Tag: zoology

Questions Related to zoology

Anti-ageing hormone is 

zoology endocrine system and chemical co-ordination pineal gland pituitary gland and pineal gland pineal gland and thymus

  1. Thyroxine

  2. Melatonin

  3. Estrogen

  4. Testosterone

Show answer
Correct Option: B
Explanation:
A. Thyroxine is secreted from thyroid gland. It stimulates the consumption of oxygen by metabolically active tissues and also increases the oxidation of glucose in tissues. 
B. Melatonin is derived from amino acid tryptophan and secreted from pineal gland. It regulates the 24 hour rhythm of our body like sleep-wake cycle, temperature etc. and also affects metabolism and pigmentation.
C. Estrogen is the female sex hormone secreted from ovarian follicles and stimulate the development of female secondary sex organs.
D. Testosterone is the male sex hormone secreted from testis and stimulates the development of secondary sexual characteristics in males.
Recent studies have revealed melatonin to be an anti-ageing hormone.
So, the correct answer is 'Melatonin'.

Melanin pigment of human skin is produced by

zoology endocrine system and chemical co-ordination pineal gland pituitary gland and pineal gland pineal gland and thymus

  1. Mast cells of corium

  2. Melanocytes of corium and incorporated there

  3. Melanocytes of corium and incorporated in epidermis

  4. Melanocytes of epidermis

Show answer
Correct Option: C
Explanation:
  • Melanin is a pigment produced within the skin in melanocytes or skin cells when they are exposed to the sun. 
  • The process by which the pigment melanin is formed by the melanocytes is called melanogenesis.
  • The pigment is formed within a small membrane-bound structure called melanosomes.
  • The skin colour is determined by a bluish-white connective tissue under the dermis or corium and the haemoglobin circulating in the veins of the corium.
  • The corium is a layer of skin present between the epidermis and the subcutaneous tissues of the skin.
  • Two types of melanin are formed in the body pheomelanin (red to yellow in colour) and eumelanin (dark brown to black).
  • Those people with light complexion produce pheomelanin whereas, those with dark complexion produce eumelanin.
  • So, the correct answer is 'Melanocytes of corium and incorporated in epidermis'.

Hormone produced more in dark is 

zoology endocrine system and chemical co-ordination pineal gland pituitary gland and pineal gland pineal gland and thymus

  1. Thyroxine

  2. Melatonin

  3. Adrenaline

  4. Insulin

Show answer
Correct Option: B
Explanation:
A. Thyroxine is secreted from thyroid gland. It stimulates the consumption of oxygen by metabolically active tissues and also increases the oxidation of glucose in tissues. 
B. Melatonin is derived from amino acid tryptophan and secreted from pineal gland. It regulates the 24 hour rhythm of our body like sleep-wake cycle, temperature etc. and also affects metabolism and pigmentation.
C. Adrenaline, also known as emergency hormone, is secreted from the adrenal medulla. This hormone is associated with maintenance of homeostasis in body and is secreted in response to any kind of stress or emergency in the body.
D. Insulin is secreted from the β cells of islets of Langerhans of pancreas. Insulin acts on hepatocytes and adipocytes and increases the uptake of cellular glucose and its utilisation. 
Hence, hormone produced more in dark is melatonin because it is responsible for pigmentation.
So, the correct answer is 'Melatonin'. 

Which is not a function of thyroid hormone?

zoology endocrine system and chemical co-ordination pineal gland pituitary gland and pineal gland pineal gland and thymus

  1. Regulation of basal metabolic rate

  2. Controls metabolism of carbohydrates, proteins and fats

  3. Maintains water and electrolyte balance

  4. Regulates the diurnal rhythm

Show answer
Correct Option: D
Explanation:
Thyroid hormones are secreted from thyroid gland and regulate many functions of body like:
  • regulation of BMR (Basal metabolic rate) by thyroxine which increases consumption of glucose by metabolically active tissues.
  • regulation of proteins, carbohydrates and fats metabolism.
  • regulation of water and electrolyte balance by calcitonin which inhibits reabsorption of calcium by renal tubules.
Diurnal rhythm of body is regulated by melatonin hormone secreted from pineal gland.
So, the correct answer is 'Regulates the diurnal rhythm'.

Human endocrine gland regulating body rhythms is 

zoology endocrine system and chemical co-ordination pineal gland pituitary gland and pineal gland pineal gland and thymus

  1. Adrenal

  2. Pineal

  3. Thymus

  4. Thyroid

Show answer
Correct Option: B
Explanation:
A. The adrenal gland is composed of two tissues - adrenal medulla (internal) and adrenal cortex (external). The adrenal medulla secretes two hormones called adrenaline or epinephrine and noradrenaline or norepinephrine. These hormones increase alertness, pupillary dilation, piloerection, sweating, heartbeat, the strength of heart contraction and rate of respiration. The adrenal cortex secretes corticoids.
B. The pineal gland secretes a hormone called melatonin. This plays a very important role in the regulation of a 24 hour (diurnal) rhythm of the body. 
C. Thymus gland secretes the peptide hormones called thymosins. It plays a major role in the differentiation of T-lymphocytes, which provide cell-mediated immunity. 
D. The thyroid gland secretes tetraiodothyronine and triiodothyronine. These controls basic metabolic rate, physical growth and metabolism of proteins, fat and carbohydrate.
So, the correct answer is 'pineal'.

