Chemical Coordination and Integration - Class 11 Biology - Chapter 18 - Notes, NCERT Solutions & Extra Questions
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Extra Questions - Chemical Coordination and Integration | NCERT | Biology | Class 11
Match the hormone in column I with their function in column II
Column 1 | Column 2 |
---|---|
A. FSH |
|
B. LH |
|
C. Progesterone |
|
D. Estrogen |
|
|
Option 1: $A-5, B-4, C-1, D-2$
Option 2: $A-4, B-5, C-2, D-1$
Option 3: $A-4, B-3, C-2, D-5$
Option 4: $A-5, B-1, C-2, D-4$
To solve the question, let's match each hormone listed in Column I with their correct function from Column II:
FSH (Follicle Stimulating Hormone):
Function: This hormone plays a critical role in the reproductive processes of the body. It is known for its role in the growth of the ovarian follicles in females, which is necessary before the release of an egg from one follicle during ovulation.
Match: "Maturation of Graafian follicle" (Item 5 in Column II)
LH (Luteinizing Hormone):
Function: In females, this hormone triggers ovulation and development of the corpus luteum.
Match: "Development of corpus luteum" (Item 4 in Column II)
Progesterone:
Function: Progesterone is crucial in regulating the condition of the endometrium, the lining of the uterus, which prepares it for possible pregnancy following ovulation.
Match: "Prepare endometrium for implantation" (Item 1 in Column II)
Estrogen:
Function: This hormone primarily helps in the development of female secondary sexual characteristics.
Match: "Develops female secondary sexual characters" (Item 2 in Column II)
Given these matches:
For FSH ($ A $): Item 5
For LH ($ B $): Item 4
For Progesterone ($ C $): Item 1
For Estrogen ($ D $): Item 2
Therefore, Option 1: $ A-5, B-4, C-1, D-2 $ is the correct answer.
Column I lists the endocrine structure and column II lists the corresponding hormones. Match the two columns. Identify the correct option from those given
Option 1): $A=t$, $B=r$, $C=s$, $D=q$
Option 2): $A=t$, $B=r$, $C=q$, $D=s$
Option 3): $A=p$, $B=q$, $C=s$, $D=r$
Option 4): $A=r$, $B=t$, $C=s$, $D=q$
From the video's transcript, we understand that the primary task is to match specific endocrine structures with their corresponding hormones using the provided options.
The endocrine structures mentioned are:
Hypothalamus - This structure releases several hormones including gonadotropin-releasing hormone.
Anterior Pituitary - This gland secretes several hormones including:
Follicle-stimulating hormone (FSH)
Luteinizing hormone (LH)
Adrenocorticotropic hormone (ACTH)
Thyroid-stimulating hormone (TSH)
Growth hormone
Prolactin
Testes - They secrete testosterone, a type of androgen.
Ovaries - These glands secrete estrogen.
Now, examining the options provided:
Option 1: $A=t$, $B=r$, $C=s$, $D=q$
Option 2: $A=t$, $B=r$, $C=q$, $D=s$
Option 3: $A=p$, $B=q$, $C=s$, $D=r$
Option 4: $A=r$, $B=t$, $C=s$, $D=q$
Correlate the labels ($p, q, r, s, t$) of Column II with the hormones:
Hypothalamus correlates with gonadotropin-releasing hormone.
Anterior Pituitary correlates with FSH, LH, ACTH, TSH, growth hormone, and prolactin.
Testes correlate with androgens (like testosterone).
Ovaries correlate with estrogen.
Through the content in the video, it's mentioned that androgens are denoted by 's' and estrogen by 'q'. It also indicates pairing for Anterior Pituitary with FSH and LH, which may align with other hormones it secretes.
Considering these hints:
Option 4: $A=r$, $B=t$, $C=s$, $D=q$ seems to provide the correct alignment as per the video's description, where:
Hypothalamus ($A$) matches with 'r' - possibly gonadotropin-releasing hormone.
Anterior Pituitary ($B$) matches with 't' - possibly representing a statement that sums up all the hormones it secretes (FSH/LH/TSH/ACTH).
Testes ($C$) with 's' - androgen.
