Tag: zoology

Questions Related to zoology

Which endocrine gland becomes inactive after puberty?

zoology plants and animal hormones thymus thymus gland pineal gland and thymus

  1. Adrenal

  2. Pineal

  3. Thymus

  4. Pituitary

Show answer
Correct Option: C
Explanation:
A. Adrenal gland is present on upper side of kidneys and has two parts, adrenal cortex which secrete glucocorticoids, mineralocorticoids and sexocorticoids and adrenal medulla which secrete adrenaline and nor-adrenaline hormone.
B. Pineal gland is a small, rounded and reddish brown gland present at the dorsal side of forebrain. This gland secretes melatonin and serotonin hormones.
C. Thymus gland is associated with the development of immune system and present on the dorsal side of heart. It secretes thymosin hormone which plays an important role in the differentiation of T-lymphocytes. This gland shows maximum development in children during puberty and after that, it starts diminishing gradually and by the age of 70, it becomes a tiny structure.
D. Pituitary gland is the master gland that regulates the activity of other endocrine glands and secretes many hormones like growth hormone, follicle stimulating hormone, thyroid stimulating hormone etc.
Hence, thymus becomes inactive after puberty.
So, the correct answer is 'Thymus'.

Hassall's corpuscles are found in

zoology plants and animal hormones thymus thymus gland pineal gland and thymus

  1. Thyroid

  2. Thymus

  3. Adrenal

  4. Pineal

Show answer
Correct Option: B
Explanation:
A. Thyroid gland is situated between the trachea and larynx in the neck and secretes thyroxine hormone which increases oxygen consumption by metabolically active tissues.
B. Thymus gland is associated with the development of immune system and present on the dorsal side of heart. It secretes thymosin hormone which plays an important role in the differentiation of T-lymphocytes.
C. Adrenal gland is present on upper side of kidneys and has two parts, adrenal cortex which secrete glucocorticoids, mineralocorticoids and sexocorticoids and adrenal medulla which secrete adrenaline and nor-adrenaline hormone. Adrenaline is secreted in response to stress in the body and is known as emergency hormone. Thus, adrenal gland is an emergency gland.
D. Pineal gland is a small, rounded and reddish brown gland present at the dorsal side of forebrain. This gland secretes melatonin and serotonin hormones.
Hassall's corpuscles are known as thymic bodies. They are present in the medulla of thymus.
So, the correct answer is 'Thymus'.

An endocrine gland that atrophies at the age of 14 - 16 years is

zoology plants and animal hormones thymus thymus gland pineal gland and thymus

  1. Thyroid

  2. Thymus

  3. Pancreas

  4. Spleen

Show answer
Correct Option: B
Explanation:
A. Thyroid gland is situated between the trachea and larynx in the neck and secretes thyroxine hormone which increases oxygen consumption by metabolically active tissues.
B. Thymus gland secretes thymosin hormone which plays an important role in the differentiation of T-lymphocytes. This gland shows maximum development in children at the time of puberty (10-14 years) and after that it starts decreasing in size.
C. Pancreas is a heterocrine gland as it acts both as endocrine and exocrine gland. It secretes insulin hormone into blood and act as endocrine gland and when it secretes digestive enzymes and juice through pancreatic duct, it acts as exocrine gland.
D. Spleen is a organ of immune system which produces blood cells.
So, the correct answer is 'Thymus'.

Which of these is correctly matched with the accompanying description?

zoology plants and animal hormones thymus thymus gland pineal gland and thymus

  1. Pancreas - Delta cells of islets of Langerhans secrete a hormone which stimulates glycolysis in liver

  2. Thyroid - Hyperactivity in young children causes cretinism

  3. Thymus - Starts undergoing atrophy after puberty

  4. Parathyroid - Secretes parathormone that promotes movement of $Ca^{2+}$ ions from blood into bones during calcification

Show answer
Correct Option: C
Explanation:
A. The delta cells of islets of Langerhans of pancreas secrete somatostatin hormone which inhibits secretion of glucagon and insulin.
B. Cretinism is the retarded mental and physical development in children due to hyposecretion of thyroid hormones.
C. Thymus gland shows maximum development in children during puberty and after that it starts degenerating.
D. Parathormone is secreted from the parathyroid hormone and increases blood calcium level by increasing the reabsorption of calcium from the bones.
So, the correct answer is 'Thymus - Starts undergoing atrophy after puberty'.

Which of these has a role in immunity?

zoology plants and animal hormones thymus thymus gland pineal gland and thymus

  1. Pineal gland

  2. Thymus

  3. Adrenal gland

  4. Parathyroid gland

Show answer
Correct Option: B
Explanation:
Thymus gland is associated with the development of immune system and present on the dorsal side of heart. It contains lymphoid tissue that plays an important role in proliferation and maturation of T-lymphocytes. It secretes thymosin hormone which plays an important role in the differentiation of T-lymphocytes which are associated with cell mediated immunity. Thymosin also promotes formation of antibodies for humoral immunity. 
So, the correct answer is 'Thymus'.

