Biology · Chemical Coordination and Integration · NEET
Adrenaline and noradrenaline are made in the adrenal MEDULLA, the central (inner) tissue of the adrenal gland. The outer adrenal CORTEX makes different hormones called corticoids (glucocorticoids like cortisol and mineralocorticoids like aldosterone). NCERT is very clear: 'The centrally located tissue is called the adrenal medulla, and outside this lies the adrenal cortex.' A common NEET trap says glucocorticoids come from the medulla, which is wrong.
Yes. Adrenaline = epinephrine, and noradrenaline = norepinephrine. They are just two names for the same molecules. NCERT writes both names: 'adrenaline or epinephrine and noradrenaline or norepinephrine.' Together they are called catecholamines. NEET can use either name in a question, so learn both.
Because they are secreted very quickly in response to stress of any kind and during emergencies. They prepare the body to either fight the danger or run (flight) from it. NCERT: 'Adrenaline and noradrenaline are rapidly secreted in response to stress of any kind and during emergency situations and are called emergency hormones or hormones of Fight or Flight.'
It RAISES blood sugar, so it is a hyperglycemic hormone. Catecholamines stimulate the breakdown of glycogen (glycogenolysis), which increases blood glucose. NCERT: 'Catecholamines also stimulate the breakdown of glycogen resulting in an increased concentration of glucose in blood.' This is a very common NEET point and matches the 2025 PYQ.
Adrenaline causes pupil DILATION (widening), not constriction. It also causes increased alertness, piloerection (raising of hairs), and sweating. NCERT lists: 'increase alertness, pupilary dilation, piloerection (raising of hairs), sweating.' NEET 2025 tested exactly this trap: 'pupillary constriction' was the wrong statement.
Both hormones increase the heart beat (heart rate), the strength of heart contraction, and the rate of respiration. This delivers more oxygen and glucose-rich blood to muscles during an emergency. NCERT: 'Both the hormones increase the heart beat, the strength of heart contraction and the rate of respiration.'
Catecholamines (adrenaline/epinephrine) are amino-acid derived hormones, made from the amino acid tyrosine. In NCERT's classification by chemical nature, epinephrine is the given example of an amino-acid derivative. This was tested in NEET 2018, where epinephrine was the correct amino-acid derived hormone among steroid options.
Consider the following statements regarding function of adrenal medullary hormones: A. It causes pupillary constriction B. It is a hyperglycemic hormone C. It causes piloerection D. It increases strength of heart contraction. Choose the correct answer from the options given below:
Which of the following is an amino acid derived hormone?
Which of the following statements are correct with respect to the hormone and its function? (A) Thyrocalcitonin (TCT) regulates the blood calcium level. (B) In males, FSH and androgens regulate spermatogenesis. (C) Hyperthyroidism can lead to goitre. (D) Glucocorticoids are secreted in Adrenal Medulla. (E) Parathyroid hormone is regulated by circulating levels of sodium ions.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Catecholamines are the common name for adrenaline (epinephrine) and noradrenaline (norepinephrine), the two hormones secreted by the adrenal medulla. They are amino-acid derived hormones made from tyrosine.
The adrenal medulla, the central part of the adrenal gland sitting on top of each kidney, secretes adrenaline and noradrenaline. There is one pair of adrenal glands, one above each kidney.
Increased alertness, pupil dilation, piloerection (raising of hairs), sweating, faster heart beat, stronger heart contraction, faster breathing, and glycogen breakdown that raises blood glucose (hyperglycemic).
Neither. Adrenaline is an amino-acid derived hormone (made from tyrosine). It is water soluble and acts through membrane receptors, unlike steroid hormones that enter cells.
NCERT notes that nicotine in tobacco stimulates the adrenal gland to release adrenaline and noradrenaline into the blood, which raise blood pressure and increase heart rate. This is why smoking affects the cardiovascular system.
