Body Fluids and Circulation - Class 11 Biology - Chapter 14 - Notes, NCERT Solutions & Extra Questions
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Extra Questions - Body Fluids and Circulation | NCERT | Biology | Class 11
'Dup' sound is produced during the closure of:
A. Bicuspid valve
B. Bicuspid valve and tricuspid valve
C. Tricuspid valve
D. Semilunar valves
The correct answer is $\mathbf{D}$. Semilunar valves
The cardiac cycle comprises various phases, specifically atrial systole, ventricular systole, and joint diastole. In this cycle:
The 'lubb' or systolic sound, which is the first heart sound, is produced by the closure of the auriculoventricular valves at the beginning of ventricular systole.
The second heart sound, 'dup', occurs during joint diastole due to the rapid closure of the semilunar valves at the start of ventricular diastole.
Study the diagram given below and then answer the questions that follow:
(a) Name the cells of the pancreas that produce (1) glucagon and (2) insulin.
(b) State the main function of (1) glucagon and (2) insulin.
(c) Why is the pancreas referred to as an exo-endocrine gland?
(d) Why is insulin not given orally but is injected into the body?
(e) What is the technical term for the cells of the pancreas that produce endocrine hormones?
(f) Where in the body is the pancreas located?
(a) Name the cells of the pancreas that produce (1) glucagon and (2) insulin.
Glucagon is produced by the Alpha cells of the Islets of Langerhans.
Insulin is produced by the Beta cells of the Islets of Langerhans.
(b) State the main function of (1) glucagon and (2) insulin.
Insulin helps in maintaining the levels of glucose (sugar) in the blood.
Glucagon increases the blood glucose levels by stimulating the conversion of glycogen to glucose in the liver.
(c) Why is the pancreas referred to as an exo-endocrine gland?
The pancreas is referred to as an exo-endocrine gland because it functions as both an endocrine gland (secreting hormones directly into the blood without using ducts) and an exocrine gland (releasing digestive juices into ducts).
(d) Why is insulin not given orally but is injected into the body?
Insulin is not administered orally because it would be degraded by the digestive juices, rendering it ineffective for therapeutic use. As a result, insulin is typically injected to ensure it enters the bloodstream directly.
(e) What is the technical term for the cells of the pancreas that produce endocrine hormones?
The technical term for these cells is Islets of Langerhans.
(f) Where in the body is the pancreas located?
The pancreas is located in the abdomen behind the stomach.
The function of the Subcutis layer of the skin is to:
A. Sweat secretion
B. Regulation of body temperature
C. Synthesis of Vitamin D
D. All of the above
The correct option is B. Regulation of body temperature
The subcutaneous layer, which is located beneath the epidermis and the dermis, plays a crucial role in maintaining normal body temperature.
The capillary epithelium, basement membrane, and podocytes together form the _______. There is a ________ charge fixed on the layers, which repels plasma components.
A Filtration membrane and negative charge
B Glomerulus and negative charge
C Juxtamedullary Nephron and positive charge
D Nephron and positive charge
The correct answer is A: Filtration membrane and negative charge.
The filtration membrane is integral to the kidney's function of filtering blood, and it consists of several integral components:
Fenestrated capillary epithelium: This features small pores that allow fluids and solutes to pass through while blocking larger structures like blood cells.
Basement membrane: Serves as a barrier to large molecules, especially proteins, ensuring they do not pass into the urine.
Podocytes: These specialized cells envelop the capillaries and have foot-like extensions called pedicels which leave narrow filtration slits. These slits allow the passage of small molecules but not larger structures.
Additionally, these components possess a negative charge, which plays a crucial role in repelling negatively charged plasma components like proteins, preventing them from passing into the filtrate.
What are blood vessels?
Blood vessels are integral components of the circulatory system, responsible for transporting blood throughout the body. There are two primary types of blood vessels:
Arteries, which transport blood away from the heart
Veins, which carry blood toward the heart
All blood vessels share a common structural architecture:
The innermost layer, or endothelium, is critical for providing a smooth lining.
Surrounding the endothelium is the subendothelial connective tissue.
Beyond this tissue is a layer of vascular smooth muscle, which is especially prominent in arteries and controls the diameter of the blood vessels.
The outermost layer is the adventitia, composed of connective tissue. It houses nerves that regulate the muscular layer and nutrient capillaries that serve larger vessels.
Which of the following blood vessels carries blood with the highest pressure?
A) Pulmonary veins
B) Superior vena cava
C) Pulmonary artery
D) Inferior vena cava
The correct answer is C) Pulmonary artery.
The pulmonary artery is distinguished from the other options as it carries blood away from the heart to the lungs. This vessel handles high pressures because it conveys blood directly after it is pumped by the right ventricle of the heart during systole (the phase of the heartbeat when the heart muscle contracts and pumps blood from the chambers into the arteries).
