Q.(a)
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🔒 Start your 14-day free trial to unlock the full solution →Part (a)Concept understanding — Parturition Hormonal Control
Let’s begin with something you already know. When a baby is ready to be born, the mother’s body doesn’t just “decide” one day — it follows a precise, hormone-driven sequence. Think of it like a carefully timed relay race: one hormone passes the baton to the next, and each step triggers the next until labour begins.
The everyday intuition
Imagine you are waiting for a train. The station master doesn’t just blow the whistle randomly. First, the train arrives at the platform, then the guard checks the signal, then the whistle blows, and only then does the train move. Parturition — the process of giving birth — works the same way. The baby’s body sends the first signal, the mother’s body receives it, and a chain of hormonal commands follows. No signal, no movement.
What parturition means
Parturition is the medical term for childbirth — the expulsion of the fully developed baby from the mother’s uterus. In NCERT Class 12 Biology (Chapter: Human Reproduction), it is described as the process that begins with the onset of labour and ends with the delivery of the baby and the placenta.
The key point: parturition is not a sudden event. It is the climax of a hormonal cascade that starts weeks earlier.
The hormonal relay: step by step
The entire process is controlled by a feedback loop between the baby’s brain, the mother’s hypothalamus, and her uterus. Here is the sequence as NCERT presents it:
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The baby’s brain starts it. As the foetus grows, its hypothalamus matures and releases corticotropin-releasing hormone (CRH). This hormone travels to the foetal pituitary gland.
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Foetal pituitary secretes ACTH. ACTH (adrenocorticotropic hormone) stimulates the foetal adrenal glands to produce cortisol.
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Cortisol from the foetus acts on the placenta. The placenta, which connects mother and baby, responds by producing oestrogen in increasing amounts. At the same time, progesterone levels fall.
The shift from high progesterone to high oestrogen is the critical switch. Progesterone keeps the uterus relaxed (quiet). Oestrogen makes the uterine muscle sensitive to contraction signals. Without this shift, labour cannot begin.
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Oestrogen stimulates the uterus to produce oxytocin receptors. The mother’s posterior pituitary gland also releases oxytocin — the hormone that causes strong, rhythmic contractions of the uterine muscles.
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Oxytocin creates a positive feedback loop. Each contraction pushes the baby’s head against the cervix. This stretching of the cervix sends nerve signals back to the mother’s brain, which releases more oxytocin. More oxytocin → stronger contractions → more stretching → even more oxytocin. This cycle continues until the baby is delivered.
Why this matters
- It explains why labour cannot be induced artificially without medical intervention — the baby’s own hormones must first signal readiness.
- It also explains why stress or illness in the mother can delay labour: if the foetal cortisol signal is weak, the oestrogen shift may not happen on time.
- In some cases, doctors use synthetic oxytocin (Pitocin) to start or strengthen labour — this mimics the natural hormone.
A quick summary of the key hormones
| Hormone | Source | Role in parturition |
|---|---|---|
| CRH | Foetal hypothalamus | Starts the cascade |
| ACTH | Foetal pituitary | Stimulates foetal adrenal glands |
Part (b)Concept understanding — Health Effects
Health Effects — A First Look
Think about the last time you drank water from a roadside stall during summer. Your mind probably weighed two things: the immediate thirst, and the vague worry about whether the water was clean. That worry — that something in the environment might harm your body — is exactly what "health effects" means.
In simple terms, health effects are the changes — good or bad — that happen to your body and mind when you are exposed to something in your surroundings. That "something" could be polluted air, contaminated food, loud noise, stress at work, or even a new medicine. The key idea is that your environment and your health are not separate; they are constantly interacting.
The precise meaning
The NCERT textbook (Class 12, Business Studies, Chapter 12 — Consumer Protection) introduces health effects in the context of consumer awareness. When you buy a product or use a service, you have a right to know whether it will harm you. Health effects, therefore, refer to the physical or mental consequences that arise from using a product, consuming a food item, or living in a particular environment.
These effects can be:
- Immediate — like a headache from a chemical smell, or food poisoning from stale food.
