MALE REPRODUCTIVE SYSTEM I

MALE
REPRODUCTIVE
PHYSIOLOGY
I
Dr. Nilesh Kate
(MBBS. MD)
DR NILESH N KATE
ASSOCIATE PROFESSOR
ESIC MEDICAL COLLEGE
GULBARGA.

An Overview of the Male reproductive
system
 Gonads :- Testis
 Accessory sex
glands :-
Seminal Vesicles,
Prostate Gland,
Bulbourethral
Glands
 Ducts :-
Epididymis,
Vas deferens,
Ejaculatory ducts
Urethra
 Supporting structures :-
Spermatic Cord
Scrotum
Penis

TESTES
 Primary reproductive organs or gonads.
 Correspond with ovaries
 Functions --
 Production of sperm.
 Secrete Testosterone.
 Suspended outside the body cavity by
scrotum

FUNCTIONAL ANATOMY OF TESTES
 Location – suspended by spermatic cord into the scrotum.
 Weight – 25 gms.
 Coverings (inner to outer)
1) Tunica vasculosa – innermost
--- made up of loose connective
tissue.
2) Tunica albuginea – Fibrous capsule of testes.
Consists of collagen fibers & elastic fibres.
Mediastinal testis – posterior part expand into
thick mass.
Numerous septa from it divide testes into Lobules.

STRUCTURE OF TESTES
 Fibrous capsule –
tunica albuginea –
surrounds testes
 Scrotal cavity – lined by
tunica vaginalis –
parietal and visceral
layers (between 2
layers small amount of
fluid is present)
Figs 27-4/5

TESTES
 Blood supply.
 Arterial – testicular
artery branch of
abdominal aorta.
 Venous – joins
Pampiniform plexus
anterior to Ductus
deferens.
 Lymphatic drainage –
lumbar & preaortic lymph
nodes.
Saturday, April 25, 2015

1
GROSS STRUCTURE
Rete
Testes
Each lobule contains
•Seminiferous tubule (1)
Compartment…
80 cm long
2 parts –
Convoluted part
Straight part. (20-30) joins to
form Rete testes.
It gives 20 efferent ductules to
form head of Epididymis.
•Interstitial compartment

Seminiferous Tubules
 Capsule– Fibroelastic
connective tissue.
 Basement
membrane ( basal
lamina)
 Epithelial layer.
(complex stratified)
 2 compartments basal
& adluminal

Seminiferous
Tubule
Primary
spermatocytes
Spermatids
sertoli cell
SpermMICROSCOPIC STRUCTURE

Seminiferous Tubules

CELLS
 Spermatogenic cells
 4-8 layers.
 Extend from basal
lamina to lumen.
 Basal compartment
early stages of
spermatogenesis.
 Adluminal – later stages
like sec Spermatocytes,
early late Spermatids &
spermatozoa.

CELLS
 SERTOLI CELLS
 Pyramidal shape.
 Occupies both compartments
 Forms tight junctions.
 Form blood-testes barrier:
 Prevents autoimmune
destruction of sperm..
 Prevents immune attack.
 Maintain luminal fluid
composition. ( low in
glucose & proteins
 High in androgen &
potassium.

SERTOLI CELLS
 FUNCTION
 Physical Support and nutrition
 Phagocytize residual bodies
 Secrete MIS, Inhibin, Transport Proteins (Fe & Cu),
Plasminogen activator, Oestrogen (aromatase),
Seminiferous tubular fluids.
 Secrete androgen-binding protein (ABP):
 Binds to testosterone and concentrates
testosterone in the tubules.

Spermatogenesis
 Definition:-
Formation of spermatozoa from spermatogonia
 Characteristic features:-
` Puberty
Mitosis and Meiosis
1 spermatogonium form 512 spermatids
Duration 74 days
Non-motile in semineferous tubules

Spermatogenesis
Spermatogonium (46)
Mitosis
Daughter Cells (46)

Spermatogenesis
Spermatogonium (46)
Mitosis
Daughter Cells (46)
Growth
Primary Spermatocyte (46)
Meiosis I
Secondary Spermatocytes (23)
Spermatogonium
Meiosis II
Early Spermatids (23)

Spermatogenesis
Spermatogonium (46)
Mitosis
Daughter Cells (46)
Growth
Meiosis I
Spermatogonium
Meiosis II
Spermiogenesis
Late Spermatids (23)