In contrast, blood vessels like the pulmonary veins (option A), superior vena cava (option B), and inferior vena cava (option D) are involved in transporting blood back to the heart and consequently carry blood at much lower pressures. These veins operate under significantly reduced pressure because they collect blood that has circulated through the body or lungs and are merely transporting it back to the heart for reoxygenation or recirculation.
Hormones are transported from the place of origin to the target cells through the $\qquad$.
A) ducts
B) blood
C) nerves
D) lymph
The correct option is B) blood.
Hormones are chemical messengers that are secreted directly into the blood, which carries them to their respective target cells. Target cells are those that have specific receptors capable of binding with the hormone, allowing for its function. Thus, hormones effectively communicate instructions from one set of cells to another, influencing bodily processes.
During active ventricular filling, which of the following happen?
A. Atria contract B. Ventricles contract C. Atria relax D. Ventricles relax
The correct answers are:
A. Atria contract
D. Ventricles relax
During the cardiac cycle, active ventricular filling occurs when the atria contract. This contraction helps to pump blood efficiently into the ventricles. Concurrently, the ventricles are in a state of relaxation to accommodate the incoming blood, optimizing the filling process.
The net direction and rate of osmosis depends on:
A) Pressure gradient
B) Concentration gradient
C) Both a and b
D) None of the above
The correct answer is C) Both A and B.
Osmosis is the diffusion of water through a selectively permeable membrane. It is influenced by both pressure gradient and concentration gradient. Water naturally moves from an area of higher water potential (or lower solute concentration) to an area of lower water potential (or higher solute concentration), driven by these gradients, until equilibrium is achieved. This movement can also be affected by pressure differences across the membrane.
"What does Lodine do in the human body?"
Iodine is a crucial trace mineral essential for various physiological functions in the human body. Its primary role involves the synthesis of thyroid hormones by the thyroid gland, which are key regulators of metabolism and weight control.
Though concentrated largely in glandular tissues, particularly the thyroid gland, iodine is present in every cell and utilized throughout all body systems and tissues.
The functions of iodine extend to maintaining DNA integrity, enhancing cognitive abilities, supporting immune function, facilitating energy metabolism, and promoting cardiovascular health. Notably, there is a significant concern among health experts that a large proportion of the population, possibly up to 95%, may be experiencing an iodine deficiency, highlighting the importance of maintaining adequate iodine levels through diet.
"If any wound occurs on our body, sometimes we are unable to feel it. Why is that?"
The immediate shock from an accident can temporarily prevent the body from feeling pain. This often occurs before the individual has even noticed the injury.
In some instances, if a person does not experience pain right away after an injury, there might be an underlying issue with their pain perception mechanisms.
Bundle of capillaries within the Bowman's capsule is:
A) Glomerulus
B) Loop of Henle
C) Malphigian capsule
D) $\mathrm{PCT}$
The correct answer is A) Glomerulus
The glomerulus is accurately described as the bundle of capillaries contained within the Bowman's capsule. These capillaries,together with the Bowman's capsule, form what is referred to as the malpighian body or renal corpuscle.
In contrast, the Loop of Henle is a long, U-shaped part of the nephron which links the proximal convoluted tubule (PCT) and the distal convoluted tubule (DCT), and it does not come into contact with the Bowman's capsule directly.
Systemic circulation is defined as the
(A) flow of oxygenated blood from the ascending aorta to the heart muscle and the return of deoxygenated blood from the heart muscle to the right atrium
(B) flow of deoxygenated blood from the right ventricle to the lungs and the return of oxygenated blood from the lungs to the left atrium
(C) flow of oxygenated blood from the left ventricle to all parts of the body and the return of deoxygenated blood from various body parts to the right atrium
(D) flow of deoxygenated blood from the digestive organs to the liver before returning to the heart
Correct Answer: C - The flow of oxygenated blood from the left ventricle to all parts of the body and the return of deoxygenated blood from various body parts to the right atrium.
Explanation:
Systemic circulation is defined as the circulation of oxygenated blood from the left ventricle to all parts of the body, and the return of deoxygenated blood from these body parts back to the right atrium. This process supports the exchange of gases, nutrients, and wastes with tissues all over the body.
A describes coronary circulation, which involves the blood circulation to the heart muscle itself.
B details pulmonary circulation, focusing on the exchange of gases in the lungs.
D refers to the hepatic portal circulation, involved with directing blood from the digestive organs to the liver for processing.
The ECG represents:
A) The structure of the heart.
B) The state of the coronary arteries.
C) Movement of blood through the heart.
D) Movement of electrical impulses through the heart.
The correct answer is D) Movement of electrical impulses through the heart.
An electrocardiogram (ECG) is a test that measures the electrical activity of the heart to assess its function and health. The ECG records this activity as line tracings on paper, with the various spikes and dips referred to as waves. Essentially, this test highlights how electrical impulses move through the heart, which is crucial for its pumping action.
Which type of connective tissue is mainly concerned with immunity?
A. Cartilage
B. Blood
C. Lymph
D. Both Blood and Lymph
The correct answer is D. Both Blood and Lymph.
