Male Reproductive System

ADVANCED DIPLOMA IN MIDWIFERY

MWMS 4013

MALE REPRODUCTIVE SYSTEM

Zuraini Haron
ILKKM Kubang Kerian

(Kejururawatan)

The Male Reproductive Systems

External Genitalia
Internal Genitalia
Male Hormones
Spermatogenesis

Male Reproductive System

 Organs:

 External – Penis, Scrotum
 Internal – testes, epididymis, deferens ducts, ejaculatory

ducts & urethra
 Glands: seminal vesicles, prostate, bulbourethral glands

 Supporting structures include scrotum & penis

Male Reproductive System

Copyright 2010, John Wiley & Sons, Inc.

Penis

 Contains urethra- root, body & glans penis

 Passage for semen and urine

 Root (radix): attached portion
 Body (corpus): 3 cylindrical masses erectile

 Dorsal: Corpora Cavernosa Penis
 Midventral: Corpus Spongiosum penis- contains urethra

 Glans penis has external urethral orifice
 Uncircumcised glans covered by prepuce

Penile clitoral structure

 Made up of 3 column tissue:
 2 corpora carvenosa on dorsal
side
 1 corpus Spongiosum on
ventral side

 Glans penis
 The enlarged and bulbous-
shaped end of the corpus
Spongiosum

 Rounded base of glans penis called
corona

Penile clitoral structure

 The raphe is the noticeable line
along the underside of the penis,
scrotum and perineum.

The urethra

 The last part of urinary tract
 The opening = urethral

orifice (meatus)
 Passage of

 Urine
 Semen during ejaculation

Arousal & Ejaculation

 Parasympathetic impulses erection

 Dilation of penile arteries
 Volume compresses veins so outflow is slowed

 Ejaculation is a Sympathetic reflex

 Peristaltic contractions in ductus deferens, seminal vesicles,
ejaculatory ducts & prostate emission

 Sphincter at urinary bladder closes
 Forceful release of semen from urethra

Function of penis

 Urinary function
 Sexual function

 Sexual intercourse
 Ejaculation

Scrotum

 Pouch that supports the testes
 Septum separates into separate sections for each testis
 Sperm requires temperatures 2-3°C below body temperature
 Allows raising and lowering testes to adjust temperature

Function of scrotum

 Keeping the testes at a temperature slightly lower than the
body temperature (34.4ºC) to enable the production of viable
sperm.

 Temp. > 36.7ºC can damage the sperm count.

Testes

 Paired oval glands about 5 cm
long and 3 cm in diameter

 Develop on embryo’s lumbar
region of the abdominal cavity
and descend into scrotum

 Starts in 7th month

Testes

Copyright 2010, John Wiley & Sons, Inc.

Microscopic structure of testes

 3 layers of testes

 Tunica vasculosa

 Inner layer of connective tissue containing
a fine network of capillaries

 Tunica albugenia

 A fibrous covering – divides the testes to
200 – 300 lobules containing seminiferous
tubules

 Lined with spermatogenic cells:
spermatagonia & sertoli cells

 Tunica Vaginalis

 Outer layer, made of peritoneum
 Parietal and visceral layer

Microscopic structure of testes

 Seminiferous (seed-carrying)
tubules

 Lined with Spermatogenic cell

 Spermatogenesis occur

 Spermatogonia (stem cell) - positioned
against the basement membrane, toward
the outside of the tubules

 Towards the lumen of the tubule are
layers cells in order of advancing maturity

 Primary Spermatocytes  Secondary
Spermatocytes  spermatids sperm
cells

 Sperm cells will release into the lumen of
seminiferous tubule

Microscopic structure of testes

 Seminiferous (seed-carrying)
tubules

 Sertoli cells – located between the
developing sperm cell – support,
protect and nourish spermatogenic
cells

 Between tubule – interstitial cell
(Leydig cell) – secretes
Testosterone

 Tubule joint to form a system of
channels that lead to epididymis

Spermatogenesis Stages

Stages:

meiosis I,

meiosis II,

spermiogenesis

Occurs in seminiferous tubules

Cell types involved: spermatagonia,
sertoli cells & interstitial cells (leydig
cells)
Move through testes  epididymis

Takes
 ~ 10 days to mature
 ~ 65–75 days from first division to

release

Spermatogenesis Stages

Initial diploid cell (spermatogonium)
undergoes mitosis beginning
puberty and turn to primary
spermatocyte

