This document summarizes male reproductive physiology. It discusses the structures of the male reproductive system including the testes, epididymis, vas deferens, seminal vesicles and prostate. It explains spermatogenesis, the process by which sperm are produced in the testes. Ejaculation and the components of semen are also described. Fertilization and the process by which a single sperm fuses with an egg to determine sex of the offspring are summarized in less than three sentences.

1. Fadi Daraghmeh, MD
OB/GYN Resident
Jordanian Royal Medical Services
Amman- Jordan
Male Reproductive Physiology

2. Introduction
 Effective public health programs, research, and
policy relating to human sexuality, pregnancy,
contraception, and the transmission of sexually
transmitted infections depends upon knowledge of
the structure (anatomy) and function (physiology) of
the male and female reproductive systems.

3. Reproductive Biology
 Reproductive physical maturity and the capacity for human
reproduction begin during puberty.
 During puberty, the hypothalamus produces hormones.
 These hormones stimulate the gonads, to produce
testosterone (males) and estrogen and progesterone
(females).
 Male puberty generally occurs between the ages of 13-15
and is characterized by the secretion of the male hormone
testosterone, which stimulates spermatogenesis, and the
development of secondary sexual characteristics.

4. Control of Testicular Function

5. Puberty Male Changes

6. Male Reproductive System

7. Structures
 The male external
structures are the penis
and the scrotum. The penis
consists of the glans , and
the shaft . The glans is
covered by a fold of skin
called the foreskin
(circumcision removes the
foreskin).
 The scrotum surrounds and
protects the two testes,
internal structures also
referred to as testicles.

8.  The testes are the male gonads and contain
hundreds of tiny seminiferous tubules where
sperm cells are produced.

9. Cell types in the seminiferous tubules
A) Germ cells
 Type A spermatogonium.
 Type B Spermatogonium.
B) Sustentacular (Sertoli)
cells
 Nurse’ cell of the testis.
 Key role in sperm.
Production.
 Arise from mesonephros.
 Secrete AMH and Inhibin.
 Phagocytose unwanted cell
components during
spermatogenesis.
C) Leydig cells
 Interstitial cells.
 Contain LH receptors.
 Produce androgens (C19
steroids!).
 20 % of testicular volume.

11. Tight junctions
 Open to allow passage of sperms prior to completion of
meiosis.
 Luminal and adluminal compartments Protects sperm from
immune attack.
 Creates specific closed environment for spermatogenesis
which is filled with secretions from Sertoli cells.
1: basal lamina
2: spermatogonia
3: spermatocyte 1st order
4: spermatocyte 2nd order
5: spermatid
6: mature spermatid
7: Sertoli cell
8: tight junction (blood testis barrier)

12. Epididymal storage of sperm
 Sperm collect in rete testis and pass into epididymis
 Epididymis 5m in length
- Passage through it takes 8-14 days
 3 parts:
1. Caput.
2. Corpus.
3. Cauda–main site of storage.
 Individual ducts join to make vas deferens
 The epididymis is a small oblong body which rests on the
surface of the testes where sperm mature and are stored.

13.  The vas deferens extends to join with the ducts of the
two seminal vesicles to form the ejaculatory ducts which
extend through the body of the prostate gland and
empty into the urethra. The prostate gland surrounds
the neck of the bladder and the urethra. The Cowper's
glands (also called the bulbourethral glands) are found
on each side of the urethra, just below the prostate
gland.

14. How do cells divide ?
• There are two types of cell division: mitosis and meiosis. Most of the time
when people refer to “cell division,” they mean mitosis, the process of
making new body cells. Meiosis is the type of cell division that creates egg
and sperm cells.
• Mitosis is a fundamental process for life. During mitosis, a cell duplicates
all of its contents, including its chromosomes, and splits to form two
identical daughter cells. Because this process is so critical, the steps of
mitosis are carefully controlled by a number of genes. When mitosis is not
regulated correctly, health problems such as cancer can result.
• The other type of cell division, meiosis, ensures that humans have the
same number of chromosomes in each generation. It is a two-step process
that reduces the chromosome number by half—from 46 to 23—to form
sperm and egg cells. When the sperm and egg cells unite at conception,
each contributes 23 chromosomes so the resulting embryo will have the
usual 46. Meiosis also allows genetic variation through a process of DNA
shuffling while the cells are dividing.

16. Process of Spermatogenesis
Sequence of
spermatogenesis
a) Spermatogonia.
b) Spermatocytes .
c) Spermatids .
d) Spermatozoa.

