Seminiferous tubules to rete testes to vasa efferentia to epididymis( head, body tail) to vas deferens
Humans sexual reproduction, viviparous, unisexual.
Each sex has pair of gonads, reproductive duct and accessory structures.
Sex organs – Testis( paired) male , ovaries (paired) Gamete formation,
Puberty, difference male, female reproductive events
1. Gametogenesis - formation of gametes (sperms/ ova)
Insemination -- transfer of sperms into the female genital
Fertilisation -- fusion of male and female gametes
leading to formation of zygote
Implantation -- development of blastocyst and its
attachment to the uterine wall
Gestation -- embryonic development ( from conception to
Parturition-- delivery of the baby ( child birth )
a pair of testes ( in
glands (rete testis,
Paired male gonads- sperm
production , oval in shape, length- 4
to 5 cm, a width 2 to 3 cm, 3 cm
situated outside the abdominal
cavity within a pouch called
Scrotum - low temp. of the testes
(2–2.5o C lower than the normal
internal body temperature) –
testis is covered by a dense
covering capsule tunica
albuginea – inside as septae
In each testis -250 compartments
called testicular lobules
Each lobule -1-3 convoluted
Seminiferous tubule - sperm production
lined on its inside by two types of cells
male germ cells (spermatogonia) - meiotic divisions - sperm formation
Sertoli cells (supporting cells)
-- provide nutrition to the germ cell
-- harmone Inhibin and ABP –Androgen Binding Protein
Interstitial spaces - The regions outside the seminiferous tubules
interstitial spaces, contain small blood vessels & interstitial cells
Leydig cells - male hormone secretion Androgen ( testosterone)
Vas deferens in
join seminal vesicle
from both sidesejaculatory duct
pass prostate gland
open into urethra –
Between urinary bladder and rectum
Alkaline mucoid fluid rich in fructose ,
Largest male gland, milky fluid 1/3 volume of
Helps in sperm motility, maintains pH – survival of
Fluid lubricating passage for sperms
Seminal plasma- secretion of all the accessory glands. Rich in fructose, calciu
and certain enzymes.
Semen – mixture of spermatozoa and seminal plasma.
Single ejaculation 200-300 million sperms, slightly alkaline,
neutralize acidity in vagina, sperms are protected.
Female reproductive system
Sectional view through pelvis
a pair of ovaries
a pair of oviducts, uterus, cervix, vagina and the external genitalia
oviducts, uterus, vagina - accessory ducts
a pair of the mammary glands ( nourishment of offspring)
All parts are integrated structurally and functionally to support the processes
of ovulation, fertilisation, pregnancy, birth and child care.
Here is the gross appearance of a normal uterus with fundus, lower uterine
segment, cervix, vaginal cuff, right fallopian tube, left fallopian tube, right ovary,
and left ovary from a young woman.
They are pearl-colored, oblong, walnut-size , on either side of vertebral
Length of 2 to 4 cm
They are attached to the uterus ( double fold mesovarium) and abdominal
wall by ligaments.
produce female sex hormones (estrogen and progesterone) and male
sex hormones, the ovaries produce and release eggs.
Each ovary is covered by a thin germinal epithelium which encloses the
ovarian stroma. The stroma is divided into two zones – a peripheral cortex
and an inner medulla.
The developing egg cells (oocytes) are contained in fluid-filled cavities
(follicles) in the wall of the ovaries. Each follicle contains one oocyte.
T.S of Ovaries
Developing follicles in different Stages
Primary follicle develops into Graafian
follicle with mature ovum,
One matures around 14th day of
menstrual cycle and ruptures to release
the oocyte – Ovulation
After release – follicle filled with blood
clot and then yellow cells – called
corpus leuteum ( progesteron)
Accessory ducts - Oviduct, Uterus, Vagina
Oviduct / Fallopian tube- 10-12 cm length, from periphery of each ovary to
Twds ovary funnel shaped infundibulum – edge finger like projections
Fimbriae. ( collectin of ovule after ovulation), wider ampulla.
Isthemuss has narrow lumen and joins uterus
The uterus - thick-walled, muscular, pear-shaped organ located in
the middle of the pelvis, behind the bladder, and in front of the
anchored in position by several ligaments to pelvic walls .
( narrow cervix --Cavity cervical canal) and the main body
Birth canal = cervical canal + vagina
Smooth muscular - strong contraction during bith
Inner glandular, cyclic changes- menstrual cycle,
The stratum functional of the endometrium sloughs
off during menstruation. The deeper stratum basal
provides the foundation for rebuilding the stratum
External genitalia - mons pubis, labia majora, labia minora, hymen and
Together called vulva.
