Pediatric Endocrinology Question And Answers

Question 1. Mention hormones secreted by anterior pituitary. Describe action of growth hormone. How is hormone synthesis regulated?
Answer:

Hormones secreted by anterior pituitary:

• Growth hormone
• Thyroid stimulating hormone (TSH)
• Adrenocorticotropic hormone (ACTH) Follicle stimulating hormone (FSH)
• Luteinizing hormone (LH) in females
• Interstitial cell stimulating hormone (ICSH) in males.
• Prolactin.

Read And Learn More: BDS Previous Examination Question And Answers

Growth hormone:

Actions:

1. On metabolism:

1. On protein metabolism.
   • GH increases the amino acids transport into the cells from the E.C.F.
   • Increases RNA translation in the cells due to which ribosomes are activated and more proteins are synthesize.
   • It stimulates transcription of DNA to RNA.
   • Inhibits the catabolism of proteins.
   • Releases insulin which has anabolic effect on proteins.
2. On fat metabolism.
   • Increases mobilization of fats from adipose tissues.
   • Increases circulating free fatty acids levels
   • Increases hepatic oxidation of fatty acids to ketone bodies.
3. On carbohydrate metabolism.
   • Increases hepatic glucose output.
   • Reduces the peripheral utilization of glucose for energy production.
   • Decreases glucose uptake by the tissues.
   • Increases the concentration of glycogen in the cells.
   • It has diabetogenic effect as it causes continuous stimulation of the B cells in the islets of langerhans
   • in pancreas to secrete more insulin.
4. On mineral metabolism.
   • Increases Ca2⁺, absorption from GIT.
   • Decreases Na⁺, K⁺, Ca2⁺ and phosphorous excretion from kidneys.

2. Effect of Bone, cartilage and viscera:

• GH increases the number of cells.
• Increases conversion of chondrocytes into osteogenic cells.
• Increases calcium absorption for mineralization of bone.
  1. Before epiphyseal closure.
     • Stimulates proliferation of chrondrocytes.
     • Stimulates DNA and RNA synthesis.
     • Increases the length of the bones.
  2. After epiphyseal fusion.
     • GH no longer increases the length of the bones.
     • However, bone thickening occurs.

3. Action of milk production:

• Increases milk production in lactating mothers.

4. Other actions:

• Stimulates erythropoiesis.
• Stimulates the growth of lymphoid tissue.
• Stimulates the growth of genetalia.

Regulation:

• Growth hormone is synthesized in the anterior lobe of pituitary gland.
• Growth hormone secretion is under negative feedback control by two hypothalamic hormones – GH releasing hormone (GHRH) and GH inhibiting hormone (GHIH) and GH releasing polypeptide (GHRP)
• Hypothalamus releases GHRH and GHRP.

• GH and GHRH inhibits its own secretion by feedback stimulating the release of GHIH from hypothalamus.

 

Question 1. Name the posterior pituitary hormones. Explain action of any one of them.
Answer:

Posterior pituitary hormones:

• Antidiuretic hormone (ADH)
• Oxytocin.

Question 3. Enumerate the hormones of anterior pituitary gland and give the important function of one hormone.
Answer:

Hormones of anterior pituitary:

• Growth hormone.
• Thyroid stimulating hormone.
• Adrenocorticotropic hormone.
• Follicle stimulating hormone.
• Luteinizing hormone in females.
• Interstitial cell stimulating hormones in males.
• Prolactin.

Question 5. Explain the regulation of secretion of thyroid hormone.
Answer:

Regulation of thyroid hormone:

1. Role of thyroid stimulating hormone (TSH) secreted by anterior pituitary.

• Increases size and secretory activity of the cells.
• Increases I- trapping mechanism.
• Increases proteolysis of thyroglobulin.
• Increases synthesis of thyroglobulin into colloid.

2. Role of hypothalamus.

• Thyrotrophin releasing hormone (TRH) is released into the hypothalamohypophyseal portal vessels and transported to the anterior pituitary.
• Here, its stimulates the secretion of TSH.

3. Role of iodine in the diet.

• When iodine level is moderate, the blood level of thyroid hormone is normal.
• When iodine intake is high, it decreases the formation and release of thyroid hormone.

