Tag: thyroid and parathyroid gland

Questions Related to thyroid and parathyroid gland

The pituitary gland by virtue of its tropic hormones controls the secretory activity of other endocrine glands. Which one of the following endocrine glands can function independently of the pituitary gland?

  1. Thyroid

  2. Gonads

  3. Adrenal

  4. Parathyroid


Correct Option: D
Explanation:

The parathyroid glands are four tiny glands, located in the neck, each gland is about the size of a grain of rice. Parathyroid gland secretes parathormone hormone, which regulates $Ca^{++}$ and phosphate ion in the body. This gland works independently to the pituitary gland. 

The pituitary gland, on the other hand, is the major endocrine gland, a pea-sized body attached to the base of the brain that is important in controlling growth and development and the functioning of the other endocrine glands, which includes thyroid, gonads and adrenals etc. 
Therefore, the correct answer is option D.

The blood calcium level falls too low because

  1. The thyroid gland releases calcitonin, which binds to bone cells

  2. The parathyroid glands release PTH, which binds to kidney cells

  3. The thyroid gland releases thyroid hormone, which binds to small intestine cells

  4. The pancreas releases glucagon, which binds to liver cells

  5. The pituitary gland releases growth hormone, which binds to bone cells


Correct Option: A
Explanation:

Parathormone of parathyroid gland increases the blood calcium level by binding to receptors present on DCT of the nephron to stimulate conditional reabsorption of calcium. Thyroid hormone does not have any specific target cell and stimulate metabolic rate by all cells. Glucagon regulates blood glucose level while growth hormone stimulate overall growth and development. Calcitonin hormone stimulates a temporary reduction in number and activity of osteoclasts (bone cells) and thereby reducing the blood calcium level. Thus, the correct answer is option A.

Parathyroid maintains the calcium level in the blood by action on which of the following organs?

  1. Bone

  2. Kidney

  3. Intestine

  4. All of the above


Correct Option: D
Explanation:
  • Parathyroid hormone regulates calcium levels in the blood, largely by increasing the levels when they are too low. 
  • It does this through its actions on the kidneys, bones and intestine. 
  • Bone parathyroid hormone stimulates the release of calcium from large calcium stores in the bones into the bloodstream. Hence, Parathyroid maintains the calcium level in the blood by action on Bone, Kidney and Intestine.
  • So, the correct answer is 'All of the above'.

Which endocrine gland becomes inactive in old age?

  1. Adrenal

  2. Pineal

  3. Thymus

  4. Pituitary


Correct Option: C
Explanation:

Thymus is well developed in new born child and grows upto the age of puberty after that it starts shrinking and almost disappears in old age.

Parathormone influences calcium absorption in small intestine by regulating metabolism of 

  1. Vitamin C

  2. Vitamin D

  3. Vitamin B

  4. Enterogastrone


Correct Option: B
Explanation:
Parathormone is secreted from the parathyroid hormone and increases blood calcium level by increasing the reabsorption of calcium from the bones. Parathormone increases calcium absorption in small intestine by regulating metabolism of vitamin D because it stimulates osteoclasts. These are the cells that cause breakdown by dissolution of calcium from bone and thus, concentration of calcium is increased in blood.
So, the correct answer is 'Vitamin D'.

Hormone responsible for regulation of calcium and phosphorus homeostasis is secreted by

  1. Pituitary

  2. Parathyroids

  3. Thymus

  4. Pancreas


Correct Option: B
Explanation:

The parathyroid glands are small endocrine glands in the neck that produce parathyroid hormone. Humans have four parathyroid glands, which are usually located behind the thyroid gland and in rare cases, within the thyroid gland or in the chest. Parathyroid glands control the amount of calcium in the blood and within the bones.

Which of the following statements is correct for 'parathormone'?

  1. It increases blood calcium level and decreases calcium store of the bone

  2. It decreases blood calcium level and increased calcium store of the bone

  3. It increases blood glucose level and decreases calcium store of the bone

  4. It decreases blood glucose level and increases calcium store of the bone


Correct Option: A

In which of the following options, hormone is not matching with its source and function?

  1. Hormone- Glucocorticoids, Source-Adrenal cortex, Function-Produces anti-inflammatory reactions

  2. Hormone-Vasopressin, Source-Posterior pituitary, Function-Stimulates resorption of water and electrolytes

  3. Hormone-Parathyroid hormone, Source-thyroid, Function-Decreases the blood $Ca^{2+}$ level

  4. Hormone-Melatonin, Source-Pineal gland, Function-Maintains sleep-wake cycle


Correct Option: C
Explanation:

Hormone released by the parathyroid gland is parathyroid hormone also called parathormone or parathyrin, this hormone regulates the Ca$^{+2}$ concentration in the serum by acting upon bone, kidney and intestine.

So, the correct answer is 'Hormone-Parathyroid hormone, Source-thyroid, Function-Decreases the blood Ca$^{+2}$ level'

The blood calcium level is lowered by the deficiency of.

  1. Thyroxine

  2. Calcitonin

  3. Parathormone

  4. Both (a) and (b)


Correct Option: C
Explanation:

Parathormone secreted by parathyroid gland regulates the level of calcium in the blood. It stimulates the release of calcium from the bones into the blood, increases calcium absorption from the intestine into the blood and it also increases calcium reabsorption from the nephrons into the blood. Therefore, its deficiency leads to low blood calcium level.

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


Correct Option: B
Explanation:

The kidney processes Vitamin D into calcitriol, the active form that is most effective in assisting intestinal absorption. This process is stimulated by parathyroid hormone. Vitamin D is an important co-factor in the intestinal absorption of calcium, as it increases the number of calcium binding proteins, involved in calcium absorption through the apical membrane of enterocytes in the small intestine.