Support by Sertoli cells

Spermatogenesis Stages

Primary spermatocyte

Diploid number of chromosomes and
their nuclei undergoes Meiosis I
(reduction division & interchange of
genetic material)
1 spermatocyte produce 2 daughter
cell (secondary spermatocyte)

Spermatogenesis Stages

Secondary spermatocyte

 Haploid cell
 Undergoes Meiosis II – further

rearrangement of genetic material
 Influence by LH

Spermatogenesis Stages

Spermiogenesis

each spermatid develops into a sperm
cell
The largest part of the spermatid
containing the nucleus
Process requires support of Sertoli cell
Often called “nurse cell”

Mature spermatozoon

Developed from one original
spermatogonia
2 spermatogonia will carry an ‘x’
female determining chromosome

Mature spermatozoon

~300 million /day

 Life time ~ 48 hrs in female tract

 Structure: Head, neck, body, tail
 Tail- flagellum = motility
 Body: mitochondria = energy
 Head-chromosomes + acrosomal

cap

 Acrosome-enzymes  penetrating
egg

Hormonal Control of the testes

 At puberty- hypothalamus  GnRH  Pituitary  LH & FSH

 LH Leydig cells  testosterone Negative feedback to suppress
LH & GnRH

 FSH + testosterone stimulate spermatogenesis

 Sertoli cells  inhibin  inhibits FSH release  optimum
sperm production

Hormonal
Control

Copyright 2010, John Wiley & Sons, Inc.

Androgen Effects

 Prenatal: male pattern of development:

 Male ducts, descent of testes, external genitals and brain regions

 Puberty: enlargement of organs, secondary characteristics

 Muscular and skeletal growth, hair patterns, thickening of skin

 Sexual function: sexual behavior, spermatogenesis and
libido

 Stimulation of anabolism: stimulate protein synthesis and
muscle and bone growth

Ducts: Sperm Route

 Epididymis vas (ductus) deferens  ejaculatory duct (by
seminal vesicles)  urethra in prostate

 Pass bulbourethral glands (alkaline + mucus fluid)  penis
and ejaculation

Epididymis

 Epi = above or over
 Didymis = testis
 A comma-shaped organ, lies along the posterior border of the

testes (convoluted)
 Each contains tightly coiled ductus epididymis

Epididymis

Function:
 Site of sperm maturation (10 – 14 day period)
 Stores sperm, and help propels them during sexual arousal by

peristaltic contraction of its smooth muscle into the ductus
deferens.
 Sperm may remain in the storage for several month
 If not ejaculated, the sperm will eventually phagocytized and

reabsorbed

Vas (ductus) deferens

 Less convoluted
 Ascends along the posterior border of the epididymis

penetrates the inguinal canal  enters the pelvic cavity 
loops over the side and down the posterior surface of the
urinary bladder
 Heavy coat of three layers of muscles

Vas (ductus) deferens

 Function

 Stores sperm which can remain
viable for several months

 Convey sperm from the epididymis
toward the urethra during sexual
arousal by peristaltic contraction

Spermatic cord

 Name given to the cord-like structure
consist of

 Vas deferens (Deferent duct)
 Arteries
 Veins
 Nerves
 Lymphatic vessels

Ejaculatory Duct

 Formed by the union of the duct
from vas deferens and seminal
vesicle

 Function:

 Carry sperm into the urethra

Urethra

 The terminal duct of the male
reproductive system

 Passes trough the prostate,
deep perineal muscle and penis

 Function:

 Passageway for urine and sperm

Accessory Glands

 Seminal vesicles: seminal fluid

 Fructose (sperm ATP production)
 + alkalinity (neutralize acid in tracts)
 + prostaglandins-activation of sperm

 Prostate: surrounds upper urethra

 Increases volume + adds antibiotics
 Secretes milky, slightly acidic (pH 6.5) contains

 Citric acid
 Acid phosphatase
 protein-digesting enzymes

 Bulbourethral glands

 More alkalinity + mucus fluid

Semen

 2.5 – 5 ml in every ejaculation
 pH – 7.2 – 7.7
 Mixture of

 Sperm (50 – 150 million per ml)
 Secretion from seminal vesicles
 Prostate glands
 Bulbourethral glands