Ovaries ($D$) with 'q' - estrogen.
Thus, the answer appears to be: Option 4: $A=r$, $B=t$, $C=s$, $D=q$. This setup aligns hypothalamus, anterior pituitary, testes, and ovaries correctly with their major hormones.
Name the endocrine gland attached to the base of the brain.
The endocrine gland attached to the base of the brain is the pituitary gland. It is connected to the hypothalamus by a stalk-like structure, located at the base of the optic chiasm.
"The hormones vasopressin (ADH) and oxytocin are released by:
A. Anterior lobe of pituitary
B. Middle lobe of pituitary
C. Posterior lobe of pituitary
D. Hypothalamus."
The correct answer is C. Posterior lobe of pituitary.
The posterior lobe of the pituitary gland is responsible for the release of the hormones vasopressin and oxytocin. These hormones are initially synthesized in the hypothalamus and subsequently transported to the posterior pituitary where they are stored until their release into the bloodstream.
Vasopressin, also known as Antidiuretic Hormone (ADH), is released in response to factors such as stress and dehydration. It plays a crucial role in regulating the body's retention of water by enhancing water reabsorption in the kidney's distal convoluted tubules and collecting ducts. This action helps maintain body water balance, and a deficiency of ADH can lead to significant increases in urine output, known as diabetes insipidus. Additionally, vasopressin helps to increase blood pressure by constricting peripheral blood vessels.
Oxytocin is an essential hormone for uterine contractions during childbirth and also stimulates the mammary glands to facilitate milk ejection during breastfeeding. Due to these functions, oxytocin is often referred to as the "milk-ejection hormone" and "birth hormone." Unlike vasopressin, oxytocin can decrease blood pressure by dilating peripheral blood vessels.
Identify the gland in the picture. What happens if its secretion is beyond the required level in the body?
The gland shown in the picture is the pituitary gland, which is situated at the base of the brain. When the pituitary gland secretes hormones at levels higher than normal, it can lead to various conditions depending on the age of the individual:
In children, excessive secretion can cause gigantism, characterized by an abnormal increase in the size of bones and muscles.
In adults, it leads to acromegaly, which involves the enlargement of bones and tissues, particularly noticeable in the hands, feet, and facial features.
Name the region of the alimentary canal which receives secretions from the different accessory glands.
A. Pylorus - End part of the stomach
B. Duodenum - Beginning of the small intestine
C. Cecum & ileum junction - Junction of the small and large intestine
D. Large intestine
The correct option is B. Duodenum - Beginning of the small intestine
The duodenum is the initial part of the small intestine where secretions from various accessory glands are delivered through the common bile duct. These secretions are crucial for the digestion of food within the small intestine.
Which of the following statements is/are true about parathyroid hormone?
A. It acts on bones and stimulates the process of bone resorption.
B. It stimulates reabsorption of calcium ions by the renal tubules.
C. It increases calcium ions absorption from digested food.
D. All of the above.
The correct answer is D. All of the above.
Parathyroid hormone, secreted by the parathyroid glands, plays a crucial role in regulating blood calcium levels. Its primary function is to elevate calcium levels when they drop below normal. This hormone achieves this through several mechanisms:
It acts on bones, promoting the resorption or demineralization process, which moves calcium from the bones into the bloodstream.
It enhances the reabsorption of calcium ions in the renal tubules, which prevents calcium from being excreted in urine, thereby retaining it in the blood.
It also boosts the absorption of calcium ions from digested food in the gastrointestinal tract.
Therefore, statements A, B, and C are all correct, making D the accurate comprehensive choice.
Define hormones and their role in our body. Why are they called chemical messengers? [3 MARKS]
1. Definition of Hormones:
A hormone is a chemical substance produced in the body, which controls and regulates the activity of specific cells or organs. These substances are transported throughout the body via the bloodstream to various target sites.
2. Role of Hormones in the Body:
Hormones play a crucial role in the body, even though they are secreted in very small quantities. They are essential for proper growth and development.
3. Hormones as Chemical Messengers:
They are referred to as chemical messengers because they transmit information from endocrine glands to different parts of the body, facilitating communication and coordination between various bodily functions.
