CHEMICAL COORDINATION AND INTEGRATION MCQs for NEET UG BIOLOGY — Easy, Page 2

31 Easy

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ADH deficiency shows which of the following condition?

View answer and explanation

Correct option: B

Polyuria

Option B (Polyuria) is correct because ADH (Antidiuretic Hormone) deficiency leads to diabetes insipidus, characterized by excessive urine production (polyuria).

Solution approach

Correct Answer + Core Reason: Polyuria. ADH deficiency results in the inability of the kidneys to concentrate urine, leading to excessive urination.

Step-by-Step Solution:

Step 1: Recall the function of ADH (Antidiuretic Hormone) also known as Vasopressin.

Step 2: ADH promotes water reabsorption in the kidneys, specifically in the distal convoluted tubules and collecting ducts.

Step 3: A deficiency in ADH leads to a condition called diabetes insipidus, where the kidneys cannot reabsorb water effectively.

Step 4: This results in the production of large volumes of dilute urine (polyuria).

Step 5: Polydipsia (excessive thirst) is a consequence of polyuria, as the body tries to compensate for the water loss.

Why other options are wrong:
- Option A: Polydipsia occurs as a result of polyuria, but polyuria is the direct consequence of ADH deficiency.
- Option C: While both polydipsia and polyuria are associated with ADH deficiency, polyuria is the direct result of the deficiency.
- Option D: Glucosuria (glucose in the urine) is associated with diabetes mellitus, not ADH deficiency.

Key Concepts:
- ADH function
- Diabetes insipidus
- Polyuria and polydipsia

Memory Aids:
- ADH: Anti-Diuretic Hormone (prevents diuresis, i.e., excessive urine production)

Quick Tips:
- Differentiate between diabetes insipidus (ADH deficiency) and diabetes mellitus (insulin deficiency).

32 Easy

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Compared to a bull, a bullock is docile because of

View answer and explanation

Correct option: C

Lower levels of blood testosterone

Option C (Lower levels of blood testosterone) is correct because castration reduces testosterone levels, leading to decreased aggression and docility.

Solution approach

Correct Answer + Core Reason: Lower levels of blood testosterone. Testosterone is the primary hormone responsible for aggression in bulls.

Step-by-Step Solution:
Step 1: Understand the difference between a bull and a bullock.
Step 2: A bullock is a castrated bull.
Step 3: Recall that testosterone is the primary male sex hormone responsible for aggressive behavior.
Step 4: Castration reduces testosterone levels.

Why other options are wrong:
- Option A: Thyroxine is a thyroid hormone that regulates metabolism and is not directly related to aggression.
- Option B: Cortisone is a glucocorticoid involved in stress response and inflammation, not aggression.
- Option D: Adrenaline/noradrenaline are involved in the fight-or-flight response but are not the primary hormones responsible for the difference in temperament between a bull and a bullock.

Key Concepts:
- Testosterone
- Castration
- Hormonal influence on behavior

Memory Aids:
- Testosterone = Aggression

Quick Tips:
- Remember that castration reduces testosterone levels, leading to reduced aggression.

33 Easy

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Which of the following hormones are secreted by pancreas?

View answer and explanation

Correct option: A

Insulin and glucagon

Option A (Insulin and glucagon) is correct because these are the two primary hormones secreted by the pancreas to regulate blood sugar levels.

Solution approach

Correct Answer + Core Reason: Insulin and glucagon. These hormones are produced by the islets of Langerhans in the pancreas.

Step-by-Step Solution:

Step 1: Recall the hormones secreted by the pancreas.

Step 2: The pancreas secretes insulin (from beta cells) and glucagon (from alpha cells) to regulate blood glucose levels.

Why other options are wrong:
- Option B: Epinephrine and norepinephrine: These hormones are secreted by the adrenal medulla.
- Option C: Thyroxine and melanin: Thyroxine is secreted by the thyroid gland, and melanin is a pigment produced by melanocytes.
- Option D: Lactocin and oxytocin: These hormones are secreted by the pituitary gland.

Key Concepts:
- Pancreas
- Insulin
- Glucagon
- Endocrine system

Memory Aids:
- Remember that the pancreas has both endocrine (hormone-secreting) and exocrine (enzyme-secreting) functions.

Quick Tips:
- Associate insulin and glucagon with the pancreas.

34 Easy

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FSH (Follicle stimulating hormone) is produced by

View answer and explanation

Correct option: B

Anterior pituitary lobe

Option B (Anterior pituitary lobe) is correct because FSH is produced and secreted by the anterior pituitary gland.

Solution approach

Correct Answer + Core Reason: Anterior pituitary lobe. FSH is produced by the anterior pituitary gland.

Step-by-Step Solution:

Step 1: Recall the hormones produced by the pituitary gland:
- Anterior pituitary: produces FSH, LH, ACTH, TSH, prolactin, and growth hormone.
- Middle pituitary: produces melanocyte-stimulating hormone (MSH).
- Posterior pituitary: stores and releases vasopressin and oxytocin (produced by the hypothalamus).

Step 2: Identify the source of FSH: FSH is produced by the anterior pituitary lobe.

Why other options are wrong:
- Option A: Adrenal cortex produces steroid hormones like cortisol and aldosterone.
- Option C: Middle pituitary lobe produces MSH.
- Option D: Posterior pituitary lobe stores and releases vasopressin and oxytocin.

