Lecture 1 - Male repro system Flashcards by Anmol Landa

Passage and production of semen

Spermatogenesis occurs in the seminiferous tubules
Sperm travels to the rete testes
Then through efferent ductules to the head of the epididymis where sperm matures and becomes motile
Via the vas deferens which joins to the seminal vesicle to form the ejaculatory duct, sperm travels to the urethra.
Semen passes through the preprostatic, prostatic, membranous, bulbous and spongy urethra
Exits via the navicula fossa

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What does the seminal vesicle do?

Produces 65% of the ejaculatory fluid

Contains:
Fructose - nutrition for sperm
Coagulation factors - coagulates sperm when ejaculated

Alkaline - neutralises acidic pH in vagina

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What does the prostate gland do?

Produces 25% of the ejaculatory fluid

Contains:
Proteolytic enzymes - break down clotting factors

Slightly acidic

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Cowper’s gland (bulbourethral gland)

Secretes a thick alkaline mucus-like fluid
Decreases friction
Neutralise pH of urine before ejaculation

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What happens at the head of the epididymis

Sperm matures
Fluid is absorbed
Sperm becomes more concentrated and motile

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Tunica albinginea

White coat of connective tissue covering the seminiferous tubules.

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Tunica vaginalis

Serous peritoneum that enveloped the testes

Containing a parietal and visceral layer with a cavity in between

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Hydrocoele

Fluid can accumulate within the tunica vaginalis causing a hydrocoele.

Can see via transillumination of the scrotum.

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Sertoli cells

Within the seminiferous tubules

Stimulated by FSH to produce sperm

Removes cytoplasm
Sperm shrinks and becomes more streamlined

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Leydig cells

Stimulated by LH to produce testosterone

Rich in SER for lipid metabolism to make testosterone and have big nuclei

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Where are leydig cells located

In the interstitium between the seminiferous tubules

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Testicular blood supply

Testicular artery arises from abdominal aorta

The pampiniform plexus of veins wrap around the artery

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Left testicular vein

Drains into the left renal vein and then the IVC

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Counter current heat exchange

The pampiniform plexus wraps around the testicular artery with blood flow in opposite directions to maintain a temperature of 35 degrees

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Lymphatic drainage of the testes

Para-aortic lymph nodes - spread during testicular malignancies

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Lymphatic drainage of the scrotum

Inguinal nodes (superficial)

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Lymphatic drainage of the vas deferens and seminal vesicles

Internal and external iliac nodes

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Varicocoele

If the pampiniform plexus is obstructed due to e.g. renal pathology, the veins may enlarge forming a varicocoele

feels like a bag of worms

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Testicular torsion

If the tunica vaginalis extends more superiorly, it can twist along its axis and compress the spermatic cord which can occlude venous drainage

Medical emergency - blood can be restricted and lead to ischaemia therefore loss of testes

If one teste is necrosed immune privilege is lost so antigens are detected and attack the contralateral teste

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How to treat testicular torsion

Surgery - make an incision and detangle testes

Orchiopexy - Can permanently fix the teste to the scrotum wall and prevent torsion

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Septum of scrotum

Testes cannot swap sides due to the septum separating them

Descent of testes

The gubernaculum connects the bottom of the scrotum to the pole of the testes and guides the testes down through the abdominal wall without penetration.

Once at the scrotum the gubernaculum becomes the scrotal ligament

Allowing testes to exist at optimum temperature

Inguinal canal

Because the testes evaginates in the abdominal wall it forms the inguinal canal

3 layers of spermatic fascia

External fascia (EO)
Cremasteric fascia (IO)
Internal fascia (TF)

3 layers of spermatic muscle

External oblique Internal oblique Transversalis fascia

3 arteries supplying the spermatic cord

Testicular artery Artery to vas deferens Cremasteric artery

3 veins supplying the spermatic cord

Pampiniform plexus of veins Vein to vas deferens Cremasteric veins

3 nerves of the spermatic cord

Ilioinguinal nerve Sympathetic to the vas deferens Genital branch of the genitofemoral nerve (cremasteric)

3 other

Vas deferens Obliterated processus vaginalis Lymphatics

Cremasteric fascia

Contains muscle fibres which make up the cremasteric muscle and pull testes up higher when cold

Water under the bridge

Ureters pass underneath the testicular artery and vas deferens

Vasectomy

Vas deferens is sectioned and sealed to prevent sperm from entering the urethra thus preventing fertilisation. Sperm count decreases but there is no difference to the ejaculate as sperm makes up only 2-5%

Ejaculatory duct

The vas deferens and seminal vesicles join to form the ejaculatory ducts (x2) which travel through the prostate gland into the urethra posteriorly

BPH

Benign prostatic hyperplasia - enlargement of the prostate gland particularly the transitional zone which compresses the urethra

Where do prostate cancers tend to be located

Peripheral zone - superficial | May not affect urinary flow

How much volume do the testes and epididymis contribute towards the ejaculatory fluid?

10%

2 types of tissue in the penis

Corpus cavernosum | Corpus spongiosum

Corpus spongiosum

Expansile tissue which the urethra travels through | Patent during passage of sperm

Corpus cavernosum

Paired tissue Main erectile tissue Attached to bone

Catheterisation

2 bends in the penis make it hard to catheterise Therefore: - Straighten penis - Pull penis down

Functions of a penis

Expulsion of urine via the urethra Expulsion of sperm Removal of competitors sperm Attraction of mates

What causes an erection and what controls it?

Vasodilation of penile arterioles and compression of penile veins Controlled by the parasympathetic NS

How is an erection terminated and what controls it? (Ejaculation)

The sympathetic NS causes vasoconstriction of the penile arterioles and dilation of the vein

Penis enlargement

Cut suspensory ligaments of penis to the pubic symphysis so hangs lower but doesn't increase length when erected

Tunica albuginea of penis

White lining of penis around the corpora cavernosa and corpus spongiosum which holds the penis in the correct position when erect . Collagen fibres are transverse and longitudinal which holds shape

Blood supply of the penis

Penile artery from the internal pudendal artery

Causes of scrotal swelling

Inguinal hernia Testicular torsion Hydroceole Testicular tumour

How to discriminate between a testicular hernia and testis swelling

Transillumination - hydrocoele | Palpate - can’t palpate an inguinal hernia above the lump

Why is a varicocele more common on the left?

The left testicular drains into the left renal vein before it drains into the IVC therefore renal vein pathology can affect the left testicular vein

Why do hydroceles get bigger when a male coughs or cries?

Use of abdominal muscles increase intra-abdominal pressure Therefore peritoneal fluid moves down and more is collected in the tunica vaginalis space

Crime steroid reflex

Slightly stroking the superior, inner thigh Causes immediate contraction of the cremesteric muscle that pulls up the testis - rules out testicular torsion