Good

1. By
Tewodros G.
Jimma University
Department of Biomedical Sci.
Unit of Physiology

2. 1. Reproduction
 process by which new individuals of species are produced and genetic
material is passed from generation to generation.
2. Sexual Pleasure [coitus, coupling]
█ Gonads [Testis and Ovaries]
☞ Function
1. Gametogenesis: Haploid Cell
Formation
2. Endocrine Function: Sex Hormone
Synthesis
Function of Reproductive System

3. Gametogenesis

5. Functional Structures of Male Reproductive System
 Main difference b/n the male and female
depends primarily upon the ± Y-
chromosome
Male reproductive system consists of:
1. Male Gonads (Testis) -Essential Sex Organs
Function:  Spermatogenesis (formation
of spermatozoa)
 Endocrine function (produces
male sex hormone. i.e.,
testosterone, inhibin &
↓↓estrogen
2. Accessory Sex Organs
I. Tubular structures (genital tracts)
II. Accessory glands
III. Supporting structures

6. I. Tubular structures (genital tracts)
• Epididymis
• Vas deference (Ductus Deference)
• Ejaculatory duct
• Urethra
☞ Used for store and transport of sperms
II. Accessory glands
- Seminal vesicle
- Prostate gland
- Bulbourethral gland
☞ Produce substances that protect the sperms
and facilitate their movement
II. Supporting structures
− penis, scrotum & spermatic cord
☞ Supports urethra, testes, epididymis and contains blood
vessels, nerves & lymphatic‘s

7.  Seminal Vesicles, Prostate Glands and Bulbourethral Glands
 secret a fluids collectively called Seminal Plasma
Accessory Glands
Predict
Following deposition of semen in the vagina, a clotting reaction makes the semen thick and
sticky. Within a few minutes, the semen becomes more watery. Propose a reason for these
changes to semen.

8.  produces 60% of the volume of the seminal fluid
 secrete viscous [jellylike], sticky and white-yellow fluid, containing fructose,
ascorbic acid, prostaglandins and fibrinogen.
 Fructose - sugar that nourished the sperms as they travel through the female
reproductive tract (i.e., fructose is used for ATP production for sperm cells)
 Prostaglandins
 stimulates the contraction of smooth muscles in the male reproductive
tracts, thereby helping to transport sperm from their storage site
 promote widening [slight dilation] of the external orifice of cervix
 Ascorbic acid - Increase the sperm’s resistance to infection
 Fibrinogen - clotting protein helps the seminal fluid to form a temporary clot in
the vagina [i.e., coagulate the semen after ejaculation, making it a sticky,
jellylike fluid]
Seminal Vesicles

9.  It makes up 35% of the seminal fluid
 Secretes a thin, milky and alkaline fluid, contains several substances [Composition]:
 Citric acid is used by sperms for ATP production via Krebs cycle
 Proteolytic enzymes [clotting enzymes ] such as prostate-specific antigen (PSA),
pepsinogen, lysozyme, amylase and hyaluronidase
– Clotting Enzymes act on fibrinogen, which secreted from the seminal vesicles to
produce fibrin, which “clots” the semen, thus helping to keep the ejaculated
sperms in female reproductive tract during withdrawal of the penis
 Fibrinolysin is a fibrin degrading enzyme ☞ seminal clot is broken down ☞ thus
releasing the mobile sperms within the female tract.
 Acid phosphatase its function is unknown
 Seminal plasmin is antibiotic that can destroy bacteria and prevents urinary tract
infections [UTI]
☞ Enhances the motility and fertility/viability of the sperms
Prostate Gland
The thin, milky secretions of the prostate have an alkaline pH and help to neutralize the
acidic urethra, as well as the acidic secretions of the seminal vesicles, and the vagina

