pCO₂) in the alveoli: 40 mm Hg
From this information, we can see that:
$\mathrm{pO}_{2}$ in the atmospheric air is higher than in the alveoli.
$\mathrm{pCO}_{2}$ in the atmospheric air is lesser than in the alveoli.
Therefore, the correct answer is:
(ii) $\mathrm{pO}_{2}$ higher, $\mathrm{pCO}_{2}$ lesser
Explain the process of inspiration under normal conditions.
During inspiration, the process of drawing atmospheric air into the lungs is as follows:
Contraction of Diaphragm: The diaphragm contracts, moving downward and increasing the volume of the thoracic chamber in the antero-posterior axis.
External Intercostal Muscles: The external intercostal muscles contract, lifting the ribs and sternum upward and outward, increasing the volume of the thoracic chamber in the dorso-ventral axis.
Increase in Thoracic Volume: As a result of these muscle contractions, the overall volume of the thoracic cavity increases.
Increase in Pulmonary Volume: The increase in thoracic volume causes a corresponding increase in pulmonary (lung) volume.
Decrease in Intra-pulmonary Pressure: The increase in pulmonary volume decreases the intra-pulmonary pressure to below the atmospheric pressure.
Air Movement into Lungs: Because of the lower intra-pulmonary pressure compared to atmospheric pressure, air is drawn into the lungs.
This sequence of events facilitates inspiration effectively under normal conditions.
How is respiration regulated?
Respiration is regulated primarily by the neural system through specialized centers in the brain:
Respiratory Rhythm Centre: This center, located in the medulla region of the brain, is responsible for regulating the basic rhythm of respiration.
Pneumotaxic Centre: Situated in the pons region of the brain, this centre can moderate the functions of the respiratory rhythm centre. It can reduce the duration of inspiration, thereby altering the respiratory rate.
Chemosensitive Area: Positioned adjacent to the respiratory rhythm centre, this area is highly sensitive to CO₂ and hydrogen ions (H⁺). An increase in these substances activates this centre, which then signals the respiratory rhythm centre to adjust the respiratory process to eliminate CO₂ and H⁺.
Receptors in Aortic Arch and Carotid Artery: These receptors can detect changes in CO₂ and H⁺ concentration and send signals to the rhythm centre for necessary adjustments.
It is important to note that the role of oxygen (O₂) in the regulation of respiratory rhythm is quite insignificant compared to CO₂ and H⁺.
In summary, the regulation of respiration involves complex interactions between different brain centres and chemoreceptors to ensure that CO₂ levels and pH are maintained within a narrow range.
What is the effect of $\mathrm{pCO}_{2}$ on oxygen transport?
The effect of $\mathrm{pCO}_{2}$ on oxygen transport is significant. Here’s a concise explanation:
High $\mathrm{pCO}_{2}$: In the tissues, where the partial pressure of $\mathrm{CO}_{2}$ is high, the oxygen dissociation curve shifts to the right. This means that oxygen dissociates more readily from oxyhaemoglobin, facilitating the delivery of $\mathrm{O}_{2}$ to the tissues.
Low $\mathrm{pCO}_{2}$: In the alveoli, where $\mathrm{pCO}_{2}$ is low, haemoglobin binds to $\mathrm{O}_{2}$ more readily. This facilitates the uptake of oxygen from the lungs into the blood.
Thus, $\mathrm{pCO}_{2}$ affects the binding and release of oxygen by modifying the affinity of haemoglobin for oxygen, a phenomenon described by the Bohr effect.
What happens to the respiratory process in a man going up a hill?
When a person ascends a hill, several changes occur in the respiratory process:
Decreased Oxygen Availability: At higher altitudes, the atmospheric pressure decreases, resulting in lower partial pressure of oxygen (( pO_2 )). This means there is less oxygen available in each breath.
Increased Breathing Rate: The body responds to the lower ( pO_2 ) by increasing the breathing rate (hyperventilation) to take in more oxygen.
Increased Heart Rate: The heart rate typically increases to pump more oxygenated blood to tissues.
Increased Diffusion Gradient: The concentration gradient for oxygen between the alveoli and blood also drives a more efficient diffusion of oxygen into the blood.
Acclimatization: Over time, the body undergoes acclimatization, which involves producing more red blood cells to improve oxygen transport capacity.
These physiological adjustments are crucial to cope with the reduced oxygen levels at higher altitudes.
What is the site of gaseous exchange in an insect?
In insects, the site of gaseous exchange is the tracheal tubes. This network of tubes transports atmospheric air directly to the body tissues.
Define oxygen dissociation curve. Can you suggest any reason for its sigmoidal pattern?
The oxygen dissociation curve is a graph that plots the percentage saturation of hemoglobin with oxygen (O₂) against the partial pressure of oxygen (pO₂).
