Q.Why is oxytocin called birth hormone ?
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The Master Gland and Its Messengers
The pituitary gland sits at the base of your brain, about the size of a pea. But don't let its size fool you — it's called the "master gland" because it controls so many other glands in your body. Think of it as the CEO of a company: it doesn't do all the work itself, but it sends out orders that make other departments (thyroid, adrenal glands, ovaries, testes) do their jobs.
The pituitary has two distinct parts: the anterior lobe (front) and the posterior lobe (back). They're like two different departments that happen to share the same building. The anterior lobe makes its own hormones; the posterior lobe stores and releases hormones that were actually made in the brain (the hypothalamus).
Anterior Pituitary Hormones (Made Here)
The anterior pituitary produces six major hormones. Each one targets a specific organ or tissue elsewhere in the body.
Growth Hormone (GH)
GH stimulates growth in almost every tissue — especially bones and muscles. It's most active during childhood and adolescence. If too little is secreted, a child may have stunted growth (pituitary dwarfism). Too much can lead to gigantism in children or acromegaly (enlarged hands, feet, jaw) in adults.
Thyroid-Stimulating Hormone (TSH)
TSH travels to the thyroid gland in your neck and tells it to release thyroid hormones (T3 and T4). Those thyroid hormones then regulate your metabolism — how fast your body burns energy. Without TSH, your thyroid goes dormant.
Adrenocorticotropic Hormone (ACTH)
ACTH targets the adrenal cortex (the outer layer of the adrenal glands, which sit on top of your kidneys). It triggers the release of cortisol, a stress hormone that helps manage blood sugar, inflammation, and immune responses.
Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH)
These two work together as the gonadotropins — they control the reproductive system.
- In females: FSH stimulates the growth of ovarian follicles (which contain eggs); LH triggers ovulation (release of the egg) and helps form the corpus luteum.
- In males: FSH helps produce sperm; LH stimulates testosterone production from the testes.
Prolactin
Prolactin's main job is to initiate and maintain milk production in the mammary glands after childbirth. It's normally kept in check by dopamine from the hypothalamus — that's why prolactin levels stay low unless a woman is breastfeeding.
The anterior pituitary is sometimes called the adenohypophysis. Its hormones are all protein or peptide hormones — they can't cross cell membranes, so they bind to surface receptors and trigger second messengers inside the cell.
Posterior Pituitary Hormones (Stored Here, Made Upstairs)
The posterior pituitary doesn't make its own hormones. Instead, the hypothalamus (the brain region just above it) produces two hormones, which then travel down nerve fibres into the posterior pituitary for storage and release.
Oxytocin
Oxytocin is best known for two actions:
- Childbirth: It stimulates strong contractions of the uterine muscles during labour.
- Milk ejection: When a baby suckles, oxytocin is released, causing milk to be "let down" from the mammary glands.
It's also involved in bonding and social behaviour — sometimes called the "love hormone."
Vasopressin (Antidiuretic Hormone, ADH)
Vasopressin acts on the kidneys. It tells them to reabsorb more water back into the blood, producing more concentrated urine. This is how your body conserves water when you're dehydrated.
If vasopressin is deficient, you get diabetes insipidus — not the sugar-related diabetes, but a condition where you produce huge volumes of dilute urine and feel constantly thirsty.
Don't confuse diabetes insipidus (ADH deficiency) with diabetes mellitus (insulin deficiency). Both cause frequent urination, but the underlying hormones and mechanisms are completely different.
Summary Table
| Part | Hormone | Target | Main Effect |
|---|---|---|---|
| Anterior | GH | Bones, muscles, tissues | Growth |
Oxytocin triggers strong, coordinated contractions of the smooth muscle of the uterus wall during childbirth, helping to expel the foetus, which is why it is referred to as the birth hormone. …
Oxytocin earns the name 'birth hormone' because it causes the uterine muscle contractions that drive labour and delivery.