A number of metabolic processes are interwoven by:
A) Non-coordination B) Subordination C) Coordination D) All of these
The correct answer is C) Coordination.
Coordination is crucial in metabolic processes, as it involves the integration and efficient functioning of different body systems. Metabolic processes are regulated through the coordinated interactions among various bodily functions and organs, ensuring optimal health and physiological balance. Non-coordination refers to the inability to synchronize body parts effectively, which is not applicable in this context where synchronization is essential.
Do you agree with the statement, "All hormones are chemical signals"? Yes/No. Justify your answer.
Yes, I agree with the statement that "All hormones are chemical signals."
Hormones are biochemical substances that act as messengers in the body. They can be classified into three main types based on their chemical structure: peptides, amines, and steroids. These hormones play a crucial role in regulating metabolism and other vital functions by signaling cells to initiate specific biochemical reactions.
Therefore, given their fundamental role in mediating metabolic processes through chemical changes, it is accurate to describe hormones as 'chemical messengers'.
"Crypts of Lieberkuhn release enzymes into the intestinal juice under the regulation of which hormone?
A) Cholecystokinin
B) Duocrinin
C) Enterocrinin
D) Villikinin"
The correct answer is C) Enterocrinin.
Enterocrinin is a hormone secreted by the epithelium of the entire small intestine. It specifically stimulates the crypts of Lieberkuhn to release enzymes into the intestinal juice, which is vital for digestion.
Other options and their functions include:
Cholecystokinin – Stimulates the gallbladder and pancreas to release their respective juices.
Duocrinin – Prompts Brunner's gland to secrete mucus.
Villikinin – Accelerates the movement of the villi.
Which of the following hormones is secreted by both the pancreas and the hypothalamus?
A) Somatostatin
B) Insulin
C) Glucagon
D) None of the above
The correct answer is A) Somatostatin.
Somatostatin is a hormone secreted by the delta cells of the islets of Langerhans in the pancreas, as well as by the hypothalamus. This hormone plays a critical role in inhibiting the secretion of various other hormones. For instance, it inhibits the release of growth hormone from the anterior pituitary and also suppresses the secretion of insulin and glucagon within the pancreas.
In contrast, insulin is specifically produced by the beta cells of the pancreas, and glucagon by the alpha cells. Neither of these hormones are produced by the hypothalamus. Thus, making somatostatin the unique hormone in this context that is secreted by both the pancreas and the hypothalamus.
Arrange the steps in signal transduction of steroid hormones across the cell in the correct order: I. Interaction of complex with DNA II. Formation of hormone-receptor complex III. Physiological responses IV. Binding of hormone to the intracellular receptor V. Biochemical actions
A. II → IV → I → III → V
B. IV → I → II → V → III
C. IV → II → I → V → III
D. II → IV → III → I → V
The correct option is C IV → II → I → V → III.
The sequence of events in the signal transduction of steroid hormones involves the following steps:
Binding of the hormone to the intracellular receptor (Step IV): This is the initial and crucial step where the steroid hormone enters the cell and binds to a specific receptor inside the cell.
Formation of hormone-receptor complex (Step II): Following the binding, the hormone and receptor form a complex, which is capable of exerting further actions within the cell.
Interaction of the complex with DNA (Step I): The hormone-receptor complex then moves to the cell nucleus and binds to specific DNA sequences, initiating transcriptional activities.
Biochemical actions (Step V): The interaction with DNA leads to the production of mRNA and subsequently proteins, which are responsible for carrying out and regulating multiple biochemical processes within the cell.
Physiological responses (Step III): Finally, the proteins and other molecules produced as a result of transcriptional activation lead to the required physiological responses throughout the organism.
Hence, the progression of steps is as outlined in Option C: IV → II → I → V → III, representing a coherent pathway from hormone binding to physiological effects.
Insulin is a
A. Steroid hormone
B. Peptide hormone
C. Amine hormone
D. None of the above
The correct answer to the type of hormone insulin is is:
B. Peptide hormone
Insulin is classified as a peptide hormone, derived from amino acids, and is essential in regulating glucose metabolism in the body.
