The male reproductive system produces sperm and sex hormones. Sperm are produced in the testes through spermatogenesis and stored in the epididymis. Hormones like FSH, LH and testosterone regulate sperm production and male characteristics. During sexual activity, erection occurs when blood flow increases to the penis. Ejaculation involves the contraction of muscles to expel semen containing sperm from the penis.

1. The Physiology of
Reproductive System
By : Mukemil A

2. Introduction
 Reproduction:- is scope of physiology by w/c organism continues
their species. and it makes s/thing different from non- living thing
 In the human reproductive process two sex cells are involved,
male gamete (sperm cell) and female gamete (egg cell) they meet
at uterine tube, (fertilized) and form new individual like us.

3. Sex determination
 The male and female sex organs consist of three sets of structures:
• gonads,
• internal genitalia,
• and the external genitalia.
 Gonads are the organs that produce gametes
o The male gonads are the testes which produce sperm
o The female gonads are the ovaries, which produce eggs
 The undifferentiated gonadal cells destined to produce eggs and
sperm are called germ cells

4. Sex determination cont…..
 Each nucleated cell of the body except eggs and sperm
contains 46 chromosomes called diploid.
 Eggs and sperm are haploid cells with 23 chromosomes,
 But When egg and sperm unite, forms zygote that
contain 46 chromosomes number, 23 chromosome
coming from mother and 23 from the Father.

6. Sex determination cont…..
 The 22 pairs of autosomal chromosomes
 direct development of the human body with variable
characteristics such as hair color and blood type.
 The two sex chromosomes (one pair)
 X or Y, contain genes that direct the development of
internal and external sex organs.

7. Sex determination cont…..
 Before differentiation of gonad it is called bipotential w/c mean it
has potential to be male or female.
 It will be differentiate at 7 week.
 Bi Potential (germ cell) has two genital layer :-
 internal genitalia -contain Wolffian duct and Mullerian duct
 external genitalia- contain genital tubercle urethral fold,
groove &scrotum

9. Sex determination cont…..
 The presence or absence of a Y chromosome determines whether the zygote develop in
to male or female. But how??????????????
 presence SRY gene (sex determining region of Y chromosome) this region of Y
chromosome secret protein and this protein bind DNA and activate gens to develop
medulla of germ cell in to tastes . then,
 Seminiferous tubule part of testis contain Sertoli cell which produce glycoprotein
(AMH) to inhibit and degenerate Mullerian duct
 interstitial space contain lyding cell w/c secret testosterone (responsible to develop
Wolffian duct) and DHT(dihydrotestosterone) responsible to develop accessory glands
of male.
 If SRY gen absent, the female gonad (Mullerian duct) develop in to ovary.

10. Sex determination cont…..
 So, if Y chromosome present, the embryo will become
male, even zygote has multiple X chromosomes like XXY
zygote will become male.
 In the absence of a X chromosome (YO) the zygote will
die because the larger X chromosome contains essential
genes that are missing from the Y chromosome.
 In the absence of a Y chromosome (XO), an embryo will
develop into a female. But, a zygote that gets only one X
chromosome called (Turner s syndrome). It is abnormal
b/c Two X chromosomes are needed for normal female
reproductive function.

11. Male reproductive physiology

12. Components of male reproductive System
Testes
 Series of ducts
 Seminiferous tubules
 Rete testis
 Efferent ductali
 Ductus epididymis
 Ductus deferens
 Urethra
Accessory glands
 Seminal vesicles
 Prostate glands
 Ejaculatory duct
 Cowpers glands
• Supporting structures
– Scrotum
• 2 chambered sac
that contains testes
• Dartos and
cremaster muscles
help regulate
temperature
– Penis
• Perineum
– Diamond-shaped
areas between thighs.

