Chapter-3 Human Reproduction (NCERT) A detailed presentation of the one of the important chapter of class 12. This chapter carries high weightage for both CBSE as well NEET examination

1. HUMAN REPRODUCTION
• GAMETOGENESIS- Formation of gametes
• INSEMINATION- Transfer of male gametes into female
reproductive tract
• FERTILISATION- Fusion of male and female gamete to form
zygote
• CLEAVAGE & BLASTULATION- Development of zygote to form
blastocyst
• IMPLANTATION- Attachment of blastocyst to uterine wall
• GESTATION- Embryonic development
• PARTURITION- Delivery of baby

2. MALE REPRODUCTIVE SYSTEM
It includes:
1. Primary sex organs –
a pair of testes
2. Accessory ducts
3. Glands
4. External genitalia

3. •Testes
• Paired Structures; Located outside the
abdomen in Scrotum
• FUNCTION OF SCROTUM:- Maintain
optimal temperature
• Each testis divided into compartments called
Testicular Lobules.
• Each testicular lobe contain 1-3 highly coiled
Seminiferous tubules.

4. • Seminiferous tubule:- Main site of Sperm formation
• Each seminiferous tubules is lined by :
1. Male germ cells- Form sperms
2. Sertoli cells- Provide Nutrition
• Outside region of seminiferous tubules contain
Interstitial spaces which have
1. Blood vessels
2. Leydig cells or Interstitial cells- Secrete
Androgens

5. ACCESSORY DUCTS
• Seminiferous tubules  Retetestis 
Vasaefferentia  Epididymis Vas
deferens
• Vas deferens + duct of seminal vesicle
 Ejaculatoryduct whichopen into
urethra.

6. MALE ACCESSORY GLANDS
• Pair of Seminal Vesicles
• A Prostate Gland
• A Bulbourethral Gland
• Secretions of seminal vesicles, prostate gland and Bulbourethral gland – Seminal Plasma
• Sperms alongwith Seminal plasma is calledSemen.

7. MALE EXTERNAL GENITALIA
•Male external genitalia  Penis
•Made up of Special Erectile tissue
•There is common passage for both Urine and Sperms
•The urethra runs through Penis.
•The function of Penis is to facilitate insemination

8. FEMALE REPRODUCTIVE SYSTEM
• All these parts are integrated structurally and
functionally to support
1. the processes of ovulation
2. fertilisation
3. Pregnancy
4. Birth
5. child care.
1. Primary sex organs- a pair of
OVARIES.
2. Secondary sex organs-
• OVIDUCTS
• UTERUS
• CERVIX VAGINA.
3. External genitalia.
4. Mammary glands.

9. OVARIES
• Location:- LOWER ABDOMEN
• Thin EPITHELIUM covers it
• Ovarian Stroma inside.
• Ovarian stroma divided into:-
1. Outer CORTEX
2. Inner MEDULLA.
• Functions:-
1. Female gamete formation
2. Releasing Female sex hormones (ESTROGEN &
PROGESTERONE)

10. SECONDARY SEX ORGANS
1. OVIDUCTS:-Has three parts
• InfundibulumwithFIMBRIAE
• Ampulla
• Isthmus
2. UTERUS:-InvertedPear
• Perimetrium
• Myomoetrium
• Endometrium
3. CERVIX+ VAGINA:- Birth Canal

11. EXTERNAL GENITALIA
• Mons pubis:- Outermost cushion of fatty tissue covered with Skin and pubic
hairs.
• Labia majora and Labia minora:- Folds of tissue surrounding vaginal opening.
• Hymen:- Thin membrane that partially covers vaginal opening
• Clitoris:- A tiny finger-like structure located between folds of labia minora above
the urethral opening.

12. MAMMARY GLANDS
• Paired structures with glandular tissue and
fattytissue.
• Glandular tissue 15-20 Mammarylobes.
• Eachmammarylobe contains cluster of cells
called Alveoli.
• Alveoli is the mainsite of milksecretion and
storage (lumen of alveoli)
• Alveoli Mammarytubules  Mammary
duct  Mammaryampulla Lactiferous
duct.

13. GAMETOGENESIS
• SPERMATOGENESIS
• The Formation of Sperms from immature
male germ cell (Spermatogonia) in testes.
• It initiates on the onset of pubery.
• OOGENESIS
• The Formation of Ovumfrom immature
female germ cell (oogonia) in ovaries.
• It initiates during embryonic development

14. SPERMATOGENESIS
• MULTIPLICATIONPHASE :- Male Germ Cells
called Spermatogonia (2n) undergoes Mitotic
division to increase their number and Form
Primary Spermatocytes(2n).
• GROWTH PHASE:-Primary spermatocytes
enlarges in size and prepares to undergo
maturation division.