Growth hormone in humans is secreted by:
A) Adrenal gland
B) Thymus
C) Pituitary gland
D) Thyroid gland
The correct answer is C) Pituitary gland.
The pituitary gland is a small, pea-sized organ situated at the base of the brain, directly below the hypothalamus. It is connected to the hypothalamus by a collection of nerve fibers. One of the primary hormones that the pituitary gland produces is the growth hormone, which plays a crucial role in the body's growth and development.
Exophthalmic goitre occurs due to:
A. hyposecretion of thyroxine
B. hypersecretion of thyroxine
C. hypersecretion of thyrocalcitonin
D. hyposecretion of thyrocalcitonin
The correct answer is B. hypersecretion of thyroxine.
Exophthalmic goitre is characterized by an enlargement of the thyroid gland along with a notable symptom called exophthalmos, where the eyes bulge outward. This condition is typically caused by hyperthyroidism, which results from the hypersecretion of thyroxine. Thyroxine plays a crucial role in regulating the body's metabolic rate.
Contrarily, hyposecretion of thyroxine leads to hypothyroidism, which significantly lowers the basal metabolic rate of the body.
Thyrocalcitonin, another hormone secreted by the thyroid gland, helps regulate the levels of calcium in the blood but is not involved in controlling the metabolic rate or contributing to exophthalmic goitre.
Which of the hormones is not produced by the argentaffin cells?
A. Serotonin
B. Somatostatin
C. Histamine
D. Gastrin
The correct answer is D. Gastrin.
Enteroendocrine cells, found at the base of gastric glands, are of two primary types: argentaffin cells and gastrin or G cells. Each of these cell types secretes different hormones that have specific roles in the gastrointestinal system:
Serotonin, secreted by argentaffin cells, is crucial for stimulating the smooth muscles, thereby aiding the peristaltic movements of the intestines.
Somatostatin, also produced by argentaffin cells, has a regulatory role in controlling the secretion of other gastrointestinal hormones.
Histamine, another product of argentaffin cells, helps in gastric secretion by stimulating acid production in the stomach and also aids in the dilation of blood vessels in the relevant area.
On the other hand, Gastrin, which is not produced by argentaffin cells but by G cells, is vital for promoting gastric mucosal growth, gastric motility, and the secretion of hydrochloric acid into the stomach. This distinguishes Gastrin from the hormones produced by argentaffin cells.
Match the following: \begin{tabular}{|l|l|} \hline Column I & Column II \ \hline 1. Pituitary & A. Above kidneys \ \hline 2. Thyroid & B. Base of brain \ \hline 3. Pancreas & C. Around neck \ \hline 4. Adrenal & D. Below stomach \ \hline \end{tabular}
A) $1-A, 2-B, 3-C, 4-D$
B) $1-B, 2-C, 3-D, 4-A$
C) $1-B, 2-D, 3-A, 4-C$
D) $1-B, 2-C, 3-A, 4-D$
Correct Answer: B) $1-B, 2-C, 3-D, 4-A$
Explanation:
Pituitary gland: Placed at the base of the brain, matches with B.
Thyroid gland: Found around the neck, matches with C.
Pancreas: Situated below the stomach, corresponding to D.
Adrenal glands: Located above the kidneys, aligning with A.
Therefore, option B is the correct match for all the given pairs, according to their respective locations in the human body.
Which of the following hormones contain iodine?
A) Adrenaline
B) Thyroxine
C) Testosterone
D) Insulin
The correct answer is B) Thyroxine.
Thyroxine is the hormone among the given options that contains iodine. Specifically, each molecule of thyroxine incorporates four iodine atoms. This is crucial because iodine is essential for the hormone's biological activity and its role in regulating metabolism. None of the other options (Adrenaline, Testosterone, Insulin) contain iodine in their molecular structure.
Which part of a nerve cell sends out signals?
A. Synapse
B. Dendrite
C. Axon
D. Axon terminals
The correct answer is D. Axon terminals.
Axon terminals are critical components of nerve cells, as they are involved in forming synaptic connections with other neurons or effector cells. These terminals play a pivotal role in the transmission of electrical impulses between neurons, thereby facilitating communication within the nervous system.