13. Male reproductive physiology….
 Male reproductive function subdivides into three major parts w/c
are:-
 Regulation of male reproductive function by d/t hormone
 Spermatogenesis (formation of sperm cell)
 Performance of male sexual act

14. Testicles (singular, testis)

15. Testes…..
 It is a pair of glandular organ that located in the
sac of scrotum, responsible for production of
sperm cell as well as male sexual hormone
(testosterone).
 Testes are wrapped by tunica vaginalis that
extended from abdominal peritoneum and divided
in to several lobules by tunica albuginea, each
lobule contain tightly coiled tube called
seminiferous tubule.

16.  testes can produce 12 trillion and 400 million sperm cells during
life time and in single ejaculation respectively.
 The scrotum serves as thermostat for sperm b/c sperm needs 3-5
degree faranite below body temperature to survive
seminiferous tubule
 The wall of seminiferous tubule contain:- germ cell ,Sertoli cell
and leyding cell.
 germ cell produces several immature spermatocytes from
puberty till to death. (Site of spermatogenesis)
 Sertoli cell support and protect until develop into spermatid
and immature spermatozoa in the seminiferous tubule.
 Leyding cells are produce male sex hormone (testosterone)
collectively known as androgen that maintain secondary
sexual characteristics of male
Capillary
Sertoli cell
Leydig cells
Spermatogonium
Leydig cells
Sertoli cells
Basal lamina
Germ cell

17. .
Sertoli cell
It is a ring like structure that surround lumen of seminiferous tubule,
extend from basal compartment into lumen
Its function
1. Provide Sertoli cell barrier to chemicals from interstitial to lumen
except testosterone hormone.
2. Nourish developing sperm and Secrete luminal fluid that Allow
sperm motility until leave epididymis then after by peristaltic movement
of v.deference .
3., secret androgen-binding protein serve as receptor for testosterone
hormone.
4. produce inhibin hormone, which inhibits FSH secretion from
Pituitary gland.
5. during embryonic life,secret Müllerian inhibiting substance (MIS),
which causes the primordial female duct system to regress

18.  Function of Epididymis and Vas deferens (composed 10% of
seminal fluid) :
it is 7m and 35cm long respectively.
 Site for sperm maturation
 Sperm Storage before ejaculation
 Seminal Vesicles (takes 60% of seminal fluid)
 secretes a mucoid material containing an abundance of
fructose(as energy source) citric acid, and other nutrient
substances,
 as well as large quantities of prostaglandins(contractile
effect on cx and ux then sperm can move up ward) and
fibrinogen(as clotting factor).

19.  Prostate Gland (takes 30% of semen fluid)
 secretes milky alkaline fluid that contains
• calcium,
• citrate ion, phosphate ion,
• a clotting enzyme,
 It neutralize acidic area of vagina (3.5-4) into alkaline
environment (6-6.5) because sperm can proceed its motility at this
PH value.
 Make sperm cell milky appearance
 Bulbourethral gland
 Secrete mucus to make sperm mucoid appearances

20. Hormonal control of male reproductive system
 Hypothalamus secret and release GnRH to stimulate anterior
pituitary gland then, it release LH and FSH
 FSH: - stimulate Sertoli cell to secrete
 androgen binding hormone
 inhibin hormone
 to form barrier b/n interstitial space and lumen(blood-testis-barrier)
 LH: - stimulate leyding cells to release -testosterone hormone
(collectively known as androgen hormone).
 TH -cross Sertoli cell and enters lumen to support survival and
development of germ cell

21.  when FSH and LH reaches its peak value in the plasma (every 90
minute) :-
 Testosterone exerts a negative feedback inhibition on both the
hypothalamus and the anterior pituitary to reduce mainly LH
secretion.
 Inhibin exerts a negative feedback inhibition on FSH secretion in
the anterior pituitary.

22. Function of testosterone hormone
• Maintain spermatogenesis
• Maintain secondary sexual characteristics development
• Maintain male accessory organ development
• Stimulate bone and muscle growth

23. Spermatogenesis
 It is process of formation sperm cell in the seminiferous tubule.
 Unlike oogenesis spermatogenesis starts at puberty (13 years old)
b/c of immature male gonadal cell (testes).
 At puberty, FSH and testosterone hormone stimulates Sertoli cell.
Then, it produce paracrine agent in to germ cell to began
spermatogenesis.
 Matured Germ cell known as spermatogonium starts division and
differentiation to increase number of cell (spermatogonia) and to
yield primary spermatocyte in the basal membrane under the
process of mitotic division.

