🌸 Chapter 2
Human Reproduction
(SUMMARY NOTES )
🧩 1. Overview
Human beings reproduce sexually, involving:
1.
Formation
of gametes (sperms & ova)
2.
Fusion
(fertilization) → zygote
3.
Embryonic
development → foetus
4.
Birth
of offspring
Reproduction ensures continuity of species and transfer
of genetic material.
🧔 2. MALE REPRODUCTIVE
SYSTEM
Main parts:
- Testes (Primary organ):
- Located in scrotum (2–2.5°C
below body temp).
- Contain seminiferous
tubules (site of spermatogenesis).
- Leydig (Interstitial) cells secrete testosterone.
- Sertoli cells nourish sperms.
Accessory ducts:
- Rete testis → Vasa efferentia →
Epididymis → Vas deferens → Ejaculatory duct → Urethra
Glands:
1.
Seminal
vesicles –
fructose for sperm energy
2.
Prostate
gland – milky
alkaline secretion
3.
Bulbourethral
gland –
lubrication before ejaculation
External genitalia: Penis (copulatory organ)
🧠 Keyword: Spermatogenesis occurs in
seminiferous tubules under FSH & testosterone.
✏️ Diagram: Male Reproductive System
(For quick drawing in exam)
Label: Testis, Epididymis, Vas deferens, Seminal vesicle, Prostate gland,
Urethra, Penis.
👩🦰 3. FEMALE
REPRODUCTIVE SYSTEM
Main parts:
- Ovaries (Primary organ):
- Produce ova (eggs) and
hormones (estrogen, progesterone).
- Ovarian follicle develops into
Graafian follicle.
Accessory ducts:
- Fallopian tube (Oviduct): Fimbriae → Infundibulum →
Ampulla → Isthmus
➤ Site of fertilization: Ampulla - Uterus (Womb): Site for implantation &
fetal growth
➤ Layers – Perimetrium, Myometrium, Endometrium - Cervix & Vagina: Passage for sperm and
childbirth.
✏️ Diagram: Female Reproductive
System
Label: Ovary, Oviduct, Uterus, Cervix, Vagina, Endometrium.
⚙️ 4. GAMETOGENESIS
🧬 Spermatogenesis:
- Begins at puberty.
- Spermatogonia → Primary spermatocyte →
Secondary spermatocyte → Spermatid → Spermatozoa.
- Controlled by FSH & Testosterone.
🧫 Oogenesis:
- Begins before birth.
- Oogonia → Primary oocyte →
Secondary oocyte (released at ovulation).
- Meiosis II completes only after
fertilization.
🔄 5. MENSTRUAL CYCLE (28
days)
|
Phase |
Days |
Main Events |
|
Menstrual |
1–5 |
Shedding of endometrium |
|
Follicular |
6–13 |
Follicle grows, estrogen rises |
|
Ovulation |
14 |
LH surge, egg released |
|
Luteal |
15–28 |
Corpus luteum forms, progesterone secreted |
🧠 Keywords:
- FSH – follicle growth
- LH – ovulation
- Estrogen – rebuild endometrium
- Progesterone – maintain
endometrium
⚗️ 6. FERTILIZATION AND IMPLANTATION
- Fertilization:
- Occurs in ampulla of
oviduct.
- Sperm releases enzymes (acrosomal
reaction) to penetrate ovum.
- Male & female nuclei fuse
→ zygote (diploid).
- Implantation:
- Zygote → Morula → Blastocyst →
implants into uterine wall (6–7 days post-fertilization).
- Trophoblast helps in embedding
blastocyst.
🧠 Keyword: Fertilization restores diploid
number and determines sex (XX/XY).
👶 7. EMBRYONIC DEVELOPMENT
- Cleavage: Rapid mitotic divisions →
Morula → Blastocyst
- Gastrulation: Formation of three germ layers
– ectoderm, mesoderm, endoderm.
- Organogenesis: Organs develop from germ
layers.
🩸 8. PLACENTA &
PREGNANCY
Placenta:
Temporary organ between mother & fetus.
Functions:
- Nutrient, gas & waste
exchange
- Hormone secretion: hCG, hPL,
estrogen, progesterone
- Provides antibodies (immunity)
Hormones of pregnancy:
- hCG: Maintains corpus luteum
- Progesterone: Maintains endometrium
- Estrogen: Uterine growth
- hPL: Fetal metabolism & mammary
gland preparation
- Relaxin: Loosens pelvic ligaments
👩🍼 9. PARTURITION
& LACTATION
Parturition (Childbirth):
- Triggered by fetal ejection
reflex.
- Oxytocin causes uterine contractions
(positive feedback).
- Stages: Dilation → Expulsion →
Placental stage.
Lactation:
- Prolactin: Milk production
- Oxytocin: Milk ejection
- Colostrum: Yellowish milk rich in
antibodies (IgA) – gives passive immunity.
🧠 10. REPRODUCTIVE HEALTH
LINKS
(Quick connection with next chapter)
- Contraceptives: Barrier
(condom), Hormonal (pills), IUDs, Surgical (vasectomy, tubectomy).
- Assisted Reproductive
Technologies (ART): IVF, ICSI, ZIFT, GIFT.
🧾 11. IMPORTANT DEFINITIONS
(NCERT Keywords)
|
Term |
Definition |
|
Spermatogenesis |
Formation of sperm in testes |
|
Oogenesis |
Formation of ovum in ovary |
|
Ovulation |
Release of ovum from ovary |
|
Fertilization |
Fusion of male and female gametes |
|
Implantation |
Attachment of blastocyst to uterine wall |
|
Placenta |
Organ connecting mother and fetus |
|
Colostrum |
First milk rich in antibodies |
|
Corpus luteum |
Temporary gland after ovulation secreting progesterone |
|
Menstrual cycle |
Cyclic changes in female reproductive system |
|
Puberty |
Stage of sexual maturity |
📊 12. DIAGRAMS TO PRACTICE
FOR BOARD EXAM
1.
Male
Reproductive System
2.
Female
Reproductive System
3.
Structure
of Sperm
4.
Structure
of Ovum
5.
Spermatogenesis
(flow chart)
6.
Oogenesis
(flow chart)
7.
Menstrual
Cycle (graph of hormone levels)
8.
Blastocyst
& Implantation diagram
(Practice neat labeled diagrams — 2 marks each in boards.)
💡 13. QUICK REVISION
POINTERS (NEET + BOARDS)
- Fertilization site → Ampulla
of oviduct
- Implantation → Endometrium
of uterus
- Corpus luteum → Secretes progesterone
- Testis temp → 2–2.5°C below
body temp
- FSH → follicle growth
- LH surge → ovulation
- Trophoblast → placenta
formation
- Pregnancy hormone → hCG
- First milk → colostrum
- Twins → Dizygotic (fraternal)
or Monozygotic (identical)
🏁 14. HIGH-SCORING ANSWER
TIPS
✅ Always draw labeled diagrams.
✅ Write hormone names in CAPITALS.
✅ Mention site + function in 2-mark answers.
✅ Highlight keywords (use underline in exam).
✅ For NEET, focus on numerical facts (timing, hormones, layers).
