2. REPRODUCTIVE EVENTS
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,
hormones
Puberty, difference male, female reproductive events
1. Gametogenesis - formation of gametes (sperms/ ova)
2.
3.
4.
5.
6.
Insemination -- transfer of sperms into the female genital
tract
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
birth )
Parturition-- delivery of the baby ( child birth )
4.
a pair of testes ( in
scrotum)
accessory ducts,
glands (rete testis,
vasa efferentia
epididymis, vas
deferens
external genitalia.
(Penis)
5. Testi
s
Paired male gonads- sperm
harmones
production , oval in shape, length- 4
to 5 cm, a width 2 to 3 cm, 3 cm
thick
situated outside the abdominal
cavity within a pouch called
scrotum.
Scrotum - low temp. of the testes
(2–2.5o C lower than the normal
internal body temperature) –
spermatogenesis
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
6. 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
called
interstitial spaces, contain small blood vessels & interstitial cells
Leydig cells - male hormone secretion Androgen ( testosterone)
8. Vas deferens in
abdomen over
urinary bladder
join seminal vesicle
from both sidesejaculatory duct
Ejaculatory duct
ejaculatory ducts
pass prostate gland
open into urethra –
common passage
urethra opens
urethral meatus
10. Accessory Glands
Seminal vesicles
Between urinary bladder and rectum
Alkaline mucoid fluid rich in fructose ,
ascorbic acid
Prostate glands
Largest male gland, milky fluid 1/3 volume of
semen
Helps in sperm motility, maintains pH – survival of
sperms
Cowper’s glands/
Bulbourethral glands
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.
12.
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.
13. 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.
14. Ovarie
s
They are pearl-colored, oblong, walnut-size , on either side of vertebral
column.
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.
15.
16. 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)
17. Accessory ducts - Oviduct, Uterus, Vagina
Oviduct / Fallopian tube- 10-12 cm length, from periphery of each ovary to
uterus
Twds ovary funnel shaped infundibulum – edge finger like projections
Fimbriae. ( collectin of ovule after ovulation), wider ampulla.
Isthemuss has narrow lumen and joins uterus
18. Uterus /Womb
The uterus - thick-walled, muscular, pear-shaped organ located in
the middle of the pelvis, behind the bladder, and in front of the
rectum.
anchored in position by several ligaments to pelvic walls .
( narrow cervix --Cavity cervical canal) and the main body
(corpus).
Birth canal = cervical canal + vagina
perimetrium
Extenal, thin
Layers –
myometrium
Smooth muscular - strong contraction during bith
endometrium
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
funct
19. External genitalia - mons pubis, labia majora, labia minora, hymen and
clitoris
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
organs
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.
20. Mammary glands
Paired, Glandular,
variable fats
Glandular tissue –
mammary lobes cluster
of cells – alveoli
Alveoli secrete milkstored in lumen
Alveoli- mammary
tubules – mammary
duct
Many ducts join to form
ampulla- lactiferous
duct
21. GAMETOGENESIS
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
gametogenesis.
begins at puberty- increase in the
secretion of gonadotropin releasing
hormone (GnRH) – Hypothalamus
secretes
22. Spermatogenesis and harmones
(GnRH) gonadotropin releasing hormone
Hypothalamic harmone
anterior pituitary gland
luteinising hormone (LH)
Follicle stimulating
hormone (FSH)
Leydig cells
Stimulates synthesis and secretion
of androgens
Sertoli cells
Androgen stimulates
spermatogenesis
Secretion of factors for
spermatogenesis
23. FSH Gametokinetic factor
Testesteron secondary sexual
characters.
Testersteron also reduces (GnRH)
gonadotropin releasing hormone
Inhibin- reduces rate of
spermatogenesis
Negative feedback
24.
25. Spermatogenes
is
Spermatogoni
a
(2n) = 46
• inside wall of
Seminiferous
tubules
• Mitotic
division ,
increase in
number
• Few are
called
primary
spermatocytes
• Meiosis ,
periodically
• After first meiotic/
reduction division
• Recombination,
crossing over
• Haploid ,
genetically similar
secondary
spermatocytes
n = 23
• 2 equal cells
• Second meiotic
division
Spermatids
n =23
4 equal cells
Spermatids are transformed to sperrmatozoa/ sperm by Spermeiogenesis.