10.  Protection of sperms from vaginal acidic environment
‾ Vagina has high acidic environment (pH between 3.5 and 4.0) to prevent bacterial
growth & sperm can’t survive in this type of environment.
‾ Alkaline secretion of prostate gland is needed to lessen the acidity of the vagina
& bring pH values closer to neutral
Bulbourethral gland (Cowper’s gland)
 Situated at the base of the penis
 Secrete thick, alkaline mucus fluid
helps to neutralize the acidity in the urethra during sexual arousal and
provide lubrication during sexual intercourse
 It makes ~1% of the seminal fluid

11. Seminal Fluid / Semen
Seminal
Fluid
Function
• Vehicle for sperm
• Motility
• Buffering medium
• Energy source
Secreted by
• Epididymis
• Seminal vesicles
• Prostate
• Cowper’s gland
Its volume and composition depends on testosterone
 Semen is the fluid ejaculated during male sexual act
 made up of spermatozoa (4%) and seminal plasma (96%)
 Volume of semen in a typical ejaculation is 2.5–5ml, with 30–150 million sperms
per ml.
 Volume of semen and sperm count decrease rapidly with repeated ejaculation.
 Sperm count lower than 25 million sperms per ml is usually associated with
infertility (sterility) inability to fertilize an egg

12.  A very large number of sperm is required for successful fertilization because only
a tiny fraction ever reaches the secondary oocyte

14. Composition of human Normal semen: Semenalysis
Volume = 2.5-5 ml
pH = 7.2-7.7
Colour:
 Gray-white-yellow
Sperm count:
 30-150 million/ml
Sperm motility:
 >50% after 1 hr of
ejaculation
 >40% after 3 hrs
Sperm morphology
 >50% normal
Chemical composition
 Zn > 75 µg/ml ( Marker for prostate)
 Mg >70 µg/ml Markers for
 Fructose >1200 µg/ml SV function
 PGE1 & PGE2 >30-200 µg/ml
 Acid phosphate >100-300 µg/ml
 Citric acid >3 mg/ml
 Carnitin >250 µg/ml
Glcerylphosphorylcholine >650 µg/ml

15.  Internal compartments of
the testes contains tightly
coiled tubules called
seminiferous tubules
 sperms are produced
 The process by which the
seminiferous tubules of the
testes produce sperms is
called spermatogenesis
 Seminiferous Tubules
 functional unit of testis
 90% of testicular mass
 Leydig cells
 Seminiferous tubules
Testis / Male gonad
Seminiferous tubules contain two types of cells:
–Spermatogenic cells
–Sertoli cells

17. Spermatogenic Cells
 Germinal cells
Give rise to spermatozoa
 Controlled by FSH
Leydig Cells
 Interstitial cells
 Secrete testosterone
 Controlled by LH
Sertoli [sustentacular]Cells
 Non-germinal cells
 Nurse cells
 Maintain & promote the development of
sperm:
 Nourishment of spermatozoa
 Mechanical support
 Secrete inhibin & estrogen
 Defense (phagocytosis)
 Eat old sperm cells & excess
cytoplasm
 Act as blood - testis barrier
 Secret ABP
Testis contain three types of cells

18. Embedded among the spermatogenic cells in the seminiferous
tubules are large Sertoli cells , which extend from the basement
membrane to the lumen of the tubule
Blood–testis Barrier (BTB)
 Tight junctions between the sustentacular cells form a blood–testis barrier
between spermatogonia and sperm cells . BTB isolates the developing
sperm cells from the immune system. This barrier is necessary because
developing sperm cells form surface antigens that could stimulate an
immune response, resulting in their destruction

20. Spermatogenesis
 Occurs in seminiferous tubules during active sexual life
 spermatogenesis takes 65–75 days
 It begins with spermatogonia, which contain diploid number
of chromosomes (2n)
 Spermatogonia are stem cells; when they undergo
mitosis
I. Some spermatogonia remain near the basement
membrane of the seminiferous tubule (Type A
spermatogonia), which are undifferentiated state
☞serve as a reservoir of cells for future sperm production
II. Rest of the spermatogonia lose contact with the
basement membrane (Type B spermatogonia)
☞undergo developmental changes and differentiate
into primary spermatocytes