The sigmoidal (S-shaped) pattern of the oxygen dissociation curve can be explained by the following reasons:
Cooperative Binding: Hemoglobin undergoes a conformational change when oxygen binds to one of its subunits. This increases the affinity for oxygen in the remaining subunits, making it easier for additional oxygen molecules to bind. This cooperative nature of binding causes the initial part of the curve to rise slowly (as the first oxygen molecules bind) and then more steeply (as subsequent molecules bind more readily).
Partial Pressure Influence: At lower partial pressures of oxygen, hemoglobin binds oxygen less readily, portraying the initial flat portion of the curve. As the partial pressure increases, the binding affinity increases sharply, causing the steep middle section of the curve.
Plateau Phase: At very high partial pressures of oxygen (such as in the pulmonary capillaries), hemoglobin becomes almost fully saturated, leading to the plateau at the top of the curve.
This sigmoidal shape is essential for efficient oxygen loading in the lungs (high pO₂) and unloading in the tissues (lower pO₂).
Have you heard about hypoxia? Try to gather information about it, and discuss with your friends.
Hypoxia is a condition characterized by inadequate oxygen supply to the tissues and organs of the body. It can occur due to various reasons and can affect the entire body or a localized area.
Types of Hypoxia:
Hypoxic Hypoxia: Caused by low oxygen levels in the blood due to insufficient oxygen in the air, decreased lung function, or reduced oxygen-carrying capacity of the blood.
Anaemic Hypoxia: Results from a decrease in the oxygen-carrying capacity of the blood, due to conditions like anemia or carbon monoxide poisoning.
Stagnant Hypoxia: Occurs due to reduced blood flow to tissues, which can be a result of heart failure or circulatory shock.
Histotoxic Hypoxia: Caused by the inability of tissues to use oxygen, even though there is adequate oxygen supply. This can be due to poisoning like cyanide poisoning.
Symptoms of Hypoxia:
Shortness of breath
Rapid heartbeat
Dizziness and confusion
Bluish skin color (cyanosis)
Fatigue
Causes of Hypoxia:
High altitudes where oxygen levels are low
Respiratory diseases like COPD or asthma
Heart diseases leading to impaired blood flow
Severe anemia
Toxic substances
Diagnosis and Treatment:
Diagnosis can be made through:
Pulse oximetry
Arterial blood gas analysis
Treatment aims to restore the oxygen supply:
Oxygen therapy
Treating the underlying cause (e.g., medications for heart conditions, blood transfusions for anemia)
Hyperbaric oxygen therapy in case of severe poisoning
Understanding hypoxia is essential for effectively managing various health conditions that can impair oxygen delivery to the body's tissues.
Distinguish between
(a) IRV and ERV
(b) Inspiratory capacity and Expiratory capacity.
(c) Vital capacity and Total lung capacity.
(a) IRV and ERV
Inspiratory Reserve Volume (IRV):
Definition: The additional volume of air that a person can inspire by a forcible inspiration after a normal tidal volume inspiration.
Average Volume: 2500-3000 mL.
Expiratory Reserve Volume (ERV):
Definition: The additional volume of air that a person can expire by a forcible expiration after a normal tidal volume expiration.
Average Volume: 1000-1100 mL.
(b) Inspiratory Capacity (IC) and Expiratory Capacity (EC)
Inspiratory Capacity (IC):
Definition: The total volume of air a person can inspire after a normal expiration.
Components: Tidal Volume (TV) + Inspiratory Reserve Volume (IRV).
Expiratory Capacity (EC):
Definition: The total volume of air a person can expire after a normal inspiration.
Components: Tidal Volume (TV) + Expiratory Reserve Volume (ERV).
(c) Vital Capacity (VC) and Total Lung Capacity (TLC)
Vital Capacity (VC):
Definition: The maximum volume of air a person can breathe in after a forced expiration, or the maximum volume of air a person can breathe out after a forced inspiration.
Components: Tidal Volume (TV) + Inspiratory Reserve Volume (IRV) + Expiratory Reserve Volume (ERV).
Total Lung Capacity (TLC):
Definition: The total volume of air accommodated in the lungs at the end of a forced inspiration.
Components: Residual Volume (RV) + Expiratory Reserve Volume (ERV) + Tidal Volume (TV) + Inspiratory Reserve Volume (IRV).
What is Tidal volume? Find out the Tidal volume (approximate value) for a healthy human in an hour.
Tidal Volume (TV) is the volume of air inspired or expired during a normal respiration. For a healthy human, this is approximately 500 mL.
To find the approximate tidal volume in an hour for a healthy human:
A healthy human breathes 12-16 times per minute.