- Long-term — like lung disease from years of breathing polluted air, or hearing loss from constant loud music.
- Direct — like a burn from a faulty appliance.
- Indirect — like stress and anxiety caused by unsafe living conditions.
Health effects are not just about illness. They also include positive effects — for example, the health benefit of drinking clean water or using a well-designed ergonomic chair. The term is neutral; it simply describes the outcome of an exposure.
Why it matters for a commerce/humanities student
You might think health effects belong only in biology or medicine. But in commerce and humanities, they are central to consumer protection, business ethics, and public policy.
Consider a company that sells packaged food. If the food contains a harmful preservative, the health effect on consumers could be serious — and the company faces legal action, loss of reputation, and financial penalties. That is why the Consumer Protection Act, 2019, gives you the right to safety — meaning products must not cause harm under normal use.
Similarly, in economics, health effects are part of externalities. A factory that pollutes a river creates a negative health effect for people downstream — but the factory does not pay for that harm. Understanding health effects helps you see why governments regulate industries and why consumers need protection.
A few key points to remember
- Health effects can be physical (like a rash, cough, or injury) or mental (like anxiety, depression, or stress).
- They can arise from products (food, medicines, electronics), services (healthcare, transport), or environmental factors (air, water, noise). …
Part (a)
(i) The milk of the first few days is essential because it is rich in antibodies, especially IgA, which provide the newborn with passive immunity, protecting it against infections while its own immune system is still immature. …
Part (a): The first milk, colostrum, is rich in IgA antibodies that give the newborn passive immunity.
Part (b): The exaggerated immune response to weak airborne antigens is allergy, mediated by IgE antibodies, with mast cells releasing histamine and serotonin.
Part (a)
- Why the initial milk is essential The milk produced during the first few days after childbirth is a thick, yellowish fluid rich in antibodies, particularly Immunoglobulin A (IgA). A newborn's own immune system is immature, so these maternal antibodies coat the infant's gut and provide passive immunity, protecting it from infections during this vulnerable period.
- Term for this milk …
Showing the 12 most recent of 31 on this concept.
- CBSE 2026Set 57/3/11 markMCQQ.Foetal ejection reflex in human female triggers the release of which hormone ? (A) Oxytocin from foetal pituitary gland (B) hCG from placenta (C) Progesterone from corpus luteum (D) Oxytocin from maternal pituitary gland
›Reveal solutionSolution
The foetal ejection reflex triggers the release of oxytocin from the maternal pituitary gland, which then drives uterine contractions during childbirth.
The foetal ejection reflex is a beautifully coordinated physiological event that marks the final stage of pregnancy. When the baby's head presses against the cervix and vaginal walls, sensory nerve impulses travel from the cervix to the hypothalamus in the mother's brain. This neural signal is the trigger — it tells the posterior pituitary gland to release oxytocin into the mother's bloodstream.
Oxytocin is the key hormone here. It acts directly on the smooth muscles of the uterus, making them contract more strongly. These contractions push the baby further down, which stretches the cervix even more, which in turn signals the release of even more oxytocin. This is a classic positive feedback loop — the more the uterus contracts, the more oxytocin is released, and the stronger the contractions become. The cycle continues until the baby is delivered.
ImportantThe oxytocin that drives this process comes from the mother's posterior pituitary gland, not from the foetus. The foetal pituitary is not involved in this reflex. …
- CBSE 2026Set 57/3/11 markMCQQ.Some statements regarding drugs and alcohol are given below :(i) Adolescents are more vulnerable to peer pressure.(ii) Drug addiction leads to increased tolerance level of the receptors present in our body.(iii) Alcohol affects the central nervous system.(iv) Excessive use of drugs helps to increase energy.(v) Anabolic steroids decrease aggressiveness. Choose the option with correct statement(s). (A) Statements (i),(iv) and(v) are correct (B) Statements (i),(ii) and(iii) are correct (C) Only statements(i) and(v) are correct (D) Only statement(iii) is correct
›Reveal solutionSolution
Only statements (i), (ii), and (iii) are factually correct; statements (iv) and (v) are false.
