HUMAN REPRODUCTION — NEET NOTES
NCERT Based • Detailed Notes • PYQ Focused • Easy Language
Introduction
Human reproduction is the process by which humans produce offspring through sexual reproduction.
In humans:
- Male gamete = Sperm
- Female gamete = Ovum
Fusion of sperm and ovum forms:
Zygote
Main Events of Human Reproduction
- Gametogenesis
- Insemination
- Fertilisation
- Cleavage
- Implantation
- Gestation
- Parturition
Mind map of chapter
Male Reproductive
System
Major Parts
- Testes
- Accessory ducts
- Accessory glands
- External genitalia
TESTES
Important Points
- Present in scrotal sac
- Oval-shaped organs
- Outside abdominal cavity
Why outside?
For maintaining:
2–2.5°C lower temperature
Necessary for:
Spermatogenesis
Structure of Testis
Each testis contains:
Seminiferous Tubules
These are tightly coiled structures where:
Sperm formation occurs
Cells Present in Seminiferous Tubules
1. Male Germ Cells
Function:
Produce sperms
2. Sertoli Cells
Function:
- Nourishment to sperms
- Support sperm development
PYQ
Which cells are called “nurse cells”?
Sertoli cells
Interstitial Cells / Leydig Cells
Located:
Between seminiferous tubules
Function:
Testosterone secretion
Important Hormone
Testosterone helps in:
- Spermatogenesis
- Secondary sexual characters
Male Accessory Ducts
Path of sperm:
Seminiferous Tubules
↓ Rete Testis ↓ Vasa Efferentia ↓ Epididymis ↓ Vas Deferens ↓ Urethra
Epididymis
Function:
Storage and maturation of sperms
Accessory Glands
1. Seminal Vesicles
Secrete:
Fructose-rich fluid
Provides energy to sperms.
2. Prostate Gland
Secretes:
Alkaline fluid
Helps in sperm motility.
3. Bulbourethral Glands
Secrete mucus for:
Lubrication
Semen
Composition
- Sperms
- Seminal plasma
Seminal plasma contains:
- Fructose
- Calcium
- Enzymes
Spermatogenesis
Formation of sperm from:
Spermatogonia
Occurs in:
Seminiferous tubules
Starts:
At puberty
Phases of Spermatogenesis
1. Multiplication Phase
Spermatogonia divide mitotically.
2. Growth Phase
Primary spermatocyte formed.
3. Maturation Phase
Meiosis occurs.
Primary spermatocyte ↓ Secondary spermatocyte ↓ Spermatids
Spermiogenesis
Transformation of:
Spermatids → Sperms
Spermiation
Release of sperm from:
Sertoli cells
Hormonal Control of Spermatogenesis
Hypothalamus secretes:
GnRH
Pituitary secretes:
- LH
- FSH
LH
Acts on:
Leydig cells
Stimulates testosterone secretion.
FSH
Acts on:
Sertoli cells
Helps sperm formation.
FEMALE REPRODUCTIVE SYSTEM
Parts
- Ovaries
- Fallopian tubes
- Uterus
- Cervix
- Vagina
- External genitalia
Ovaries
Functions:
- Ovum formation
- Hormone secretion
Hormones:
- Estrogen
- Progesterone
Structure of Ovary
Contains follicles in different stages:
- Primary follicle
- Secondary follicle
- Graafian follicle
Graafian Follicle
Mature follicle containing:
Secondary oocyte
Fallopian Tubes
Parts
- Infundibulum
- Ampulla
- Isthmus
Fertilisation occurs at:
Ampullary-Isthmic Junction
⭐ MOST IMPORTANT PYQ
Uterus
- Pear-shaped organ
- Site of implantation
- Development of embryo
Inner lining:
Endometrium
OOGENESIS
Formation of ovum in ovary.
Starts:
During foetal life
Important Arrest Stages
Primary Oocyte
Arrested in:
Prophase-I
Secondary Oocyte
Arrested in:
Metaphase-II
PYQ FAVORITE
Menstrual Cycle
Average duration:
28 days
1. Menstrual Phase
Days:
1–5
Features:
- Endometrium breaks down
- Bleeding occurs
2. Follicular Phase
FSH stimulates:
Follicle development
Estrogen level:
Increases
Endometrium regenerates.
3. Ovulation
Occurs around:
14th day
Triggered by:
LH surge
Graafian follicle ruptures and releases ovum.
4. Luteal Phase
Ruptured follicle becomes:
Corpus luteum
Corpus luteum secretes:
Progesterone
Function: Maintain endometrium.
FERTILISATION
Fusion of:
Sperm + Ovum
Occurs at:
Ampullary-Isthmic Junction
ACROSOME REACTION
Acrosome releases enzymes to penetrate ovum.
Important enzymes:
- Hyaluronidase
- Acrosin
Cleavage
Rapid mitotic divisions of zygote.
Stages: Zygote ↓ Morula ↓ Blastocyst
Implantation
Attachment of:
Blastocyst to uterine wall
Occurs:
6–7 days after fertilisation
Pregnancy and Placenta
Placenta
Temporary connection between mother and foetus.