Mons pubis a pad of fatty tissue over the pubic bone, covered with
hair during puberty, protects the internal sexual and Reproductive
Clitoris- erectile, hooded organ at the upper joining of the labia, a lot
of nerve endings, providing sexual pleasure
labia majora - fleshy folds of tissue, surround the vaginal opening.
labia minora – innner folds
Haymen - just inside the opening of the vagina, a mucous
membrane. General protection
often torn during the first coitus (intercourse) , or it may be so soft and
pliable that no tearing occurs.
torn during exercise / sports or insertion of a tampon or diaphragm
the presence or absence of hymen is not a reliable indicator of
virginity or sexual experience.
Glandular tissue –
mammary lobes cluster
of cells – alveoli
Alveoli secrete milkstored in lumen
tubules – mammary
Many ducts join to form
The process of formation of haploid gametes from diploid germ cells in
the gonad is called gametogenesis.
Sperrmatogenesis : - The process of
formation of haploid sperms from diploid
spermatogonia by meiosis called
begins at puberty- increase in the
secretion of gonadotropin releasing
hormone (GnRH) – Hypothalamus
Spermatogenesis and harmones
(GnRH) gonadotropin releasing hormone
anterior pituitary gland
luteinising hormone (LH)
Stimulates synthesis and secretion
Secretion of factors for
FSH Gametokinetic factor
Testesteron secondary sexual
Testersteron also reduces (GnRH)
gonadotropin releasing hormone
Inhibin- reduces rate of
(2n) = 46
• inside wall of
• Few are
• Meiosis ,
• After first meiotic/
• Haploid ,
n = 23
• 2 equal cells
• Second meiotic
4 equal cells
Spermatids are transformed to sperrmatozoa/ sperm by Spermeiogenesis.
Sperm heads embeded in sertoli cells.
Released from tubules by spermiation
Structure of Human sperm
Plasma membrane envelops entire boby.
• Elongated haploid nucleus
• Anterior cap like acrosome
• Acrosome has enzymes. It is derived from Golgi complex
during division – fertilization of ovum
Connecting head and middle piece
• 2 centrioles – proximal ( after fertilization aster and spindle
)and distal ( give rise to axoneme – central axis of tail)
• Many mitochondria (produce energy for the movement of tail
• Long slender
200-300 sperms – one ejaculation 60% mus have mormal shape , size and 4
The process of formation of haploid ovum from diploid oogonia cells in the
ovary is called oogenesis. This begins at begins at embryonic development.
• At birth many million in fetal ovary
• Propahse –I of meiotic division.
• Temporary arrested in this stage
• Primary oocyte+ granulosa cells
• May follicles degenerate before puberty
• 60,000 to 80,000 in each ovary
• Primary follicles surrounded by granulosa cells
• Secondary follicles – fluid filled cavity – antrum
• Theca layer – internal theca and extermnal theca
• Primary Oocyte (2n) size increases and first meiotic division
– unequal large haploid secondary oocyte+ 1st polar body
• Nutrient rich cytoplasm
• Polar body divides????
• Tertiary follicles into Graffian follicle
• Membrane Zona pellucida
Where? Seminiferous / follicles???
1st 2nd meiotic division – 2nd after
Sizes of cells formed / end products
No of cells ( sperms / ova formed)
Transformation??? As in
Difference between ovum and sperm
Menstruation is the term given to
the periodic discharge of blood,
tissue, fluid and mucus from the
reproductive organs of sexually
mature females. The flow usually
lasts from 3 - 6 days each month
and is caused by a sudden
reduction in the hormones estrogen
Length of menstrual cycle- first day of
the last menstrual bleeding to the first
day of the next menstruation.
Average Menstrual cycle – 28 days
Average Flow -4-7 days
Dysmenorrhea-abdominal and lower
Hormones start to do their thing at the onset of
puberty, and various types of hormones are involved
These hormones are:
1) Promotes the development and
maintenance of female reproductive
structures (especially the endometrial lining
of the uterus),
2) Assists in the control of fluid and
electrolyte balance within the body.
3) Prepares the follicle for the release of an
Estrogen also has many other functions.
Secreted at ovulation, helps to
prepare the endometrium (womb
lining) for the implantation of an
egg, prepares mammary galnds for
milk production. Primarily concerned
with the procreation and survival of the
FSH Follicle Stimulating
Stimulates the follicles (a follicle is a
balloon shaped structure which is filled
with fluid and contains an egg, follicles
are found in the ovaries) to ripen
several eggs. At the same time the
ovaries release oestrogen.
LH Lutenising hormone:
Further develops the follicles, triggers
ovualtion and stimulates production of
other hormones necessary for the post
ovulatory stage of the menstrual cycle.
