Kit Library / Science / Biology
⚡ Topic Learning KitShared by a Veda learner · Generated with Veda AI
Veda Bites are swipeable micro-lessons — each one teaches exactly one idea. The bites below come from this kit — swipe through them in the app.
💡 Key Idea
One cycle, four phases, one egg.
The menstrual cycle is a recurring ~28-day ovarian cycle in females, ending in menstruation. It is divided into four phases controlled by hormones.
↳ The cycle is counted from the first day of menstrual flow to the next onset, about 28 days later.
📖 Definition
Three M-words that define reproductive life.
↳ Menstruation is absent before puberty, during pregnancy, and after menopause.
⭐ Important Fact
Three to five days of flow.
↳ Flow duration (3–5 days) is shorter than the full cycle (28 days) — don't confuse the two.
⚙️ Process
FSH, LH, estrogen, progesterone — the four conductors.
↳ FSH builds the follicle, estrogen rebuilds the uterus, LH releases the egg, progesterone prepares for implantation.
🕰️ Timeline
Day 14 is the turning point.
↳ Ovulation on day 13–14 splits the cycle into pre-ovulatory (follicular) and post-ovulatory (luteal) halves.
📖 Definition
Two gametes fuse — inside the fallopian tube.
↳ Fertilisation happens in the fallopian tube, NOT in the uterus.
⭐ Important Fact
300 million enter, only one fertilises.
↳ Despite millions of sperms, only one fertilises the egg — the rest are absorbed.
⚙️ Process
Acrosome enzymes open the door.
↳ Fertilisation usually occurs within 24 hours of ovulation and restores the diploid (23 pairs) chromosome number.
📖 Definition
The embryo digs in — pregnancy begins.
↳ Implantation occurs in the uterus (not the oviduct) and is essential for nourishment and O₂ from the mother.
⚙️ Process
Morula to blastocyst in four days.
↳ The zygote divides as it travels down the fallopian tube, reaching the uterus as a blastocyst by day 4.
📖 Definition
Two blood supplies, never mixing.
Foetal villi embed into maternal crypts, forming the placenta. A membrane always separates foetal and maternal blood — they never mix.
↳ Materials exchange across a membrane between foetal and maternal blood — the two bloods never directly mix.
⭐ Important Fact
Nutrition, respiration, excretion — all in one organ.
↳ The foetus uses the mother's digestive, respiratory and excretory systems through the placenta.
⚠️ Common Mistake
Fertilisation ≠ implantation location.
↳ Fertilisation = fallopian tube; Implantation = uterus. Never swap them.
⭐ Important Fact
Only 416 eggs ever get a chance.
↳ A female's reproductive window is about 32 years, with roughly 416 eggs maturing in that time.
🎯 Exam Tip
Know which hormone does what, and when.
↳ Link each hormone to its phase and target organ — this is the most commonly tested area.
This topic covers the human female reproductive cycle — the four phases of the menstrual cycle, the process and site of fertilisation, implantation of the blastocyst, and the structure and functions of the placenta. It a…
Full explanation, worked examples & memory tricks in the app
All 17 questions, laddered from warm-up to topper-level, each with its answer and the reasoning behind it.
Q1. The first menstruation at puberty is called:
BeginnerAnswers and explanations are in the Veda app.
Q2. The menstrual cycle is counted from:
BeginnerAnswers and explanations are in the Veda app.
Q3. Which hormone is responsible for the LH surge that triggers ovulation?
BeginnerAnswers and explanations are in the Veda app.
Q4. Fertilisation in humans normally occurs in the:
BeginnerAnswers and explanations are in the Veda app.
Q5. Ovulation occurs on the 13th or 14th day of the menstrual cycle when the mature Graafian follicle ruptures under the influence of **LH**.
BeginnerAnswers and explanations are in the Veda app.
Q6. A student says a missed period always means pregnancy. Which statement best corrects this?
IntermediateAnswers and explanations are in the Veda app.
Q7. During the follicular phase, the growing ovarian follicle secretes a hormone that:
IntermediateAnswers and explanations are in the Veda app.
Q8. If the corpus luteum degenerates, what is the immediate consequence?
IntermediateAnswers and explanations are in the Veda app.
Q9. Which enzyme action allows a sperm to enter the egg?
IntermediateAnswers and explanations are in the Veda app.
Q10. The fusion of male and female pronuclei is called:
IntermediateAnswers and explanations are in the Veda app.
Q11. Why is implantation described as a must for the embryo?
IntermediateAnswers and explanations are in the Veda app.
Q12. Which statement about maternal and foetal blood in the placenta is correct?
IntermediateAnswers and explanations are in the Veda app.
Q13. A woman's cycle is at day 14. Which event is most likely occurring?
AdvancedAnswers and explanations are in the Veda app.
Q14. Assertion (A): The placenta is called an endocrine organ. Reason (R): The placenta produces progesterone and estrogen to maintain pregnancy.
AdvancedAnswers and explanations are in the Veda app.
Q15. Which sequence correctly traces the journey from fertilisation to implantation?
AdvancedAnswers and explanations are in the Veda app.
Q16. A drug blocks the LH surge in a female. What is the most direct consequence?
AdvancedAnswers and explanations are in the Veda app.
Q17. Given the hormonal sequence of the menstrual cycle, if a woman experiences a surge in estrogen just before ovulation, which of the following sequences correctly describes the subsequent hormonal events leading to implantation?
AdvancedAnswers and explanations are in the Veda app.
40 flashcards in this kit — the app reviews them with spaced repetition so the right card returns on the right day.
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Word Match
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True False
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Memory Match
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Flashcard Battle
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Speed Quiz
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Guess Term
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Sequence Builder
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Categorization
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Revision Battle
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