Blood and lymph are both key in the body's immune function. Blood carries cells and substances that fight off infections, while lymph is integral to the lymphatic system that supports immune responses. In contrast, cartilage is primarily involved in structural support and therefore not directly related to immunity.
What would be the cardiac output of a person having 72 heartbeats per minute and a stroke volume of 50 ml?
A) 360 ml
B) 3600 ml
C) 7200 ml
D) 5000 ml
The correct answer is Option B: 3600 ml.
To determine the cardiac output, we need to multiply the stroke volume by the heart rate. The stroke volume represents the amount of blood pumped by the left ventricle per heartbeat, and the heart rate is the number of heartbeats per minute. Therefore, we calculate it as: $$ \text{Cardiac Output} = \text{Stroke Volume} \times \text{Heart Rate} $$ For a stroke volume of $50 , \text{ml}$ and a heart rate of $72 , \text{beats per minute}$, the cardiac output is: $$ 50 , \text{ml/beat} \times 72 , \text{beats/min} = 3600 , \text{ml/min} $$ Thus, the cardiac output is 3600 ml/min, making the correct answer Option B.
Pulmonary semilunar valves are closed during $\qquad$ systole.
A) ventricular
B) atrial
C) continuous
D) discontinuous
The correct answer is B) atrial.
During atrial systole, blood flows from the atria into the ventricles via the bicuspid and tricuspid valves. The pulmonary semilunar valves are closed during this phase to prevent the backflow of blood into the ventricles. The closure of these valves contributes to the second heart sound, known as the 'Dub' sound, which can be heard through a stethoscope placed on the chest.
Capillaries unite together to form:
A. arteries
B. ventricles
C. veins
D. atria
The correct answer is C. veins.
Capillaries are small blood vessels where the exchange of water, oxygen, carbon dioxide, and many other nutrients and waste substances between blood and tissues occur. After this exchange, the blood in the capillaries that now contains waste products needs to be returned to the heart. This returning journey begins when capillaries join together to form veins, which take the blood back to the heart for purification. Thus, the correct choice is C. veins.
What are the upper chambers of the human heart called?
A) Septum
B) Atria
C) Ventricles
D) Vena cava
The correct answer is B) Atria.
The human heart is divided into four chambers: the two upper chambers are called auricles or atria (singular: atrium), and the two lower chambers are called ventricles. These chambers are separated by a partition known as the septum. The presence of the septum prevents the mixing of oxygenated and deoxygenated blood, ensuring efficient circulation. The term atria refers specifically to the upper chambers that receive blood entering the heart.
Abnormally increased number of RBCs is called:
A) Erythropenia
B) Polycythaemia
C) Leukocytopenia
D) Leucocythaemia
The correct answer is B) Polycythaemia.
Polycythaemia refers to the condition characterized by an abnormally high concentration of red blood cells (RBCs) in the bloodstream. This increase in RBCs causes the blood to become thicker, thus hindering effective circulation throughout the body.
Which one of the following is a correct matching pair?
A Lub - sharp closure of AV valves at the beginning of ventricular systole
B Dub - sudden opening of semilunar valves at the beginning of ventricular diastole
C Pulsation of the radial artery - valves in the blood vessels
D Initiation of the heartbeat - Purkinje fibers
The correct option is A Lub - sharp closure of AV valves at the beginning of ventricular systole
During the beginning of ventricular systole, the contraction of the ventricular muscles leads to the closure of the atrioventricular (AV) valves (bicuspid and tricuspid valves), producing the 'lub' sound. This sound marks the start of ventricular systole. The 'dub' sound, on the other hand, is produced by the closure of semilunar valves at the end of ventricular systole.
The pulsation of the radial artery is due to rhythmic contraction and relaxation in the aorta, not valves in the blood vessels.
Lastly, the initiation of the heartbeat occurs in the SA node, not the Purkinje fibers.
"What is the sphincter of Boyden, and what will happen if it is closed due to some reasons?"
The Sphincter of Boyden is a smooth muscle sphincter located in the common bile duct just before the hepatopancreatic ampulla. It is organized into two sections, a superior and an inferior sphincter. Its primary role is to control the flow of bile into the duodenum.
If the Sphincter of Boyden becomes closed for any reason, it can lead to an obstruction of bile flow. This can cause various digestive issues and discomfort for the patient. In such cases, medical intervention, ranging from medication to surgery, might be necessary to address the issue.
I hope this provides a clear answer to your question. All the best!
Capillaries have very thick walls.
A. True
B. False
Answer: B. False
Capillaries actually have very thin walls, which is essential for their function. The principal role of capillaries is to facilitate the transport of digested food, oxygen, and other necessary materials to all cells in the body. The thin walls of the capillaries allow substances to easily move in and out through the process of diffusion.
Then the volume of water displaced by the completely immersed body is $\qquad$ the volume of the body.
A) does not depend upon
B) equal to
C) less than
D) greater than
The correct answer is B) equal to.
According to Archimedes' Principle, when a body is completely submerged in a fluid, the volume of water displaced by the body is equal to the volume of the body itself.