The secretion of hormones is a
complex affair.Various parts of the
body become involved in a myriad of
It is the balance and interplay
between these hormones which
regulate the specific events that
make up the menstrual cycle.
Factors like nutrition, stress, exercise,
and belief systems can all influence
how the hormones work and what we
experience during our cycles.
Fertilization and implantation
Coitus , insemination
The motile sperms swim rapidly, pass
through the cervix, enter into the uterus
and finally reach the junction of the
isthmus and ampulla (ampullary-isthmic
junction) of the fallopian tube
Ovum after release at this point
Fertilisation - if the ovum and sperms are
transported simultaneously to the
The process of fusion of a sperm with an
ovum is called fertilisation.
Meiotic division of secondary oocyte
after sperm enters plasma membrane
of the ovum.
Second meiotic division – second
polar body and ovum / ootid
Ovum + Sperm = Zygote
Explain sex determination of a child
Significance of fertilization
Restoration of diploidy
Recombination of genes
Ovum does not have centriole – sperm
centriole is introduced
Ovum activation completes division
Gives polarity, development – organ
Zygote from oviduct to uterus– mitotic division, first cleavage in first 36
Embryo with 8 – 16 cells – Morula
Morula – division continues – hollow ball called Blastocyst.
After attachement, endometrium
grows and covers blastocyst,
( in 2-3 days), then pregnancy
MATERNAL ADAPTATION TO
Terms used to denote Fetal Growth
- From ovulation to
Zygote - From fertilization to implantation
Embryo - From implantation to 5-8 weeks
- From 5-8 weeks until term
- Developing embryo or
fetus and placental structures throughout
chorionic villi – finger like porjections
Villi surrounded by maternal blood,
They develop eventually into placenta
Inner cell mass – ectoderm,
mesoderm, endoderm - different
Inner mass also have stem cells
Organic connection between developing foetus and uterine wall of
mother- phisiological exchange of substances
Transportation of nutrients (aa, monosugars, vitamins etc)
Diffusion of gases O2 and CO2
Nitrogenous substances transport from foetus to mother
Stoarage of glycogen acts as liver before its development.
Support fetal growth -Acts as endocrine gland to secrete harmones
like human chorionic gonadotropin (hCG), human
placental lactogen (hPL), estrogens, progestogen
Relaxin by ovary dialation of uterus during birth.
foetal ejection reflex.
Sexually transmitted diseases(STD)
venereal diseases (VD) or
reproductive tract infections (RTI)
Diseases / infections – transmitted through
Gonorrhoea, syphilis, genital herpes*,
chlamydiasis, genital warts, trichomoniasis,
hepatitis-B*, AIDS* (HIV infection)
transmitted by sharing of injection needles,
surgical instruments, etc., with infected
persons, transfusion of blood, or from an
infected mother to the foetus too.
* not curable, others are
Absence or less significant symptoms in
the early stages of infection
minor symptoms include itching, fluid
discharge, slight pain, swellings, etc., in
the genital region
Infected females - asymptomatic hence,
may remain undetected for long.
Complications-- pelvic inflammatory
(PID), abortions, still births, ectopic
pregnancies, infertility or even cancer
of the reproductive tract.
Avoid sex with unknown
(ii) Always use condoms during coitus.
(iii) In case of doubt, go to a qualified
doctor for early detection and
get complete treatment if diagnosed
High risk 15-24
unable to produce children inspite of
unprotected sexual co-habitation. – After after
Reasons for infertility - physical, congenital,
diseases, drugs, immunological or even
Role of infertility clinics
assisted reproductive technologies (ART)
Test tube baby programme
In vitro fertilisationand sperms from
ova from the wife/donor (female)
the husband/donor (male) are collected.
2. induced to form zygote under simulated conditions
in the laboratory.
3. The zygote or early embryos (with upto 8
blastomeres) could then be transferred into the
fallopian tube -- ZIFT–zygote intra fallopian
Embryos with more than 8 blastomeres, into the uterus
(IUT – intra uterine transfer)
Further development in the uterus
Embryos formed by in-vivo fertilisation could be used
for such transfer to assist
Women no ova formed- Transfer of an
ovum collected from a donor into the
fallopian tube (GIFT – gamete intra
fallopian transfer) ,Fertilisation
Intra cytoplasmic sperm injection
(ICSI) – sperm injected into ovum
Less sperm count / unhealthy
artificial insemination (AI) technique
semen collected - from the husband or
a healthy donor is artificially
introduced either into the vagina or
into the uterus (IUI – intra-uterine
insemination) of the female.
Requires high precision
Facilities in few centre