Pineal gland is located

zoology endocrine system and chemical co-ordination pineal gland pituitary gland and pineal gland pineal gland and thymus

  1. On kidney

  2. In brain

  3. In pancreas

  4. Near thyroid

Show answer
Correct Option: B
Explanation:
Pineal gland, known as epiphysis, is located on dorsal side of forebrain. It is a small, rounded, stalked and reddish brown gland that resembles a pine cone. It secretes melatonin and serotonin hormone. Melatonin regulates circadian rhythm of body, pigmentation, metabolism and defence capability. Serotonin acts as a neurotransmitter and regulates functions of many organs of body like memory, sleeping, learning etc.
So, the correct answer is 'In brain'.

Which of these is not a placental hormone?

zoology endocrine system and chemical co-ordination pineal gland pituitary gland and pineal gland pineal gland and thymus

  1. Progesterone

  2. HCG

  3. Estrogen

  4. Melatonin

Show answer
Correct Option: D
Explanation:
Melatonin is secreted from pineal gland. This hormone regulates circadian rhythm of body like sleep-wake cycle, temperature of body etc. It also maintains pigmentation, metabolism and defence capability.
Progesterone, estrogen and HCG (Human chorionic gonadotropin) are secreted from placenta during pregnancy. In addition to placenta, progesterone is also secreted from corpus luteum and estrogen is also secreted from ovarian follicles.
So, the correct answer is 'Melatonin'.

Hormone regulating diurnal rhythm/sleep wake cycle is 

zoology endocrine system and chemical co-ordination pineal gland pituitary gland and pineal gland pineal gland and thymus

  1. Thymosin

  2. Glucagon

  3. Melatonin

  4. Oxytocin

Show answer
Correct Option: C
Explanation:
Melatonin is secreted from pineal gland which is located on dorsal side of forebrain. Its secretion is stimulated by MSH (Melanocyte stimulating hormone) secreted from intermediate lobe of pituitary gland. Melatonin regulates circadian rhythm of the body like sleep-wake cycle because melatonin levels rise at night and fall in the morning. High levels of melatonin induce sleep. It also regulates pigmentation, metabolism and defence capability.
So, the correct answer is 'Melatonin'.

Match the columns 


I II III
1. Melatonin a. Thyroid i. Acts on renal tubules
2. MSH b. Adrenal ii. Rregulates blood calcium level
3. Aldosterone c. Pituitary iii. Maintains diurnal rhythm of our body
4. TCT d. Pineal iv. Acts on melanocytes

zoology endocrine system and chemical co-ordination pineal gland pituitary gland and pineal gland pineal gland and thymus

  1. 4-a-iv, 3-d-iii, 1-b-ii, 2-c-i

  2. 1-d-iii, 2-c-iv, 3-b-i, 4-a-ii

  3. 1-b-i, 4-a-iii, 3-c-ii, 2-d-iv

  4. 2-c-ii, 1-b-i, 4-c-iv, 3-c-iii

  5. 2-c-iv, 3-a-ii, 1-d-iii, 4-b-i

Show answer
Correct Option: B
Explanation:
1. Melatonin is secreted from pineal gland and regulates diurnal rhythm of body.
2. MSH (Melanocyte stimulating hormone) is secreted from intermediate lobe of pituitary gland and acts on melanocytes to secrete melanin which regulates pigmentation.
3. Aldosterone is secreted from adrenal gland and acts on renal tubules to stimulate water absorption.
4. TCT (Thyrocalcitonin) is secreted from thyroid gland and regulates blood calcium level.
So, the correct answer is '1-d-iii, 2-c-iv, 3-b-i, 4-a-ii'.

Name the gland which is located under corpus callosum.

zoology endocrine system and chemical co-ordination pineal gland pituitary gland and pineal gland pineal gland and thymus

  1. Adrenal gland

  2. Thyroid gland

  3. Pineal gland

  4. Thymus gland

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 (Cortisol), mineralocorticoids (Aldosterone) and sexocorticoids (Androgen) and, adrenal medulla which secrete adrenaline and nor-adrenaline hormone.
B. Thyroid gland is situated between the trachea and larynx in the neck and secretes thyroxine hormone which increases oxygen consumption by metabolically active tissues.
C. Pineal gland is a small, rounded and reddish brown gland present at the dorsal side of forebrain. It is located under corpus callosum (bridge between right and left sides of brain). This gland secretes melatonin and serotonin hormones.
D. 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.
So, the correct answer is 'Pineal gland'.