Male Reproductive Anatomy

What is the role of the testis?

• The male gonad that produces spermatozoa

• makes testosterone

• makes fluids

What is the purpose of the scrotum?

• a two-lobed protective sac

• has thinner skin to help keep testes cool

• sweat glands and thermosensitive nerves

• houses the testes

What is the gubernaculum?

tissue in the scrotum that anchors the testis

What is the tunica dartos?

• A layer of smooth muscle in the scrotum that helps thermoregulate the testis

• can do sustained contractions

• androgen controlled

What are the different layers of the testes? Outside in.

• testicular capsule

• parenchyma

• mediastinum

• Rete tubules

What cells produce testosterone and which layer are they in?

Leydig cells in the parenchyma

Where is the site of spermatogenesis in the testes?

seminiferous tubules

What is the name of the cells that make up the outer layer of the seminiferous tubule?

basement membrane; peritubular cells

What is the main layer of the seminiferous tubule called?

germinal epithelium

What is the order of sperm maturity from basement membrane going inwards?

Spermatogonium, Primary Spermatocyte, Secondary Spermatocyte, Spermatids

What is the mediastinum?

• core of testis

• dense connective tissue

• houses rete tubules

What is the path that sperm take from start to finish?

Seminiferous tubules, rete tubule, mediastinum, rete testis, vasa efferentia, epididymal head, epididymal body, epididymal tail, vas deferens, ampulla, colliculus seminalis, prostate, bulbourethral gland, penis, glans penis

What is the role of the epididymis?

• environment for final maturation of sperm (motility and fertility)

• sperm storage in the tail of epididymis

What are the different regions of the epididymis?

• head/caput

• body/corpus

• tail/cauda

Sperm from the head of the epididymis are _________

NOT motile and NOT fertile

Sperm from the body of the epididymis are _________

Somewhat mobile and fertile. Can bind to the ova

Sperm from the tail of the epididymis are _________

Motile, fertile, and can bind to the ova

What is the vas deferens?

also called the ductus deferens. transports sperm out of the tail and through the spermatic cord during ejaculation

What are the functions of the spermatic cord?

• suspends/supports testis (esp. in pendulous scrotums)

• pathway for lymphatics, nerves, vasculature

• houses vas deferens, pampiniform plexus, cremaster muscle

• thermoregulation

Which parts of the male repro tract help with thermoregulation?

Tunica dartos in the scrotum and pampiniform plexus in the spermatic cord

What is the pampiniform plexus?

• primary thermoregulator

• the testicular artery runs through this

• convoluted veins and arteries

  • arterial blood is warmer than venous blood; veins wrap around the artery

What happens when the testis get too hot?

there is a severe compromise in spermatogenesis. Leydig cells still work, but produce hormone at a less efficient rate

What is the function of the cremaster muscle?

• plays minor role in temp control

• contracts/relaxes, allowing for pumping action and bloodflow

• NON-SUSTAINED contractions

What are the male accessory sex glands?

1. Vesicular glands/seminal vesicles

2. Bulbourethral gland/Cowper’s gland

3. Prostate

4. Ampulla

What is the open part of the pelvic genitalia where urine and seminal fluid mix before entering the penis?

the Colliculus Seminalis

What do the accessory sex glands do?

Produce fluids so that when sperm is added, seminal fluid is created

Which species of interest have vertically oriented (pendulous) testes?

bull, ram, rabbit, human

Which species of interest have oblique oriented testes?

boar, dog

Which species of interest have horizontal oriented testes?

stallion

Where is the tail of the epididymis ALWAYS pointing?

to the coolest point in the testes

What are the differences in a boar compared to a bull?

1. corkscrew glans penis

2. highly developed vesicular gland

3. testes oriented oblique

4. highly developed bulbourethral gland

5. disseminate prostate

6. no ampulla

What are the differences in a stallion compared to a bull?

1. muscular vascular penis

2. highly developed ampulla

3. testes oriented horizontally

4. no disseminate prostate

What are the differences in a dog compared to a bull?

1. muscular vascular penis

2. bulbus glandis locks during mating

3. no seminal vesicles

4. no disseminate prostate

5. no bulbourethral glands

6. highly developed prostate

What are the differences in a tom compared to a bull?

1. no seminal vesicles

2. no disseminate prostate

3. barbed glans penis

What are the differences in a ram compared to a bull?

1. disseminate prostate

2. filiform appendage

What are the differences in a human compared to a bull?

1. no disseminate prostate

2. can develop benign prostate hyperplasia

What characterizes the muscular-vascular penis?

more erectile tissue, corpus cavernosum is softer with large sinuses, no sigmoid flexure, engorges therefore no sigmoid flexure

What characterizes the fibroelastic penis?

limited erectile tissue, connective tissue encased by tunica albuginea, sigmoid flexure, does not increase in length or diameter

What is the corpus spongiosum?

a tissue that wraps around the urethra

Which species of interest have a fibroelastic type penis?

bull, boar, ram

Which species of interest have a muscular-vascular type penis?

stallion, dog, tom, human