24. Spermatogenesis cont.….
 Primary spermatocyte inters in to central compartment of
tubule to under go meiotic division.
 Generally, one primary spermatocyte gives four sperm cell at
the end.
 In the1st meiotic division Each of Primary spermatocyte
divides into two secondary spermatocyte.
 In the second meiotic division, each of secondary
spermatocyte divides into two spermatids, each with 23 single
chromosomes, the haploid number characteristic of a gamete
 Then spermatids differentiate in to sperm

25. Chromosomes
per
cell
Chromatids
per
chromosome
Spermatogonia 46 2
Mitosis
Differentiation
Primary spermatocytes 46 2
1st meiotic division
Secondary spermatocytes 23 2
2nd meiotic
division
Spermatids
23 1
Differentiation
Spermatozoa 23 1

26. • T + FSH initiates spermatogenesis.
• T completes meiosis.
• T alone can maintain
spermatogenesis.
Spermatids/(haploid 1N DNA)
Primary spermatocytes/(diploid 4N DNA)
Testosterone + FSH
Primordial germ cell (2N DNA)
Mitosis

27.  Finally, The spermatids differentiate into spermatozoa (sperm).
This process involves several remodeling and elongation of
sperm cells like:-
 Formation of acrosome.
 Condensation and elongation of nucleus
 Formation of mid-piece and flagellum
 After spermatid develop into sperm, cytoplasm of Sertoli cell will be
retract and sperm migrate in to luminal fluid to bath itself.

28. a. Head (penetrating power + genetic material)
• Acrosome: enzymes needed to
penetrate the ovum.
• Nucleus: n number of chromosomes
(23 chromosomes)
b. Mid-piece (metabolic, energy generating)
• Mitochondria: provides ATP for
locomotion
c. Tail (locomotor, motile power)
• Flagellum: Propyls the spermatozoon

29. Pathway for Sperm Conduction via male Genital organ
Since, sperm is immature it is none motile so, Sertoli cell secret fluid that allow movement of sperm till to
some part of epididymis. Then, contraction of cremaster muscle undergoes peristaltic movement for rest
part until sperm mature.
Sperm is synthesis in seminiferous tubule and (stored and matured) in epididymis and vas deference.
Semen contains bulky and abundant fluid from seminal vesicle , prostate gland and sperm.

30. male sexual act
Erection
 normally during rest time, the pines is flaccid due to dominance and release of
norepinephrine from sympathetic nerves system causes contraction of smooth
muscle. consequently, decrease amount of blood flow in to small artery of
pines
 But, during any stimulation of Pinal mechano receptor surround glans of pines
or thought, emotion, sight abt it activate non cholinergic neuron to release
nitric oxide and inhibit release of norepinephrine. Then, Nitric oxide (NO)
relax smooth muscle and dilate small artery allow high blood flow with extent
pressure this makes pines to rigid or erect. Period of erection takes 5-10 sec.
 Erectile dysfunction known as impotency which is common and recently best
drug for it is sildenafil (Viagra) w/c enhance the action of NO.

31. male sexual act cont.…
Ejaculation
 It is the discharging of semen from pines. When the stimulation of
mechano receptor peak (erect) stimulation of sympathetic nerves system is
activated to contract smooth and skeletal muscle. It has two phases of
sequence;
1. Contraction of epididymis, vas deference, ejaculatory duct, SV, PG
to empty semen in to urethra
2. contract urethral muscle and skeletal muscle to expel 3ml of semen
w/c include 300 million sperm.
 So, erection involve inhibition of sympathetic nerves system while,
ejaculation involve stimulation of sympathetic nerves system
 The process of contraction of muscle during ejaculation with high pleasure
and some systemic change (increase BP and HR) is called orgasm.
 The last one is latency period it is a time between two erections. Is
variable man to man from (minute to hour).