15. • MATURATION PHASE:- The Primary spermatocyte (2n) undergoes Meiosis-1 to form Two
Secondary spermatocytes (n) which undergoes Meiosis-2 to form Four Spermatids (n).
• SPERMIOGENESIS- Differentiation Phase- The Spermatids transform into Spermatozoa
(Sperms).
The mature sperms heads got embedded into SERTOLI cells.
• SPERMIATION:- Release of mature sperms from Seminiferous Tubules.

16. Multiplication
Growth
Maturation
Differentiation

17. HORMONAL
CONTROL
OF SPERMATO-
GENESIS

18. STRUCTURE OF SPERMATOZOA
• Motile and flagellated structure
• Have four parts:
1. Head – Comprises of Acrosome and
Nucleus
2. Neck- contain two centrioles
3. Middle piece- contain Mitochondria
4. Tail- Longest structure.

19. OOGENESIS
• Starts during Embryonic Development
• Comprises of three phase:
1. Multiplicative phase:- Female germ
cells called Oogonia undergo Mitosis.
2. Growth phase: Oogonia increase in
size to form Primary oocytes.
3. Multiplicative phase:- Primary oocyte
undergo Meiosis

20. STRUCTURE OF OVUM• It is pherical, non-motile
gamete with nutrition
rich cytoplasm.
• Enclosed in egg
envelopes
1. Vitelline membrane
2. Zona Pellucida
3. Corona radiata

21. MENSTRUAL CYCLE
• The cyclic changes occuring in reproductive system of females of primate mammals
is called Menstrual cycle.
• MENARCHE: The first Menstruation beginning at puberty.
• MENOPAUSE:Ceasing of Menstrual cycle in the age of 50s
• It is periodically repeated on an average of 28/29 days.

23. FERTILISATION
• Insemination
• Movement of Sperm and Seondary oocyte to
Ampullary-ishtmic junction.
• Enzymes of acrosome dissolve egg envelopes
• Completion of Meiosis-2 of secondary oocyte
• Prevention of polyspermy
• Fusion of nuclei of sperm and ovum.

24. SEX- DETERMINATION IN HUMANS
• Human beings have 46 chromosomes.
• Out of which one pair is sex
chromosome.
• Male have XY
• Female have XX
• Each gamete carries only one sex
chromosome

25. CLEAVAGE AND
BLASTULATION
• Zygote starts dividing by rapid maitotic division called Cleavage.
• Daughter cells are called Blastomeres.
• Embryo with 8-16 celled stage is called Morula.
• Morula divide further and transform into Blastula (Blastocyst in
humans).
• The process of formation of Blastula is called Blastulation.
• Blastocyst has:
1. Outer layer called Trophoblast.
2. Inner cell Mass.

26. • Trophoblast layer attach to
endometrium. Thus,
blastocyst become
embedded in uterine wall.
The process is called
Implantation and it leads
to pregnancy.

27. POST EMBRYONIC DEVELOPMENT
• Trophoblast develop finger-like projections called
cchorionic villi.
• Chorionic villi and uterine tissue together form
Placenta.
• Placenta is connected to embryo through an umbilical cord
which help in transport of substances to and from the
foetus.

28. • Placenta also acts as an endocrine tissue
and produces several hormones like
1. humanchorionic gonadotropin(hCG)
2. humanplacental lactogen (hPL)
3. Estrogens
4. progestogens, etc.
Relaxin released by ovary- later in pregnancy.

29. Te inner cell mass (embryo) differentiates into three layers:- Ectoderm, Mesoderm & Endoderm.
• Foetal development
• 1 month- heart is formed
• 2 months- limbs and digits are formed
• (First trimester) 3 months- major organ systems are formed
• 5 months- appearance of hairs and the first movements of the foetus
• (Second trimester) 6 months- body is covered with fine hair, eyelids separate, eyelashes are formed.
• 9 months- foetus is fully developed

30. PARTURITION
• Induced by complex Neuro-
endocrine Mechanism.
• First signal for paturition
arises from fully developed
foetus and placenta- Foetal
EjectionReflex.

31. LACTATION
• First milk produced-
COLOSTRUM.
• Rich in antibodies especially IgA.
• Only source of immunity to
newborn