Male Reproductive Tract Anatomy

Question 1

What are the 3 layers of connective tissue around the penis?

Answer 1

1. Tunica albuginea: Tough fibrous capsule that lies directly on surface of testes
2. Parietal vaginal tunic
3. Visceral vaginal tunic

Question 2

What is the seminiferous tubule?

Answer 2

• The site of spermatogenesis

- Mass of coiled tubules surrounded by the tunica albuginea

Question 3

What is the role of the spermatic cord?

Answer 3

Suspends each individual testis within the scrotum from the abdomen.
(deferent duct, vessels-arteries/veins/lymphatic, cremaster muscle, CT, nerves covered by peritoneum).

Question 4

What is the rete testes?

Answer 4

• Network of tubules into which sperm are delivered from the seminiferous tubules

Question 5

What is the role of interstitial cells (leydig cells)?

Answer 5

• Found in CT between seminiferous tubules

- Secrete testosterone

Question 6

Where are sertoli cells found and what is their role?

Answer 6

• Found within the seminiferous tubules

- Nourish the developing sperm (nurse cells)

Question 7

What is the epididymis?

Answer 7

• Coiled portion of external duct system. Connects efferent ductules with ductus deferens (Head, body and tail of epididymis)
• Houses the sperm until mature and motile and expelled by ejaculation

Question 8

How do the sperm get to the external environment from production site?

Answer 8

Convoluted seminiferous tubules –> Straight seminiferous tubules –> Rete Testis –> Testis –> Efferent ductules –> Epididymal duct (head –> tail) –> Ductus deferens –> Urethra –> Penis

Question 9

What is Chryptorchidism?

Answer 9

• Absence of one or both testes from the scrotum

Question 10

What are the accessory sex glands?

Answer 10

1. Ampullary gland
2. Vesicular gland
3. Prostate
4. Bulbourethral gland
   - All paired except PROSTATE
   - Produce the bulk of ejaculate/semen for a transport medium for sperm

Question 11

What are the 3 tissue types evident of testicular parenchyma?

Answer 11

1. Seminiferous tubules (cells lining these produce spermatozoa)
2. Intersitial cells (Leydig)
3. Connective tissue

Question 12

What are the muscles that allow contraction/relaxation of the spermatic cord to change proximity of testes to body and surface area for evaporative cooling?

Answer 12

1. Dartos muscle

2. Cremaster muscle

Question 13

What is the role of the pampiniform plexus?

Answer 13

Counter-current heat exchange

• Coiled testicular artery plus network of veins
• Exchange of heat from warmer arterial blood to cooler venous blood.

Question 14

What are the 3 sections of the penis?

Answer 14

1. Root - penis firmly affixed to pelvis via 2 ‘legs’ (crura) made of muscular and erectile tissue
2. Body - Erectile tissue
3. Apex - Erectile tissue + bone in dog (os penis)

–> prepuce - fold of skin covering penis in flaccid state (internal lamina & external (hairy) lamina

Question 15

What position do the testes lie in ruminants?

Answer 15

• Inguinal

- Pendulous scrotum

Question 16

What position do the testes lie in dogs/ horses?

Answer 16

• Scrotum between thighs

Question 17

What position do the testes lie in cats/boar?

Answer 17

• Perineal scrotum

Question 18

Where are the ampullary glands found?

Answer 18

• Glandular tissue in wall of distal ductus deferens

- Present in stallion, bull, boar, dog (but very little in cat/pig)

Question 19

What makes up the prostate?

Answer 19

• Compound (body) and diffuse (disseminate part) portions
• Body: pair of variably fused lobes (thick CT capsule, Traberculae from capsule divide gland into lobules)
• Disseminate part: individual glands in submucosa urethra.

Question 20

What only 2 accessory glands do the cat and dog possess?

Answer 20

• Prostate

- Ampullary gland

Question 21

What are some major variations in the penis between different species?

Answer 21

1. Relative proportion of tunica albuginea to erectile tissue in corpora cavernosa
   - Musculocavernous&raquo_space; Fibroelastic
2. Extent of the glans
3. Termination of urethra
4. Presence of os penis

Question 22

What are some features of the Musculocavernous penis?

Answer 22

• Extensive cavernous space
• CT capsule contains smooth muscle
• increase diameter and length on erection
• Blood collects in cavernous space
• Primates, dogs, cats, stallion

Question 23

What are some features of the Fibroelastic penis?

Answer 23

• Limited cavernous space
• Thick CT capsule, NO smooth muscle
• Increased rigidity but NO increase length/diameter on erection
• Sigmoid flexure in penis
• Does not need large amount of blood for erection
• Boar, ruminants

Question 24

What is the Os Penis?

Answer 24

• dogs and cats

- distal end of the cavernosum ossifies –> os penis