We will use an average value of 14 breaths per minute for this calculation.
$$ \text{Tidal Volume in an hour} = 500 , \text{mL/breath} \times 14 , \text{breaths/minute} \times 60 , \text{minutes}$$
$$ \text{Tidal Volume in an hour} = 500 \times 14 \times 60 = 420,000 , \text{mL} = 420 , \text{liters} $$
So, the approximate tidal volume for a healthy human in an hour is 420 liters.
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Ask Chatterbot AINotes - Breathing and Exchange of Gases | Class 11 NCERT | Biology
Comprehensive Class 11 Notes on Breathing and Exchange of Gases
In this article, we will delve into the critical topic of breathing and exchange of gases, essential for understanding human physiology in Class 11 biology.
Introduction to Breathing and Exchange of Gases
Breathing is a fundamental process where oxygen $(\mathrm{O}_{2})$ is taken in from the atmosphere and carbon dioxide $(\mathrm{CO}_{2})$ is expelled. This exchange is vital for cellular respiration, where cells utilise $\mathrm{O}_{2}$ to derive energy by breaking down molecules like glucose.
Respiratory Organs
Different animals have evolved varied mechanisms for gas exchange based on their habitats and organisational levels:
Lower Invertebrates: Sponges and flatworms utilise simple diffusion across their body surface.
Earthworms: Use their moist cuticle for breathing.
Insects: Have a network of tracheal tubes for gas transport.
Aquatic Arthropods and Molluscs: Use gills for branchial respiration.
Terrestrial Vertebrates: Rely on lungs for pulmonary respiration. Amphibians, like frogs, can also perform cutaneous respiration through their moist skin.
Human Respiratory System
The human respiratory system includes the nostrils, nasal passage, pharynx, larynx, trachea, bronchi, and lungs. Here's a simplified diagram of the human respiratory system:
Nasal Passage: Warms and filters the air.
Pharynx and Larynx: Passageway for air; the larynx is also involved in sound production.
Trachea: A tube extending into two primary bronchi.
Bronchi and Bronchioles: Branch into a network ending in alveoli.
Alveoli: Sites of gas exchange.
Mechanism of Breathing
Breathing includes two phases: inspiration (inhalation) and expiration (exhalation). The diaphragm and intercostal muscles play a crucial role by creating pressure gradients.
Inspiration: Diaphragm contracts, increasing thoracic volume, causing air to flow into the lungs.
Expiration: Diaphragm relaxes, reducing thoracic volume, pushing air out of the lungs.
The breathing rate averages 12-16 breaths per minute and is evaluated using tools like a spirometer.
Respiratory Volumes and Capacities
Tidal Volume (TV): Air volume during normal breath (~500 mL).
Inspiratory Reserve Volume (IRV): Additional inhaled air (~2500-3000 mL).
Expiratory Reserve Volume (ERV): Additional exhaled air (~1000-1100 mL).
Residual Volume (RV): Air remaining post-exhalation (~1100-1200 mL).
Capacities are derived from these volumes for clinical assessments:
Inspiratory Capacity (IC): TV + IRV
Expiratory Capacity (EC): TV + ERV
Functional Residual Capacity (FRC): ERV + RV
Vital Capacity (VC): ERV + TV + IRV
Total Lung Capacity (TLC): RV + ERV + TV + IRV
Exchange of Gases
Gas exchange happens primarily in the alveoli based on partial pressure gradients:
graph TD;
A[Atmospheric Air] --> B[Alveoli]
B -->|Diffusion| C[Deoxygenated Blood]
C -->|Transport| D[Oxygenated Blood]
D -->|Diffusion| E[Tissues]
E -->|CO2| D
D -->|CO2| B
B -->|CO2| A
Transport of Gases
Oxygen $(\mathrm{O}_{2})$: Mainly carried by haemoglobin as oxyhaemoglobin.
Carbon Dioxide $(\mathrm{CO}_{2})$: Transported as carbamino-haemoglobin, bicarbonate ions, and dissolved in plasma.
Regulation of Respiration
Neural regulation involves:
Respiratory Rhythm Centre: Located in the medulla.
Pneumotaxic Centre: Located in the pons, modulates breathing rhythm.
Chemosensitive Area: Senses $\mathrm{CO}_{2}$ and hydrogen ion levels.
Disorders of the Respiratory System
Asthma: Causes wheezing and difficulty in breathing.
Emphysema: Alveolar damage resulting from smoking.
Occupational Disorders: Exposure to dust can lead to lung damage; protective measures are essential.
Summary
Understanding breathing and gas exchange is crucial for grasping the respiratory system's role in maintaining homeostasis and supporting cellular functions. This intricate system ensures that $\mathrm{O}_{2}$ reaches cells for metabolism, and $\mathrm{CO}_{2}$ is efficiently removed, maintaining the body's pH and gas balance.
We hope these comprehensive Class 11 notes provide a solid foundation and clear understanding of the essential concepts in breathing and exchange of gases.
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