Functions of Placenta
- Nutrition
- Respiration
- Excretion
- Hormone secretion
Placental Hormones
- hCG
- hPL
- Estrogen
- Progesterone
hCG
Maintains:
Corpus luteum
Pregnancy test detects:
hCG
Pregnancy Duration
Normal duration:
9 months / 280 days
Parturition
Delivery of baby.
Triggered by:
Oxytocin
Lactation
Milk secretion after childbirth.
Colostrum
First milk secreted after delivery.
Rich in:
IgA antibodies
Provides passive immunity.
NCERT MOST IMPORTANT LINES
- Seminiferous tubules are the sites of sperm formation.
- LH stimulates Leydig cells.
- FSH stimulates Sertoli cells.
- Fertilisation occurs in ampullary-isthmic junction.
- Implantation occurs in uterus.
- Colostrum contains antibodies.
MOST IMPORTANT NEET PYQs
Q1.
Which hormone causes ovulation?
LH surge
Q2.
Which cells secrete testosterone?
Leydig cells
Q3.
Which cells nourish sperms?
Sertoli cells
Q4.
Site of fertilisation?
Ampullary-isthmic junction
Q5.
First milk after childbirth?
Colostrum
SUPER FAST REVISION TABLE
| Topic | Important Point |
|---|---|
| Sperm formation | Seminiferous tubules |
| Testosterone | Leydig cells |
| Nurse cells | Sertoli cells |
| Ovulation | Day 14 |
| Fertilisation | Ampullary-isthmic junction |
| Implantation | Uterus |
| First milk | Colostrum |
| Pregnancy hormone | hCG |
NEET EXAM TREND
From this chapter NEET asks:
✅ NCERT line-based questions
✅ Diagram questions
✅ Hormonal control
✅ Site-based questions
✅ Match the following
✅ Statement-based MCQs
So NCERT reading is VERY important 😄
HUMAN REPRODUCTION — NEET PYQ TREND (Topic Wise)
1. Testis & Seminiferous Tubules
Frequently Asked:
Function of seminiferous tubules
Sertoli cells
Leydig cells
PYQs:
NEET 2024 → Sertoli cells function
NEET 2022 → Testosterone secreting cells
AIIMS 2019 → Seminiferous tubules site of sperm formation
---
2. Spermatogenesis
Frequently Asked:
Stages
Hormonal control
Spermiogenesis vs Spermiation
PYQs:
NEET 2023 → Hormonal regulation of spermatogenesis
NEET 2020 → Spermiogenesis definition
NEET 2018 → Role of FSH and LH
---
3. Male Accessory Glands
Frequently Asked:
Functions of seminal vesicles
Prostate gland secretion
PYQs:
NEET 2021 → Fructose-rich secretion
AIPMT 2016 → Accessory gland functions
---
4. Oogenesis
Frequently Asked:
Arrest stages
Primary oocyte
Secondary oocyte
PYQs:
NEET 2024 → Metaphase-II arrest
NEET 2021 → Prophase-I arrest
NEET 2019 → Oogenesis starts during fetal life
---
5. Menstrual Cycle
Frequently Asked:
Ovulation day
LH surge
Corpus luteum
Hormones during phases
PYQs:
NEET 2023 → LH surge causes ovulation
NEET 2022 → Corpus luteum function
NEET 2020 → Menstrual phase events
AIPMT 2015 → Estrogen role
---
6. Fertilisation
MOST IMPORTANT TOPIC ⭐
Frequently Asked:
Site of fertilisation
Acrosome reaction
Capacitation
PYQs:
NEET 2024 → Site of fertilisation
NEET 2021 → Acrosome enzymes
NEET 2018 → Capacitation
---
7. Implantation
Frequently Asked:
Blastocyst implantation
Time after fertilisation
PYQs:
NEET 2022 → Implantation timing
AIIMS 2018 → Blastocyst attachment
---
8. Placenta
Frequently Asked:
Placental hormones
Placenta functions
PYQs:
NEET 2023 → hCG hormone
NEET 2020 → Placenta functions
AIPMT 2017 → Hormones secreted by placenta
---
9. Parturition & Lactation
Frequently Asked:
Oxytocin
Colostrum
IgA antibodies
PYQs:
NEET 2024 → Colostrum importance
NEET 2021 → Oxytocin role
NEET 2019 → Passive immunity
---
MOST REPEATED NEET QUESTIONS ⭐
Topic Repeated Question
Fertilisation Site of fertilisation
Menstrual Cycle LH surge
Oogenesis Arrest stages
Placenta hCG hormone
Testis Sertoli vs Leydig cells
Lactation Colostrum
---
HIGH WEIGHTAGE AREAS FOR NEET
MUST DO TOPICS:
✅ Menstrual Cycle
✅ Spermatogenesis
✅ Oogenesis
✅ Fertilisation
✅ Placenta
✅ Hormonal Control
इन topics से almost हर साल question आता है 😄
All the best all of you.