Key Concepts:
- Anterior pituitary
- FSH (Follicle-Stimulating Hormone)
- Pituitary hormones

Memory Aids:
- Anterior Pituitary: FLAT PiG (FSH, LH, ACTH, TSH, Prolactin, GH)

Quick Tips:
- Remember the hormones produced by each lobe of the pituitary gland.

35 Easy

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Group of neurosecretory cells present in hypothalamus are mainly responsible for

View answer and explanation

Correct option: B

Secretion of hormones

The correct answer is Secretion of hormones because neurosecretory cells in the hypothalamus produce hormones that regulate the pituitary gland.

Solution approach

Correct Answer + Core Reason: Secretion of hormones. Neurosecretory cells in the hypothalamus are responsible for hormone secretion.

Step-by-Step Solution:

Step 1: Recall the function of neurosecretory cells in the hypothalamus.

Step 2: Neurosecretory cells are specialized neurons that produce and secrete hormones. In the hypothalamus, these cells produce releasing and inhibiting hormones that regulate the anterior pituitary gland.

Step 3: While the hypothalamus is involved in controlling body temperature, the urge of eating and drinking, and swallowing, these functions are not primarily attributed to the neurosecretory cells themselves, but rather to other neurons and circuits within the hypothalamus.

Why other options are wrong:
- Option A: While the hypothalamus regulates body temperature, this is not the primary function of neurosecretory cells.
- Option C: While the hypothalamus regulates the urge of eating and drinking, this is not the primary function of neurosecretory cells.
- Option D: Swallowing is controlled by the brainstem, not primarily by neurosecretory cells in the hypothalamus.

Key Concepts:
- Neurosecretory cells
- Hypothalamus function
- Hormone secretion

Memory Aids:
- Neurosecretory = Hormone Secretion

Quick Tips:
- Remember that neurosecretory cells are specialized neurons that produce hormones.

36 Easy

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The gland which performs both endocrine and exocrine function is

View answer and explanation

Correct option: C

Pancreas

Option C (Pancreas) is correct because the pancreas has both endocrine (hormone secretion) and exocrine (enzyme secretion) functions.

Solution approach

Correct Answer + Core Reason: Pancreas. The pancreas has both endocrine and exocrine functions.

Step-by-Step Solution:

Step 1: Define endocrine and exocrine functions.

Step 2: Endocrine glands secrete hormones directly into the bloodstream.

Step 3: Exocrine glands secrete substances through ducts onto epithelial surfaces.

Step 4: The pancreas has endocrine functions through the islets of Langerhans, which secrete insulin and glucagon.

Step 5: The pancreas has exocrine functions through acinar cells, which secrete digestive enzymes into the pancreatic duct.

Why other options are wrong:
- Option A: The adrenal gland primarily has endocrine functions, secreting hormones like cortisol and adrenaline.
- Option B: The thyroid gland primarily has endocrine functions, secreting hormones like thyroxine (T4) and triiodothyronine (T3).
- Option D: The pituitary gland primarily has endocrine functions, secreting hormones that regulate other endocrine glands.

Key Concepts:
- Endocrine glands
- Exocrine glands
- Pancreas
- Insulin
- Glucagon

Memory Aids:
- Think of the pancreas as a "dual-function" organ, performing both endocrine and exocrine roles.

Quick Tips:
- Remember that the pancreas is the only gland listed that performs both endocrine and exocrine functions.

37 Easy

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Which hormone produces calorigenic effect?

View answer and explanation

Correct option: A

Thyroxine

Option A (Thyroxine) is correct because thyroxine (T4), a thyroid hormone, increases the basal metabolic rate and thus produces a calorigenic effect, increasing heat production in the body.

Solution approach

Correct Answer + Core Reason: Thyroxine. Thyroxine increases the basal metabolic rate and heat production.

Step-by-Step Solution:

Step 1: Define calorigenic effect.

Step 2: A calorigenic effect is the production of heat in the body.

Step 3: Thyroxine (T4) is a thyroid hormone that increases the basal metabolic rate (BMR), leading to increased heat production.

Step 4: FSH (follicle-stimulating hormone) is involved in reproductive function.

Step 5: Insulin regulates blood glucose levels.

Why other options are wrong:
- Option B: FSH is a reproductive hormone and does not directly produce a calorigenic effect.
- Option C: Insulin regulates blood glucose levels and does not directly produce a calorigenic effect.
- Option D: Only thyroxine produces a calorigenic effect among the given options.

Key Concepts:
- Calorigenic effect
- Role of thyroxine in metabolism

Memory Aids:
- Thyroxine = Temperature

Quick Tips:
- Remember that thyroid hormones are key regulators of metabolism and heat production.

38 Easy

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Which of following is not a role of parathormone?

View answer and explanation

Correct option: D

Decreased

{Ca}^{2+}

absorption by the renal tubules

Option D (Decreased

{Ca}^{2+}

absorption by the renal tubules) is correct because parathormone increases, not decreases, calcium reabsorption by the renal tubules.

Solution approach

Correct Answer + Core Reason: Decreased ${Ca}^{2+}$ absorption by the renal tubules. Parathormone increases calcium reabsorption in the kidneys, not decreases it.

Step-by-Step Solution:

Step 1: Understand the function of parathormone (PTH).

Step 2: PTH is secreted by the parathyroid glands and regulates calcium levels in the blood.

Step 3: PTH increases calcium levels by:
- Increasing calcium reabsorption by the renal tubules.
- Increasing calcium absorption from digested food (indirectly via vitamin D activation).
- Mobilizing calcium from bones into the blood.