Thymosin hormone is secreted by 

zoology plants and animal hormones thymus thymus gland pineal gland and thymus

  1. Thyreid

  2. Thymus

  3. Parathyroid

  4. Hypothalamus

Show answer
Correct Option: B
Explanation:
A. Thyroid gland is situated between the trachea and larynx in the neck and secretes thyroxine hormone which increases oxygen consumption by metabolically active tissues.
B. Thymus gland is associated with the development of immune system and present on the dorsal side of heart. It secretes thymosin hormone which plays an important role in the differentiation of T-lymphocytes.
C. Parathyroid gland is present in the form of four small pouches which are embedded in the posterior surface of lobes of thyroid gland. This gland secretes parathormone which increases calcium reabsorption from the bones and causes mobilisation of calcium in the blood.
D. Hypothalamus is present in the forebrain. This gland secretes hormones that regulate the synthesis and secretion of hormones of pituitary gland. 
So, the correct answer is 'Thymus'.

Thymus gland has a role in 

zoology plants and animal hormones thymus thymus gland pineal gland and thymus

  1. $Na^+$ $K^+$ balance

  2. Immune system

  3. Maintaining glucose level

  4. Maintaining $Ca^{2+}$ level

Show answer
Correct Option: B
Explanation:
Thymus gland is a lobular gland present on dorsal side of heart. It is associated with the development of immune system. It contains lymphoid tissue that plays an important role in proliferation and maturation of T-lymphocytes. It secretes thymosin hormone which plays an important role in the differentiation of T-lymphocytes which are associated with cell mediated immunity. Thymosin also promotes formation of antibodies for humoral immunity. It also controls resistance to infection and formation of lymphocytes. Thymus gland degenerates with age resulting in decreased production of thymosin. That's why older people have weak immunity. 
So, the correct answer is 'Immune system'.

Which of these is the correct combination for gland, hormone and its function?

zoology plants and animal hormones thymus thymus gland pineal gland and thymus

  1. Anterior pituitary - oxytocin - contraction of uterine muscles

  2. Anterior pituitary - vasopressin - induces reabsorption of water in nephron

  3. Thymus - thymosin - proliferation of T-lymphocytes

  4. $\alpha$-cells - glucagon - uptake of glucose by cells

Show answer
Correct Option: C
Explanation:
A. Oxytocin is secreted from the posterior pituitary and helps in the contraction of uterus during childbirth and also stimulates release of milk from mammary glands i.e. lactation.
B. Vasopressin or Anti diuretic hormone (ADH), is secreted from the posterior part of pituitary gland. This hormone increases reabsorption of water in kidneys and this results in decreased rate of urine production.
C. Thymus gland is associated with the development of immune system and present on the dorsal side of heart. It secretes thymosin hormone which plays an important role in the differentiation of T-lymphocytes.
D. Glucagon is secreted from αα-cells of islets of Langerhans of pancreas. It increases blood sugar level by stimulating glycogenolysis (i.e. break down of glucose) and gluconeogenesis (synthesis of glucose).
Hence, option C is the correct combination for gland, hormone and its function.
So, the correct answer is 'Thymus - thymosin - proliferation of T-lymphocytes'.

Which is not the function of endocrine gland, located in upper dorsal side of heart and aorta?

zoology plants and animal hormones thymus thymus gland pineal gland and thymus

  1. Plays important role in development of immune system

  2. Induces differentiation of T-lymphocytes

  3. Induces formation of RBCs

  4. Induces development of T-lymphocytes

Show answer
Correct Option: C
Explanation:
Thymus gland is a lobular structure present on dorsal side of heart and aorta. It is associated with the development of immune system. This gland consists of lymphoid tissue which plays an important role in the maturation and proliferation of T-lymphocytes. It secretes thymosin hormone which stimulates differentiation of T-lymphocytes associated with cell-mediated immunity. Thymosin also promotes formation of antibodies for humoral immunity.
RBCs formation is induced by erythropoietin secreted from juxtaglomerular cells of kidney. 
So, the correct answer is 'Induces formation of RBCs'. 

Which of the following helps in differentiation of cells of immune system?

zoology plants and animal hormones thymus thymus gland pineal gland and thymus

  1. Cortisol

  2. Thyroxine

  3. Thymosin

  4. Steroid

Show answer
Correct Option: C
Explanation:
A. Cortisol is secreted by adrenal cortex of adrenal gland. It produces anti-inflammatory reactions and suppresses the immune response.
B. Thyroxine is secreted by thyroid hormone. It controls basal metabolic rate and physical growth.
C. Thymosin is secreted by thymus gland. It plays a major role in the differentiation of T -lymphocytes which provide cell-mediated immunity.
D. Steroids are secreted by adrenal cortex of adrenal medulla. Example aldosterone, cortisol, androgens.
So, the correct answer is 'Thymosin'.