21.  Primary spermatocytes, like
spermatogonia are diploid (2n);
they have 46 chromosomes.
shortly after it forms, primary
spermatocyte replicates its DNA
and then meiosis begins
 The two cells formed by meiosis I
are called secondary
spermatocytes.
− Each secondary spermatocyte
has 23 chromosomes (n),
haploid cells
− No replication of DNA occurs in
the secondary spermatocytes
 By meiosis II, the two cells of the secondary spermatocytes
produce four haploid cells called spermatids

23. A single primary spermatocyte therefore
produces four spermatids via two rounds of
cell division (meiosis I and meiosis II).
 The final stage of spermatogenesis is spermiogenesis,
which is the development of haploid spermatids into sperms
 No cell division occurs and each spermatid becomes a
single sperm cell
 During spermiogenesis, the spherical shape of
spermatids transform into elongated, slender form of
sperms
 Sperms released into the lumen of the seminiferous
tubule
☞ Of every four spermatids emanating from a
primary spermatocyte, two contain X
chromosomes and two have Y chromosomes

24.  Structural Maturation occurs in lumen of
seminiferous tubule
☞ Mature sperm cells contain the head,
neck and tail.
 Acrosomal development
Acrosome develop at the head contain
enzymes, hyaluronidase or proteases
 Proteases are meant for effective
penetration of egg during fertilization
 Cytoplasmic reduction
 Flagellar growth
 Discharge of organelles
 Condensation of nucleus
Mature Sperm Cell
Functional Maturation occurs in Epididymis and requires Testosterone

25.  The final maturation of the sperm cells occurs within the epididymis
 It takes 12–16 days for sperm cells to travel through the epididymis.
☞ As they pass through the epididymis the acrosome matures, the ability
to fertilize an oocyte develops, and the flagella become capable of
movement

26. Factors Affecting Spermatogenesis
A. Hormones
FSH:
− Stimulates Sertoli cells
to produce androgen
binding protein (ABP)
☞ Facilitates
spermatogenesis
LH:
− Stimulates Leydig cells
to produce testosterone
Inhibin
− Inhibits the release of
FSH
T3/T4: Required to normal
process of spermatogenesis
Gonadotropes
OC MB
GnRH
↑FSH
LH
Interstitial cells
of Leydig
Spermatogenesis
Sertoli cells
Testosterone
0.65µg/dl
Inhibin
↓Estradiol
-
-
PRL
Sertoli cell include inhibin, follistatin, and activin. Whereas activin
stimulates secretion of FSH, inhibin and follistatin decrease the
levels of FSH. By suppressing FSH release from the pituitary
gonadotrophs and reducing FSH secretion induced the activin.

29. ☞FSH acts indirectly to stimulate
spermatogenesis.
FSH and testosterone act
synergistically on the sertoli cells
FSH stimulate the sertoli cells to
secrete the androgen-binding
protein (ABP) into the lumen of
the seminiferous tubules
ABP binds to testosterone and
keeping its concentration high
Testosterone stimulates the final
steps of spermatogenesis in the
seminiferous tubules.

30. Once the degree of
spermatogenesis required for
male reproductive functions
has been achieved
Sertoli cells release inhibin,
a protein hormone and its
role is inhibiting FSH
secretion by the anterior
pituitary.
If spermatogenesis is
proceeding too slowly, less
inhibin is released, which
permits more FSH secretion
and an increased rate of
spermatogenesis.

