The document summarizes key aspects of the human reproductive system, including: 1) It describes the average menstrual cycle as lasting 28 days and divided into the follicular, ovulation, and luteal phases. 2) Hormonal control of the cycle involves LH and FSH secretion regulated by rising and falling estrogen and progesterone levels, culminating in the LH surge that triggers ovulation. 3) The ovarian and uterine cycles involve cyclical changes in the ovaries, uterus, cervical mucus, vagina, and breasts across the phases of the menstrual cycle.

1. The Reproductive system
Dr Sankalp Jha
MBBS (RG KAR, Kolkata)
MD (AIIMS, Delhi)
Asst Prof. Physiology
AIMS, Faridabad

2. Menstrual cycle
• Regular natural change that occurs in the female reproductive system (specifically the
uterus and ovaries) that makes pregnancy possible.
• Required for the production of oocytes, and for the preparation of the uterus for
pregnancy.
• Average menstrual cycle is 28 days long, can range anywhere from 21 to 35 days in adults.
• Divided into
✓ follicular phase (days 1-14 in an average 28 day cycle)
✓ ovulation (around day 14 in an average cycle)
✓ luteal phase (days 15-28 in an average cycle)

3. Control of the Cycle
Regression of the corpus
luteum (luteolysis) is the
key to the menstrual
cycle.
PGF2α appears to be a
physiologic luteolysin, but
is only active when
endothelial cells producing
ET-1 are present.
In some domestic animals,
oxytocin secreted by the
corpus luteum appears to
exert a local luteolytic
effect.
LH and FSH secretion is
regulated by the rise and
fall of estrogen and
progesterone.
Estrogen secretion from
the follicle triggers a burst
of LH secretion resulting in
ovulation.
Luteolysis occursagain
resulting in a new cycle
starting.

4. Menstrual cycle
Ovarian Cycle Uterine Cycle
Cyclical
Changes in the
Uterine Cervix
Vaginal Cycle
Cyclical
Changes in the
Breasts
Changes
During
Intercourse

5. Ovarian Cycle

6. Ovarian Cycle
& Uterine
Cycle

7. Cyclical
Changes in
the Uterine
Cervix
The mucosa of the uterine cervix does not undergo
cyclical desquamation.
Estrogen makes cervical mucus thinner and more
alkaline.
Progesteronemakes cervical mucus thick, tenacious
and cellular.
Mucus is thinnest at the time of ovulation, with
increased elasticity.
Mucus dries in an arborizing, fern-like pattern when
spread on a slide.
After ovulation and during pregnancy, mucus becomes
thick and fails to form the fern pattern.

8. Vaginal
Cycle
Estrogenscause the
vaginal epithelium
to become cornified
and identifiable in
vaginal smears.
Progesteronecauses
a thick mucus to be
secreted and the
epithelium to
proliferate and
become infiltrated
with leukocytes.
Rat vaginal smears
have relatively
marked cyclical
changes.
Humans and other
species have similar
changes, but are not
as clear-cut.

9. Cyclical Changes in the Breasts
• Lactation does not occur until the end of pregnancy.
• Estrogens cause proliferation of mammary ducts and progesterone causes
growth of lobules and alveoli.
• Many women experiences breast swelling, tenderness, and pain around 10
days before menstruation.
• These changes are due to distention of the ducts, hyperemia, and edema
of the interstitial tissue of the breast.
• All these changes regress during menstruation.

10. Changes
During
Intercourse
Fluid is secreted onto the vaginal walls due to release of VIP from
vaginal nerves
Lubricatingmucus is also secreted by the vestibular glands
Upper part of the vagina is sensitive to stretchand tactile stimulation
Visual, auditory, and olfactory stimuli can add to the sexual
excitement
During orgasm,autonomically mediated rhythmic contractionsoccur
in the vaginal walls
Impulses travel via the pudendal nerves and produce rhythmic
contractionof the bulbocavernosus and ischiocavernosusmuscles
Vaginal contractionsmay aid sperm transportbut are not essential
for it

11. Hormones produced by the ovaries
Estrogen (estradiol,
estrone, and
estriol)
Progesterone
Androgens
(testosterone and
androstenedione)

12. Estrogen:
Effects on
the Female
Genitalia
Facilitates growth of ovarian
follicles and increases motility of
uterine tubes
Responsible for cyclic changes in
endometrium, cervix, and vagina
Increases uterine blood flow and
amount of uterine muscle

13. Estrogen:
Effects on the
Endocrine
Organs
Decreases FSH
secretion and can
inhibitor increase
LH secretion
Used for postcoital
contraception,but
probablyprevents
implantation rather
than changes in
gonadotropin
secretion
Increases secretion
of angiotensinogen
and thyroid-
bindingglobulin
Exerts protein
anaboliceffect and
causes epiphysial
closure in humans

14. Estrogen:
Effects on the
Central
Nervous
System
Responsible for
estrous behavior
in animals and
increased libido
in humans
Act directly on
certain neurons
in the
hypothalamus
Increase the
proliferation of
dendrites on
neurons
Increase the
number of
synaptic knobs
in rats

15. Estrogen: Effects
on the Breasts
Produce duct growth in the breasts
and are largely responsible for breast
enlargement at puberty in girls.
Responsible for the pigmentation of
the areolas.
Have an effect on the overall control
of breast growth and lactation.