Step 4: Therefore, decreasing calcium absorption by the renal tubules is NOT a role of parathormone.

Why other options are wrong:
- Option A: PTH increases calcium reabsorption by the renal tubules.
- Option B: PTH increases calcium absorption from digested food (indirectly).
- Option C: PTH mobilizes calcium from bones into the blood.

Key Concepts:
- Parathormone function
- Calcium regulation
- Renal tubules

Memory Aids:
- PTH = Pulls calcium from bones.

Quick Tips:
- Remember the three main ways PTH increases blood calcium levels.

39 Easy

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Statement-A : Hormones are nutrient chemical molecules ingested with balanced diet.

Statement-B : Hormones act as intracellular messengers and are produced in trace amounts. Choose the correct option.

View answer and explanation

Correct option: C

Both statements

A

and

B

are incorrect

Option C (Both statements

A

and

B

are incorrect) is correct because hormones are not nutrients and act as intercellular messengers.

Solution approach

Correct Answer + Core Reason: Both statements $A$ and $B$ are incorrect. Hormones are not nutrients and act as intercellular messengers.

Step-by-Step Solution:

Step 1: Analyze statement A: Hormones are nutrient chemical molecules ingested with a balanced diet. This is incorrect; hormones are not nutrients.

Step 2: Analyze statement B: Hormones act as intracellular messengers and are produced in trace amounts. This is incorrect; hormones act as intercellular messengers.

Step 3: Since both statements are incorrect, the correct option is C.

Why other options are wrong:
- Option A: Both statements are incorrect.
- Option B: Statement A is incorrect.
- Option D: Statement B is incorrect.

Key Concepts:
- Hormone properties
- Intercellular messengers
- Nutrients

Memory Aids:
- Hormones = not nutrients, intercellular

Quick Tips:
- Remember the basic properties of hormones.

40 Easy

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Calcium level decreases in the blood due to hyposecretion of

View answer and explanation

Correct option: A

Parathyroid hormone

Option A (Parathyroid hormone) is correct because parathyroid hormone increases blood calcium levels, so its hyposecretion would lead to decreased blood calcium.

Solution approach

Correct Answer + Core Reason: Parathyroid hormone. Hyposecretion of parathyroid hormone leads to decreased blood calcium levels.

Step-by-Step Solution:

Step 1: Understand the function of parathyroid hormone: Parathyroid hormone (PTH) increases blood calcium levels.

Step 2: Consider the effect of hyposecretion: If PTH is hyposecreted, blood calcium levels will decrease.

Step 3: Analyze the options:
- Parathyroid hormone: increases blood calcium levels; hyposecretion leads to decreased calcium.
- Calcitonin: decreases blood calcium levels; hyposecretion would not cause a further decrease.
- Thyroxine: primarily regulates metabolism; does not directly affect calcium levels.
- Adrenaline: prepares the body for emergency situations; does not directly affect calcium levels.

Why other options are wrong:
- Option B: Calcitonin decreases blood calcium levels, so its hyposecretion would not cause a further decrease in calcium.
- Option C: Thyroxine primarily regulates metabolism and does not directly affect calcium levels.
- Option D: Adrenaline prepares the body for emergency situations and does not directly affect calcium levels.

Key Concepts:
- Parathyroid hormone (PTH)
- Calcium regulation
- Hyposecretion

Memory Aids:
- PTH: Pulls calcium from bone into blood.

Quick Tips:
- Remember the roles of PTH and calcitonin in calcium homeostasis.

41 Easy

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Sella turcica protects our

View answer and explanation

Correct option: D

Pituitary

Option D (Pituitary) is correct because the sella turcica is a saddle-shaped depression in the sphenoid bone that houses and protects the pituitary gland.

Solution approach

Correct Answer + Core Reason: Pituitary. The sella turcica is a bony structure that protects the pituitary gland.

Step-by-Step Solution:

Step 1: Recall the location and function of the sella turcica.

Step 2: The sella turcica is a part of the sphenoid bone in the skull.

Step 3: It forms a protective bony enclosure for the pituitary gland.

Step 4: Therefore, the sella turcica protects the pituitary gland.

Why other options are wrong:
- Option A: The liver is located in the abdominal cavity and is not protected by the sella turcica.
- Option B: The thyroid gland is located in the neck and is not protected by the sella turcica.
- Option C: The adrenal glands are located on top of the kidneys and are not protected by the sella turcica.
- Option D: The pituitary gland is located within the sella turcica.

Key Concepts:
- Skeletal System
- Endocrine System
- Pituitary Gland
- Sella Turcica

Memory Aids:
- Sella Turcica = Saddle, Pituitary sits in the saddle.

Quick Tips:
- Remember anatomical locations of major organs and glands.

42 Easy

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Vasopressin stimulates reabsorption of water and reduction of urine secretion. Hence, vasopressin is otherwise called

View answer and explanation

Correct option: C

Antidiuretic hormone

Option C (Antidiuretic hormone) is correct because vasopressin promotes water reabsorption in the kidneys, reducing urine output, hence it's also known as antidiuretic hormone (ADH).

Solution approach

Correct Answer + Core Reason: Antidiuretic hormone. Vasopressin promotes water reabsorption, hence it is called antidiuretic hormone.

Step-by-Step Solution:

Step 1: Recall the function of vasopressin.

Step 2: Vasopressin stimulates reabsorption of water in the kidneys.

Step 3: Reabsorption of water reduces urine secretion.

Step 4: Antidiuretic hormones (ADH) reduce urine output.