31. B. Temperature
 An optimum testicular
temperature is 32-35oC
█ Testicular temperature
adjusting mechanisms:
1. Testicular Muscles
2. Lack of adipose tissue in
the scrotal skin
3. Abundant sweat glands in
the scrotal skin

32. █ Scrotum is a saclike structure containing the testes. It is divided into right & left
compartments by an incomplete connective tissue septum
☺ Externally the scrotum consists of skin.
☺ Beneath the skin is a layer of loose connective tissue and a layer of
smooth muscle, called the Dartos muscle
 When the scrotum is exposed to cool temperatures
☞ Dartos Muscle contracts, causing the skin of scrotum to become firm and wrinkled
and reducing the overall size of the scrotum.
☞ At the same time, extensions of abdominal muscles connected to the testes, called
Cremaster Muscles, contract. Consequently, the testes are pulled nearer to the
body, and their temperature is raised.
 During warm weather or exercise
☞ Dartos and cremaster muscles relax, the skin of the scrotum becomes loose and
thin, and the testes descend away from the body, which lowers their temperature.
Regulation of Testicular Temperature

33. C. Diet
In complete starvation, spermatogenesis arrested and the tubules degenerate.
 Vitamin A deficiency leads to sperm production stops
 Vitamin B12 & folic acid for DNA & RNA synthesis
 Vitamin E deficiency results in degeneration of seminiferous tubules
D. Irradiation
 X-ray, atomic radiation causes complete an irreversible damage to testis
→ sterility.
E. Other factors
 Drugs, hypoxia, bacterial toxins, cocaine.

35.  Male Sexual Act is a complex series of reflexes that result in erection of the
penis, secretion of mucus into the urethra by the bulbourethral glands, emission,
and ejaculation.
 Mediated through the brain and spinal cord.
█ Psychic stimuli, such as sight, sound, odor, or thoughts, can affect the brain
and cause a psychic erection.
 Action potentials from the brain affect sexual functions through
parasympathetic centers (S2–S4) and sympathetic centers (T10– T12)
in the spinal cord
█ Tactile stimulation can generate action potentials affecting these centers.
Rhythmic massage of the penis, especially the glans, and surrounding
tissues, such as the scrotal, anal, and pubic regions, is an important
source of sensory action potentials that can activate reflexes causing
erection, emission, and ejaculation
 As a result of this type of stimulation, action potentials also ascend the
spinal cord to the cerebrum to produce conscious sexual sensations

36. Has 3 stages:
1. Erection: First major component of male sexual act
 Controlled by PaNS
 Initiated by psychic and tactile stimulations
 Action potentials in parasympathetic neurons
cause voltage-gated Ca2+ channels to open,
and Ca2+ diffuse into presynaptic terminals
Calcium ions initiate the release of
acetylcholine (ACh) from presynaptic
vesicles.
ACh binds to ACh receptors on
the smooth muscle cells and
activates a G protein mechanism
Male Sexual Act
Mechanism of Erection

37. The activated G protein (GTP)
convert ATP to cAMP, causes
relaxation of the smooth muscle of
erectile tissues and dilatation of
penile arteries
Entry of large volume of blood both
to penile arteries and sinusoids of
erectile tissues
Expansion of the
erectile tissue
Compresses the veins (outlets) 
 Venous occlusion  Stiffening of erectile tissues (corpora
cavernosa and corpus spongiosum)  erection of penis
Activate G protein, stimulation of adenylate cyclase
and increase in cAMP → decreases the intracellular
[Ca2+] due to ↑reuptake of Ca2+ by sarcoplasmic
reticulum → causing the blood vessel dilation by
allowing the smooth muscle to relax

38. Calcium ions also activate nitric
oxide synthase in the presynaptic
vesicles and promotes the synthesis
of nitric oxide[NO] from arginine
NO binds to guanylate cyclase
enzymes in the smooth muscle of
erectile tissues and activates them
█ cGMP producing the relaxation of
smooth muscles of erectile tissue and
dilation the blood vessels of penile
arteries by ↓Intracellular [Ca2+]

39. The activated enzymes convert GTP
to cGMP, which causes relaxation of
the smooth muscle of erectile
tissues and dilatation of penile
arteries
Entry of large volume of blood both
to penile arteries and sinusoids of
erectile tissues
Expansion of the
erectile tissue
Compresses the veins (outlets) 
Venous occlusion  Stiffening of erectile tissues (corpora
cavernosa & corpus spongiosum)  erection of penis