4. Role of other factors.

• Leptin from adipose tissue and a-melanocyte stimulating hormone from pituitary increase the release of TRH and synthesis of thyroid hormone.
• Low body temperature stimulates synthesis of thyroid hormone.
• Stress, somatostatin, glucocorticoids and dopamine decreases the secretion of thyroid hormone.

Question 6. Myxedema.
Answer:

It is the thyroid disorder characterized by edematous appearance.

Causes:

• Hypothyroidism.
• Lack of thyroid hormone.

Features:

• Goiter.
• Puffiness of face with periorbital swelling.
• Dropping of upper eyelid.
• Loss of hair.
• Atherosclerosis.
• Nonpitting type of edema.
• Dry, thickened, rough and yellow skin.
• Anaemia.
• Fatigue.
• Low BMR.
• Hypersensitive to cold.
• Memory loss
• Hoarseness of voice.
• Increase in body weight.
• Increase in serum cholesterol.
• Constipation.

Question 7. Thyroid hormones.
Answer:

1. Tri-iodo-thyronine-T3:

• It is iodine containing amino acids secreted by the follicular cells.
• It has less affinity for plasma proteins and combines loosely with them.
• Thus, it is released quickly.
• It acts on the target cells immediately.
• It forms only 9-10% of total secretion.

Synthesis:

• It is synthesized by oxidative condensation of mono-iodo-tyrosine (MIT) and Di-iodo tyrosine (DIT).MIT + DIT → Tri-iodo-thyronine (T3)

2. Tetraiodothyronine – T4:

• It is secreted by the follicular cells.
• It has more affinity for plasma proteins and strongly binds to it.
• Thus, it is released slowly and acts slowly.

Synthesis:

• It is synthesized by coupling of 2 molecules of Di-iodo- tyrosine (DIT).DIT + DIT Thyroxine, T4

3. Calcitonin:

• It is calcium-lowering hormone.
• It is secreted by parafollicular cells which lie in between the follicular cells.
• It is polypeptide chain with 32 amino acids.
• It decreases the blood calcium level by acting on bones, kidney and intestine.
• Thus, it counteracts the action of parathormone.

Question 8. What are the manifestations of cretinism?
Answer:

Manifestations of cretinism:

• Mental retardation.
• Dwarfism.
• Protruded abdomen.
• Enlarged, protruded tongue.
• Dripping of saliva.
• Failure of sexual development.
• Baby develops croaking sound while crying.
• The enlarged tongue obstructs swallowing and breathing.

Causes:

• Congenital absence of thyroid gland
• Genetic disorder.
• Lack of iodine in the diet.

Question 9. Explain the role of parathormone in the regulation of blood calcium level.
Answer:

Regulation of blood calcium by PTH:

• FTH maintains blood calcium level with the critical range of 9-11 mg %.
  • Bones:
    • PTH stimulates osteoblasts and osteoclasts and promote bone resorption.
    • Thus increases plasma Ca2⁺
    • Permeability of bone cells to Ca2⁺ is increased.
    • This causes osteoblasts to pump Ca2⁺ into extracellular fluid (ECF).
  • Kidneys:
    • PTH increases Ca2⁺ reabsorption from renal tubules.
    • PTH decreases Ca2⁺ excretion in urine.
    • Thus, it raises blood calcium level.
  • GIT:
    • PTH increases the absorption of calcium ions from the GIT indirectly.
    • It increases the formation of 1,25-dihydroxycholecalcifer in the kidneys.
    • This increases the absorption of Ca⁺
  • Lactating mammary glands:
    • PTH decreases the amount of Ca2⁺ secreted into the milk.

Question 12. What is the role of adrenal gland in condition of stress?
Answer:

• The exposure to any type of stress, increases the secretion of ACTH.
• This is turn, increases glucocorticoid secretion.
• The increase level of glucocorticoid offers resistance to the body against stress by following ways
  1. Glucocorticoids increases transport of amino acids from tissues to liver cells.
     • This causes synthesis of new proteins to withstand stress.
     • It releases more fatty acid to generate more energy during stress.
     • It enhances vascular reactivity to catecholamines and fatty acid mobilizing action of catecholamines, which withstand stress.
     • It prevents severity of other body changes caused by stress.

Question 13. What are the hormones of adrenal cortex? Describe the action of glucocorticoids.
Answer:

Hormones of adrenal cortex:

• Mineralocorticoids
• Glucocorticoids
• Sex hormones.