Step 5: Therefore, vasopressin is otherwise called antidiuretic hormone.

Why other options are wrong:
- Option A: Sinovial fluid is found in joints, not related to vasopressin.
- Option B: Neurotransmitters transmit signals between neurons, not related to vasopressin's primary function.
- Option C: Vasopressin is also known as antidiuretic hormone.
- Option D: Growth regulating substances affect growth, not primarily water reabsorption like vasopressin.

Key Concepts:
- Endocrine System
- Vasopressin
- Antidiuretic Hormone (ADH)
- Kidney Function
- Water Reabsorption

Memory Aids:
- ADH = Anti-Diuretic (reduces urine).

Quick Tips:
- Know the hormones involved in fluid balance.

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In males, the spermatogenesis is regulated by

View answer and explanation

Correct option: C

Both (a) and (b)

Option C (Both (a) and (b)) is correct because both FSH and androgens are essential for spermatogenesis in males.

Solution approach

Correct Answer + Core Reason: Both (a) and (b). FSH and Androgens both play a role in spermatogenesis.

Step-by-Step Solution:
Step 1: Recall the hormones involved in spermatogenesis.
Step 2: FSH (Follicle-Stimulating Hormone) acts on Sertoli cells, which help in spermatogenesis.
Step 3: Androgens (e.g., testosterone) are essential for the development and maturation of sperm.

Why other options are wrong:
- Option A: FSH alone is not sufficient for spermatogenesis; androgens are also required.
- Option B: Androgens alone are not sufficient for spermatogenesis; FSH is also required.
- Option D: Hypothalamus releases GnRH, which stimulates the pituitary to release FSH and LH. LH then stimulates androgen production. While the hypothalamus plays a role, it doesn't directly regulate spermatogenesis.

Key Concepts:
- Spermatogenesis
- FSH
- Androgens
- Hormonal regulation

Memory Aids:
- FSH = Sperm support
- Androgens = Sperm development

Quick Tips:
- Remember the interplay between FSH and androgens in spermatogenesis.

44 Easy

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Glycosuria and ketonuria is indicative of

View answer and explanation

Correct option: B

Diabetes mellitus

Option B (Diabetes mellitus) is correct because glycosuria (glucose in urine) and ketonuria (ketones in urine) are classic indicators of uncontrolled diabetes mellitus.

Solution approach

Correct Answer + Core Reason: Diabetes mellitus. Glycosuria and ketonuria are indicative of uncontrolled diabetes mellitus due to insulin deficiency or resistance.

Step-by-Step Solution:

Step 1: Glycosuria refers to the presence of glucose in the urine. This occurs when blood glucose levels are so high that the kidneys cannot reabsorb all the glucose back into the bloodstream, leading to glucose spilling into the urine.

Step 2: Ketonuria refers to the presence of ketone bodies in the urine. This occurs when the body does not have enough glucose for energy and starts breaking down fat for fuel, producing ketones as a byproduct.

Step 3: In diabetes mellitus, either the body does not produce enough insulin (Type 1) or the cells do not respond to insulin properly (Type 2), leading to high blood glucose levels and the breakdown of fat for energy.

Step 4: The combination of glycosuria and ketonuria strongly suggests uncontrolled diabetes mellitus.

Why other options are wrong:
- Option A: Starvation can lead to ketonuria as the body breaks down fat for energy, but it does not typically cause glycosuria unless there is an underlying diabetic condition.
- Option C: Diabetes insipidus is a condition characterized by excessive thirst and urination due to a problem with the hormone vasopressin (ADH), not glucose metabolism. Therefore, it does not directly cause glycosuria or ketonuria.
- Option D: While starvation can cause ketonuria, the presence of both glycosuria and ketonuria points specifically to diabetes mellitus.

Key Concepts:
- Diabetes mellitus
- Glycosuria
- Ketonuria
- Insulin

Memory Aids:
- Think of \"sweet urine\" (glycosuria) and \"ketones\" as signs of diabetes.

Quick Tips:
- Remember the key differences between diabetes mellitus and diabetes insipidus.

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Which one of the following pairs of organs includes only the endocrine glands?

View answer and explanation

Correct option: A

Parathyroid and adrenal

Option A (Parathyroid and adrenal) is correct because both parathyroid and adrenal glands are exclusively endocrine glands.

Solution approach

Correct Answer + Core Reason: Parathyroid and adrenal. Both are exclusively endocrine glands.

Step-by-Step Solution:

Step 1: Recall the definition of endocrine glands. Endocrine glands secrete hormones directly into the bloodstream.

Step 2: Consider each option:
- A. Parathyroid and adrenal: Both are endocrine glands.
- B. Pancreas and parathyroid: The pancreas is both an endocrine and exocrine gland.
- C. Thymus and testes: The testes are both endocrine and exocrine glands.
- D. adrenal and ovary: The ovary is both an endocrine and exocrine gland.

Step 3: Identify the pair that includes only endocrine glands.

Why other options are wrong:
- Option B: Pancreas and parathyroid: Pancreas is both endocrine and exocrine.
- Option C: Thymus and testes: Testes are both endocrine and exocrine.
- Option D: adrenal and ovary: Ovary is both endocrine and exocrine.

Key Concepts:
- Endocrine vs. exocrine glands

Memory Aids:
- Endocrine = \"into\" the blood.

Quick Tips:
- Know the primary functions of different organs.