40. The erection reflex

42. 2. Orgasm [Emission and Ejaculation]
 Found after the ejection of seminal fluid out of male ductile system
Mechanism:
 Emission is the accumulation of sperm cells and secretions of prostate gland and
seminal vesicles in the urethra. Sympathetic centers (T10–T12) in the spinal cord,
which are stimulated as the level of sexual tension increases due to rhythmic
stimulation of sensory impulse during intercourse, control emission.
Sympathetic action potentials cause peristaltic contractions of the smooth muscles
of reproductive ducts (epididymis, vas deferens) and stimulate the smooth muscles
of seminal vesicles and the prostate gland to release their secretions.
Consequently, semen accumulates in the prostatic urethra
This produces sensory action potentials that pass through the pudendal nerves
to the spinal cord. Integration of these action potentials results in both
sympathetic and somatic motor output

43.  Sympathetic action potentials cause constriction of the internal urethral
sphincter of urinary bladder so that semen and urine are not mixed.
→ During this time, the sphincter at the neck of the bladder is tightly closed to
prevent semen from entering the bladder and urine from being expelled
along with the ejaculate through the urethra.
 Somatic motor action potentials are sent to urethral skeletal muscle
surrounding the bulb of the penis, stimulating several rhythmic contractions that
cause ejaculation.
→ Rhythmic contractions of these muscles occur at 0.8-second intervals and
increase the pressure within the penis, forcibly expelling the semen through
the urethra to the exterior. This is the phase of ejaculation
3. Resolution Reversion of erection
Sympathetic stimulation also constricts the smooth muscles of penile arteries 
blood leaves the erectile tissues  penis become flaccid

44. Physiological changes during Male Sexual Act
 ↑HR ↑BF ↑MR
 ↑CO ↑ABP ↑Energy out put
Stimulation of the CNS
Hyperventilation
Sympathetic stimulation Sexual flash
Emotional excitement
Sensation of pleasure
 Premature ejaculation Spinal damage
 Absence of emission Diabetic neuropathy
 Impotence Hypotension
 Periapism Testicular failure
 Male Sterility
Problems associated with male sexual act

45. Problems associated with the male sexual act
 Erectile Dysfunction/ Impotence
 Inability of the penis to attain or hold an erection long
enough for sexual intercourse.
 Many cases of impotence are caused by insufficient
release of nitric oxide (NO), which relaxes the smooth
muscle of the penile arterioles and erectile tissue
 Diabetes mellitus; physical abnormalities of the penis; Systemic disorders such
as syphilis, vascular disturbances (arterial or venous obstructions); neurological
disorders, surgery, testosterone deficiency and; Drugs (alcohol, antidepressants,
antihypertensives)
Other causes of erectile dysfunction
Sildenafil blocks the activity of an enzyme that converts cGMP to GMP. This allows cGMP to accumulate in
smooth muscle cells in the arteries of erectile tissues and causes them to relax. This response is effective in
enhancing erection of the penis in males. Sildenafil’s action is not specific to erectile tissue of the penis. It also
causes vasodilation in other tissues and can increase the workload of the heart.

46.  Priapism
 Persistent & painful erection of the penis
that does not involve in sexual desire or
excitement.
 Condition may last up to several hours and is
accompanied by pain and tenderness.
 It results from abnormalities of blood
vessels and nerves.
 Premature Ejaculation
 Ejaculation occurs too early during foreplay
or shortly after penetration.
 usually caused by anxiety, other
psychological problems or an unusually
sensitive foreskin or glans penis
 Absence of emission (anorgasmia)

47. Male Sterility
 Congenital absence of testis
 Cryptorchidism
 Infection with STD
 Destruction of the seminiferous tubules
 Irradiation
 Impotence
 Hypogonadism
 Genetic defects
 Functional disorders of prostate and seminal vesicles
 Genital tract obstruction
 Testicular failure
Causes of male sterility

49. Female reproductive system
 Female reproductive system consists of:
1.Essential Sex Organs (female gonads): 2 ovaries
Function:
Oogenesis – This gametogenic potential is established early in the fetus
Endocrine secretion- endocrine role of the ovaries is not realized until puberty
2.Accessory sex organs :
Oviducts, Uterus, Vagina & External genitalia
1. Oviduct/ Fallopian /Uterine Tube
Function
Site of fertilization
Site of ectopic pregnancy
Transport ovum from the ovaries to the uterus
 Peristaltic contractions of the muscularis and
ciliary action of the mucosa of uterine tube
 Move the oocyte or fertilized ovum toward the uterus.

