Biology · General Awareness

Human Endocrine System

1,530 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

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'.

Multiple choice zoology excretory system of human structure of nephron excretory system nephron

Cells of macula densa produce

  1. Erythropoietin

  2. Renin

  3. Angiotensinogen

  4. Angiotensin
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Macula densa are specialized cells present in the distal convoluted tubule of nephron where distal convoluted tubule come in contact with the afferent renal arteriole of the glomerulus. When blood volume has decreased the cells of macula densa give signals to juxtaglomerular cells to secrete renin enzyme. Hence cells of macula densa produce renin in response to low blood volume by stimulating juxtaglomerular cells.

So, the correct answer is 'Renin'.

Multiple choice biology life processes: control and coordination structure and function of brain human brain nervous and endocrine system in humans

Endorphin release is stimulated by

  1. Sleep

  2. Endogenous rhythm

  3. Exercise

  4. Carotene-rich food
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Endomorphins are the chemical substance which is present in the neurons. It helps in the perception of pain, reactions to stress, and cardiovascular, respiratory and digestive functions. They are produced within the body so they are known as endogenous. They specifically work by binding to opoid receptors which are mainly found in nervous system and regulates the motor neurons which helps to coordinate the physical activity.
So, the correct answer is option C.
Multiple choice biology life processes: control and coordination structure and function of brain human brain nervous and endocrine system in humans

Endorphin is produced by

  1. Pituitary

  2. Hypothalamus

  3. Medulla oblongata

  4. Both A and B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Endomorphins are the chemical substance which is present in the neurons. It helps in the perception of pain, reactions to stress, and cardiovascular, respiratory and digestive functions. They are produced within the body so they are known as endogenous. They specifically work by binding to opoid receptors which are mainly found in nervous system and regulates the motor neurons which helps to coordinate the physical activity. The hypothalamus activates the pituitary to release ACTH which also stimulates the release of endomophins.
So, the correct answer is option D.
Multiple choice biology reproduction in living organisms regeneration asexual modes of reproduction reproduction in animals

Factors controlling regeneration seem to be

  1. Neural

  2. Hormonal

  3. Both neural and hormonal

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

Formation of new cells or tissues from injured parts of the body is called Regeneration. It is controlled by epithelial cover, neural trophic factor, and hormones like adrenal and pituitary glands.

So, the correct option is ‘Both neural and hormonal’.

Multiple choice biology control and coordination in living organisms parathyroid gland thyroid and parathyroid gland thyroid, parathyroid and thymus gland

Parathormone influences calcium absorption in the small intestine by regulating the metabolism of

  1. Vitamin C

  2. Vitamin D
  3. Vitamin $B _{6}$

  4. Enterogasterone
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Vitamin D increases blood concentrations of calcium. It is generated through the activity of parathyroid hormone within the kidney. The most important effect of vitamin D is to facilitate absorption of calcium from the small intestine. Along with thyroid hormone, vitamin D also enhances fluxes of calcium out of bone.

Multiple choice biology control and coordination in living organisms parathyroid gland thyroid and parathyroid gland thyroid, parathyroid and thymus gland

Parathormone regulates

  1. Blood calcium level

  2. Blood calcium and phosphate level

  3. Body temperature

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Parathyroid hormone (PTH), parathormone or parathyrin, is secreted by the chief cells of the parathyroid glands. It acts to increase the concentration of calcium ($Ca^{2+}$) in the blood. Parathormone also inhibits the reabsorption of phosphate by the kidney tubules, thereby decreasing serum phosphate concentrations. This potentiates the ability of parathormone to increase serum calcium concentrations because fewer insoluble calcium-phosphate complexes are formed when serum phosphate concentrations are low.

Multiple choice biology control and coordination in living organisms parathyroid gland thyroid and parathyroid gland thyroid, parathyroid and thymus gland

The hormones responsible for regulation of calcium and phosphorous metabolism is secreted by

  1. Pancreas

  2. Thyroid

  3. Thymus

  4. Parathyroid
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Parathormone of parathyroid gland reduces the blood phosphate level while increases the blood calcium level. Antagonistic functions of insulin and glucagon hormones of pancreas maintain the homeostasis of blood glucose level. Thyroid hormones regulate the metabolic rate of the body. Thymus hormone serves in the differentiation of lymphocytes present inside the lobules. Thus, the correct answer is D.

Multiple choice biology control and coordination in living organisms parathyroid gland thyroid and parathyroid gland thyroid, parathyroid and thymus gland

Parathyroid hormone

  1. Is produced by the thyroid gland

  2. Is released when blood calcium levels fall

  3. Stimulates osteoblasts to lay down new bone

  4. Stimulates calcitonin release
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Parathyroid hormone is secreted by the parathyroid glands and is the most important regulator of calcium levels in the blood and within the bones. Parathyroid hormone is mainly controlled by the negative feedback of calcium levels in the blood to the parathyroid glands. Low calcium levels in the blood stimulate parathyroid hormone secretion, whereas high calcium levels in the blood prevent the release of parathyroid hormone.

Multiple choice biology control and coordination in living organisms parathyroid gland thyroid and parathyroid gland thyroid, parathyroid and thymus gland

Parathormone is secreted during 

  1. Increased blood calcium level

  2. Decreased blood calcium level

  3. Increased blood sugar level

  4. Decreased blood sugar level
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Parathyroid hormone is mainly controlled by the negative feedback of calcium levels in the blood to the parathyroid glands. Low calcium levels in the blood stimulate the parathyroid hormone secretion, whereas high calcium levels in the blood prevent the release of parathyroid hormone.