Spermatogenesis
Spermatogonium (46)
Mitosis
Daughter Cells (46)
Growth
Meiosis I
Spermatogonium
Meiosis II
Spermiogenesis
Late Spermatids (23)
Spermatozoa (23)
(Lumen)

SPERMIOGENESIS
 Nucleus – Head
 Centriole – proximal forms
basal body & distal forms
axial filaments
 Golgi app – cap
(Proteolytic enzymes)
 Mitochondria – surrounds
tail (movements)
 Cell membrane --
coverings

EM of a Mature sperm cell
55-65 micrometre in length

STRUCTURE OF SPERMATOZOON (55-65 μm)
 Head
Acrosome
 Neck
Basal body
 Tail
Middle piece
Principal piece
End piece
 Axoneme – central skeleton.
 Fibrous sheath
 Mitochondria – ATP for
motility.

SPERMATOZOA
 120 millions per day
 Maturation and capacitation
Role of Epididymis – secretions makes more motile
Role of seminal vesicle and prostate gland –
stimulate sperm motility
Role of female genital tract – Uterus & tubular
musculature – sucking effect.
Capacitation – Get ability to fertilize in female genital
tract.

FACTORS AFFECTING
SPERMATOGENESIS
 Temperature.
 Need lower than body temp
(320
c)
 Mechanisms – location
outside, evaporative
cooling in scrotum,
countercurrent heat
exchanger in artery & vein.
 Defective --Hot bath,
Cryptorchidism &
varicocoele
 Seasonal variation
 Sperm count more in
winter than in summer.
 Infectious diseases.
 Mumps – degeneration
of semineferous
tubules
 Hormonal control

SEMEN
 Fluid ejaculated during orgasm.
 Volume --2-5 ml/ ejaculate
 Vas deferens contribute 10%-
 Seminal vesicle- 60%
 Prostate gland- 30%
 pH -7.5
 Fibrinogen-help for coagulum- It dissolves after 15 to 30 min
because of fibrinolysin.(from Prostate)
 Life span of the sperm in the vagina 1-2 days.
 Low temp.-several week .
 -100’C(frozen for years)

COMPOSITION OF HUMAN
SEMEN
 Color : White, opalescent
 Specific gravity : 1.028
 pH : 7.35 – 7. 50
 Sperm count : 35-200 million
average about 100 million/ml.
 Fructose (1.5 – 6.5mg/ ml)
 Phosphorylcholine
 Ergothioneine
 Ascorbic acid
 Flavins
 Prostaglandins
From seminal vesicles
(contributes 60% of total volume )

COMPOSITION OF HUMAN
SEMEN
 Spermine
 Citric acid
 Cholesterol,
 Phospholipids
 Fibrinolysin, fibrinogenase
 Zinc
 Acid phosphatase
 calcium
 Phosphate
 Bicarbonate
 Hyaluronidase
From prostate
(contributes 30% of total volume )
buffers

Epididymis
~ 7 m long
Head - superior,
receives
spermatozoa
Body – distal and
inferior
Tail - leads to
Ductus deferens
Rete testis and
Efferent ductules

EPIDIDYMIS
 Route of exit of Sperm
 Nutrition
 Provide Motility

Function: Sperm storage and
maturation
Epididymis

VAS DEFERENS
 Continuation of tail of epididymis
 Route of exit of sperm
 Ductus deferens stores sperm
 Vasectomy – ligated and sectioned

Function: Transport sperm to
urethra
Vas Deferens

SEMINAL VESSICLES.
 Do not store sperm
 Provide the bulk of the semen, a mixture
of secretions, sperm and mucous
 Fructose and prostaglandins from
seminal vesicles

Function: Produce 60% of alkaline semen
including fructose to provide energy for
sperm.
Ejaculatory Duct
SEMINAL VESSICLES

Bulbourethral glands (Cowper’s
glands)
Pea size, paired, at base of
penis
Produce about 10% of semen
Alkaline mucus - function??
Protection from acidic Ph in
vagina

Function: Secretes mucous &
alkaline buffers to neutralize
acidic conditions of urethra.
Cowper’s Gland

PROSTATE GLAND.
 Largest accessory glands
 Alkalinity and clotting enzymes from
prostate.

