Question

Identify hormones not antagonistic in function
a. Growth hormone- somatostatin
b. Calcitonin-Parathormone
c. Adrenaline-noradrenaline
d. Insulin- Glucagon

Answer 1

The endocrine system maintains homeostasis in the body by the action of antagonistic hormones. These hormones work against each other to keep the body functions within limits.

Complete answer:
Hormone pairs like growth hormone - somatostatin, calcitonin – parathormone and insulin - glucagon, are antagonistic in nature. They constantly fight against each other to maintain homeostasis within the body.

Option A:
Growth hormone also called somatotropin is synthesized in the somatotrophs of the anterior pituitary gland. It is an important hormone for normal human growth. Its synthesis is inhibited by the growth hormone inhibiting hormone called somatostatin which is secreted by delta cells of pancreas.

Option B:
Parathormone regulates the concentration of calcium in extracellular fluid. It is secreted by the parathyroid gland when the level of calcium drops below normal in plasma. Calcitonin secreted by parafollicular cells or C-cells of thyroid gland inhibits the release of calcium into the blood.

Option D:
Both insulin and glucagon are hormones secreted by specialized cells of pancreas. The alpha cells secrete glucagon whereas beta cells secrete insulin. Function of Insulin is to lower the level of glucose in the blood whereas glucagon increases the level of glucose when it falls below the normal range.

Option C:
Adrenaline and noradrenaline are catecholamines (neurotransmitters) which also act as hormones. They have similar or complementary functions. They are a part of a sympathetic and parasympathetic nervous system. They play an important role in our body's natural fight or flight response to stress. Secretion of adrenaline increases blood sugar levels, increases heart rate and allows the relaxation of smooth muscle in the airways to improve breathing. These effects provide the body with extra energy to fight stress. Effects of noradrenaline include increased heart rate, increased blood pressure, widening of pupils and air passages in the lungs and also narrowing of blood vessels in non-essential organs.

Hence, the correct answer is option (C).

Note: The endocrine system primarily depends on feedback mechanisms to regulate hormone production and secretion in the circulatory system. Most of the endocrine glands adhere to negative feedback control that acts to maintain the homoeostasis.