Question

A man suddenly sees a tiger. His heartbeat goes up, blood pressure increases, etc. Which hormone is released at this time in his body?
A. Parathormones
B. Adrenaline
C. Corticoid
D. Thyroxine

Answer 1

Hint: Adrenal gland is a small, yellowish-brown paired gland situated at anterior end of each kidney like a cap. It is covered by a fibrous connective tissue capsule. The structure is internally differentiated as outer mesodermal cortex and inner ectodermal medulla of nervous origin.

Complete step by step answer: Adrenal medulla is the central part of adrenal gland and is derived from nervous tissue i.e. it is ectodermal in origin. Glandular cells of adrenal medulla are called chromaffin cells that secretes two hormones- 80% adrenaline or epinephrine and 20% nor-adrenaline or nor-epinephrine. Both these hormones are amine hormones and are derivatives of catechol, so collectively called catecholamine.
Adrenaline is a sympathomimetic hormone because it has the same biological effects as a sympathetic nervous system.
It increases the rate of heart beat and cardiac output so increases blood pressure.
It increases basal metabolic rate by 20% more than normal rate.
It increases blood sugar level in the blood by stimulating glycogenolysis in the liver.
It increases respiration rate as dilates trachea.
It increases lipolysis in adipose tissue.
It causes pupillary dilation.
It increases blood supply to the heart, skeletal muscles and brain acts as vasodilator.
It stimulates the contraction of arrector pili muscles to erect the body hair called piloerection.
Thus, when a man suddenly sees a tiger. His heartbeat goes up, blood pressure increases, etc. as adrenaline is released at this time in his body
Hyperactivity of adrenaline causes hypertension which may cause death.
So, the correct answer is “Option B”.

Note: In general adrenaline prepares the body to face emergency conditions of physical and emotional stress like fall in blood pressure, muscular exertion, pain, cold injury, anger, fear, etc. So epinephrine is also called the emergency hormone of hormones of “fight, fight or flight” and adrenal glands are called glands of emergency.