Actions of glucocorticoids:

1. On carbohydrate metabolism.

• It increases the blood glucose level by.
  • Promoting gluconeogenesis.
  • Increases liver glucose formation
  • Prevents peripheral utilization of glucose by cells.

2. On protein metabolism.

• It causes protein breakdown.
• Inhibits transport of amino acids into the cells.
• Increases transport of amino acids in liver to produce glucose.

3. On fat metabolism.

• Favours mobilization of fatty acids from adipose tissue to liver and increases gluconeogenesis.
• Increases the concentration of fatty acids in blood.
• Increases the utilization of fat for energy.

4. On mineral metabolism.

• Increases retention of Na⁺ and excretion of K by the kidney.
• Decreases blood Ca2⁺ by inhibiting its absorption from intestine and increases its excretion through urine.

5. On water metabolism.

• Increases aldosterone secretion to cause excessive retention of water.

6. On muscles.

• Increases the release of amino acids from muscles.

7. On bone.

• Glucocorticoids excess.
• Inhibits new bone formation.
• Causes bone matrix breakdown.
• Decreases serum Ca2⁺

8. On blood cells.

• Decreases the number of circulating eosinophils
• Increases destruction of eosinophils.
• Decrease no. of basophils, lymphocytes.
• Increases circulating neutrophils, RBCs and platelets.

9. On vascular response.

• It is essential for constrictor action of adrenaline and nonadrenaline.
• Enhances catecholamine synthesis.
• Sensitizes arterioles to the constrictor action of noradrenaline.

10. On CNS.

• It is essential for normal functioning of nervous system.

11. Permissive action.

• It is essential for catecholamines to produce pressor response and bronchodilation.

12. On resistance to stress.

• It enhances the body resistance to stress.

13. Anti-inflammatory and anti-allergic action.

• Inhibits inflammatory response to tissue injury.
• Suppresses clinical manifestation of allergy.

14. Immunosuppressive action.

• It suppresses the body immune by decreasing the number of circulating T-lymphocytes.

Question 14. What is aldosterone? Describe the regulation of synthesis of aldosterone.
Answer:

Aldosterone is mineralocorticoid containing 21 – C atom

Regulation of its secretion:

Question 15. Mention the hormones secreted by the posterior pituitary gland. What is meant by neuroendocrine reflex.
Answer:

Hormones secreted by posterior pituitary gland:

• Anti-diuretic hormone
• Oxytocin

Neuroendocrine reflex:

• It is initiated by the stimulation of sensory neurons that causes a release of a neurohormone from the neurosecretory cells.
• Example: Milk ejection reflex

Milk ejection reflex:

• Stimulation of touch receptors present on the mammary glands
• Impulse via somatic afferent nerve fibres reach paraventricular and supraoptic nuclei of hypothalamus
• These impulse releases oxytocin
• Oxytocin causes
  • Contraction of myoepithelial cells
  • Ejection of milk from mammary glands

Question 1. Hormones produced by the posterior pituitary and one action of any one of them.
Answer.

Hormones of posterior pituitary:

• Antidiuretic hormone (ADH)
• Oxytocin.

Action of ADH:

• Increases water reabsorption from renal tubules.
• Causes water retention.
• Increases peristalsis of GIT.

Question 2. Abnormalities of growth hormone.
Answer:

1. Gigantism:

• It occurs due to overproduction of growth hormone during adolescence.
• It is characterized by excessive growth of long bones.

2. Acromegaly:

• It occurs due to excessive secretion of growth hormone during adulthood.
• It is characterized by enlargement of the peripheral region.

3. Dwarfism:

• It occurs due to deficiency of growth hormone secretion.
• It is characterized by the stunted growth.

Question 3. Acromegaly.
Answer:

• It is a condition occurring due to excessive secretion of growth hormone during adulthood.

Features:

• Prognathism.
• Enlargement of sinuses
• Protrusion of supraorbital ridges, broadening of nose, thickening of lips, thickening of forehead.
• Enlargement of hands and feet.
• Kyphosis.
• Cardiomegaly, hepatomegaly, splenomegaly.
• Osteoarthritis.
• Gynaecomastia.
• Hyperglycaemia, glycosuria.
• Hypertension.

Question 4. Dwarfism.
Answer:

• It is a condition occurring due to deficiency of growth hormone secretion.