17. • Spermatogenesis begins in the seminiferous tubules of the
testes. Sperm pass into the epididymis where they mature and
become motile so they are able to move through the vas
deferens and into the seminal vesicles where they mix with
seminal fluids, rich in fructose and other nutrients.
• The prostate gland and the Cowper's glands secrete fluids which
also help to nourish and transport the sperm. This mixture of
fluids and sperm is called semen, the fluid which is expelled
from a man's penis during ejaculation. Sexual arousal can cause
fluid from the Cowper's glands to be released prior to
ejaculation. This fluid is called pre-ejaculatory fluid and does
not contain sperm unless it is leftover from a previous
ejaculation. Contrary to popular belief, there is little evidence to
support that pre-ejaculatory fluid contains enough sperm to
cause pregnancy.

18. Consists of secretions from
 Ampulla.
 Seminal vesicles.
 Prostate.
 Cowpersglands.

19. Erection and ejaculation
a) Vasodilation of the corpus callosum
b) ANS causes coordinated contractions of the vas
deferens and glands
c) Sympathetic system
 Movement of sperm into vas deferens and urethra.
 Expulsion of glandular secretions.
d) Parasympathetic system
 Erection and evacuation of urethra.

20. Ejaculate
a) 300 million sperm produced per day.
b) 3500 per second.
c) Ejaculate volume 2-5 mls.
d) Normal sperm count > 15 million/ml.
e) Most ejaculated in first half of fluid.
f) 99.9% lost before reaching egg.
g) Around 120,000 get close to egg.
h) Only 1 sperm enters.

21. Passage to the egg
A) Seminal fluid
coagulates in the vagina
1. Prevents loss.
2. Reliquifies .
3. Seminal fluid changes
acid vaginal pH to
alkali.
B)Sperm passes into cervix
1. Glycoprotein
molecules arrange in
parallel lines.
2. Micelles vibrate and
aid passage of motile
sperm.
3. Non aligned sperm
form reservoir in
cervical crypts.

22. Capacitation
a) Biochemical removal of surface
glycoprotein.
b) Initiates whiplash movement of
tail.
c) Sperm enters hyperactive state.
d) Facilitates reaching and
penetrating egg.
e) Initiated by uterine or tubal fluid.

23. Acrosome reaction
a) Allows sperm to make a slit
in the zona pellucida after
binding to it.
b) Remnants of membrane left
behind as sperm progresses.

24. Egg prior to fertilization
a) Oocyte protected by cumulus
oophorus .
b) Secrete mucus matrix.
c) Projections into egg plasma
membrane.
d) Zona pellucida secreted by egg
around projections.
e) At LH surge projections withdrawn.
f) 1st meiotic division resumes and
completes.
g) 1st polar body extruded.

25. Fertilization
During coitus (sexual intercourse) between a male and a female,
semen is released into the vagina and transported through the
uterus into the fallopian tube. Although many factors contribute to
whether or not a single act of intercourse will result in pregnancy,
most important is whether or not a sperm cell will “meet” an ovum
in the fallopian tube (fertilization). Fertilization can only occur if
intercourse takes place before the time of ovulation that usually
occurs “mid-cycle”, or about 14 days before the woman's next
menstrual period. At the time of ovulation, the ovum is released
from the ovary and transported in the fallopian tube where it
remains for about 24-48 hours. Pregnancy is most likely to occur if
fresh semen is present when ovulation occurs.

26.  Sperm cells remain viable within the female reproductive
tract for about 72 hours. Only a single sperm cell is
needed to fertilize the ovum, even though the average
ejaculation contains approximately 300 million sperm.
 During fertilization, the sperm enters the cell membrane
of the ovum so the nuclei of the sperm and egg cells
combine to form a zygote. The zygote will remain in the
fallopian tube for approximately three days before it
travels to the uterus where it will remain for
approximately four to five days before implantation into
the uterine lining.

27. Fertilization and Implantation

28. Sex Determination
Prior to fertilization, the sperm and egg cells have only half the
number of chromosomes (the genetic determinants of heredity)
of other body cells because they go through a process of cell
division called meiosis, which reduces the number of
chromosomes from 46 to 23. The 23 chromosomes from the
sperm cell combine with the 23 chromosomes from the ovum to
form a single cell (zygote) consisting of 46 chromosomes.
Sex of the offspring is determined by whether the sperm contains
an X or a Y sex chromosome. Female ova always carry an X
chromosome. If the sperm cell contains a Y chromosome, the
offspring will be a male (XY pair). If it contains an X chromosome,
the offspring will be a female (XX pair). Thus, the sperm
biologically determines sex.

30. References
 Male reproductive physiology, Anthony
Griffiths 2014, Indonesia.
 http://www.columbia.edu/itc/hs/pubhealth/
modules/reproductiveHealth/anatomy.html
http://anatomylist.com/tag/male+reproduct
ive+system+anatomy+and+physiology

31. The greatest mistake in the
treatment of diseases is that
there are physicians for the
body and physicians for the
soul, although the two cannot
be separated.
~Plato

32. Thank You