Biology · General Awareness

Human Endocrine System

1,395 Questions

The human endocrine system comprises glands that secrete hormones to regulate bodily functions like metabolism, growth, and reproduction. Competitive exams frequently test the specific roles of hormones such as adrenaline, insulin, and progesterone. Use these questions to master the locations and functions of different hormones.

Hormone functionsIslets of LangerhansFight or flight responseBlood pressure regulationFemale sex hormonesWater soluble hormones

Human Endocrine System Questions

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

Mammalian biorhythms may be due to differential secretion of

  1. FSH

  2. MSH

  3. Melatonin

  4. Sex corticoids
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • The pineal gland or pineal body (epiphysis or third eye) is a small endocrine gland.
  • It secretes melatonin (hormone) which regulates the wake/sleep patterns and photoperiodic functions.
  • Biorhythms or biological rhythms control sleep and wake cycles and other functions such as behaviour and endocrine rhythms. These functions are regulated by the circadian clock.
  • The secretion of melatonin is triggered in dark and inhibited by light.
  • So, the correct answer is 'Melatonin'.
Multiple choice zoology endocrine system and chemical co-ordination pineal gland pituitary gland and pineal gland pineal gland and thymus

Hormone melatonin is secreted by

  1. Adrenal

  2. Thymus

  3. Pituitary

  4. Pineal
Reveal answer Fill a bubble to check yourself
D Correct answer
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. 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. 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.
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.
So, the correct answer is 'Pineal'.
Multiple choice zoology endocrine system and chemical co-ordination pineal gland pituitary gland and pineal gland pineal gland and thymus

Anti-ageing hormone is 

  1. Thyroxine

  2. Melatonin

  3. Estrogen

  4. Testosterone
Reveal answer Fill a bubble to check yourself
B Correct answer
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'.
Multiple choice zoology endocrine system and chemical co-ordination pineal gland pituitary gland and pineal gland pineal gland and thymus

Hormone produced more in dark is 

  1. Thyroxine

  2. Melatonin

  3. Adrenaline

  4. Insulin
Reveal answer Fill a bubble to check yourself
B Correct answer
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'. 
Multiple choice zoology endocrine system and chemical co-ordination pineal gland pituitary gland and pineal gland pineal gland and thymus

Which of these is not a placental hormone?

  1. Progesterone

  2. HCG

  3. Estrogen

  4. Melatonin
Reveal answer Fill a bubble to check yourself
D Correct answer
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'.
Multiple choice zoology endocrine system and chemical co-ordination pineal gland pituitary gland and pineal gland pineal gland and thymus

Hormone regulating diurnal rhythm/sleep wake cycle is 

  1. Thymosin

  2. Glucagon

  3. Melatonin

  4. Oxytocin
Reveal answer Fill a bubble to check yourself
C Correct answer
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'.
Multiple choice zoology endocrine system and chemical co-ordination pineal gland pituitary gland and pineal gland pineal gland and thymus

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

  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
Reveal answer Fill a bubble to check yourself
B Correct answer
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'.
Multiple choice zoology endocrine system and chemical co-ordination pineal gland pituitary gland and pineal gland pineal gland and thymus

With increasing age, secretion of which of the following is reduced to half?

  1. HGH

  2. Estrogen

  3. GTH

  4. Melatonin
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Melatonin is secreted from pineal gland which is located at the dorsal side of forebrain. Melatonin hormone is derived from amino acid tyrosine. It regulates circadian rhythm of body like sleep-wake cycle, temperature of body etc. It also regulates pigmentation, metabolism and defence capability. With increasing age, secretion of melatonin is decreased and reduces to about half.
So, the correct answer is 'Melatonin'.
Multiple choice zoology endocrine system and chemical co-ordination pineal gland pituitary gland and pineal gland pineal gland and thymus