Synapse is:
A. a gap between two muscle cells
B. a gap between two bones
C. a gap between two neurons
D. a gap between muscle and bone
The term synapse refers to the point of contact between two neurons, specifically between the terminal branch of the axon of one neuron and the dendrites of another neuron. This contact point is crucial for the transmission of electrical signals across neurons in the nervous system.
A synapse is essentially the gap that exists between these two neurons, facilitating the neurotransmission process.
To address the multiple-choice options provided:
A synapse is not a gap between two muscle cells.
It is not a gap between two bones.
It does not represent a gap between muscle and bone.
Given the explanation and understanding of the term, the correct answer is: C. a gap between two neurons.
Which of the following is an animal hormone?
A. Auxin
B. Gibberellin
C. Insulin
D. Abscisic Acid
To determine which of these is an animal hormone, let's analyze each option briefly:
Auxin and Gibberellin are types of plant hormones, also known as phytohormones. They are primarily involved in the growth and developmental processes of plants.
Insulin is indeed an animal hormone, specifically secreted by the pancreas in animals, including humans. The beta cells within the pancreas produce insulin. This hormone plays a crucial role in regulating the blood glucose levels in the body.
Abscisic Acid is another plant hormone involved in various plant developmental processes.
Considering the options and their functions, it is evident that the correct answer is: C. Insulin is an animal hormone, primarily responsible for regulating blood glucose levels.
The term 'hormone' was first coined by ____________.
Correct Answer: C) Bayliss and Starling
William Bayliss and Ernest Starling coined the term 'hormone' in 1902. This term was used to describe the chemical factors responsible for plant growth.
Match the following from column 1 and column 2
Column 1 | Column 2 |
---|---|
A.Somatostatin | (i) Basal part of diencephalon |
B.Pituitary | (ii) Produced by the hypothalamus |
C.Hypothalamus | (iii) Master gland |
D.GnRH | (iv) Inhibits the release of growth hormone |
(A) A-(ii), B-(i), C-(iv), D-(iii)
(B) A-(iii), B-(ii), C-(iv), D-(i)
(C) A-(i), B-(iv), C-(ii), D-(iii)
(D) A-(iv), B-(iii), C-(i), D-(ii)
The correct option is D: A-(iv), B-(iii), C-(i), D-(ii)
Explanation:
Somatostatin: Also known as growth hormone-inhibiting hormone, somatostatin inhibits the release of growth hormone from the pituitary gland. Hence, A-(iv).
Pituitary: The pituitary gland is often referred to as the master gland because it regulates various endocrine activities in the body. Therefore, B-(iii).
Hypothalamus: Located in the forebrain, the hypothalamus is the basal part of the diencephalon. As a result, C-(i).
GnRH (Gonadotropin-releasing hormone): This is a hormone produced by the hypothalamus which stimulates the release of gonadotropins from the anterior pituitary gland. Thus, D-(ii).
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Ask Chatterbot AINCERT Solutions - Chemical Coordination and Integration | NCERT | Biology | Class 11
Define the following:
(a) Exocrine gland
(b) Endocrine gland
(c) Hormone
(a) Exocrine Gland:Exocrine glands are glands that release their secretions through ducts to the surface of an organ or tissue or into a body cavity. Examples include salivary glands, sweat glands, and glands within the gastrointestinal tract.
(b) Endocrine Gland:Endocrine glands are ductless glands that secrete hormones directly into the bloodstream. These hormones are transported to target organs or tissues to regulate various body functions. Examples include the pituitary gland, thyroid gland, and adrenal glands.
(c) Hormone:A hormone is a non-nutrient chemical produced by endocrine glands in trace amounts. It acts as an intercellular messenger and is transported through the blood to a distantly located target organ. Hormones regulate various physiological functions, such as metabolism, growth, and reproduction.
Diagrammatically indicate the location of the various endocrine glands in our body.
The various endocrine glands in the human body and their locations are indicated in the figure below:
Diagrammatic View of the Location of Endocrine Glands
Figure 19.1: Location of Endocrine Glands
Pituitary Gland – Located at the base of the brain.