Let’s look at each statement one by one, because this question tests not just memory but a clear understanding of how drugs and alcohol actually work in the body.
Statement (i) — Adolescents are more vulnerable to peer pressure. This is widely accepted. The teenage brain is still developing, especially the prefrontal cortex responsible for impulse control and long-term decision-making. At the same time, social belonging becomes intensely important. That combination makes adolescents genuinely more susceptible to peer influence, including pressure to try drugs or alcohol. So this statement is correct.
Statement (ii) — Drug addiction leads to increased tolerance level of the receptors present in our body. This is a precise and accurate point. With repeated use of many drugs, the body adapts. Receptors on nerve cells become less sensitive or reduce in number, so the user needs a larger dose to feel the same effect. That is exactly what tolerance means — it is a physiological change, not just a psychological one. So this statement is correct.
Statement (iii) — Alcohol affects the central nervous system. Absolutely. Alcohol is a central nervous system depressant. It slows down brain activity, impairs coordination, judgment, and reaction time, and in large amounts can lead to unconsciousness or even respiratory failure. This is one of the most basic facts about alcohol. So this statement is correct. …
- CBSE 2026Set V11 markQ.The initial few days of milk produced after parturition is ___________.
›Reveal solutionSolution
The first milk secreted after childbirth is colostrum.
The milk produced by the mammary glands during the initial few days after parturition (childbirth) is called colostrum. It is yellowish, and is rich in antibodies (especially IgA) that provide essential passive immuni …
- CBSE 2026Set ANNUAL1 markMCQQ.Which hormone is involved to induce parturition?(a) Prolactin(b) Adrenaline(c) Oxytocin(d) Progesterone
›Reveal solutionSolution
Parturition (delivery) is induced by a neuro-endocrine reflex in which the posterior pituitary hormone oxytocin causes powerful uterine contractions.
At the end of pregnancy, signals from the fully-developed foetus and the placenta induce mild uterine contractions called the 'foetal ejection reflex'. This triggers release of oxytocin from the maternal posterior pituitary, which acts on the uterine (myometrial) muscle causing strong contractions, which in turn stimulate further oxytocin release (a positiv …
- CBSE 2026Set ANNUAL1 markQ.The milk produced during the initial few days of lactation is called ________.
›Reveal solutionSolution
The yellowish fluid secreted by the mammary glands during the first few days of lactation is called colostrum, and it is rich in antibodies (IgA) essential for building the newborn's immunity.
After parturition, the mammary glands of the mother start producing milk (lactation) under the stimulus of the hormone prolactin. The milk produced during the initial few days of lactation is called colostrum. Colostrum contains several antibodies (mainly Immunoglobulin A, IgA) that are absolutely essential for building the immune system (passive im …
- CBSE 2026Set ANNUAL1 markQ.Why is mother's milk considered very essential for the new-born infants?
›Reveal solutionSolution
Mother's milk (colostrum) supplies antibodies (IgA) for passive immunity plus complete nutrition, protecting the newborn.
The milk produced during the initial few days of lactation is called colostrum. It is yellowish and contains several antibodies, chiefly immunoglobulin A (IgA). Since the newborn's own immune system is not yet developed, these maternal antibodies provide passive immunity that protects the infant against infections.
…
- CBSE 2026Set ANNUAL1 markQ.“Smoking causes oxygen deficiency in human body”. Justify the statement.
›Reveal solutionSolution
Carbon monoxide in cigarette smoke binds haemoglobin more strongly than oxygen, reducing oxygen transport — so smoking causes oxygen deficiency.
Tobacco smoke contains carbon monoxide (CO) and nicotine. Haemoglobin, the oxygen-carrying pigment of blood, has a much higher affinity for CO than for oxygen (about 200 times). When a person smokes, CO binds haemoglobin to form stable carboxyhaemoglobin, so that much less haemoglobin is available to bind and transport oxygen.
…
- CBSE 2026Set ANNUAL1 markQ.Write True or False. Cocaine is obtained from the leaves of the Erythroxylum coca and acts as a stimulant on the central nervous system.