Thromboplastin required for blood clotting at the site of injury is released by:
A) Thrombocytes
B) Monocytes
C) Basophils
D) Neutrophils
The correct answer is A) Thrombocytes
Thrombocytes, commonly known as platelets, are responsible for releasing thromboplastin at the site of an injury. Thromboplastin plays a crucial role in the blood clotting process. It initiates the conversion of inactive prothrombin into active thrombin. Subsequently, thrombin transforms inactive fibrinogen into fibrin, which forms the mesh-like structure that traps cells and leads to the formation of a blood clot.
State whether true or false: Tonsils and Peyer's patches are parts of the lymphatic system.
A) True
B) False
The correct answer is A) True.
Tonsils and Peyer's patches are indeed parts of the lymphatic system. Specifically, these structures are considered secondary lymphoid tissues, which serve as monitoring and filtration systems for the lymph fluid in different body areas. The tonsils are located in the pharyngeal region (throat), while Peyer's patches are found in the small intestine. Their main role in the immune function highlights their importance within the lymphatic system.
The first loop of the small intestine is called:
A) jejunum
B) duodenum
C) ileum
The correct answer is Option B: duodenum.
The small intestine is divided into three distinct sections: the duodenum, jejunum, and ileum.
The duodenum is the initial section directly attached to the stomach. It is characterized by its U-shaped structure.
Following the duodenum is the jejunum, primarily responsible for nutrient absorption.
Lastly, the pathway leads into the ileum, which is the final segment of the small intestine.
"The presence of striations is a feature of:
A) Heart muscle B) Blood vessels C) Muscles of ureters D) Stomach muscle"
SThe correct answer is A) Heart muscle.
The heart is composed of cardiac muscle, which is characterized by visible stripes or striations. These striations occur due to the highly organized arrangement of actin and myosin proteins in the muscle tissue, which are essential for contraction.
Compared to blood, our lymph has
A. Plasma without proteins
B. more WBCs and no RBCs
C. more RBCs and less WBCs
D. no plasma
The correct answer is B. more WBCs and no RBCs.
Lymph is essentially a type of mobile connective tissue and is made up of lymph plasma and lymph corpuscles. It is similar in composition to blood plasma but notable differences include the absence of red blood cells (RBCs) and large plasma proteins. Lymph generally contains a higher concentration of white blood cells (WBCs), which are key to the immune response.
Enzyme TPA or tissue plasminogen activator is used for:
A. Dissolving blood clots B. Maintaining plasma content C. Clearing turbidity of juices D. Stimulating thromboplastin production
The correct answer is A. Dissolving blood clots.
Tissue Plasminogen Activator (TPA) is an enzyme primarily involved in the breakdown of blood clots. It is naturally produced by endothelial cells in the blood vessels and can also be synthesized in laboratories. TPA serves as a crucial thrombolytic agent, utilized significantly in medical treatments for conditions like heart attacks and strokes by dissolving the obstructive clots.
How many chambers are there in a frog's heart?
A. 1 B. 2 C. 3 D. 4
A frog's heart consists of three chambers. These chambers include two atria and one ventricle. Frogs are amphibians, meaning they can live in both terrestrial and aquatic environments, which relates to their unique cardiovascular structure.
In contrast, if we consider the human heart, it has four chambers: two atria and two ventricles. This distinction highlights the different adaptations between species.
Therefore, the correct answer to how many chambers there are in a frog's heart is three. The option C (3) is the correct answer.
While swimming, the weight of the body is supported by the water pressure.
Correct Option: A (water pressure)
A liquid exerts pressure in the upward direction, which is termed as upthrust or buoyant force. This force counterbalances the weight of the body while swimming, allowing us to feel lighter.
What part of the blood carries minerals, sugar, and other foods to the body's cells?
Option 1: diabetes insipidus Option 2: diabetes mellitus Option 3: hypoglycemia Option 4: Both a and b
The correct option is Option 1: diabetes insipidus.
Blood is composed of plasma and several types of cells. These blood cells consist of erythrocytes (RBCs), leukocytes (WBCs), and thrombocytes (platelets). Each component of blood serves a specific function:
Plasma helps maintain blood pressure and regulate body temperature. It contains a complex mix of substances such as minerals, salts, hormones, and proteins, which the body uses to perform important functions.
Red blood cells (RBCs) carry oxygen.
White blood cells (WBCs) are part of the immune system.
Platelets are essential for blood clotting.
In summary, plasma is responsible for carrying minerals, sugar, and other nutrients to the body's cells.
Having more than the normal count of platelets in one microliter of blood is known as ____________.
Erythrocytopenia
Thrombocytopenia
Thrombocytosis
Leukopenia
The correct option is C Thrombocytosis.
Thrombocytosis is a condition in which there are an excessive number of platelets in the blood. Platelets are blood cells in plasma that stop bleeding by sticking together to form a clot. Having too many platelets in your blood can lead to stroke, heart attack, or a clot in the blood vessels.