Serotonin and melatonin are hormones secreted by 

  1. Pancreas

  2. Pineal body

  3. Pituitarygland

  4. Thymus
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
A. Pancreas has two types of cells in the islet of Langerhans called alpha cells and beta cells which produce glucagon and insulin respectively.
B. Pineal body secreted melatonin and serotonin.
C. Pituitary gland has two parts adenohypophysis and neurohypophysis. Adenohypophysis secretes growth hormone (GH), thyroid stimulating hormone (TSH), adrenocorticotrophic hormone (ACTH), melanocyte stimulating hormone (MSH), prolactin (PRL), follicle stimulating hormone(FSH)  and luteinizing hormone (LH). Neurohypophysis secretes vasopressin and oxytocin. 
D. Thymus secretes peptide hormones thymosins.
So, the correct answer is 'Pineal body'.
Multiple choice zoology endocrine system and chemical co-ordination pineal gland pituitary gland and pineal gland pineal gland and thymus

Melatonin is produced from 

  1. Pineal gland

  2. Adrenal gland

  3. Parathyroid gland

  4. Ovary
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
A. Pineal gland produces melatonin which regulate 24 hour (diurnal) rhythm of the body.
B. Adrenal gland produces adrenaline and noradrenaline by adrenal medulla and corticoids by adrenal cortex.
C. Parathyroid gland produces parathyroid hormone (PTH).
D. Ovary produces estrogen and progesterone.
So, the correct answer is 'Pineal gland'.
Multiple choice zoology endocrine system and chemical co-ordination pineal gland pituitary gland and pineal gland pineal gland and thymus

The pineal gland secretes a hormone progesterone which helps to regulate sleep pattern. Thyroid glands release hormone which regulate the level of calcium in the blood with the help of calcitonin which is produced in the parathyroid glands. Select the correct option regarding the given paragraph.
i) Positions of pineal and parathyroid should be interchanged
ii) Progesterone must be replaced by melatonin
iii) Parathyroid should not be replaced as it is correctly mentioned.
iv) Positions of progesterone and calcitonin should be interchanged
v) Positions of thyroid and parathyroid should be interchanged 

  1. ii and v only

  2. i, ii and v only

  3. i and iii only

  4. ii and iv only
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The correct statement is- 'The pineal gland secretes a hormone melatonin which helps to regulate sleep pattern. Parathyroid Gland release hormone which regulates the level of calcium in the blood with the help of calcitonin which is produced in the thyroid gland.'

So the correct option is 'ii and v only'.

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

A hormone responsible for normal sleep-wake cycle is?

  1. Epinephrine

  2. Gastrin

  3. Melatonin

  4. Insulin
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Melatonin is a hormone secreted by pineal gland. Immediately above the optic chiasma(in the brain) in a nucleus, are present melatonin receptors that react to this hormone and synchronise the nucleus to the $24$hrs day/night rhythm, thus informing the brain when it is day and when it is night.

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

Identify the hormone with its correct matching of source and function.

  1. Oxytocin - posterior pituitary, growth and maintenance of mammary glands

  2. Melatonin- Pineal gland, regulates the normal rhythm of sleepwake cycle

  3. Progesterone- Corpus luteum, stimulation of growth and activities of female secondary sex organs

  4. Atrial natriuretic factor - ventricular wall, increases the blood pressure
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Melatonin, is a hormone that is produced by the pineal gland and regulates sleep and wakefulness. Blood levels of the pineal hormone melatonin are high at night and low during the day. There, a special center called the suprachiasmatic nucleus (SCN) initiates signals to other parts of the brain that control hormones, body temperature and other functions that play a role in making us feel sleepy or wide awake. During the day the pineal is inactive. When the sun goes down and darkness occurs, the pineal is "turned on" by the SCN and begins to actively produce melatonin, which is released into the blood. As a result, melatonin levels in the blood rise sharply and you begin to feel less alert. Sleep becomes more inviting. 

So, the correct answer is option B.

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

Which of these hormones may have a primary role in many circadian rhythms?

  1. Insulin

  2. Estradiol

  3. Melatonin

  4. Epinephrine
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The circadian rhythm or 24 hours diurnal rhythm of our body is maintained by Melatonin hormone secreted from the Pineal gland which is located on the dorsal side of forebrain. In addition, the melatonin hormone even assist in metabolism, pigmentation and even maintaining our defence capabilities.

So, the correct answer is 'Melatonin'.