Pineal Gland – Located on the dorsal side of the forebrain.
Thyroid Gland – Located on either side of the trachea in the neck.
Parathyroid Glands – Situated on the back side of the thyroid gland.
Thymus – Found between the lungs behind the sternum.
Adrenal Glands – Positioned on the anterior part of each kidney.
Pancreas – Located behind the stomach and is a composite gland.
Gonads (Testis in males and Ovary in females) – Testis located in the scrotal sac outside the abdomen; ovary located in the abdomen.
List the hormones secreted by the following:
(a) Hypothalamus
(b) Pituitary
(c) Thyroid
(d) Parathyroid
(e) Adrenal
(f) Pancreas
(g) Testis
(h) Ovary
(i) Thymus
(j) Atrium
(k) Kidney
(l) G-I Tract
(a) Hypothalamus:
Releasing hormones (e.g., Gonadotrophin releasing hormone (GnRH))
Inhibiting hormones (e.g., somatostatin)
(b) Pituitary:
Anterior Pituitary (Adenohypophysis):
Growth Hormone (GH)
Prolactin (PRL)
Thyroid Stimulating Hormone (TSH)
Adrenocorticotrophic Hormone (ACTH)
Luteinizing Hormone (LH)
Follicle Stimulating Hormone (FSH)
Melanocyte Stimulating Hormone (MSH) (Pars intermedia)
Posterior Pituitary (Neurohypophysis):
Oxytocin
Vasopressin (Antidiuretic Hormone, ADH)
(c) Thyroid:
Tetraiodothyronine (Thyroxine, T4)
Triiodothyronine (T3)
Thyrocalcitonin (TCT)
(d) Parathyroid:
Parathyroid Hormone (PTH)
(e) Adrenal:
Adrenal Medulla:
Adrenaline (Epinephrine)
Noradrenaline (Norepinephrine)
Adrenal Cortex:
Glucocorticoids (e.g., Cortisol)
Mineralocorticoids (e.g., Aldosterone)
Androgenic Steroids
(f) Pancreas:
Glucagon
Insulin
(g) Testis:
Androgens (e.g., Testosterone)
(h) Ovary:
Estrogens
Progesterone
(i) Thymus:
Thymosins
(j) Atrium:
Atrial Natriuretic Factor (ANF)
(k) Kidney:
Erythropoietin
(l) Gastrointestinal Tract (G-I Tract):
Gastrin
Secretin
Cholecystokinin (CCK)
Gastric Inhibitory Peptide (GIP)
These hormones play various roles in regulating the physiological functions in the body.
Fill in the blanks:
Hormones | Target gland |
---|---|
(a) Hypothalamic hormones | |
(b) Thyrotrophin (TSH) | |
(c) Corticotrophin (ACTH) | |
(d) Gonadotrophins (LH, FSH) | |
(e) Melanotrophin (MSH) |
Hormones | Target gland |
---|---|
(a) Hypothalamic hormones | Pituitary gland |
(b) Thyrotrophin (TSH) | Thyroid gland |
(c) Corticotrophin (ACTH) | Adrenal cortex |
(d) Gonadotrophins (LH, FSH) | Gonads (Testis/Ovary) |
(e) Melanotrophin (MSH) | Melanocytes |
Write short notes on the functions of the following hormones:
(a) Parathyroid hormone (PTH)
(b) Thyroid hormones
(c) Thymosins
(d) Androgens
(e) Estrogens
(f) Insulin and Glucagon
Functions of Hormones
(a) Parathyroid Hormone (PTH)
Increases the Ca2+ levels in the blood by acting on bones to stimulate bone resorption, promoting reabsorption of Ca2+ by the renal tubules, and increasing Ca2+ absorption from the intestines.
Plays a significant role in calcium balance in the body along with thyrocalcitonin (TCT).
(b) Thyroid Hormones
Include thyroxine (T4) and triiodothyronine (T3).
Regulate basal metabolic rate.
Support the process of red blood cell formation, and control the metabolism of carbohydrates, proteins, and fats.
Influence water and electrolyte balance.