Features:

• Stunded growth.
• Sexual immaturity.
• Hypothyroidism.
• Adrenal insufficiency.

Question 5. Gigantism.
Answer:

• It is a condition occurring due to over production of growth hormone.

Features:

• Tall stature
• Gynaecomastia
• Large hands and feet
• Hyperglycaemia, glycosuria Coarse facial features.
  Loss of libido.

Question 8. Goiter.
Answer:

It means enlargement of the thyroid gland.

Types:

1. Toxic Goitre.

• Occurs in hyperthyroidism.
• It occurs due to tumour of the gland which increases the number of hormone secreting cells.

2. Nontoxic Goitre.

• It occurs in hypothyroidism.
• It occurs due to enlargement of the gland.
• It has 2 subtypes.
  • Endemic colloid goitre.
    • It is due to the deficiency of iodine.
  • Idiopathic nontoxic goitre.
    • It occurs due to unknown causes.

Question 9. Hypothyroidism.
Answer:

• It is the condition resulting from reduced circulating levels of free T4 and T3.
• It occurs due to autoimmune disease, which causes destruction of the gland.
• Mostly, it begins as glandular inflammation called thyroiditis.
• Eventually it results in fibrosis of the gland.
• It leads to

1. Myxedema in adults.

• It is characterized by edematous appearance.

2. Cretinism in children,

• It may occur due to iodine deficiency.

Question 10. Functions of calcium.
Answer:

Calcium is essential for.

• Formation and growth of bones and teeth.
• Neuronal activity.
• Blood coagulation.
• Neurotransmitter release
• Muscular activity for excitation – contraction coupling.
• Secretory activity of the glands.
• Secretion of hormones.
• For the action of intracellular enzymes.

Question 11. Parathormone.
Answer:

• It is a protein hormone secreted by chief cells of parathyroid gland.

Function:

• It maintains the blood calcium level within normal range by acting on bone, kidney and GIT.

Regulation:

• The secretion of parathormone is regulated by blood calcium level.
• A fall in calcium level stimulates secretion and rise in calcium level inhibits secretion.

Question 14. Insulin.
Answer:

Insulin is secreted by B cells in the islets of langerhans of pancres.

Functions:

• It is the only hormone that reduces blood glucose level.
• Causes protein synthesis.
• Stimulates fat synthesis
• Promotes growth.

Question 15. Glycosuria.
Answer:

• It is the presence of glucose in the urine.
• Normally glucose does not appear in urine.
• But, when glucose level rises above 180 mg/dl in blood, glucose appears in urine.
• It is the renal threshold level for glucose.

Question 16. Hormones regulating blood glucose.
Answer:

• Hormone that decreases blood glucose. Insulin is the only hormone.
• Hormones that increases blood glucose.
• Epinephrine and nor-epinephrine.
• Glucagon
• Adrenal cortical hormones
• Growth hormone.
• ACTH.
• Thyroid hormones.

Question 17. Thyrotoxicosis.
Answer:

Synonym:

• Grave’s disease

Fetures:

• It is an autoimmune disease which causes hyperthyroidism.
• Normally thyroid stimulating hormone (TSH) combines with surface receptors of thyroid cells and causes the synthesis and secretion of thyroid hormones.
• But, in Grave’s diseases the thyroid stimulating autoantibodies produced by B-lymphocytes activate the TSH receptors and increase the secretion of thyroid hormone.

Question 18. Glucogon.
Answer:

• It is secreted from a-cells in the islets of Langerhans of pancreas.

Functions:

• Increases blood glucose level.
• Stimulates glycogenolysis.
• Promotes gluconeogenesis.
• Inhibits secretion of gastric juice.
• Increases secretion of bile from liver.

Question 19. Aldosterone.
Answer:

It occurs in plasma in a very small concentration, 60% being bound to protein mainly to albumin.

Actions:

• It increases the reabsorption of sodium from renal tubules.
• Aldosterone by stimulating Na+ reabsorption it causes water
  retention.
• This increases ECF volume which leads to increases in blood pressure.
• Aldosterone increases potassium excretion.
• Enhances sodium absorption from intestine.
• Sodium is reabsorbed from sweat glands through the action of aldosterone.

Question 20. Hormones produced by adrenal cortex.
Answer:

1. Mineralocorticoids.

• Secreted by zona glomerulosa of adrenal cortex.
  1. Aldosterone,
     • Increases sodium reabsorption from renal tubules.
     • Increases potassium excretion.
  2. Deoxycorticosterone.

