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 mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Which of the following hormones triggers the release of androgens?

  1. FSH

  2. ACTH

  3. LH

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

  • The hypothalamus secretes gonadotropin-releasing hormone (GnRH) which stimulates the pituitary gland into secreting luteinizing hormone (LH) and follicle-stimulating hormone (FSH). 
  • LH stimulates testicular Leydig cell secretion of Testosterone whereas FSH stimulates spermatogenesis in Sertoli cells of the seminiferous tubules. 
  • An androgen is any natural or synthetic steroid hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. 
  • The major androgen in males is testosterone. Hence,  LH hormones trigger the release of androgens.
So, the correct answer is 'LH'.

Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

As per accepted concept of hormone action, if receptor molecules are removed from target organs, the target organs will

  1. Continue to respond to hormone but in opposite way

  2. Continue to respond to hormone without any difference

  3. Continue to respond to hormone but will require higher concentration

  4. Stop responding to hormone
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Hormones bind to specific proteins known as hormone receptors to produce their effects. These receptors are present on target tissues only. There are two types of receptors in target tissues:
  • Membrane bound receptors : These are present on the cell membrane of target cells.
  • Intracellular receptors: These are present inside the target cell.
When a hormone binds to its receptor, hormone receptor complex is formed. This complex leads to some biochemical changes in target tissue. Hormones regulate metabolism and physiological functions of target tissue.
Hence, if receptor molecules are removed from target organs, the target organs will stop responding to hormones.
So, the correct answer is 'Stop responding to hormone'.
Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Receptors for protein hormones are found

  1. Inside nucleus

  2. Inside cytoplasm

  3. On surface of ER

  4. On the plasma membrane of the cell
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Protein hormones are peptide hormones which are derived from amino acids. These are insoluble in lipids and hence can't enter the target cell (cell membrane is a lipid bilayer). These act as primary messengers at the surface of target cell by binding to cell surface receptors and this results in the formation of a hormone-receptor complex.
So, the correct answer is 'On the plasma membrane of the cell'.
Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

In hormone action, if receptor molecules are removed from target organ, the target organ will 

  1. Continue to respond to hormone

  2. Not respond to hormone

  3. Continue to respond but requires higher concentration

  4. Continue to respond but in the opposite way
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Hormones bind to specific proteins known as hormone receptors to produce their effects. These receptors are present on target tissues only. There are two types of receptors in target tissues:
  • Membrane bound receptors : These are present on the cell membrane of target cells.
  • Intracellular receptors: These are present inside the target cell.
When a hormone binds to its receptor, hormone receptor complex is formed. This complex leads to some biochemical changes in target tissue. Hormones regulate metabolism and physiological functions of target tissue.
Hence, if receptor molecules are removed from target organ, the target organ will not respond to hormone.
So, the correct answer is 'Not respond to hormone'.
Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Steroid hormones, estrogen and testosterone bind to

  1. Membrane ion channels

  2. Enzyme-linked membrane receptors

  3. G-Protein linked membrane receptors

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

Hormones are of 2 types based on their chemical composition. 

  1. Protein hormones: They are build up of amino acids and are soluble in water. 
  2. Steroid hormones: They are build up of fats and are not soluble in water. 
  3. Since the steroid hormones are not soluble in water they can pass through the plasma membrane and bind to the receptors in the cytoplasm.  
So the answer is Cytoplasmic receptors. 

Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Which one of the following pairs of hormones are the examples of those that can easily pass through the cell membrane of the target cell and bind to a receptor inside it(mostly in nucleus)?

  1. Insulin, glucagon

  2. Thyroxine, insulin

  3. Somatostatin, oxytocin

  4. Cortisol, testosterone
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Cortisol and testosterone are lipid soluble hormones, which can directly pass through the cell membrane of the target cell and bind with intracellular receptors. So, the correct answer is option D.

Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Steroid hormones 

  1. Work via second messenger

  2. Trigger rapid, short term response in cells

  3. Alter the activity of genes

  4. Initiate open channels in plasma membrane
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Steroid hormones are derived from cholesterol. They are in the form of lipids. Their receptors are intracellular i.e. located inside the cell. These hormones are lipid soluble and hence, cross the cell membrane easily to enter the cell. The hormone binds to receptor and a hormone-receptor complex is formed. The complex then binds to transcription factors which then bind to DNA and this causes activation and transcription of a particular gene. This leads to synthesis of specific proteins that affect the metabolism of cells.
Hence, steroid hormones alter the activity of genes.
So, the correct answer is 'Alter the activity of genes'.
Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Which of these can pass easily through cell membrane of target cells and bind to internal receptors?

  1. Thyroxine, insulin

  2. Somatostatin, Oxytocin

  3. Insulin, glucagon

  4. Cortisol, testosterone
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A. Thyroxine, insulin hormones are protein hormones. 

B. Somatostatin, oxytocin are protein hormones. 
C. Insulin, glucagon are protein hormones.
D. Cortisol, testosterone are steroid hormones. 
Steroid hormones are made up of fats and are not soluble in water, hence they can easily pass through the cell membrane.
So, the answer is Cortisol, testosterone. 

Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

(A) Every receptor is unique for a hormone
(B) Every hormone is unique for a receptor.

  1. Both true

  2. Both false

  3. A true B false

  4. B true B false
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In the human body, every receptor is specific for a hormone and every hormone is specific for a receptor.

So, the correct option is ‘Both true’.

Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Which one of the following is proteinaceous in chemical nature?

  1. Thyroxine

  2. Insulin

  3. Progesterone

  4. Oxytocin
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Thyroxine is a proteinaceous hormone, formed by the addition of iodine to amino acid tyrosine which is then combined with protein thyroglobulin

So, the correct answer is 'Thyroxine'

Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Which one of the following is not a second messenger in hormone action ?

  1. cGMP

  2. Calcium

  3. Sodium

  4. cAMP
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Second messengers are the organic molecules and sometimes the metal ions, acting as intracellular signals, whose production or release usually amplifies a signal such as a hormone, received at the cell surface. Sodium (Na) is not a second messenger to be discovered. In addition to cyclic AMR Cyclic Guanosine Monophosphate (CGMP) functions as a second messenger in certain cases. Calcium ions (Ca++) also act as second messenger in phospholipase c - ca* second messenger system.

So, the correct answer is 'Sodium'.
Multiple choice zoology endocrine system and chemical co-ordination mechanism of hormone action coordination in human beings- chemical control endocrine system in humans

Choose the correct answer from the alternatives given.
A major difference in the mechanism of action between steroid and peptide hormones is that:

  1. steroid hormones affect the synthesis of proteins, whereas peptide hormones affect the activity of proteins already in the cell

  2. target cells react more rapidly to steroid hormones than they do to peptide hormones

  3. steroid hormones bind to a receptor protein, whereas peptide hormones bind to G protein

  4. steroid proteins affect metabolism, whereas peptide hormones affect membrane permeability
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Peptide hormones are hydrophilic due to which they are unable to cross the lipid plasma membrane. They bind to the receptors on the plasma membrane and affect the activity of proteins inside the cell called secondary messenger. These secondary messengers then perform the action required. The steroid hormones are hydrophobic, they can cross the plasma membrane directly and are able to affect the synthesis of proteins directly in the cells.

Hence, the correct answer is 'steroid hormones affect the synthesis of proteins, whereas peptide hormones affect the activity of proteins already in the cell'.