50. 50
2. Uterus: A hollow muscular organ in non-pregnant woman
Function:
Site of normal pregnancy
 Growth and development of fetus
Produces pressure during labor & site of menstruation
 Undergoes cyclic changes to prepare it for implantation
of a fertilized ovum
 Has 2 layers:
 Functional layer/stratum functionale
 Borders of uterine lumen, that sloughed off during
menstruation
 Contains uterine glands
 Basal layer/stratum basale
 Source of cells for regeneration of functional layer
 Retained during menstruation
Endometrium

51. 3. Vagina:
 Muscular tube (8-10cm long) extends from the
cervix to external genitalia
 Houses of many harmless bacteria
 whose acidic secretions prevent or retards
the growth harmful organisms
 Mucosa of the vagina glands contains large
stores of glycogen and lactate
– Harbors Lactobacillus decompose these
substances to maintain the acidic pH (b/n 3.5
and 4.0) in the wall of the vagina
Function
Copulatory organ of Female, Birth Canal and
allows passage of menstruation
4. External genitalia: Clitoris, Labia minora & Majora

52. 52
1. Bartholin's Glands [Vulvovaginal
or Vestibular Glands]
☞ Lie on either side of the vaginal
opening and produce a mucoid
substance, which provides
lubrication during intercourse
☞ Equivalent to bulbourethral
glands of male
2. Paraurethral [skenes] Glands
☞ on the wall of urethra and
secretes mucus
☞ Equivalent to prostate gland of
male
Female Reproductive Organs have two Local Glands

53. Physiology of sexual intercourse in Women
Sexual excitement initiated by psychic stimuli or tactile stimulations
Parasympathetic impulse
 Increase the flow blood to external genitalia causes erection of the clitoris
 Local glands are stimulated and increase their secretions of mucus to the walls
of vaginal for lubrication
 Increase the sensitive of the upper part of vagina to stretch
 Rhythmic tactile stimulation of the clitoris and labia minora together with other
stimuli such as tactile of breasts and auditory.
 All these rhythmic stimulation of sensory impulse pass through the
pudendal nerves to the spinal cord. Integration of these action potentials
results in both sympathetic and somatic motor output
→ Sympathetic APs cause peristaltic contractions of the uterus and walls
of vagina; constrict the anal and urinary sphincters
→ Somatic motor APs cause peristaltic contractions of the pelvic muscles

54.  During orgasm, rhythmic contractions of the vaginal walls and pelvic muscles are
produced
Orgasm in females is accompanied by peristaltic contractions of the walls of
vagina, uterus and the pelvic muscles (bulbocavernosus & ischiocavernosus
muscles).

55. Female Sexual Cycle
█ Non pregnant females during their reproductive years normally exhibit cyclical
changes in the ovaries and uterus
 Each cycle takes about a month and involves both oogenesis and preparation
of the uterus to receive a fertilized ovum
█ Hormones secreted by the hypothalamus, anterior pituitary and ovaries control the
main events
 Female Sexual Cycle
− Repetitive changes that take place in the female reproductive organs during
her reproductive life
 Changes in the Uterus, Cervix, Vagina, Breast and Body Temperature
− Appears at puberty and continues until menopause
− Two Types:
 Ovarian Cycle
 Endometrial or Uterine Cycle