Oxytocin is a hormone synthesised in the hypothalamus and released from the posterior pituitary (neurohypophysis). Near the end of pregnancy, the uterus becomes highly sensitive to oxytocin. As labour begins, rising oxytocin levels stimulate the smooth muscle of the uterine wall (myometrium) to undergo strong, rhythmic contractions. These contractions push the foetus through the birth canal during delivery. This surge of contractions triggered by oxytocin is central to the process of parturition, which is why oxytocin is popularly call …
- CBSE 2026Set ANNUAL1 markMCQQ.Which of the following hormones is secreted by posterior pituitary (Neurohypophysis)?(a) Prolactin(b) Luteinizing hormone(c) Vasopressin(d) Growth hormone
›Reveal solutionSolution
Vasopressin (ADH) is a posterior pituitary (neurohypophyseal) hormone.
The posterior pituitary (neurohypophysis) does not itself synthesise hormones; instead it stores and releases two hormones synthesised by the hypothalamus: oxytocin and vasopressin (antidiuretic hormone, ADH). Vasopressin acts on the kidney to promote reabsorption of water (antidiuretic action) and helps maintain osmotic balance of body fluids, while also causing vasoconstriction to raise blood pressure at high doses.
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- CBSE 2026Set ANNUAL1 markQ.Write True/False: Acromegaly is a disease caused by the deficiency of growth hormone.
›Reveal solutionSolution
This statement is False — Acromegaly results from too much growth hormone (GH) in adults, not too little; GH deficiency instead causes dwarfism (in children) or related growth-deficiency conditions.
Growth hormone (GH/somatotropin), secreted by the anterior pituitary, regulates the growth of the body, including bones and soft tissues. If GH is secreted in excess in adults (after the epiphyseal growth plates of long bones have already fused), it cannot cause an increase in height, but it causes abnormal enlargement of the extremities — hands, feet, and facial bones (jaw, forehead) — a condition called Acromegaly. In contrast, if GH is under-secret …
- CBSE 2026Set ANNUAL1 markQ.Answer in one word/sentence: The disease named diabetes insipidus is caused by the deficiency of which hormone?
›Reveal solutionSolution
Diabetes insipidus results from a deficiency of Antidiuretic Hormone (ADH/vasopressin), leading to the excretion of large volumes of dilute urine.
ADH (vasopressin) is produced by the hypothalamus and released from the posterior pituitary; it acts on the kidney's distal convoluted tubule and collecting duct, increasing their permeability to water and thereby promoting water reabsorption, which concentrates the urine. When ADH secretion is deficient, the kidney tubules cannot reabsorb enough water, resulting i …
- CBSE 2026Set ANNUAL1 markMCQQ.The master gland of the endocrine system is(a) Thyroid gland(b) Adrenal gland(c) Pituitary gland(d) Pancreas
›Reveal solutionSolution
The pituitary is the master gland of the endocrine system, so the answer is (C).
The pituitary gland (hypophysis), located at the base of the brain, secretes several hormones that control other endocrine glands — for example, TSH (controls the thyroid), ACTH (controls the adrenal cortex), and gonadotropins (control the gonads). Because it directs the activity of so many other glands, it is called the master gland.
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- CBSE 2024Set ANNUAL1 markMCQQ.Assertion (A) : Vasopressin released by posterior pituitary is also called Anti-diuretic Hormone (ADH). Reason (R) : ADH increases the permeability of (PCT) Proximal Convoluted Tubule and collecting tubules to increase reabsorption of water and decrease the urine output.(a) Both Assertion (A) and Reason (R) are true and Reason (R) is correct explanation of Assertion (A).(b) Both Assertion (A) and Reason (R) are true but Reason (R) is not correct explanation of Assertion (A).(c) Assertion (A) is true but Reason (R) is false.(d) Both Assertion (A) and Reason (R) are false.
›Reveal solutionSolution
ADH (vasopressin) is correctly identified as being released from the posterior pituitary, but it regulates water reabsorption at the distal convoluted tubule (DCT) and collecting duct — not the proximal convoluted tubule (PCT), which reabsorbs water obligatorily regardless of ADH.
The Assertion states that vasopressin, released by the posterior pituitary (neurohypophysis), is also called Anti-Diuretic Hormone (ADH). This is correct — vasopressin and ADH are the same hormone, secreted by the hypothalamus and released from the posterior pituitary; it decreases urine formation and volume.
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- CBSE 2023Set zoology1 markQ.What is the full form of TSH?
›Reveal solutionSolution
TSH stands for Thyroid Stimulating Hormone, secreted by the anterior pituitary to regulate thyroid activity.