16. Estrogen: Female
Secondary Sex
Characteristics:
Development of secondary sex
characteristics in females at
puberty.
Distribution of body fat, growth
of pubic hair, and the
development of the uterus and
fallopian tubes.

17. Estrogen:
Other
Actions
Effect on the synthesis of certain
proteins
Release of certain hormones
Activity of certain enzymes

18. Estrogen: Mechanism of Action
Two principal types of nuclear estrogen receptors: ERα and Erβ
ERα found in uterus, kidneys, liver, heart, while ERβ found in ovaries, prostate, lungs,
gastrointestinal tract, hemopoietic system, CNS
ERα and ERβ can form homodimers and heterodimers
ERα gene knockoutscause sterility, osteoporosis and growth abnormalities; ERβ
knockoutscause infertility
Most effects of estrogens are genomic, but some are rapid and mediated by cell
membrane receptors
Membrane receptors produce effects by intracellular mitogen-activated protein kinase
pathways

19. Progesterone action
Principal target organs
of progesterone are
uterus, breasts and
brain
Responsiblefor
progestational changes
in endometriumand
cyclicalchanges in
cervix and vagina
Antiestrogeniceffect
reduces excitabilityand
sensitivity to oxytocin
while increasing
membrane potential
Stimulates
developmentof lobules
and alveoliin breast
Complex feedback
effects at hypothalamic
and pituitarylevels
InhibitsLH secretion
and potentiates
inhibitoryeffect of
estrogens
Thermogenic and
stimulatesrespiration
Causes natriuresis, but
no significantanabolic
effect

20. Progestrogen: Mechanism of Action
Progesterone binds to the progesterone receptor and releases a heat shock
protein, which exposes the DNA-binding domain of the receptor
Mifepristone binds to the receptor, but does not release the heat shock
protein, blocking the binding of progesterone
Maintenance of early pregnancy depends on the stimulatory effect of
progesterone on endometrial growth and its inhibition of uterine contractility
There are two isoforms of the progesterone receptor- PRA and PRB
Substances that mimic the action of progesterone are known as progestational
agents, gestagens, or progestins and are used in oral contraceptive agents

21. Relaxin
Relaxinis a polypeptidehormone found in variouslocationsin
both men and women.
During pregnancy, relaxinrelaxes the pubic symphysis, dilatesthe
uterine cervix, and inhibitsuterine contractions.
In nonpregnant women, relaxin is found in the corpus luteum and
endometrium during the secretory phase of the menstrual cycle;
its function is unknown.
In men, relaxin is found in semen, where it helpsmaintainsperm
motility and aidsin sperm penetrationof the ovum.
Humans havetwo relaxin genes on chromosome9 that code for
two structurally different polypeptides.
Only one gene is active in the ovary and prostate.

22. CONTROL OF
OVARIAN FUNCTION
FSH from the pituitary is responsible for the early
maturation of the ovarian follicles
FSH and LH together are responsible for the final
maturation of the ovarian follicles
A burst of LH secretion is responsible for ovulation
and the initial formation of the corpus luteum
A smaller midcycle burst of FSH secretion occurs,
though its significance is uncertain
LH stimulates the secretion of estrogen and
progesteronefrom the corpus luteum

23. CONTROL OF
OVARIAN FUNCTION:
Hypothalamic
Components
The hypothalamus is key in controlling
gonadotropin secretion via GnRH secreted into the
portal hypophysial vessels.
GnRH is normally secreted in episodic bursts which
cause circhoral peaks of LH secretion.
If GnRH is administered episodically at a rate of
one pulse per hour, LH secretion is stimulated.
Fluctuations in the frequency and amplitude of the
GnRH bursts are important in generating hormonal
changes responsible for the menstrual cycle.

24. CONTROL OF
OVARIAN FUNCTION:
Hypothalamic
Components
Frequency of GnRH pulses is increased by
estrogens and decreased by progesterone
and testosterone.
At the time of the midcycle LH surge, the
sensitivity of the gonadotropes to GnRH is
greatly increased.
Norepinephrine and epinephrine increase
GnRH pulse frequencies, while opioid
peptides reduce frequency of GnRH pulses.
Long-acting GnRH analogs are used to inhibit
LH secretion in precocious puberty and
cancer of the prostate.