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According to accepted concept of hormonal action, if receptor molecules are removed from target organs, then the target organ will

View answer and explanation

Correct option: D

Not respond to the hormone

Option D (Not respond to the hormone) is correct because receptors are essential for hormone binding and initiating a response in the target organ.

Solution approach

Correct Answer + Core Reason: Not respond to the hormone. Receptors are necessary for hormone binding and subsequent cellular response.

Step-by-Step Solution:

Step 1: Hormones exert their effects by binding to specific receptors on or in target cells.

Step 2: If the receptor molecules are removed, the hormone cannot bind to the target organ.

Step 3: Without hormone-receptor binding, the signaling pathway is not activated, and the target organ will not respond to the hormone.

Why other options are wrong:
- Option A: The target organ cannot respond in the opposite way without receptors. The presence of receptors is essential for any response.
- Option B: The target organ cannot continue to respond without receptors. Receptors are the starting point of the hormone's action.
- Option C: The target organ will not respond at all without receptors, regardless of hormone concentration.

Key Concepts:
- Hormone-receptor interaction
- Signal transduction
- Target cell response

Memory Aids:
- No receptor, no response.

Quick Tips:
- Always remember that receptors are crucial for hormone action.

47 Easy

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Assertion: Vasopressin is also known as anti-diueretic hormone.

Reason: Vasopressin stimulates the reabsorption of water and electrolyte by distal tubules and there by
reduces diuresis.

View answer and explanation

Correct option: A

If both the assertion and the reason are true and the reason is a correct explanation of the assertion

The correct answer is A (If both the assertion and the reason are true and the reason is a correct explanation of the assertion) because vasopressin's antidiuretic effect is due to its stimulation of water reabsorption.

Solution approach

Correct Answer + Core Reason: If both the assertion and the reason are true and the reason is a correct explanation of the assertion. Vasopressin is indeed known as antidiuretic hormone, and its function is to stimulate water reabsorption, thereby reducing diuresis.

Step-by-Step Solution:

Step 1: Analyze the assertion: Vasopressin is also known as anti-diuretic hormone. This is true.

Step 2: Analyze the reason: Vasopressin stimulates the reabsorption of water and electrolyte by distal tubules and thereby reduces diuresis. This is also true.

Step 3: Determine if the reason explains the assertion: The reason correctly explains why vasopressin is called an antidiuretic hormone.

Why other options are wrong:
- Option B: The reason *is* a correct explanation of the assertion.
- Option C: The assertion is true, so this option is incorrect.
- Option D: Both the assertion and the reason are true, so this option is incorrect.

Key Concepts:
- Vasopressin (ADH)
- Antidiuretic effect
- Water reabsorption

Memory Aids:
- Vasopressin = ADH = Anti-Diuretic Hormone

Quick Tips:
- Remember the function of vasopressin in regulating water balance.

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Islets of Langerhans is a normal human pancreas comprise only

View answer and explanation

Correct option: B

1-2% of pancreatic tissue

Option B (1-2% of pancreatic tissue) is correct because Islets of Langerhans, the endocrine component of the pancreas, constitute only a small fraction of the total pancreatic mass.

Solution approach

Correct Answer + Core Reason: 1-2% of pancreatic tissue. Islets of Langerhans make up a small portion of the pancreas.

Step-by-Step Solution:

Step 1: Recall the structure of the pancreas: The pancreas has both exocrine (digestive enzymes) and endocrine (hormones) functions. The Islets of Langerhans are the endocrine part.

Step 2: Consider the relative proportions: The exocrine portion makes up the vast majority of the pancreatic tissue, while the endocrine portion is a small fraction.

Step 3: Identify the correct percentage: The Islets of Langerhans comprise approximately 1-2% of the total pancreatic tissue.

Why other options are wrong:
- Option A: 2-3% is slightly higher than the actual percentage.
- Option C: 3-4% is significantly higher than the actual percentage.
- Option D: 4-5% is much higher than the actual percentage.

Key Concepts:
- Pancreas structure
- Islets of Langerhans
- Endocrine vs. Exocrine function

Memory Aids:
- Islets are small islands within the larger pancreas.

Quick Tips:
- Remember the relative proportions of exocrine and endocrine tissue in the pancreas.

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Hormones are non-nutrient chemicals, which acts as…….. messengers and are produced in trace amount

View answer and explanation

Correct option: A

Intercellular

Option A (Intercellular) is correct because hormones act as intercellular messengers.

Solution approach

Correct Answer + Core Reason: Intercellular. Hormones transmit signals between cells.

Step-by-Step Solution:

Step 1: Define the role of hormones as messengers.

Step 2: Hormones travel through the bloodstream to target cells.

Step 3: This communication is between cells (intercellular).

Why other options are wrong:
- Option B: Intracellular messengers act within a cell, not between cells.
- Option C: Extracellular refers to the environment outside cells, but hormones act on target cells.
- Option D: Hormones are messengers.

Key Concepts:
- Hormones
- Intercellular communication
- Intracellular communication

Memory Aids:
- Hormones = between cells = intercellular

Quick Tips:
- Understand the difference between intercellular and intracellular communication.

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An adenohypophysis hormone, which is regulated by feedback mechanism is

View answer and explanation

Correct option: B

TSH

Option B (TSH) is correct because TSH (Thyroid Stimulating Hormone) is an adenohypophysis hormone regulated by a feedback mechanism involving thyroid hormones.

Solution approach

Correct Answer + Core Reason: TSH. TSH is regulated by the levels of thyroid hormones in the blood through a negative feedback loop.

