The document summarizes the male reproductive system. It describes the external organs including the scrotum and penis. It then details the internal organs such as the testes, epididymis, vas deferens, and accessory glands including the seminal vesicles, prostate, and bulbourethral glands. It explains spermatogenesis, the process by which sperm are produced in the testes. Finally, it provides an overview of sperm structure and function, including fertilization.
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Male reproductive organs
1. Review of Male Reproductive
Organ
By- Isha Thapa Magar
Master in Nursing (WHD)
TU, IOM
3. Male Reproductive Organs
External Male
Reproductive Organs
1. Scrotum
2. Penis
Internal male reproductive
organs
1. Testis
2. Epididymis
3. Vas Deferens
4. Accessory Glands
a. Seminal Vesicles
b. Prostate Gland
c. Bulbourethral Glands
4. Scrotum
• A pouch of skin formed from lower part of
abdominal wall.
• Scrotum forms a pouch in which testes are
suspended outside body.
• Scrotum keeps testes at a temperature slightly
cooler than body temperature.
5. Penis
• Penis is male external genital organ for passage of
urine and semen to exterior.
• It is about 10 cm long, 4 cm breath flaccid muscular
cylindrical organs.
• Composed mainly of three cylindrical columns of
erectile tissue.
7. Testis
• Testis are oval-shaped male reproductive organs
located in scrotum, just behind penis.
• Testis are 4.5 cm in length, 2.5 cm breath, 3 cm in
thicken and weight about 10-14 gm.
• In embryo, testis develop within upper abdominal
cavity and during 7th month of fetal life they
migrate into scrotum.
8. • Each testis consists of 200 to 300 lobules.
• Each testis is made of tightly coiled
structures called seminiferous tubules.
9. • Testes contain 3
types of cells:
1. Germ cells
2. Sertoli cells,
and
3. Leydig
(interstitial)
cells
11. • Germ cells undergoing progressive differentiation
and development into mature spermatozoa.
• Sertoli cells are supporting cells
• Ledyig (interstitial) cells are testosterone producing
cells
12. Epididymis
• Epididymis is a tightly coiled tubes against testicles.
• Is comma shaped structure which consists of head,
body and tail, that is continuous with vas deferens.
• It acts as maturation and storage place for sperm.
14. Vas deferens
• Vas deferens is a thin tube and continuation of
epididymis to urethra in penis.
• They transport sperm from the epididymis in
anticipation of ejaculation.
16. Accessory glands
• Accessory glands are
– Seminal Vesicles
– Prostate Gland
– Bulbourethral gland
• These glands produce nourishing fluids for
sperms that enter urethra.
17. Seminal Vesicles
• Seminal Vesicles are sac-like structures attached to
vas deferens at one side of bladder.
• They produce a sticky yellowish fluid that contains
fructose.
19. Prostate Gland
• Prostate Gland surrounds ejaculatory ducts at base of
urethra, just below the bladder.
• Is responsible for making production of semen, a
liquid mixture of sperm cells, prostate fluid and
seminal fluid.
21. Bulbourethral Glands
- Bulbourethral Glands are two small glands located on
sides of urethra just below prostate gland.
- These glands produce a clear, slippery fluid that
empties directly into urethra.
23. Spermatogenesis
Introduction
• Spermatogenesis is the process by which
primitive male gametes become mature sperm.
• Spermatogenesis takes place in the seminiferous
tubules under influence of Follicle stimulating
hormone (FHS) and testosterone.
24. • Pituitary gland secretes luteinizing hormone (LH),
which stimulates synthesis and secretion of
testosterone by Leydig cells, and follicle-
stimulating hormone (FSH), which acts with
testosterone on Sertoli cells to stimulate
spermatogenesis
25. • Germinal epithelial cells lining seminiferous tubules are
called spermatogonia.
• They are present at birth but do not produce spermatozoa
until puberty.
• At puberty, spermatozoa begin to actively divide under
influence (FSH) and continues throughout adult life.
• Spermatogonia enter maturation process every 16 days, and
development from spermatogonia stem cells to mature sperm
cells takes about 75 days.
27. Process of Spermatogenesis
1. Shortly before puberty, primordial gremial cells
develop into spermatogonia and remains in wall of
seminiferous tubules.
2. Mitosis cell division occurs resulting differentiation
of Spermatogonia into primary spermatocytes.
3. Each primary spermatocytes contains 22 pairs of
autosomes and one pair of sex chromosomes.
28. 3. Through First meiotic division, secondary
spermatocytes are formed having haploid number
of chromosomes either 23,X or 23, Y from primary
oocytes.
4. Immediately follows, second meiotic division
with formation of four spermatids, each containing
haploid number of chromosomes, two with 23, X
and two with 23, Y.
29. • After formation of spermatids , extensive
morphological differentiation of spermatids
occurs without further cell division to convert
them into spermatozoa/sperm. This process is
called Spermiogenesis.
34. Introduction
• Spermatozoon is a motile cell gamete and shaped liked
a tadpole.
• Structure:
1. Head: head region of sperm that contains DNA.
2. Mid piece: narrow middle part of cell contains
mitochondria.
3. Tail: wavelike motion of flagellum propels sperm
forward.
36. Contd..
• At each ejaculation, 2-4ml of semen is released.
• Seminal fluid contains about 100 million sperm per
milliliter, of which 20-25% are likely to be abnormal.
• Survival time of spermatozoa is approximately 72
hours.
• Only one spermatozoon is necessary to fertilize ovum.
37. Sperm Transport
• During ejaculation, mature spermatozoa are released from vas
deferens along with fluid from prostate, seminal vesicles, and
bulbourethral glands.
• Following ejaculation, released spermatozoa must undergo
capacitation to become competent to fertilize oocyte.
• Capacitation occurs within cervical mucus and involves
removal of inhibitory mediators such as cholesterol from sperm
surface, tyrosine phosphorylation, and calcium ion influx.
38. • When sperm reach tubal isthmus they are slowly released
into ampulla, further reducing number of sperm that reach
oocyte.
• Sperm transport from posterior vaginal fornix to fallopian
tubes occurs within 2 minutes during follicular phase of
menstrual cycle
39. Fertilization
• As capacitated sperm near and pass through cumulus cells
surrounding oocyte, hydrolytic enzymes are released from
acrosome via exocytosis in a process called acrosome
reaction.
• Following acrosome reaction, sperm binds to and
penetrates zona pellucida.
• Resulting sperm to fuse with plasma membrane of oocyte,
an event that promotes changes in oocyte and prevent entry
by additional sperm.
40. • As first sperm penetrates zona pellucida, cortical
granules are released ( cortical reaction) from
oocyte.
• This stops oocyte’s zona pellucida from binding new
sperm and inhibits penetration by previously bound
sperm, further reducing possibility of polyspermy.