25. Feedback
regulation of
ovarian
function

26. Feedback
regulation
of ovarian
function
During the follicular phase, FSH is modestlyelevated and inhibinB is low,
leadingto follicular growth
At 36-48 hours before ovulation,estrogen levels become positiveand initiate
an LH surge, leadingto ovulation9hours later
During the luteal phase, LH and FSH are low due to elevated levels of
estrogen,progesterone, and inhibin
Estrogen exerts a negativefeedbackeffect on LH secretion,but when elevated
for a minimumamount oftime (36 hours or more) can result in a positive
feedbackeffect and LH surge
Progesterone can inhibit the positivefeedbackeffect of estrogen
The mechanismof switchingnegativeto positivefeedbackin the luteal phase
is unknown

27. Oogenesis
The release of an egg from the ovary is known
as ovulation and usually occurs around
the midpoint of the menstrual cycle.
This process begins at puberty and continues
until menopause.
Ova are produced in the ovaries through a
process known as oogenesis.​

28. Oogenesis
Image credit: CatalystUniversity

29. Spermatogenesis
• ​Begins with the production of spermatogonia, stem cells
that divide and grow to become primary spermatocytes.
• Primary spermatocytes undergo meiosis, a type of cell
division, to form secondary spermatocytes.
• Secondary spermatocytes divide again to form
spermatids, which will eventually mature into sperm cells.
• Mature sperm cells are released into the epididymis,
where they can be stored until they are ready to be
ejaculated.

30. Spermatogenesis

31. Spermatogenesis
Image credit: http://janux.ou.edu.

32. Catalyst University
Spermatogenesis
Oogenesis
Image credit: CatalystUniversity

33. Male
hormones
and
its functions
Male hormones, or androgens, are hormones that are
produced primarily by the testes and are responsible for
the development of male characteristics during puberty.
Main androgens: testosterone, dihydrotestosterone,
dehydroepiandrosterone, and androstenedione
Responsible for the development of male physical
characteristics such as facial hair, body hair, and a deeper
voice
Regulating sex drive and libido as well as controlling the
production of sperm.

34. Male
hormones
and
its functions

35. Semen
• Sperm
• Vas deferens fluid ~10%
• Seminal vesicles fluid ~60%
• Prostategland fluid ~30%
• Mucous glands

36. Fertilization &
Implantation
Fertilization involves chemoattraction, adherence to the zona pellucida,
penetration, and fusion.
Millions of sperm are deposited in the vagina during intercourse and 50-
100 reach the ovum.
Sperm bind to a receptor in the zona, followed by the acrosomal reaction.
Fertilin on the surface of the sperm head mediates fusion to the ovum
membrane.
A reduction in the membrane potential of the ovum prevents polyspermy.
The blastocyst reaches the 8- or 16-cell stage and is surrounded by an
outer layer of syncytiotrophoblast and an inner layer of cytotrophoblast.
Implantation occurs on the dorsal wall of the uterus and a placenta then
develops.

37. Fertilization &
Implantation
FIGURE 22-22 Sequentialevents in fertilizationin mammals

38. Functions of
breast
Providing
nourishment for
infants
Produce hormones
such as estrogen
and progesterone
which help regulate
the menstrual cycle
and reproductive
health
Also play a role in
sexual pleasure, as
they are often a
source of
stimulation during
sexual activity
Role in self-image,
as they are often
used as a marker of
femininity and
sexual attractiveness

39. Application and
implication in
providing nursing
care
Nurses play an important role in providing care to
patients with reproductive health issues.
Provide counseling on contraception, fertility options,
and other reproductive health topics.
Provide support and education regarding the menstrual
cycle, ovulation, fertilization, implantation, and other
reproductive processes.
Provide guidance on the care of the breasts and male
reproductive organs, as well as information about the
hormones involved in these processes.
Provide care for patients who are experiencing fertility
issues, miscarriages, or other reproductive health
issues.

40. Thank you
Dr Sankalp Jha
MBBS (RG KAR, Kolkata)
MD (AIIMS, Delhi)
AsstProf. Physiology
AIMS, Faridabad
Drsankalp.aims@gmail.com
9681097683 (whatsapp)
Lecture PPT_Reproductivesystem_Nursing_Dr SankalpJha.pdf

41. Reference
• Barrett KE, Barman SM, Boitano S, Brooks HL. Ganong's
Review of Medical Physiology. 25th ed. McGraw-Hill
Education; 2016
• http://janux.ou.edu (Created by the University of Oklahoma,
Janux is an interactive learning community)
• https://www.youtube.com/watch?v=hKa57JPfKDE
(Catalyst University)