Thyrocalcitonin (TCT) regulates blood calcium levels by decreasing it.
(c) Thymosins
Play a major role in the differentiation of T-lymphocytes, which provide cell-mediated immunity.
Promote the production of antibodies to provide humoral immunity.
(d) Androgens
Regulate the development, maturation, and functions of the male secondary sex organs.
Stimulate muscular growth, growth of facial and axillary hair, and other male secondary sex characteristics.
Play a stimulatory role in spermatogenesis.
Influence male sexual behavior and have anabolic effects on protein and carbohydrate metabolism.
(e) Estrogens
Stimulate the growth and activities of female secondary sex organs and the development of growing ovarian follicles.
Responsible for the appearance of female secondary sex characteristics, such as a high-pitch voice.
Influence the development of the mammary glands.
(f) Insulin and Glucagon
Insulin: Produced by β-cells, it enhances cellular glucose uptake and utilization, promoting glycogenesis, thereby decreasing blood glucose levels (hypoglycemia).
Glucagon: Produced by α-cells, it promotes glycogenolysis and gluconeogenesis in the liver, resulting in increased blood glucose levels (hyperglycemia).
Give example(s) of:
(a) Hyperglycemic hormone and hypoglycemic hormone
(b) Hypercalcemic hormone
(c) Gonadotrophic hormones
(d) Progestational hormone
(e) Blood pressure lowering hormone
(f) Androgens and estrogens
(a) Hyperglycemic hormone and hypoglycemic hormone
Hyperglycemic hormone: Glucagon
Hypoglycemic hormone: Insulin
(b) Hypercalcemic hormone
Hypercalcemic hormone: Parathyroid hormone (PTH)
(c) Gonadotrophic hormones
Gonadotrophic hormones: Luteinizing hormone (LH) and Follicle stimulating hormone (FSH)
(d) Progestational hormone
Progestational hormone: Progesterone
(e) Blood pressure lowering hormone
Blood pressure lowering hormone: Atrial natriuretic factor (ANF)
(f) Androgens and estrogens
Androgens: Testosterone
Estrogens: Estrogen
Which hormonal deficiency is responsible for the following:
(a) Diabetes mellitus
(b) Goitre
(c) Cretinism
Diabetes mellitus: Deficiency of insulin.
Goitre: Deficiency of thyroid hormones (such as thyroxine, T₄, and triiodothyronine, T₃).
Cretinism: Deficiency of thyroid hormones (particularly during pregnancy and early development).
Briefly mention the mechanism of action of FSH.
Follicle-stimulating hormone (FSH) binds to membrane-bound receptors on target cells in the ovaries (in females) and testes (in males). This binding leads to the formation of a hormone-receptor complex which triggers the generation of secondary messengers inside the cell. These secondary messengers then regulate cellular metabolism and stimulate processes such as the development of ovarian follicles and spermatogenesis.
Match the following:
Column I | Column II |
---|---|
(a) $\mathrm{T}_{4}$ | (i) Hypothalamus |
(b) PTH | (ii) Thyroid |
(c) $\mathrm{GnRH}$ | (iii) Pituitary |
(d) $\mathrm{LH}$ | (iv) Parathyroid |
(a) $\mathrm{T}_4 $ - (ii) Thyroid
(b) PTH - (iv) Parathyroid
(c) GnRH - (i) Hypothalamus
(d) LH - (iii) Pituitary
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Ask Chatterbot AINotes - Chemical Coordination and Integration | Class 11 NCERT | Biology
Comprehensive Guide on Chemical Coordination and Integration: Class 11 Notes
Introduction
Chemical coordination and integration are crucial for maintaining homeostasis and regulating physiological processes in the human body. These mechanisms ensure that the body's cells, tissues, and organs work in harmony to perform complex functions.
Endocrine Glands and Hormones
Definition and Functions
Endocrine glands are ductless glands that secrete hormones directly into the bloodstream. Hormones act as messengers, conveying signals from one cell to another to coordinate various bodily functions.
Differences from Neural Coordination
While the neural system provides rapid but short-lived communication, the endocrine system ensures prolonged and continuous regulation through hormones, which affect target cells and organs at a distance.