2. Glucocorticoids.

• They act mainly on glucose metabolism and increases blood glucose level,
• They are
  • cortisol
  • cortisone
  • corticosterone.

3. Sex hormones.

• They are secreted mainly in zona reticularis
• They are.
  • Androgen mainly
  • Oestrogen and progesterone in small amounts.

Question 21. Functions of glucocorticoids.
Answer:

• Increases blood glucose level
• Causes protein breakdown
• Provide resistance to stress
• Has anti-inflammatory and antiallergic action.
• Has immunosuppressive action.
• Enhances catecholamine synthesis
• Increases Na* reabsorption and K+ excretion.
• Increased retention of water
• Required for proper functioning of nervous system.

Question 22. Addison’s disease.
Answer:

• It is the failure of adrenal cortex to secrete all the corticosteroids.

Types:

• Primary addison’s diseases
• Secondary addison’s diseases
• Tertiary addisons’s disease

Features:

• Hypotension.
• Anorexia, nausea, vomiting, diarrhoea
• Decreased resistance to stress
• Mental confusion
• Muscular weakness
• Dehydration
• Decreased cardiac output
• Hypolglycaemia
• Suspectibility to infection.
• Hypersensitive to taste and smell.

Question 23. LH in males and females.
Answer:

In males:

• It stimulates the interstitial cells of Leydig cells in testes.
• Thus, it is known as interstitial cell stimulating hormone.
• It is essential for the secretion of testosterone from Leydig cells.

In famels:

• It causes maturation of vesicular follicle into graffian follicle.
• Responsible for ovulation.
• Required for formation of corpus luteum.
• Activates secretory functions of corpus luteum.

Question 24. Milk ejection reflex
Answer:

Milk Ejection Reflex: 

1. Contraction of myoepithelial cells

2. Ejection of milk from mammary glands

Question 25. Name hormones that help to maintain calcium homeostasis.
Answer:

Hormones Regulating Plasma Calcium Are:

• Vitamin D
• Parathormone
• Calcitonin

Question 26. Mention four functions of cortical hormones.
Answer:

Functions of cortical hormones

• Increases the blood glucose levels
• Favours mobilisation of faaty acids
• Increases retention of sodium ions and excretion of potassium ion
• Increases aldosterone secretion
• Increases release of amino acids from muscles.

Question 27. Name any four hormones that act on bone.
Answer:

Hormones acting on bone:

• Growth hormone-stimulates bone formation
• Parathyroid hormone-stimulates formation and resorption
• Calcitonin – permits formation, inhibits skeletal resorption, promotes mineral deposition.

Question 28. Name three hyperglycaemic hormones.
Answer:

Hyperglycaemic hormones:

• Glucagon
• Growth hormone
• Glucocorticoids
• Epinephrine
• Thyroid

Question 29. List the hormones synthesized by the anterior pituitary.
Answer:

Hormones secreted by anterior pituitary:

• Growth hormone
• Thyroid stimulating hormone
• Adrenocorticotropic hormone
• Follicle stimulating hormone
• Luteinizing hormone in females
• Interstitial cell stimulating hormone in males
• Prolactin

Question 30. Osteoporosis
Answer:

• Osteoporosis is a bone resorption disease characterized by decreased density of normally mineralized bone which results in the thinning of bone tissue and decreased mechanical strength.
• It leads increased fragility of bones and increased risk of bone fracture.

Causes:

• In females following menopause due to deficiency of estrogen
• Tobacco smoking
• Malnutrition
• Vitamin D deficiency
• Excess consumption of alcohol
• Use of proton pump inhibitors

Question 31. Dwarfism versus cretinism
Answer:

Question 32. Antidiuretic hormone.
Answer:

• It is hormone secreted by posterior pituitary

Actions:

• Increases the water reabsorption from distal convoluted tubule and collecting duct
• Increases urea absorption from collecting duct
• Promotes sodium reabsorption from the thick ascending limb of loop of Henle
• Causes constriction of the arteries in all parts of the body
• Causes contraction of smooth muscle and increases peristalsis of GIT and detrusor contraction

Regulation:

• Stimulants of ADH are
  • Decrease in the ECF volume
  • Increase in osmolar concentration in the ECF

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