3. Reproductive Physiology
The gonads are endocrine glands whose
functions are:-
1. Gametogenesis (the production of germ cells)
2. Secretion of sex hormones
Reproductive Physiology includes:-
Male Reproductive Physiology
Female Reproductive Physiology
5. Contents
Physiologic Anatomy of the Male Sexual
Organs
STRUCTURE OF THE TESTES
SPERMATOGENESIS
FUNCTION OF SEX ACCESSORY GLANDS
Testosterone
REGULATION OF THE TESTES
7. STRUCTURE OF THE TESTES
The male gonads are the testes
the testes have two functions:
spermatogenesis
secretion of testosterone
8. STRUCTURE OF THE TESTES
The testes occupy the scrotum
Scrotum lies outside the body cavity
Scrotum is maintained at 35° to 36°C
This lower temperature, essential for normal
spermatogenesis
This lower temperature is maintained by a
countercurrent exchange heat mechanism
10. Sertoli cells
The Sertoli cells lining the seminiferous tubules
Sertoli cells, which support the developing sperm
Sertoli cells have three important functions that
support spermatogenesis:-
1. Provide nutrients to the differentiating sperm
2. creating blood-testes barrier
3. Secrete an aqueous fluid into the lumen of the
seminiferous tubules (help to transport sperm into
the epididymis.)
13. Leydig cells
interstitial cells of Leydig
Are Located Between the tubules in the testes
Leydig cells is synthesis and secretion of
testosterone
14. SPERMATOGENESIS
Location:-
Spermatogenesis occurs along the length of the seminiferous
tubules
Phases:-
(1) Mitotic divisions of spermatogonia generate the
spermatocytes
(2) meiotic divisions of the spermatocytes, which decrease the
chromosome number and produce haploid spermatids
(3) spermiogenesis, in which spermatids are transformed into
mature sperm
Period (spermatogenesis)
requires about 74 days
16. Hormonal Factors That Stimulate
Spermatogenesis
Testosterone:- secreted by the Leydig cells is
essential for growth and division of the
testicular germinal cells
Luteinizing hormone, stimulates the Leydig
cells to secrete testosterone
Follicle-stimulating hormone, stimulates the
Sertoli cells; for the conversion of the
spermatids to sperm
20. FUNCTION OF SEX ACCESSORY GLAN
Epididymis
the primary location for the maturation , acquire
motility and storage of sperm.
The ampulla of the vas deferens
storage area for sperm
Nourishes (citrate and fructose) the ejaculated sperm
seminal vesicles
Nutritive (citrate and fructose) for the ejaculated
sperm
Secrete prostaglandins and fibrinogen
21. Prostaglandins are believed to aid fertilization
in two ways:-
(1) Prostaglandins react with cervical mucus to
make it more penetrable by sperm
(2) prostaglandins induce peristaltic
contractions in the female reproductive tract
FUNCTION OF SEX ACCESSORY GLAN
22. prostate gland
milky aqueous solution rich in citrate, calcium,
and enzymes
Alkaline secretion:
neutralizing acidic secretions from the vas
deferens and the vagina
FUNCTION OF SEX ACCESSORY GLAN
23. FUNCTION OF SEX ACCESSORY GLAN
semen
Secretions (90%)
male sex accessory
glands
sperm (10%)
24. Testosterone
synthesis and secretion of testosterone
Testosterone is synthesized and secreted by the
Leydig cells of the testes
Chemistry of the Testosterone
Steroid hormone
Functions of Testosterone
male secondary sex characteristics (endocrine effect)
exert an important protein-anabolic (endocrine effect)
(Testosterone + FSH) maintain spermatogenesis
(paracrine effect)
25. Dihydrotestosterone (DHT)
Testosterone is converted to dihydrotestosterone
(DHT) by 5α reductase
DHT formation is a way of amplifying the action of
testosterone in target tissues.
Humans have two 5α reductase:-
Type 1 5α reductase is present in skin throughout the
body and is the dominant enzyme in the scalp.
