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Male Reproductive System

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Learning objectives

1. Describe the testes and its function

2. Describe the duct system and their functions

3. D

escribe the accessory glands and theirfunctions

4. Describe the scrotum

5. Describe the structure and function of the

penis

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General Arrangement

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Testis (plu. Testes )

Situated in the scrotum

Two coverings

Tunica

vaginalis

Tunica albugenia

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Testis

Tunica vaginalis

Parietal layer and visceral

layer

Thin cavity with little fluid

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Testis

Tunica Albugenia

Fibrous capsule of the testis

Thickened posteriorly

Mediastinum of the testis

Septa divide the testis into

lobules (250-300)

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Testis

Seminiferous tubules

Highly convoluted

Situated within lobules (1-5)

Lined by germinal epithelium

Open to rete testes in the

medistinum

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Seminiferous tubules

lined by germinal epithelium

Spermatogonium

Primary spermatocyte

Secondary spermatocyte

Early & late spermatids

Spermatogenesis

Mature spermatozoa

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Spermatogenisis

Spermatogonium

Primary spermatocyte

Secondary spermatocyte

Early spermatids

Late spermatids

Mature spermatozoa

64 75 days

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Sustentacular cells ( Sertoli cells)

Blood-testis barrier

Supply nutrients

Secrete testicular fluid

Phagocytosis

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Interstitial cells (Leydigs cells)

Lie in the spaces between

seminiferous tubules

Testosterone

Secondary sexual features

of the male

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Functions of the testis

1. Spermatogenesis ( production of mature sperms )

2. Endocrine function ( Secretion of testosterone)

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Duct system

Epididymis

Vas deferens

Ejaculatory duct

Urethra

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Epididymis

Long tubule / highly coiled

Lies on the posterior surface

of the testis

Divided in to head, body

& tail

Efferent ductules open to head

Tail continuous with the vas

deferens

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Epididymis

Functions

Capacitates sperms

Supplies nutrients to sperms

Stores the sperms

Removes dead sperms

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Vas deferens

Extends from the tail of the epididymis to ejaculatory ducts

Part of it is in the scrotum & the rest is in the pelvic cavity

Very thick muscular

wall with small lumen

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Vas deferens

Function

Propels sperms from

the epididymis to

ejaculatory ducts during

ejaculation

Peristalsis of smooth

muscles

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Ejaculatory ducts

Formed by the union of

vas deferens & duct of the

seminal vesicle

Passes through the prostate

gland

Opens to the urethra

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Male urethra

extends from internal

urethral orifice to external

urethral orifice has prostatic, membranous

& penile parts

passage for urine andsemen

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Male urethra

midline urethral crest

prostatic sinuses on either sides

ejaculatory ducts open to seminal

colliculus on the urethral crest

prostatic ducts open to prostatic

sinuses

In prostatic urethra

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Accessory glands

Seminal vesicles

Prostate gland

Bulbo-urethral glands

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Seminal vesicles

Located behind the bladder

above the prostate gland

Its ducts join the vas

deferens to form the

ejaculatory ducts

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Seminal vesicles

60% of seminal

fluid volume

Yellowish, viscous & alkaline

Fructose & ascorbic acidCoagulating enzyme ( vesiculase)

Prostaglandins

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Prostate gland

lies inferior to bladder urethra & ejaculatory ducts passthrough it

several ducts opens

to prostatic

urethra

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Prostate gland Thick capsule

Secretory units embedded

in a fibro-muscular stroma

Secretions

Acidic (Citrate)

Fibrinolysins, hyaluronidase,

acid phosphatse &

Prostaglandins

Prostate Specific Antigen

(PSA)

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Bulbo-urethral glands (Cowpers glands)

lie inferior to prostate gland

ducts open to penile urethra

secretes pure mucous just

before ejaculation

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External genital organs

Scrotum Penis

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Scrotum

Sac of skin & superficial fascia with a midline septum

Hangs from the

root of the penis

Testes are

suspended in it

Provides optimal

temperature for

spermatogenesis

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Penis

Root Shaft Glans

Skin over the shaft is loose

Forms a cuff over the glans ( prepuce)

Urethra opens to exterior

on the glans ( vertical slit)

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Structure of the penis

Three cylindrical bodies of erectile tissue

Two corpora cavernosa

One corpus spongiosum

Spongy network of connective tissueand smooth muscles with large

vascular space

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Structure of the penis corpus spongeosum expands

distally to form the glans of the

penis.

penile urethra passes through

it

Copora cavernosa lie on both

sides of the corpos spongeosum

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Structure of the penis

Proximal part of the copora cavernosa

Covered with ischiocavernosus

muscles

Functions of the penis Copulation

Passage of urine and semen

Whole length of the corpus spongeosum

Covered with bulbospongeosus

muscle