Human Endocrine System
Overview of Endocrine Glands
The human endocrine system consists of several glands, including the pituitary, pineal, thyroid, adrenal, pancreas, parathyroid, thymus, testis (in males), and ovary (in females).
Hormone-Secreting Organs
In addition to the primary endocrine glands, organs such as the heart, kidney, and gastrointestinal tract also produce hormones.
Major Endocrine Glands and Their Hormones
The Hypothalamus
The hypothalamus is located at the base of the brain and regulates various bodily functions through neurosecretory cells. It produces releasing and inhibiting hormones, which control pituitary hormones like Gonadotrophin-releasing hormone (GnRH) and somatostatin.
The Pituitary Gland
The pituitary gland, situated in the sella turcica, has two main parts: adenohypophysis (anterior pituitary) and neurohypophysis (posterior pituitary). It secretes hormones including growth hormone (GH), prolactin (PRL), and oxytocin.
The Pineal Gland
Located on the dorsal side of the forebrain, the pineal gland secretes melatonin, which regulates sleep-wake cycles and other diurnal rhythms.
Thyroid Gland
The thyroid gland, composed of two lobes connected by the isthmus, produces thyroxine (T4) and triiodothyronine (T3), which regulate metabolism, growth, and development.
Parathyroid Gland
The parathyroid glands, located behind the thyroid, secrete parathyroid hormone (PTH) which raises blood calcium levels.
Thymus
The thymus plays a vital role in immune development, secreting thymosins that help T-lymphocyte differentiation and antibody production.
Adrenal Gland
Anatomical Structure
The adrenal glands, located above each kidney, have an outer adrenal cortex and an inner adrenal medulla.
Adrenal Medulla vs Adrenal Cortex
The adrenal medulla secretes adrenaline and noradrenaline for the fight-or-flight response. The adrenal cortex produces glucocorticoids and mineralocorticoids, involved in carbohydrate metabolism and electrolyte balance, respectively.
Pancreas
Exocrine and Endocrine Functions
The pancreas functions both as an exocrine and endocrine gland. Its endocrine part, the Islets of Langerhans, produces insulin and glucagon.
Hormones (Insulin and Glucagon)
Insulin reduces blood glucose levels, while glucagon increases them, maintaining glucose homeostasis.
Gonads: Testis and Ovary
Testis
The testes produce testosterone, which promotes male secondary sexual characteristics and spermatogenesis.
Ovary
The ovaries produce oestrogen and progesterone. Oestrogen supports the development of female secondary sexual characteristics, while progesterone maintains pregnancy.
Other Hormone-Secreting Organs
Heart
The heart secretes atrial natriuretic factor (ANF), which lowers blood pressure by dilating blood vessels.
Kidney
The kidney produces erythropoietin, stimulating red blood cell production.
Gastrointestinal Tract
The gastrointestinal tract secretes hormones like gastrin, secretin, cholecystokinin (CCK), and gastric inhibitory peptide (GIP), regulating digestive juices and aiding digestion.
Mechanism of Hormone Action
Hormones exert their effects by binding to specific receptors. There are two main types of receptors: membrane-bound receptors and intracellular receptors.
graph TD;
Hormone-->|Binds|Receptor;
Receptor-->|Activates|Second_Messenger;
Second_Messenger-->|Activates|Target_Cell_Response;
Hormone-->|Enters|Cell;
Cell-->|Binds|Intracellular_Receptor;
Intracellular_Receptor-->|Alters|Gene_Expression;
Common Disorders Related to Hormonal Imbalances
Diabetes Mellitus
A condition caused by insulin deficiency or resistance, leading to high blood sugar levels.
Addison's Disease
A disease caused by inadequate hormone production by the adrenal cortex, leading to fatigue and weakness.
Glandular Dysfunction
Issues with any endocrine gland can result in significant health problems due to hormone imbalance.
Summary
Chemical coordination and integration involve intricate interactions between various endocrine glands and hormones to regulate body functions, ensuring homeostasis and overall health. Proper understanding of these systems is crucial for diagnosing and treating endocrine disorders.
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