56.  A series of events occur in the ovaries during and after the maturation of oocyte
 Regulated by FSH and LH
 Has three phases
1. Follicular Phase
2. Ovulation Phase
3. Luteal Phase
I. Follicular Phase [5th to 13th day following mense]
Several Primordial Follicles start to grow BUT only one will typically reach
maturation AND developed into Primary Follicle [contain Primary Oocyte
and Granulose Cells] at the beginning of the Monthly Cycle
Secondary Follicle start to produce Cholesterol rich Follicular Fluid called
Liquor Folliculi, accumulated in the cavity antrum, rich in estrogen
On the 6th day, a mature follicle called Graafian Follicle is formed.
In the Mature Graafian Follicle, just before Ovulation, the Primary Oocyte
producing the First Polar Body and Secondary Oocyte
This phase is under the regulation of FSH and LH
Ovarian Cycle

58.  The phase from the 1st day of menstruation to day of ovulation is known as the
Follicular or Preovulatory Phase
 since follicular enlargement is brought about by estrogen secretion, this
phase is also known as the Estrogenic Phase

59. II. Ovulation phase (14th to 15th day)
Wall of the graafian follicle ruptures and the ovum is
released in to oviduct
Mechanism of Ovulation: LH is the hormone of ovulation
During final maturation of follicle (12-13 days), APG
produces large amount of LH via positive feedback (LH
surge)
LH reaches peak level 12 hrs before ovulation
↑LH→ ↑antral fluid volume
↑ Estrogen secretion
↑BF to graafian follicles → ↑follicular swelling → ↑pressure →rupture → release of
ovum

61. III. Luteal phase (15th to 25th day)
 After the rupture of the graafian follicle and shedding of the ovum, the remaining
part of the graafian follicle collapses
 Under the influence of LH, the granulosa cells hypertrophied and proliferated then
transformed into Corpus Luteum
Function of Corpus Luteum: secret ↑↑Progesterone, ↑Estrogen
 If fertilization [pregnancy ] occurs, corpus luteum stays active for more than 10
days by human Chorionic Gonadotropin (hCG)
 This hormone is produced by the chorion of embryo. Like LH, hCG
stimulates the secretory activity of corpus luteum
 The presence of hCG in maternal blood or urine is an indicator of pregnancy
Menstruation does not occur until delivery
☞ As a result of continuous progesterone and estrogen secretion
 If no fertilization occurs, corpus luteum stays active for 10 days and eventually
replaced by scar tissue called Corpus Albicanus

63. Changes in concentration of anterior pituitary and ovarian hormones during
Ovarian cycle

64. Role of the Pituitary Gland on Ovarian Cycle
█ Pituitary Secretes FSH and LH
 FSH stimulates the growth of ovarian follicles
 LH
 Responsible for the final maturation of
follicles (12-14 days)
 Estrogen secretion from ovary
 Sudden increase in levels of plasma LH
results in ovulation
 Also causes the development of ruptured
ovarian follicle into corpus luteum
Follicular Phase  FSH and LH
Ovulation Phase  LH
Luteal Phase  LH and results in formation of
corpus luteum
↑↑secretion progesterone and estrogens

65. Hormonal regulation of oogensis and ovulation
Gonadotropes
OC MB
GnRH
LH
FSH
↑ ↑Estrogen
↑progesterone
↑ ↑Progesterone
↑Estrogen
• Final maturation of
graafian follicle
• Stimulates estrogen
secretion
• Promotes ovulation
• Luteininzation
•Follicular growth
•Maturation of graafian follicles
Ovarian hormones
Ovary
↓Androgen
↓Inhibin

66.  Endometrial /Uterine cycle
 A concurrent series of changes in the endometrium of the uterus
☞ To prepare it for the arrival of a fertilized ovum that will develop there
until birth
 If fertilization does not occur, levels of progesterone and estrogens decline
due to degeneration of the corpus luteum
☞ withdrawal of progesterone and estrogens causes the stratum
functional of the endometrium slough off → menstruation
 Regulated by Ovarian Hormones
 Endometrial Cycle has 3 phases
1. Bleeding Phase
2. Proliferative Phase
3. Secretory Phase
Endometrial Cycle

