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

Melatonin ______.

  1. triggers estrous in healthy rats

  2. inhibits estrous in healthy rats

  3. cannot prevent estrous in light induced estrous rats

  4. has no effect on estrous cycle
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Melatonin inhibits estrous (reproductive cycle) in healthy rats, particularly in response to longer dark periods (winter conditions). Melatonin is secreted by the pineal gland in response to darkness and regulates seasonal reproductive cycles in many mammals. It can suppress estrous in light-induced constant estrous rats by maintaining natural photoperiodic signaling.

Multiple choice

Androgen is a hormone secreted by ______.

  1. adrenal cortex

  2. ovary

  3. testis

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

Androgens (such as testosterone) are primarily secreted by the testes in males. While the adrenal cortex does produce small amounts of androgens, the testes are the main source. The ovaries produce small amounts of androgens as precursors to estrogen, and the parathyroid secretes parathyroid hormone, not androgens. Therefore, the testis is the correct answer as the primary androgen-secreting gland.

Multiple choice

Clomiphene and tamoxifen are

  1. gonadotrophins

  2. growth hormones

  3. dopamine receptor stimulants

  4. antioestrogens

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Clomiphene and Tamoxifen are selective estrogen receptor modulators (SERMs) that act as antiestrogens. They block estrogen receptors in certain tissues - Clomiphene is used for ovulation induction, while Tamoxifen treats estrogen receptor-positive breast cancer.

Multiple choice

The ______________ works closely with the nervous system in regulating certain activities of the body by secreting hormones directly into the bloodstream.

  1. endocrine system

  2. immune system

  3. digestive system

  4. respiratory system

  5. cardiovascular system
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Yes, it is correct. The endocrine system works closely with the nervous system in regulating certain activities of the body by secreting hormones directly into the bloodstream.

Multiple choice

Which of the following is not a characteristic of hormones?

  1. They are specific chemical messengers.

  2. The endocrine glands secrete them regularly in bulk.

  3. They are poured directly into the blood.

  4. They act on specific tissue/organ.

  5. They get destroyed immediately after their action is over.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The endocrine glands secrete them in small amounts.

Multiple choice

__________________ regulates carbohydrate, protein and fat metabolism in the body so as to provide the best balance for growth.

  1. Pituitary hormone

  2. Thyroxine hormone

  3. Pancreatic hormone

  4. Adrenalin

  5. Parathyroid hormone
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Thyroxine hormone regulates carbohydrate, protein and fat metabolism in the body so as to provide the best balance for growth. It has influence over physical and mental development of an individual.

Multiple choice

Which of the following statements is incorrect?

  1. Insulin is secreted by the by β-cells islets of Langerhans.

  2. Human insulin is a polypeptide of 51 amino acids arranged in a single chain.

  3. Banting and Best isolated insulin from dog’s pancreas.

  4. Insulin regulates carbohydrate metabolism.

  5. Humulin is synthetic human insulin.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Human insulin is a polypeptide of 51 amino acids arranged in two chains (A and B) bearing 21 and 30 amino acids, respectively.

Multiple choice

Which one of the following statements is not correct?

  1. The insulin produced in the human body is chemically a steroid compound.

  2. Persons who have had organ transplants are treated with steroids to suppress immune responses.

  3. Proteases are often used in the manufacture of responses.

  4. Some yeasts are able to grow on straight chain hydrocarbons.

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The question asks for the INCORRECT statement. Option A states that insulin is a steroid compound, which is FALSE - insulin is actually a peptide hormone (protein) composed of amino acids, not a steroid. All other statements are correct: steroids are used to suppress immune responses after organ transplants, proteases are used in pharmaceutical manufacturing, and some yeasts can metabolize hydrocarbons.

Multiple choice

Which of the following components is/are a precursor of progesterone?

  1. Cephalins

  2. Steroid

  3. Ergosterol

  4. Coprosterol

  5. Lecithins
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Progesterone belongs to a group of steroid hormones called the progestogens, and is the major progestogen in the body. In mammals, progesterone, like all other steroid hormones, is synthesised from pregnenolone, which in turn is derived from cholesterol.

Multiple choice

Directions: The sentence below or part thereof has been underlined. The underlined part may have an error of grammar or diction. Select the option that best corrects the error, if any.

The thyroid gland collects Iodine from the blood, produces thyroxin, an important hormone which stores it an in active form.

  1. Blood, produces thyroxin which is an important hormone which stores in an inactive form.

  2. Blood to produce thyroxin an important hormone which it stores in an inactive form.

  3. Blood, to manufacture thyroxin, an important hormone to store in an inactive form.

  4. Blood, to store an inactive hormone called thyroxin which is important.

  5. Blood, produces thyroxin which is in store in an inactive form.

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Options (C) and (D) are totally incorrect for wrong word substitution, (E) does not specify where thyroxin stored is and (A) is just a repetition of the original incorrect sentence. Hence (B) is the answer.

Multiple choice

The source of antidiuretic hormone (ADH) is the

  1. adrenal cortex

  2. posterior pituitary

  3. pineal

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

Antidiuretic hormone (ADH, vasopressin) is produced in the hypothalamus but stored in and released from the posterior pituitary into circulation. The anterior pituitary releases different hormones (FSH, LH, ACTH, etc.), and the adrenal cortex releases cortisol and aldosterone.