Open circulatory system, which does not participate in the transport of $O_{2}$, occurs in:
A. Echinodermata
B. Annelida
C. Arthropoda
D. Vertebrata
An open circulatory system is characterized by the blood (or hemolymph) not being entirely contained within blood vessels. Instead, the fluid flows freely through cavities and tissues, allowing direct exchange between the hemolymph and body cells. Unlike the closed circulatory system, the blood is not always confined to vessels but rather fills body cavities, bathing the organs directly.
In an open circulatory system:
Hemolymph (the equivalent of blood in these organisms) circulates openly in body cavities.
This fluid is not primarily responsible for the transport of $ O_2 $; in many organisms with open circulatory systems, oxygen transport is managed differently, such as via a tracheal system in insects.
Let's briefly look at the given options to identify where this system is found and does not participate in the transport of $ O_2 $:
A. Echinodermata - These organisms have a water vascular system for locomotion and circulation, but they have a reduced or absent circulatory system.
B. Annelida - It possesses a closed circulatory system.
C. Arthropoda - Notably includes insects, which have an open circulatory system with hemolymph that does not primarily transport $ O_2 $. Instead, insects use a tracheal system for direct gas exchange with tissues.
D. Vertebrata - These organisms have a closed circulatory system where blood circulates within vessels.
Given these explanations, the correct answer is:
C. Arthropoda
In Arthropoda, the open circulatory system does not primarily serve to transport oxygen. Rather, the tracheal system efficiently manages gas exchange directly with tissues, making option C the correct choice.
Name the process of squeezing out of WBCs from capillaries
A. Diapedesis
B. Phagocytosis
C. Diffusion
D. Clotting
The correct option is A. Diapedesis
Explanation:
Diapedesis refers to the process by which white blood cells (WBCs) squeeze out of the capillaries and migrate towards sites of infection or inflammation.
In contrast, phagocytosis is the process whereby WBCs engulf and digest pathogens or debris.
The other options are:
Diffusion: Movement of molecules from an area of high concentration to an area of low concentration.
Clotting: The process of blood clot formation to prevent bleeding.
Hence, the correct term for WBCs squeezing out of capillaries is diapedesis.
The capillaries join together to form a ________________.
The capillaries join and widen to become venules, which in turn widen and converge to become veins.
Which of the following are the three principal body fluids in humans?
Option 1) Lubricant and shock absorption
Option 2) Body temperature regulation
Option 3) Structural support for molecules
Option 4) All of the above
The correct option is Option 1) Lubricant and shock absorption.
Blood, tissue fluids, and lymph are the principal body fluids in humans. These fluids have critical roles in the body:
Transporting oxygen and nutrients: They carry essential substances to various parts of the body.
Removing metabolic wastes: They help in excreting waste products from the body.
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Ask Chatterbot AINCERT Solutions - Body Fluids and Circulation | NCERT | Biology | Class 11
Name the components of the formed elements in the blood and mention one major function of each of them.
The components of the formed elements in the blood are:
Erythrocytes (Red Blood Cells or RBCs)
Major Function: Transport of respiratory gases, primarily oxygen and carbon dioxide, via hemoglobin.
Leucocytes (White Blood Cells or WBCs)
Major Function: Defense and immune responses. For example, neutrophils and monocytes are phagocytic and destroy foreign organisms, while lymphocytes (B and T cells) are responsible for adaptive immune responses.
Platelets (Thrombocytes)
Major Function: Blood coagulation (clotting) to prevent excessive loss of blood from injuries by releasing clotting factors.
Each of these components plays a crucial role in maintaining the body's homeostasis and overall health.
What is the importance of plasma proteins?
The plasma proteins play several critical roles in the body:
Fibrinogens: These are essential for the clotting or coagulation of blood.
Globulins: Primarily involved in the defense mechanisms of the body.
Albumins: Help in osmotic balance, maintaining the proper distribution of fluids in different body compartments.
These roles are vital for maintaining homeostasis, immune response, and preventing excessive blood loss during injuries.
Match Column I with Column II :
Column I | Column II |
---|---|
(a) Eosinophils | (i) Coagulation |
(b) RBC | (ii) Universal Recipient |
(c) AB Group | (iii) Resist Infections |
(d) Platelets | (iv) Contraction of Heart |
(e) Systole | (v) Gas transport |
Column I | Column II |
---|---|
(a) Eosinophils | (iii) Resist Infections |
(b) RBC | (v) Gas transport |
(c) AB Group | (ii) Universal Recipient |
(d) Platelets | (i) Coagulation |
(e) Systole | (iv) Contraction of Heart |
Why do we consider blood as a connective tissue?
Blood is considered a connective tissue because:
Special Connective Tissue: Blood consists of a fluid matrix called plasma and formed elements such as erythrocytes (RBCs), leucocytes (WBCs), and platelets.
Origin: It originates from the mesoderm, the same germ layer from which other connective tissues are derived.