Function: Produces up to 1/3 of the
semen & includes nutrients & enzymes to
activate sperm.
Prostate

Pathway
of Sperm
 Seminiferous tubules
 Rete testis
 Epididymis
 Vas (Ductus) deferens
 Ampulla of vas deferens
 Ejaculatory duct
 Prostatic urethra
 Membranous urethra
 Penile (spongy) urethra
Fig 27.8

URETHRA: EJACULATION
 During emission phase of ejaculation
sperm are emptied into urethra by
sympathetically induced contractions
 Motor neuron induced contractions of
skeletal muscles at base of penis expell
the semen during expulsion phase of
ejaculation

Functions: Transport urine & semen
Urethra
Bladder

SPERMATIC CORD
 Suspends the testes
 Contains –
Ductus deferens
Vessels and nerves
 Coverings –
Internal spermatic fascia
Cremastric fascia
External spermatic fascia

Spermatic Cord
Can be palpated as it
passes over the pubic brim.
Constituents :
1. Pampiniform plexus of
spermatic vein
2. Spermatic artery
3. Ductus (vas) deferens
4. Lymphatics
5. Nerves-ilioinguinal and genitofemoral
Fig 27.3

SCROTUM
Function: supports and protects
testes
Structure: Skin & underlying
superficial fascia
 Dartos muscle in dermis
 Cremaster muscle - continuous
with abdominal wall muscles (?)
Involuntary contraction
(cremasteric reflex) in response
to ________
Scrotal sac forms 2
separate chambers
Cremaster muscle

Function: Maintain temperature of
testes approx. 30
C below normal body
temp.
Scrotu
m

Penis
Root - fixed to ischial ramus
Body with erectile tissue.
Glans – enlargement of corpus
spongiosum
Prepuce - foreskin – partially
covers glans and surrounds
external urethral meatus (may
be removed in circumcision.)
Preputial glands - produce
smegma (supports bacterial
growth, such as E. coli)
Fig 27.9

Functions: Urination and
Copulation
Penis

MALE SEXUAL ACT
 Stages of the male sexual act
1.Erection
2.Emission
3.Ejaculation
NERVE SUPPLY
i) Parasympathetic nerve (nervi erigentis) (S2, S3 and S4 ): Supply to
the erectile tissue of the penis. Takes part in erection of penis.
-impotance.
 ii) Sympathetic nerves (hypogastric nerve) (T12,L1, L2):Supply to
epididymis, vasdeferens,seminal vesicles, ejaculatory ducts. Takes
part in emission.
iii)Somatic (pudendal nerve) (S2,S3 and S4): Supply to bulbus
cavernosus.It takes part in ejaculation.

Sexual sensations
 Sexual end organs.
 Sexual signals pass trough pudendal nerve.
Penis.
 Pudental nerve
 Sacral plexes
 Undefined of the brain

STAGES
 PENILE ERECTION
 Role of parasympathetic nerves
 Erection ---- by sacral portion of spinal cord- pelvic
nerves- penis
 Nitric oxide – vasoactive peptide ach relax the
artery of the penis & relax the trabecular network of
smooth muscles fibres in the erected tissue of
corpora cavarnosa and corpora spongiosa
 Arterial blood – venous blood occluded by
compressing central vein of penis.
 Ballooning effect erectile tissue –penis become hard
& elongated

LUBRICATION
 Parasympathetic stimulation- promotes erection &
urethral gland & bulbourethral gland to secrete
mucus
 Mucus help for lubrication at coitus.
 Most of the lubrication of coitus is produced by
female sex organ.
Painful sensation- inhibit sexual sensation

EMISSION & EJACULATION
 Sympathetic nerve
T12 L1 L2
hypogastric and pelvic sympathetic
nerve plexus
to intiate emission and ejaculation
 Contraction of vasdeferns
 Expulsion of semen in to urethra
 Contract prostate & seminal vesicle
 Expel prostatic and seminal fluid in to
urethra
 All the fluid mix in the internal
urethra with mucus –emission. it is
called fore runner of the ejaculation

Filling of the urethra
Pundenal nerve
Sacral
Feeling a sudden fullness & excite rhythmical contraction
Contraction of ischiocavernous & bulbocavernous muscle
Compress the base of the penile erection
Rhythmical , wavelike impulse in pressure
Ejaculation of semen from the urethra to the exterior
ejaculation

Emission and ejaculation is
called male orgasm .

MALE REPRODUCTIVE SYSTEM I

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