Question

54-58

1. The vestibulospinal tract:
   1. connects the vestibular region to the spinal cord
   2. is a descending tract
   3. both a. and b. are correct
   4. neither a. nor b. is correct

2. Gonadotrophs:
   1. are found in the pituitary gland
   2. are hormones released by the testicles (and/or ovaries)
   3. both a. and b. are correct
   4. neither a. nor b. is correct

3. The pancreas releases:
   1. glycogen, which leads to the liver converting glucagon into glucose for use
   2. insulin, which binds to receptors, causing an increase of glucose transporters in cell membranes
   3. both a. and b. are correct
   4. neither a. nor b. is correct

4. “Down regulation”:
   1. can occur after hormones have been caught by receptors
   2. does not exist – “up regulation” exists
   3. refers to diffusion when hormones move from an area of high to low concentration
   4. none of the above is correct

5. Parathyroid hormone:
   1. leads to osteoclasts digesting bone tissue
   2. is released in response to low blood Ca²⁺ levels
   3. both a. and b. are correct
   4. neither a. nor b. is correct

Answer 1

54. Option 'c' (both a and b are correct) is the correct option

Justification:

• Option 'a' is correct because vestibulospinal tract is a part of vestibular system and it connects the medial vestibular nucleus to the ventral horns in the cervical region of the spinal cord (C6 vertebrae).
• Option 'b' is correct because vestibulospinal tract is a descending tract which originates from vestibular nuclei of the brain stem and it descends on the ipsilateral side of spinal cord.

So, both a and b options are correct and hence, option 'c' is correct.

55. Option 'c' (both a and b are correct) is the correct option

Justification:

• Option 'a' is correct because gonadotrophic cells comprise 10% of the pituitary gland and they release follicle stimulating hormone (FSH) and luteinizing hormone (LH). So, gonadotrophs are found in the pituitary gland.
• Option 'b' is correct because, as gonadotrophs release follicle stimulating hormone (FSH) and leutinizing hormone (LH), these hormones act on testes for gametogenic function.

So, options a and b are correct and hence, option 'c' is correct.

56. Option 'd' (neither a nor b is correct) is correct

Justification:

• Option 'a' is INCORRECT because pancreas release glucagon NOT glycogen, and when the amount of glucose is low in blood stream, glucagon causes liver to convert the stored glycogen to glucose and is released into the blood stream.
• Option 'b' is INCORRECT because pancreas release insulin, which binds to the receptors of it in the plasma membrane and this binding causes decrease or translocation of glucose transporters in the cell membrane, but NOT an increase of glucose transporters.

So, neither of the options are correct and hence, option 'd' is correct.

57. Option 'd' (none of the above is correct) is correct

Justification:

• Option 'a' is INCORRECT because down regulation occurs when a cell decreases its number of receptors, but down regulation does not occur due to the hormone caught by the receptors.
• Option 'b' is INCORRECT because along with the down regulation, up regulation also exists. Up regulation occurs when the cell increases its number of receptors.
• Option 'c' is incorrect because, the process of diffusion when hormones move from an area of high concentration to low concentration is called 'passive diffusion' but NOT 'down regulation'.

So, neither of the options are correct and hence, option 'd' is correct.

58. Option 'c' (both a and b are correct) is correct

Justification:

• Options 'a' and 'b' are CORRECT because the parathyroid hormone is released when the blood calcium levels are low and this hormone helps in increasing the blood calcium levels by stimulating osteoclasts, which breaks down or digests the bone tissue to release calcium into the blood stream.

So, option 'c' (both a and b are correct) is correct.

Thank you!