Step-by-Step Solution:

Step 1: Identify the adenohypophysis hormones (hormones secreted by the anterior pituitary gland).

Step 2: Consider the feedback mechanisms that regulate each hormone.

Step 3: TSH secretion is stimulated by TRH (Thyrotropin-Releasing Hormone) from the hypothalamus and inhibited by thyroid hormones (T3 and T4) from the thyroid gland. This is a classic negative feedback loop.

Step 4: Oxytocin and Vasopressin are secreted by the neurohypophysis (posterior pituitary), not the adenohypophysis. Cortisone is a steroid hormone produced by the adrenal cortex, not the pituitary.

Why other options are wrong:
- Option A: Oxytocin is released from the posterior pituitary and is not regulated by a feedback mechanism in the same way as adenohypophysis hormones.
- Option C: Vasopressin is released from the posterior pituitary and is not regulated by a feedback mechanism in the same way as adenohypophysis hormones.
- Option D: Cortisone is a hormone produced by the adrenal cortex, not the adenohypophysis.

Key Concepts:
- Adenohypophysis hormones
- Feedback mechanisms in hormone regulation
- TSH and thyroid hormone regulation

Memory Aids:
- TSH: Thyroid Stimulating Hormone
- TRH: Thyrotropin-Releasing Hormone

Quick Tips:
- Remember the difference between the anterior and posterior pituitary hormones.
- Understand the concept of negative feedback in hormone regulation.

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Which of the following is gastrointestine hormone?

View answer and explanation

Correct option: B

Enterogastrone

Option B (Enterogastrone) is correct because enterogastrone is a hormone secreted by the duodenum that inhibits gastric secretion and motility.

Solution approach

Correct Answer + Core Reason: Enterogastrone. Enterogastrone is a gastrointestinal hormone that inhibits gastric secretion and motility.

Step-by-Step Solution:

Step 1: Gastrointestinal hormones are hormones secreted by endocrine cells in the gastrointestinal tract that regulate various digestive processes.

Step 2: Enterogastrone is a hormone secreted by the duodenum in response to the presence of fat in the chyme.

Step 3: Enterogastrone inhibits gastric secretion and motility, slowing down the emptying of the stomach to allow for proper digestion and absorption of fats in the small intestine.

Why other options are wrong:
- Option A: Prolactin is a hormone produced by the pituitary gland that stimulates milk production.
- Option C: GH (Growth Hormone) is produced by the pituitary gland and stimulates growth and metabolism.
- Option D: FSH (Follicle-Stimulating Hormone) is produced by the pituitary gland and stimulates follicle development in females and sperm production in males.

Key Concepts:
- Gastrointestinal hormones
- Enterogastrone
- Gastric secretion
- Gastric motility

Memory Aids:
- Entero-\"gastrone\" inhibits gastric function.

Quick Tips:
- Know the major gastrointestinal hormones and their functions.

52 Easy

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…A… is essential for the normal rate of hormone synthesis in the thyroid. Deficiency of iodine in our diet results in …B… and enlargement of the thyroid gland, commonly called …C…
Select the correct combination for A, B and C

View answer and explanation

Correct option: B

A-Iodine, B-hypothyroidism, C-goitre

Option B (A-Iodine, B-hypothyroidism, C-goitre) is correct because iodine is essential for thyroid hormone synthesis, its deficiency leads to hypothyroidism and goitre.

Solution approach

Correct Answer + Core Reason: A-Iodine, B-hypothyroidism, C-goitre. Iodine deficiency leads to hypothyroidism and goitre.

Step-by-Step Solution:

Step 1: Recall the role of iodine in thyroid hormone synthesis.

Step 2: Iodine is essential for the normal rate of hormone synthesis in the thyroid (A = Iodine).

Step 3: Deficiency of iodine results in decreased thyroid hormone production, leading to hypothyroidism (B = hypothyroidism).

Step 4: The enlargement of the thyroid gland due to iodine deficiency is called goitre (C = goitre).

Step 5: Therefore, the correct combination is A-Iodine, B-hypothyroidism, C-goitre.

Why other options are wrong:
- Option A: Ferrous is not directly involved in thyroid hormone synthesis, and hypothyroidism causes goitre, not the other way around.
- Option B: Iodine deficiency causes hypothyroidism and goitre.
- Option C: Ferric is not directly involved in thyroid hormone synthesis, and hypothyroidism causes goitre, not the other way around.
- Option D: Sodium is not directly involved in thyroid hormone synthesis, and hypothyroidism causes goitre, not the other way around.

Key Concepts:
- Endocrine System
- Thyroid Gland
- Iodine
- Hypothyroidism
- Goitre

Memory Aids:
- Iodine = Important for thyroid.

Quick Tips:
- Understand the relationship between iodine, thyroid hormones, and goitre.

53 Easy

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Immune response of old age person becomes weak due to the degeneration of ……. Gland

View answer and explanation

Correct option: C

Thymus

Option C (Thymus) is correct because the thymus gland degenerates with age, leading to a weakened immune response due to decreased T-lymphocyte production.

Solution approach

Correct Answer + Core Reason: Thymus. Degeneration of the thymus weakens the immune response in old age.

Step-by-Step Solution:

Step 1: Understand the role of the thymus gland in the immune system.

Step 2: The thymus gland is responsible for the maturation of T-lymphocytes, which are crucial for cell-mediated immunity.

Step 3: With age, the thymus gland undergoes involution (degeneration), leading to a decrease in the production of T-lymphocytes.