Sperm heads embeded in sertoli cells.
Released from tubules by spermiation
27. Structure of Human sperm
Plasma membrane envelops entire boby.
Part of
sperm
Details
Head
• Elongated haploid nucleus
• Anterior cap like acrosome
• Acrosome has enzymes. It is derived from Golgi complex
during division – fertilization of ovum
Neck
Connecting head and middle piece
Middle
part
• 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
– motility)
Tail
• Long slender
• Vibration
200-300 sperms – one ejaculation 60% mus have mormal shape , size and 4
30. OOGENESIS
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
Oogonia
Primary
oocyte
Primary
follicle
Secondary
follicles
• 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
31. Contnd.
Tertiary
follicles
Secondary
oocyte
• 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
Secondary
oocyte
32.
HW difference
Spermatogenesis
0ogenesis
Gonads when
Where? Seminiferous / follicles???
Yolk/nutrition accumulation
1st 2nd meiotic division – 2nd after
ovulation
Sizes of cells formed / end products
No of cells ( sperms / ova formed)
Polar bodies
Transformation??? As in
spermiogenesis
33. HW
Difference between ovum and sperm
Size
Shape
Covering membranes
Cytoplasm
Golgi bodies
Mitochondria
Centrioles
Reserved food
Movement
Life span
34.
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
and progesterone.
35.
36. MENSTRUATION
CHARACTERISTICS
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
back pain
38. Hormones start to do their thing at the onset of
puberty, and various types of hormones are involved
These hormones are:
Estrogen
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
egg.
Estrogen also has many other functions.
39. Progesterone:
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
fetus.
40. FSH Follicle Stimulating
Hormone:
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.
41. 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
chemical transactions.
42. 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.
44. 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
ampullaryisthmic junction.
The process of fusion of a sperm with an
ovum is called fertilisation.
46. Fertilization
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
47. 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
forming areas
48. Cleavage,
Morula
Zygote from oviduct to uterus– mitotic division, first cleavage in first 36
hrs
2,4,8,16 blastomere
Embryo with 8 – 16 cells – Morula
Morula – division continues – hollow ball called Blastocyst.
Fluid filled
cavity
Inner cell
mass/
embryoblast
Trophoblast –
gets attached
with
endometrium
After attachement, endometrium
grows and covers blastocyst,
Embeded -Implantation
( in 2-3 days), then pregnancy
49. MATERNAL ADAPTATION TO
PREGNANCY
Terms used to denote Fetal Growth
Ovum
- From ovulation to
fertilization
Zygote - From fertilization to implantation
Embryo - From implantation to 5-8 weeks
Fetus
- From 5-8 weeks until term
Conceptus
- Developing embryo or
fetus and placental structures throughout
pregnancy.
50. Pregnanacy
chorionic villi – finger like porjections
on trophoplast
Villi surrounded by maternal blood,
uterine tissues
They develop eventually into placenta
Inner cell mass – ectoderm,
mesoderm, endoderm - different
organs
Inner mass also have stem cells
51. Role of
placenta
Organic connection between developing foetus and uterine wall of
mother- phisiological exchange of substances
1.
Transportation of nutrients (aa, monosugars, vitamins etc)
2.
Diffusion of gases O2 and CO2
3.
Nitrogenous substances transport from foetus to mother
4.
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.
54. Sexually transmitted diseases(STD)
venereal diseases (VD) or
reproductive tract infections (RTI)
Diseases / infections – transmitted through
sexual intercourse
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
55. Symptoms
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
diseases
(PID), abortions, still births, ectopic
pregnancies, infertility or even cancer
of the reproductive tract.
56. Prevention
Avoid sex with unknown
partners/multiple partners.
(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
with disease.
Social –
High risk 15-24
57. Infertility
unable to produce children inspite of
unprotected sexual co-habitation. – After after
2 years
Reasons for infertility - physical, congenital,
diseases, drugs, immunological or even
psychological.
Blaming female
Role of infertility clinics
assisted reproductive technologies (ART)
58. 1.
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
transfer
OR
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
59.
Women no ova formed- Transfer of an
ovum collected from a donor into the
fallopian tube (GIFT – gamete intra
fallopian transfer) ,Fertilisation
internal
Intra cytoplasmic sperm injection
(ICSI) – sperm injected into ovum
60. Less sperm count / unhealthy
sperms
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.