Function: It connects different parts of the body by transporting nutrients, gases, hormones, and waste products, thereby maintaining homeostasis.
Matrix Presence: Like other connective tissues, blood has an intercellular matrix (plasma) that carries cells and other components.
What is the difference between lymph and blood?
The main differences between lymph and blood are as follows:
Composition:
Blood: Blood is a fluid connective tissue comprising a fluid matrix called plasma and formed elements such as erythrocytes (RBCs), leucocytes (WBCs), and platelets.
Lymph: Lymph is a colorless fluid containing specialized lymphocytes and is formed from interstitial fluid or tissue fluid.
Function:
Blood: Transports oxygen, nutrients, hormones to cells and removes waste products and carbon dioxide. Blood also plays a crucial role in immunity (through WBCs), clotting (through platelets), and maintaining homeostasis.
Lymph: Transports immune cells and fats. It also returns interstitial fluid to the bloodstream and assists in the immune response.
Presence of Cells:
Blood: Contains red blood cells (RBCs), white blood cells (WBCs), and platelets.
Lymph: Contains specialized lymphocytes (a type of WBC) and lacks RBCs and platelets.
Circulatory Path:
Blood: Circulates through a closed network of arteries, veins, and capillaries.
Lymph: Circulates through an open lymphatic system which collects interstitial fluid from tissues and returns it to the blood circulation.
Understanding these differences highlights the specialized roles that both blood and lymph play in maintaining the body's physiological balance and immune protection.
What is meant by double circulation? What is its significance?
Double circulation refers to a circulatory system in which blood passes through the heart twice during each complete circuit. This system has two distinct pathways: pulmonary circulation and systemic circulation.
Pulmonary circulation: The blood is pumped from the right ventricle to the lungs via the pulmonary artery, where it gets oxygenated and then returns to the left atrium via the pulmonary veins.
Systemic circulation: The oxygenated blood is pumped from the left ventricle into the aorta, from where it is distributed to various body tissues. The deoxygenated blood is then collected by veins and returned to the right atrium of the heart.
Significance of Double Circulation
Efficient Oxygen Transport: It ensures the separation of oxygenated and deoxygenated blood, allowing for efficient oxygen supply to the body tissues.
High Metabolic Rate: Supports the high metabolic rate of birds and mammals by providing a continuous and efficient supply of oxygen and nutrients while removing waste products.
Pressure Maintenance: Maintains a higher pressure in systemic circulation, which is essential for forcing blood through the extensive network of capillaries in the body.
By maintaining a strict separation of oxygen-rich and oxygen-poor blood, double circulation allows for a more efficient and regulated delivery of oxygen to body tissues, which is crucial for advanced organisms like mammals and birds.
Write the differences between :
(a) Blood and Lymph
(b) Open and Closed system of circulation
(c) Systole and Diastole
(d) P-wave and T-wave
(a) Blood and Lymph
Characteristic | Blood | Lymph |
---|---|---|
Composition | Contains plasma (straw-colored fluid), RBCs, WBCs, and platelets. | Contains lymph (tissue fluid), mainly lymphocytes. |
Functions | Transports nutrients, oxygen, and waste products; involved in defense and coagulation. | Returns interstitial fluid to the bloodstream; involved in the immune response. |
Color | Red due to hemoglobin. | Colorless. |
Flow | Circulates within arteries, veins, and capillaries. | Circulates within lymphatic vessels. |
(b) Open and Closed System of Circulation
Characteristic | Open System | Closed System |
---|---|---|
Presence | Found in arthropods and molluscs. | Found in annelids and vertebrates. |
Blood Flow | Blood is pumped into open spaces (sinuses). | Blood circulates through a closed network of blood vessels. |
Regulation | Less regulated; blood flow is slower and less efficient. | More precisely regulated; blood flow is faster and more efficient. |
(c) Systole and Diastole
Characteristic | Systole | Diastole |
---|---|---|
Definition | Contraction phase of heart chambers (atria or ventricles). | Relaxation phase of heart chambers. |
Function | Pumps blood out of the heart. | Allows the heart chambers to fill with blood. |
Timing in Cardiac Cycle | Follows atrial systole; increases pressure in the ventricles. | Follows ventricular systole; decreases pressure in the ventricles. |
(d) P-wave and T-wave
Characteristic | P-wave | T-wave |
---|---|---|
Representation | Electrical excitation (depolarisation) of the atria. | Return to normal state (repolarisation) of the ventricles. |
Function | Leads to the contraction of atria. | Marks the end of ventricular systole. |
Describe the evolutionary change in the pattern of heart among the vertebrates.
