Tag: endocrine system and chemical co-ordination

Questions Related to endocrine system and chemical co-ordination

All are the function of PTH except ______________________.

zoology endocrine system and chemical co-ordination parathyroid gland thyroid and parathyroid gland thyroid, parathyroid and thymus gland

  1. PTH simulates bone reabsorption /dilution /demineralization

  2. PTH retards osteoclastic action

  3. PTH increases $Ca^{+2}$ abosorption from the digestive tube

  4. PTH stimulates reabsorption of $Ca^{+2}$ by the renal tubules

Show answer
Correct Option: A
Explanation:
The hormone released by the parathyroid glands is called the parathyroid hormone (PTH). It is also called parathyrin. This hormone is involved in the formation or mineralization of bones. It is released when the levels of calcium ions in the blood serum decreases.
Hence, the correct answer is 'PTH simulates bone reabsorption /dilution /demineralization'.

Increase in bleeding time and delay in blood coagulation is due to the deficiency of which hormone?

zoology endocrine system and chemical co-ordination parathyroid gland thyroid and parathyroid gland thyroid, parathyroid and thymus gland

  1. Thyroxine

  2. Adrenaline

  3. Noradrenaline

  4. Parathormone

Show answer
Correct Option: D
Explanation:
  • In humans, four parathyroid glands are present on the back side of the thyroid gland, one pair each in the two lobes of the thyroid gland.
  • The parathyroid glands secrete a peptide hormone called parathyroid hormone (PTH) or parathormone.
  • Parathormone increases the $Ca^{2+}$ levels in the blood.
  • Increase in bleeding time and delay in blood coagulation is due to the deficiency of parathormone because its deficiency causes a decrease in blood calcium levels and calcium ion is essential for blood coagulation.
  • So, the correct answer is 'Parathormone'.

Which of the following reasons states that parathyroid is hormone is a hypercalcemic hormone?

zoology endocrine system and chemical co-ordination parathyroid gland thyroid and parathyroid gland thyroid, parathyroid and thymus gland

  1. PTH also stimulates reabsorption of Ca2+ by the renal
    tubules

  2. PTH increases Ca2+ absorption from the digested food

  3. PTH control the metabolism of carbohydrates,
    proteins and fats

  4. Both A and B

Show answer
Correct Option: D
Explanation:

In humans, four parathyroid glands are present on the back side of the thyroid gland, one pair each in the two lobes of the thyroid gland. They secrete a peptide hormone called parathyroid hormone (PTH).
PTH increases Ca2+ absorption from the digested food. it also stimulates reabsorption of Ca2+ by the renal tubules.PTH acts on bones and stimulates the process of bone resorption (dissolution/demineralization). 
 Hence PTH is a hypercalcemic hormone, i.e., it increases the blood Ca2+ levels. Along with TCT(Thyrocalcitonin), it plays a significant role in calcium balance in the body

So, the correct option is 'Both A and B'.

Parathyroid hormone is: 

zoology endocrine system and chemical co-ordination parathyroid gland thyroid and parathyroid gland thyroid, parathyroid and thymus gland

  1. Protein

  2. Carboh

  3. Lipid

  4. Steroid

Show answer
Correct Option: A
Explanation:

  • parathyroid hormone (PTH) is a protein in nature composed of 84 amino acids. 
  • parathyroid glands make more or less parathyroid hormone (PTH) in response to the level of calcium in the blood. 
  • When the calcium in our blood goes too low, the parathyroid glands make more PTH. so, option A is correct answer .

    • Which of the following is not associated with parathyroid hormone (PTH)?

    zoology endocrine system and chemical co-ordination parathyroid gland thyroid and parathyroid gland thyroid, parathyroid and thymus gland

    1. It promotes release of $Ca^{2+}$ from bone matrix into the blood

    2. It stimulates kidney to release calcitriol

    3. More PTH is released when blood calcium level rises

    4. Hypoparathyroidism result in parathyroid terany

    Show answer
    Correct Option: B
    Explanation:
    • Parathyroid hormone- It is also known as parathormone or parathyrin.
    • It is a secreted by the parathyroid glands.
    • Its main function includes bone remodelling by releasing more PTH when the calcium in our blood goes too low, which increases the blood calcium level that is released from bones.
    • This hormone stimulates calcitriol production in the kidney as it synthesises 1-α hydroxylase and also maintains calcium levels by increasing calcium absorption in the gastrointestinal tract 
    • Hypoparathyroidism- leads to low levels of calcium in the blood which causes cramps and twitches in muscles or tetany.
    • So, the correct answer is 'More PTH is released when blood calcium level rises'.