Step 4: This decline in T-lymphocyte production results in a weakened immune response in older individuals.

Why other options are wrong:
- Option A: Thyroid: The thyroid gland regulates metabolism, not directly the immune response in the context of aging.
- Option B: Parathyroid: The parathyroid gland regulates calcium levels, not directly the immune response in the context of aging.
- Option D: Hypothalamus: The hypothalamus regulates various bodily functions, but not directly the immune response in the context of aging.

Key Concepts:
- Thymus gland
- T-lymphocytes
- Immune response
- Aging

Memory Aids:
- Thymus = T-cells = Immunity

Quick Tips:
- Remember that the thymus gland's function declines with age.

54 Easy

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Goiter can occur as a consequence of all the following except

View answer and explanation

Correct option: D

Excessive intake of exogenous thyroxine

Option D (Excessive intake of exogenous thyroxine) is correct because excessive thyroxine intake would suppress TSH and prevent goiter formation, while the other options can cause goiter.

Solution approach

Correct Answer + Core Reason: Excessive intake of exogenous thyroxine. Excessive thyroxine intake suppresses TSH and prevents goiter.

Step-by-Step Solution:

Step 1: Recall the causes of goitre.

Step 2: Goitre is the enlargement of the thyroid gland.

Step 3: Iodine deficiency can cause goitre due to increased TSH stimulation.

Step 4: Pituitary adenoma can cause goitre due to excessive TSH secretion.

Step 5: Grave's disease can cause goitre due to thyroid-stimulating antibodies.

Step 6: Excessive intake of exogenous thyroxine would suppress TSH and prevent goiter formation.

Step 7: Therefore, goitre can occur as a consequence of all the following except excessive intake of exogenous thyroxine.

Why other options are wrong:
- Option A: Iodine deficiency leads to increased TSH and goitre.
- Option B: Pituitary adenoma can cause excessive TSH secretion, leading to goitre.
- Option C: Grave's disease involves thyroid-stimulating antibodies, leading to goitre.
- Option D: Excessive thyroxine intake suppresses TSH and prevents goitre.

Key Concepts:
- Endocrine System
- Thyroid Gland
- Goitre
- TSH
- Iodine Deficiency
- Grave's Disease

Memory Aids:
- Goitre = Growth (thyroid gland enlarges).

Quick Tips:
- Understand the factors that regulate thyroid hormone production.

55 Easy

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In human adults females, oxytocin

View answer and explanation

Correct option: D

Causes strong uterine contractions during parturition

Option D (Causes strong uterine contractions during parturition) is correct because oxytocin's primary role is to stimulate uterine contractions during childbirth.

Solution approach

Correct Answer + Core Reason: Causes strong uterine contractions during parturition. Oxytocin stimulates uterine contractions during childbirth.

Step-by-Step Solution:

Step 1: Identify the function of oxytocin.

Step 2: Oxytocin is a hormone released by the posterior pituitary gland.

Step 3: Oxytocin primarily functions to stimulate uterine contractions during labor and delivery (parturition) and to promote milk ejection during breastfeeding.

Step 4: Therefore, the correct answer is that it causes strong uterine contractions during parturition.

Why other options are wrong:
- Option A: Oxytocin is secreted by the posterior pituitary, not the anterior pituitary.
- Option B: Prolactin and other hormones stimulate the growth of mammary glands, not oxytocin.
- Option C: Oxytocin does not directly stimulate the pituitary to secrete vasopressin. Vasopressin secretion is regulated by other factors like blood osmolarity.

Key Concepts:
- Oxytocin function
- Posterior pituitary hormone
- Uterine contractions
- Parturition

Memory Aids:
- "Oxytocin" sounds like "oxy-to-sin", think of "to-sin" as "to sign" the birth certificate, reminding you of its role in childbirth.

Quick Tips:
- Remember that oxytocin is a posterior pituitary hormone and its primary functions are related to childbirth and lactation.

56 Easy

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Which of the following is not a second messenger?

View answer and explanation

Correct option: A

Adenylate cyclase

Option A (Adenylate cyclase) is correct because adenylate cyclase is an enzyme that produces a second messenger (cAMP), but is not itself a second messenger.

Solution approach

Correct Answer + Core Reason: Adenylate cyclase. Adenylate cyclase is an enzyme, not a second messenger.

Step-by-Step Solution:

Step 1: Define what a second messenger is.

Step 2: Recall that second messengers are small, intracellular molecules that relay signals from receptors to target molecules.

Step 3: Identify adenylate cyclase as an enzyme that produces cAMP.

Step 4: Recognize that cAMP, calcium ions, and c-GMP are all second messengers.

Step 5: Conclude that adenylate cyclase is not a second messenger.

Why other options are wrong:
- Option B: Cyclic adenosine monophosphate (cAMP) is a second messenger.
- Option C: Calcium ions are second messengers.
- Option D: c-GMP is a second messenger.

Key Concepts:
- Second messengers
- Adenylate cyclase
- Cyclic AMP
- Calcium ions
- c-GMP
- Signal transduction

Memory Aids:
- Adenylate cyclase: Enzyme that makes cAMP

Quick Tips:
- Remember the difference between enzymes and second messengers.

57 Easy

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Vitamin that has similar action as the parathormone is

View answer and explanation

Correct option: D

Vitamin-D

Option D (Vitamin-D) is correct because Vitamin D, like parathormone, plays a crucial role in calcium regulation in the body.

Solution approach

Correct Answer + Core Reason: Vitamin D has a similar action as parathormone because both regulate calcium levels.