The evolutionary change in the pattern of heart among the vertebrates is characterized by an increase in the number of heart chambers, resulting in more efficient separation of oxygenated and deoxygenated blood. Here is a concise description:
Fishes:
2-chambered heart
Single atrium and single ventricle
Pumps deoxygenated blood to the gills, where it is oxygenated and then supplied to the body
Amphibians:
3-chambered heart
Two atria and single ventricle
Receives oxygenated blood from the lungs/skin and deoxygenated blood from the body, but they mix in the single ventricle (incomplete double circulation)
Reptiles (excluding crocodiles):
3-chambered heart
Two atria and partially divided single ventricle
Some separation of oxygenated and deoxygenated blood, but still mixes (incomplete double circulation)
Crocodiles, Birds, and Mammals:
4-chambered heart
Two atria and two ventricles
Complete separation of oxygenated and deoxygenated blood, with no mixing (complete double circulation)
These changes have led to a more efficient circulatory system, accommodating higher metabolic demands and endothermy in mammals and birds.
Why do we call our heart myogenic?
The heart is called myogenic because its normal activities are regulated intrinsically by specialized muscles known as nodal tissue. This means that the heart can generate its own action potentials without any external stimuli, allowing it to maintain rhythmic contractile activity autonomously. This self-regulation is why it's termed myogenic. Furthermore, a special neural center in the medulla oblongata can moderate this activity through the autonomic nervous system.
Sino-atrial node is called the pacemaker of our heart. Why?
The sino-atrial node (SAN) is called the pacemaker of our heart because it generates the maximum number of action potentials per minute (70-75 per minute), which initiates and maintains the rhythmic contractile activity of the heart. This auto-excitable nodal tissue ensures the heart's regular beating and thus regulates the heart's pace.
What is the significance of atrio-ventricular node and atrio-ventricular bundle in the functioning of heart?
The atrio-ventricular node (AVN) and the atrio-ventricular bundle (AV bundle) play significant roles in the functioning of the heart:
The AVN is located in the lower left corner of the right atrium close to the atrio-ventricular septum. It receives the action potential from the sino-atrial node (SAN).
The action potential is then conducted from the AVN to the AV bundle.
The AV bundle (or bundle of His) passes through the atrio-ventricular septa to emerge on the top of the interventricular septum. It then divides into right and left bundles.
These bundles give rise to Purkinje fibers that distribute the action potential throughout the ventricular musculature, causing the ventricles to contract.
In summary:
The AVN and AV bundle ensure the action potential initiated by the SAN is efficiently transmitted to the ventricles.
This transmission results in a coordinated contraction of the ventricles, essential for effective pumping of blood.
These components are crucial for maintaining the rhythmic contractile activity of the heart.
Define a cardiac cycle and the cardiac output.
Cardiac Cycle:
Cardiac cycle is the sequential event in the heart which includes the systole (contraction) and diastole (relaxation) of both the atria and ventricles.
It is cyclically repeated and ensures the movement of blood through the heart and the body.
The entire cycle typically lasts 0.8 seconds and is repeated 72 times per minute in a healthy individual.
Cardiac Output:
Cardiac output is the volume of blood pumped out by each ventricle per minute.
It is calculated as the product of stroke volume (the amount of blood pumped out during each cardiac cycle) and the heart rate (number of cardiac cycles per minute).
For an average healthy individual, the cardiac output is approximately 5 liters per minute.
Explain heart sounds.
During each cardiac cycle, two prominent sounds are produced that are of significant clinical importance:
First Heart Sound (Lub):
Associated with: Closure of the tricuspid and bicuspid valves.
Occurs when: The ventricles contract (ventricular systole), causing these valves to close due to the pressure of blood attempting to backflow into the atria.
Second Heart Sound (Dub):
Associated with: Closure of the semilunar valves.
Occurs when: The ventricles relax (ventricular diastole), leading to a decrease in ventricular pressure and causing the semilunar valves to close, preventing the backflow of blood from the arteries into the ventricles.
Draw a standard ECG and explain the different segments in it.
A standard ECG (Electrocardiogram) can be diagrammatically represented as follows:
Explanation of the Different Segments
P-Wave:
Represents: The electrical excitation (or depolarization) of the atria.
Result: Leads to the contraction of both the atria.
QRS Complex:
Represents: The depolarization of the ventricles.
Result: Initiates the ventricular contraction.
Details: The contraction starts shortly after the Q wave begins and marks the beginning of the systole.
T-Wave:
Represents: The return of the ventricles from the excited to the normal state (repolarization).
Marks: The end of the T-wave indicates the end of systole.
Additional Information:
Heart Rate Determination: By counting the number of QRS complexes in a given time period, one can determine the heart rate of an individual.
Clinical Significance: Any deviation from the normal shape of the ECG for a given lead configuration indicates a possible abnormality or disease.
Key Points:
P-Wave: Atrial depolarization.
QRS Complex: Ventricular depolarization and contraction.
T-Wave: Ventricular repolarization.
An ECG is a crucial diagnostic tool for assessing the electrical and functional status of the heart.
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Ask Chatterbot AINotes - Body Fluids and Circulation | Class 11 NCERT | Biology
Comprehensive Class 11 Notes on Body Fluids and Circulation
Introduction to Body Fluids and Circulation
All living cells require nutrients, oxygen, and other essential substances for proper functioning, while waste products need to be efficiently removed. Different animal groups have evolved various methods for this crucial transport. Simple organisms utilise water circulation through their body cavities, while complex organisms use specialised body fluids. Blood and lymph are the two primary fluids facilitating this exchange in higher organisms, including humans.