    Which of the following hormones coordinate with each other to maintain ideal blood $Ca$ level?

    zoology endocrine system and chemical co-ordination parathyroid gland thyroid and parathyroid gland thyroid, parathyroid and thymus gland

    1. Thyrocalcitonin and glucagon

    2. Parathyroid hormone and cortisol

    3. Thyrocalcitonin and Thyroxin

    4. Thyrocalcitonin and Parathyroid hormone

    Show answer
    Correct Option: D
    Explanation:
    • In addition, tetraiodothyronine or thyroxine (T4) and triiodothyronine (T3) Thyroid gland also secretes a protein hormone called thyrocalcitonin. 
    • Thyrocalcitonin(TCT) lowers blood calcium levels. It counters the actions of parathyroid hormone which increases the blood calcium level.
    • The parathyroid glands monitor the calcium in the blood 24 hours per day. The four parathyroid glands make more or less parathyroid hormone (PTH) in response to the level of calcium in the blood. When the calcium in our blood goes too low, the parathyroid glands make more PTH in order to increase the blood calcium levels.
    • Hence Thyrocalcitonin and Parathyroid hormones coordinate with each other to maintain ideal blood Ca level.
    • So, the correct answer is 'Thyrocalcitonin and Parathyroid hormone'.

    Hyposecretion of parathyroid hormone affects blood

    zoology endocrine system and chemical co-ordination parathyroid gland thyroid and parathyroid gland thyroid, parathyroid and thymus gland

    1. Iron concentration

    2. Calcium concentration

    3. Potassium concentration

    4. Sodium concentration

    Show answer
    Correct Option: B
    Explanation:
    Parathyroid gland is present in the form of four small pouches which are embedded in the posterior surface of lobes of thyroid gland. This gland secretes parathormone which increases calcium reabsorption from the bones by dissolution and demineralisation and causes mobilisation of calcium in the blood. It is a hypercalcemic hormone.
    Hence, parathyroid hormone or parathormone affects blood calcium level.
    So, the correct answer is 'Calcium concentration'.

    Blood calcium is increased by administration of 

    zoology endocrine system and chemical co-ordination parathyroid gland thyroid and parathyroid gland thyroid, parathyroid and thymus gland

    1. Glucagon

    2. Thyroxine

    3. Parathormone

    4. Calcitonin

    Show answer
    Correct Option: C
    Explanation:
    A. Glucagon is secreted from alpha cells of islets of Langerhans of pancreas. It increases blood sugar level by stimulating glycogenolysis (i.e. break down of glucose) and gluconeogenesis (synthesis of glucose).
    B. Thyroxine is secreted from thyroid gland. It stimulates the consumption of oxygen by metabolically active tissues and also increases the oxidation of glucose in tissues. 
    C. Parathormone is secreted from parathyroid gland and increases calcium reabsorption from the bones and causes mobilisation of calcium in the blood.
    D. Calcitonin is secreted from the C-cells of thyroid gland and acts on bone and kidneys to reduce blood calcium level.
    Hence, blood calcium level is increased by parathormone.
    So, the correct answer is 'Parathormone'.

    Parathormone deficiency causes

    zoology endocrine system and chemical co-ordination parathyroid gland thyroid and parathyroid gland thyroid, parathyroid and thymus gland

    1. Goitre

    2. Hypocalcemia

    3. Hypercalcemia

    4. All of the above

    Show answer
    Correct Option: B
    Explanation:
    A. Goitre is the enlargement of thyroid gland which occurs due to deficiency of iodine in the body. When the iodine levels are low, thyroid gland becomes hyper active and enlarged to compensate the deficiency of thyroid hormone in the body. The enlarged thyroid gland is visible as a swelling in the throat known as goitre.
    B. Hypocalcemia is the condition of reduced sugar levels in blood.
    C. Hypercalcemia is the condition of increased sugar levels in blood.
    Parathormone is secreted from the parathyroid hormone and increases blood calcium level by increasing the reabsorption of calcium from the bones. Hence, its deficiency will lead to decreased sugar levels in blood i.e. hypocalcemia.
    So, the correct answer is 'Hypocalcemia'.

    Gland responsible for calcium metabolism is 

    zoology endocrine system and chemical co-ordination parathyroid gland thyroid and parathyroid gland thyroid, parathyroid and thymus gland

    1. Thymus

    2. Thyroid

    3. Parathyroid

    4. Adrenal

    Show answer
    Correct Option: C
    Explanation:
    A. Thymus gland is associated with the development of immune system and present on the dorsal side of heart. It secretes thymosin hormone which plays an important role in the differentiation of T-lymphocytes.
    B. Thyroid gland is situated between the trachea and larynx in the neck and secretes thyroxine hormone which increases oxygen consumption by metabolically active tissues.
    C. Parathyroid gland is present in the form of four small pouches which are embedded in the posterior surface of lobes of thyroid gland. This gland secretes parathormone which increases calcium reabsorption from the bones and causes mobilisation of calcium in the blood.
    D. Adrenal gland is present on upper side of kidneys and has two parts, adrenal cortex which secrete glucocorticoids, mineralocorticoids and sexocorticoids and adrenal medulla which secrete adrenaline and nor-adrenaline hormone.
    Hence, the gland responsible for calcium metabolism is parathyroid gland.
    So, the correct answer is 'Parathyroid'.