Step-by-Step Solution:

Step 1: Parathormone (PTH) increases blood calcium levels by stimulating calcium release from bones, increasing calcium absorption in the intestines, and increasing calcium reabsorption in the kidneys.

Step 2: Vitamin D (specifically, its active form calcitriol) also increases blood calcium levels by promoting calcium absorption in the intestines.

Step 3: Both PTH and Vitamin D work together to maintain calcium homeostasis.

Why other options are wrong:
- Option A: Vitamin A is important for vision and immune function.
- Option B: Vitamin B is a group of vitamins involved in energy metabolism and nerve function.
- Option C: Vitamin C is an antioxidant and is important for collagen synthesis and immune function.

Key Concepts:
- Calcium regulation
- Parathormone (PTH)
- Vitamin D

Memory Aids:
- Vitamin D helps you absorb calcium from food, similar to PTH's role.

Quick Tips:
- Think of Vitamin D and PTH as partners in maintaining calcium balance.

58 Easy

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Which lobe of pituitary is connected to hypothalamus through hypophyseal portal system?

View answer and explanation

Correct option: B

Adenohypophysis

Option B is correct because the adenohypophysis (anterior pituitary) is connected to the hypothalamus through the hypophyseal portal system, which allows for direct communication and regulation.

Solution approach

Correct Answer + Core Reason: Adenohypophysis. The adenohypophysis is connected to the hypothalamus via the hypophyseal portal system.

Step-by-Step Solution:

Step 1: Recall the structure of the pituitary gland: anterior pituitary (adenohypophysis) and posterior pituitary (neurohypophysis).

Step 2: Understand the connection between the hypothalamus and the pituitary gland. The hypothalamus controls the pituitary gland.

Step 3: Identify the type of connection for each The adenohypophysis is connected via the hypophyseal portal system (blood vessels), while the neurohypophysis is connected via nerve fibers.

Why other options are wrong:
- Option A: Neurohypophysis is connected to the hypothalamus via nerve fibers, not the hypophyseal portal system.
- Option C: Pars nervosa is a part of the neurohypophysis and is connected via nerve fibers.
- Option D: Posterior lobe of pituitary is the neurohypophysis and is connected via nerve fibers.

Key Concepts:
- Pituitary gland structure (adenohypophysis and neurohypophysis)
- Hypothalamic-pituitary axis
- Hypophyseal portal system

Memory Aids:
- Adeno = Anterior = Blood (Hypophyseal Portal System)
- Neuro = Posterior = Nerves

Quick Tips:
- Remember that the anterior pituitary is regulated by releasing hormones from the hypothalamus via the portal system.

59 Easy

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Lipid soluble hormone works by interacting with

View answer and explanation

Correct option: A

Intracellular receptors

Option A (Intracellular receptors) is correct because lipid-soluble hormones can cross the cell membrane and bind to receptors inside the cell.

Solution approach

Correct Answer + Core Reason: Intracellular receptors. Lipid-soluble hormones can directly interact with intracellular receptors due to their ability to cross the cell membrane.

Step-by-Step Solution:

Step 1: Lipid-soluble hormones, such as steroid hormones, are hydrophobic and can diffuse through the plasma membrane of cells.

Step 2: Once inside the cell, these hormones bind to intracellular receptors, which are typically located in the cytoplasm or nucleus.

Step 3: The hormone-receptor complex then interacts with DNA to regulate gene expression.

Why other options are wrong:
- Option B: Intercellular receptors are not a recognized type of hormone receptor.
- Option C: While hormones can influence enzyme activity, lipid-soluble hormones primarily act through intracellular receptors, not by directly interacting with enzymes.
- Option D: Lipid-soluble hormones can influence the production of enzymes by affecting gene expression, but their primary mode of action is through intracellular receptors.

Key Concepts:
- Hormone-receptor interactions
- Lipid-soluble hormones
- Intracellular receptors
- Gene expression

Memory Aids:
- Think of lipid-soluble hormones as being able to "slip" inside the cell.

Quick Tips:
- Remember that lipid-soluble hormones typically bind to intracellular receptors, while water-soluble hormones bind to cell surface receptors.

60 Easy

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The cause of cretinism is

View answer and explanation

Correct option: A

Hypothyroidism

Option A (Hypothyroidism) is correct because cretinism is a condition caused by severe thyroid hormone deficiency during infancy or early childhood.

Solution approach

Correct Answer + Core Reason: Hypothyroidism is the cause of cretinism due to thyroid hormone deficiency.

Step-by-Step Solution:

Step 1: Cretinism is a condition characterized by stunted physical and mental growth due to congenital thyroid deficiency.

Step 2: Hypothyroidism refers to the underproduction of thyroid hormones (T3 and T4).

Step 3: The lack of thyroid hormones disrupts normal development, leading to cretinism.

Why other options are wrong:
- Option B: Hypoparathyroidism is a deficiency of parathyroid hormone, leading to low calcium levels, not cretinism.
- Option C: Hyperthyroidism is an overproduction of thyroid hormones, causing conditions like Graves' disease, not cretinism.
- Option D: Hyperparathyroidism is an overproduction of parathyroid hormone, leading to high calcium levels, not cretinism.

Key Concepts:
- Thyroid hormone function
- Endocrine disorders
- Cretinism

Memory Aids:
- Hypo- means under, Hyper- means over

Quick Tips:
- Remember that thyroid hormones are crucial for development, especially in early life.

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