›Reveal solutionSolution
True — cocaine comes from the coca plant (Erythroxylum coca) and is a CNS stimulant.
In the CBSE/NCERT Human Health and Disease chapter (drugs and alcohol abuse), cocaine is extracted from the leaves of Erythroxylum coca, native to South America. It interferes with dopamine transport in the brain and acts as a powerful **stimulant …
- CBSE 2025Set X11 markQ.____________ acts on uterine muscle and cause stronger contractions during parturition.
›Reveal solutionSolution
Oxytocin causes strong uterine contractions during childbirth.
Oxytocin, released from the posterior pituitary, acts on the smooth muscles of the uterus and causes stronger contractions during parturition (childbirth). A vigorous positive feedback loop (foetal ejec …
- CBSE 2025Set A1 markQ.Answer in one word / sentence: What is Colostrum?
›Reveal solutionSolution
Colostrum is the first milk produced after childbirth, rich in maternal antibodies that protect the newborn.
During the initial days of lactation, the mammary glands secrete a special milk called colostrum. It is yellowish and thick, and importantly contains a high concentration of immunoglobulins (mainly IgA) along with other nutrients. These maternal antibodies passed to the infant through colostrum provide passive immunity, helping protect the newborn from infections until its own immune sys …
- CBSE 2025Set ANNUAL1 markQ.Define parturition.
›Reveal solutionSolution
Parturition is the hormonally triggered process of childbirth, marking the end of gestation.
Parturition refers to the process of delivery of the fully developed foetus (and, subsequently, the placenta) from the uterus, marking the end of a full-term pregnancy (about 9 months/40 weeks in humans). It is induced by complex neuroendocrine signals, involving mild uterine contractions (Ferguson's reflex) initiated by signals from the fully developed foetus and the placenta, which stimulate release of the hormone oxytocin from the mother's pituitary; oxytocin acts on the uterine mu …
- CBSE 2024Set 57/3/11 markMCQQ.(A) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A). (B) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A). (C) Assertion (A) is true, but Reason (R) is false. (D) Assertion (A) is false, but Reason (R) is true. Assertion (A) : The chronic use of alcohol by a person leads to cirrhosis. Reason (R) : Alcohol addiction at times becomes the cause of mental and financial distress to the entire family of the addicted person.
›Reveal solutionSolution
Assertion (A) is true because chronic alcohol use damages the liver, leading to cirrhosis. Reason (R) is also true as alcohol addiction causes significant mental and financial distress to families. However, Reason (R) does not explain the biological mechanism behind Assertion (A). Therefore, both statements are true, but R is not the correct explanation for A.
When tackling Assertion-Reason questions, the strategy is always two-fold:
- Independently evaluate each statement: Determine if Assertion (A) is true or false, and if Reason (R) is true or false.
- Check for explanatory power: If both (A) and (R) are true, then determine if Reason (R) provides a correct explanation for Assertion (A). Does R answer "why" A is true?
Let's apply this approach to the given statements.
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Evaluating Assertion (A): "The chronic use of alcohol by a person leads to cirrhosis."
- Cirrhosis is a severe and irreversible scarring of the liver, which impairs its ability to function. The liver is the primary organ responsible for metabolizing alcohol. Chronic and excessive alcohol consumption overwhelms the liver's capacity to process alcohol and its toxic byproducts, leading to inflammation (alcoholic hepatitis) and eventually the destruction of liver cells, which are replaced by fibrous scar tissue. This process is known as cirrhosis.
- Therefore, Assertion (A) is a factually correct statement.
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Evaluating Reason (R): "Alcohol addiction at times becomes the cause of mental and financial distress to the entire family of the addicted person."
- Alcohol addiction is a complex disease with far-reaching consequences beyond the individual. It often leads to strained relationships, emotional instability, neglect of responsibilities, and significant financial burdens due to the cost of alcohol, lost employment, and potential medical expenses. These factors invariably cause immense mental and financial distress to the family members who are directly affected by the addicted person's behaviour and circumstances.
- Therefore, Reason (R) is also a factually correct statement.
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Determining if Reason (R) explains Assertion (A): …
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