Type 2 5α reductase is present in genital skin, the
prostate
29. The Female Reproductive System
Physiologic Anatomy of the Female Sexual
Organs
OOGENESIS
Menstrual cycle
ACTIONS OF ESTROGEN AND
PROGESTERONE
30. Physiologic Anatomy of the Female Sexual Organs
The principal organs of the human female
reproductive tract, including the
ovaries
fallopian tubes
Uterus
vagina
31. 2 million ova
7 million ova
fetal life
Birth
childhood
1 million ova
puberty
>300,000 ova
> 500 Ova
Ovum per cycle
OOGENESIS
first meiotic division
primary oocytes
first meiotic division
( completed)
secondary oocyte
32. Menstrual cycle
The menstrual cycle is a term used to describe
the monthly cycle of physiological events
which prepare the female for pregnancy
The cycle ends in menstruation if pregnancy
dose not occur
Duration-----(28 days)
Average-------(21- 35 day)
34. The menstrual cycle in the female is cyclic
change that occur in the:-
Ovaries (= ovarian cycle)
Uterus (= uterine cycle)
Other organs (e.g. cervix, vagina and breast)
Menstrual cycle
35. ovarian cycle
Ovarian cycle may be divided into three
phases:-
1. Follicular phase
2. Ovulatory phase
3. Luteal phase
36. Duration
The onset of menses from the previous cycle until day 14 (0 ---
14) day
Events of Follicular phase is mediated by FSH
primordial follicle develops (growth) into a graafian follicle
neighboring follicles become atretic
remaining follicle is called the dominant follicle
The follicular phase is dominated by estrogen
Estrogen is secreted from theca and granulosa layers which
surrounded ovum
estrogen inhibits FSH and LH secretion by the anterior
pituitary by negative feedback
Follicular phase
37. Ovulatory phase
Ovulation occurs in midcycle
Events of Ovulatory phase:-
Increase of estrogen level towards midcycle exerts a
positive feedback on LH and FSH
This positive feedback is called the FSH and LH surge
The LH surge then causes ovulation of the mature
ovum:- distended follicle ruptures, and the ovum is
shed
The ovum is picked up by the fimbriated ends of the
uterine tubes
38. Luteal phase
Duration
After ovulation and ending with the onset of menses
Events of Ovulatory phase:-
LH acts on the follicle ruptures to convert into carpus
luteum
carpus luteum secretes estrogen and progesterone.
estrogen and progesterone exert –ve feedback effect
on GnRH (Hypothalamus)
39. Uterine cycle
uterine cycle may be divided into three
phases:-
1. proliferative phase
2. secretory phase
3. Menstrual phases
40. Proliferative phase
Start after menstruation and continues to the
time of ovulation (5 day – day 14)
It depends on the action of estrogen which
causes proliferation of endometrium
The endometrium increases rapidly in
thickness from 0.5mm to 5mm (10 fold)
41. Secretory phase
Start from ovulation to mensturation
Depends on the action of progesterone
Progesterone action:-
endometrium becomes more highly
vascularized and slightly edematous
Glands become coiled and tortuous and they
begin to secrete a clear fluid
The length of endometrium in this phase is
constant
42. Menstrual phases
Menstrual blood is:
1. 75% arterial blood
2. 25% venous blood
Regression of the corpus luteum and the abrupt
loss of estradiol and progesterone cause the
endometrial lining to be sloughed
Volume (30 – 80) mL
Duration (3-8) day
43. ESTROGEN
synthesis and secretion of estrogen
Produced from (granulosa cell, carpus luteum and
placenta)
Chemistry of the estrogen
Steroid hormone
Action of estrogen
female secondary sex characteristics
Estrogens produce duct growth in the breasts
causes proliferation of endometrium
increase the bulk of uterine muscle
Facilitated effect of oxytocin on uterine muscle
44. Progesterone
synthesis and secretion of the Progesterone
Progesterone secreted by the corpus luteum, the
placenta
Chemistry of the Progesterone
Steroid hormone
Action of the Progesterone
antiestrogenic effect on the myometrial cells
Maintenance of secretory activity of uterus during
luteal phase
development of lobules and alveoli in the breast