TSH (Thyroid Stimulating Hormone), also called thyrotropin, is one of the tropic hormones produced by the anterior lobe of the pituitary gland. Its secretion is itself controlled by TRH (Thyrotropin Releasing Hormone) from the hypothalamus. TSH travels through the blood to the thyroid gland, where it stimulates the follicular cells to take up iodine and synthesise the thyroid hormones thyroxine (T4) and triiodothyroni …
- CBSE 2023Set ANNUAL1 markMCQQ.Match the column. Item: Prolactin(a) Stigma(b) Cell division(c) Platyhelminthes(d) Cochlea(e) Earthworm(f) Lactation(g) Glycolysis
›Reveal solutionSolution
Prolactin is the pituitary hormone that stimulates milk secretion from the mammary glands, so it is matched with Lactation.
Prolactin (PRL) is secreted by the acidophilic cells of the anterior pituitary (adenohypophysis). Its principal, well-known physiological role is to stimulate and maintain milk production in the mammary glands following childbirth (growth of mammary tissue during pregnancy is chiefly under oestrogen/progesterone influence, but actual milk synthesis and secretion after …
- CBSE 2022Set TERM11 markMCQQ.Which of the following hormones is secreted by Pituitary gland?(a) Thyroxine(b) Gonadotropins(c) Melatonin(d) Thymosin
›Reveal solutionSolution
Of the four hormones listed, only gonadotropins are secreted by the pituitary gland.
Matching each hormone to its actual gland of origin:
- Thyroxine: secreted by the THYROID gland, not the pituitary.
- Gonadotropins (FSH -- follicle-stimulating hormone, and LH -- luteinizing hormone): secreted by the anterior part (adenohypophysis) of the PITUITARY gland; they act on the gonads (testes/ovaries) to regulate gametogenesis and sex-hormone production. This is the correct match. …
- CBSE 2022Set ANNUAL1 markMCQQ.Match the Column-A item 'Pituitary Gland' with the correct term from Column-B.(a) Chromosome(b) Pea-shaped(c) Pectoral girdle(d) Solanaceae(e) Gymnosperm(f) Bones(g) Mg
›Reveal solutionSolution
The pituitary gland is described as pea-shaped.
The pituitary gland (hypophysis) sits in a bony cavity at the base of the brain, connected to the hypothalamus by a stalk. Despite controlling many other endocrine glands in the body by secreting a wide range of hormones (growth hormone, TSH, ACTH, FSH, LH, prolactin, oxytocin, vasopressin), it is very small …
- CBSE 2021Set zoology1 markQ.What is the full form of TSH?
›Reveal solutionSolution
TSH = Thyroid Stimulating Hormone, an anterior-pituitary hormone that stimulates the thyroid gland.
TSH is short for Thyroid Stimulating Hormone (also called thyrotropin). It is a tropic hormone secreted by the anterior lobe (pars distalis) of the pituitary gland.
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- CBSE 2020Set ANNUAL1 markMCQQ.Which of the following hormones is secreted by Pituitary gland ?(a) Thyroxine(b) Gonadotropins(c) Melatonin(d) Thymosin
›Reveal solutionSolution
Gonadotropins (like FSH and LH) are among the hormones secreted by the anterior pituitary gland (the 'master gland'), which also produces GH, TSH, ACTH, and prolactin.
The pituitary gland (hypophysis) has anterior and posterior lobes; the anterior pituitary secretes several tropic hormones including growth hormone, thyroid-stimulating hormone, adrenocorticotropic hormone, prolactin, and the gonadotropins (Follicle-Stimulating Hormone and Luteinising Hormone), which regulate the activity of the testes/ovaries.
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- CBSE 2018Set zoology1 markQ.Name the hormones stored and released by posterior pituitary gland.
›Reveal solutionSolution
The two hormones stored and released by the posterior pituitary are Oxytocin and Vasopressin (ADH) — both are synthesised in the hypothalamus and merely stored/released from the posterior pituitary.
The pituitary gland (hypophysis) has two functionally distinct parts: the anterior pituitary (adenohypophysis), which itself synthesises several hormones, and the posterior pituitary (neurohypophysis), which does not synthesise hormones of its own. Instead, neurosecretory cells of the hypothalamus synthesise two hormones, which travel down nerve axons (the hypothalamo-hypophyseal tract) to be stored in and released from the posterior pituitary:
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