Blood and Its Components
Composition of Blood
Blood is a specialised connective tissue comprising a fluid matrix called plasma and formed elements such as erythrocytes (red blood cells), leukocytes (white blood cells), and platelets.
Detailed Study of Blood Components
Plasma
Plasma is a straw-coloured viscous fluid making up about 55% of blood. It consists primarily of water (90-92%) and proteins (6-8%). Major proteins include fibrinogens (clotting), globulins (defence mechanisms), and albumins (osmotic balance). Plasma also contains minerals like sodium, calcium, magnesium, bicarbonate, chloride, and nutrients like glucose, amino acids, and lipids.
Formed Elements
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Red Blood Cells (Erythrocytes): These are the most abundant cells in blood, carrying haemoglobin, an iron-containing protein crucial for oxygen transport. RBCs are biconcave and lack a nucleus in mammals.
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White Blood Cells (Leucocytes): These nucleated cells are involved in defence mechanisms. They are of two types:
- Granulocytes: Neutrophils, eosinophils, and basophils.
- Agranulocytes: Lymphocytes and monocytes.
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Platelets (Thrombocytes): Cell fragments from megakaryocytes, platelets play a critical role in blood clotting. A reduction in their number can lead to clotting disorders and excessive bleeding.
Blood Grouping
ABO Grouping System
Blood is classified based on the presence of surface antigens (A and B) on RBCs and natural antibodies in plasma:
- Group A: Antigen A, anti-B antibodies.
- Group B: Antigen B, anti-A antibodies.
- Group AB: Antigens A and B, no antibodies.
- Group O: No antigens, anti-A and anti-B antibodies.
Rh Factor
The Rh factor is another significant antigen. Individuals can be Rh-positive (Rh+ve) or Rh-negative (Rh-ve). Rh compatibility is crucial, especially during pregnancy, to avoid erythroblastosis foetalis, where the mother's antibodies attack the foetus's RBCs.
Blood Coagulation
Blood coagulation is a vital process to prevent excessive bleeding. Fibrins form a network trapping blood cells to create a clot. This process involves converting fibrinogen to fibrins by thrombin, which itself is activated from prothrombin by thrombokinase. Calcium ions play a crucial role in clotting.
Lymph and Its Functions
Lymph, or tissue fluid, is formed when some plasma leaks out of blood capillaries, leaving larger proteins and formed elements. Lymph, collected by the lymphatic system, plays a role in immune responses and the transport of nutrients, hormones, and fats.
Circulatory Pathways in Humans
Types of Circulatory Systems
- Open Circulatory System: Found in arthropods and molluscs, where blood is pumped into open spaces or body cavities.
- Closed Circulatory System: Present in annelids and chordates, where blood circulates within closed vessels, allowing precise regulation of flow.
Human Circulatory System
Humans possess a closed circulatory system comprising a heart, blood vessels, and blood.
Cardiac Mechanics
Cardiac Cycle
The cardiac cycle includes the systole (contraction) and diastole (relaxation) phases of the atria and ventricles. This cycle repeats approximately 72 times per minute in a healthy person. Each cycle involves:
graph TD;
A[Joint Diastole] --> B[Atrial Systole];
B --> C[Ventricular Systole];
C --> D[Ventricular Diastole];
D --> A;
Regulation of Cardiac Activity
The heart’s activity is primarily auto-excitable but moderated by neural and hormonal factors. The sinoatrial node (SAN) generates action potentials, making it the heart's pacemaker.
Electrocardiograph (ECG)
An ECG is a graphical representation of the heart's electrical activity, crucial for diagnosing cardiac conditions. It includes:
- P-wave: Atrial depolarisation.
- QRS complex: Ventricular depolarisation.
- T-wave: Ventricular repolarisation.
Double Circulation in Humans
Double circulation ensures oxygenated and deoxygenated blood flows through separate pathways:
graph TD;
A[Right Ventricle] --> B[Pulmonary Artery] --> C[Lungs];
C --> D[Pulmonary Veins] --> E[Left Atrium] --> F[Left Ventricle] --> G[Aorta] --> H[Body Tissues];
H --> I[Vena Cava] --> J[Right Atrium] --> A;
Disorders of the Circulatory System
Common Conditions
- Hypertension: High blood pressure affecting heart and organs.
- Coronary Artery Disease (CAD): Narrowing of coronary arteries due to plaque deposits.
- Angina: Chest pain due to inadequate oxygen supply to the heart.
- Heart Failure: Inability of the heart to pump blood effectively, leading to congestion, especially in the lungs.
Conclusion
Understanding the intricate functions of body fluids and the circulatory system is essential for maintaining overall health. By recognising how blood, lymph, and the heart work together to transport essential nutrients and remove waste, students can appreciate the complexity and efficiency of human physiology.
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