67. Bleeding Phase (3-5)
 Desquamation of the
functional layer
 Loss of 50 ml of blood
 Caused by sudden
withdrawal of sex
hormones
 Menstruation
Proliferative Phase (6-14)
 ↑Growth & development
of the endometrial
glands
 ↑ Proliferation of
endometrial stromal
cells
 ↑ Growth of spiral
arteries
 Prepared by estrogen
Secretory Phase (15-28)
Glands become more
secretory
Arteries become more
spiral & branched
Thickness = 6mm
Caused by estrogen &
progesterone

69. Proliferative phase
Stimulated by estrogen
Rebuilds endometrium
Secretory phase
 Stimulated by progesterone
and estrogen
 Endometrium prepares for
implantation
Menstrual phase
Sudden decline of estrogen
and progesterone
Removes endometrium
Hormonal regulation of Menstrual Cycle

70.  Proliferative phase
 concurrent with follicular
maturation and influenced
by estrogens
 Secretory phase
 concurrent with the
formation corpus luteum
and influenced by
progesterone and estrogen
 Menstrual phase
 concurrent with
degeneration of corpus
luteum and caused by
sudden withdrawal of
estrogen & progesterone

72. Ovaries secrete 4 hormones
 Estrogen (E1 = estrone, E2 = estradiol & E3 = estriol)
 Progesterone
 ↓ Androgens (Thecal cells)
 ↓ Inhibin (only peptide gonadal hormone)
- Ovarian follicular cells (granulosa cells)
- Corpus luteum
Estrogen - Adrenal cortex
Sources - Placenta
- Testes
Rate of secretion
 36 µg/day in the follicular phase
 380 µg/day just before ovulation
 250 µg/day in the mid-luteal phase
 Ovaries secrete ovarian hormones (female sex hormones)
☞ The secretion of estrogen and progesterone reach peaks twice during the
endometrial cycle; once just before ovulation and once in the middle of the
luteal phase.
Role of the Ovaries

73. Function of Estrogen
1. Development of the body during puberty
 Growth and enlargement of sex organs in female
 Development of 2o-sex characteristics in female
2. Growth of the Uterus during pregnancy
3. Growth of the Breast >> >>
4. General Metabolic Effects:
 Enhances bone ossification; ↑ Protein anabolic
 ↑ Salt and water retention
 Estrogens tend to lower the levels of cholesterol in the blood. This may be one
of the reasons for the lower incidence of cardiovascular disease, such as
atherosclerosis, in women.
5. Functional relations with other hormones
 Estrogen sensitizes the uterus to the action of oxytocin during labor
 Estrogen regulates the rate secretion of LH and FSH from APG
 Estrogen stimulates secretion of ACTH that leads to hyperthrophy of adrenal
cortex

74. - Corpus luteum
Progesterone - Follicular cells
sources - Adrenal cortex
- Placenta, Testes
Rate of secretion
 1 mg/ day in the early follicular phase
 4 mg/day just before ovulation
 25 mg/day in the mid-luteal phase
1. On uterus
• Induces the progestational changes of endometrium
• Inhibits excitability of myometrium
• Stimulates secretion of thick, alkaline cervical mucous
2. On breast
• Stimulates development of secretory cells
• Stimulates differentiation of ductile system
3. On other hormones: inhibits secretion of LH and FSH
4. Has a thermogenic action
Function of Progesterone

75. Other Cyclical Changes in the Female Body
 Other changes that occur in the female body coincides with ovarian cycle
include:
BMR: Increases after ovulation by 5-10%
Body temperature: after ovulation ↑0.5-1oC
Mammary gland: after ovulation, ↑BF to the breast, tender, painful and
swelling
Vagina: Epithelial lines are cornified in the 1st half of the cycle. Then after,
become more proliferative. Thick mucus secretion
Cervical secretion: In the 1st half of the cycle, cervical secretions are thin,
alkaline, which makes suitable medium for sperm survival.
Sexual desire:↑libido in the middle of the cycle (ovulation) and highest towards
the end of the cycle