Origin of the Ejaculate Flashcards
Scrotum
~1500 species don’t have them
- Some never had one= elephants, hyraxes, anteaters, sloths,
- Some had one and lost it= whales, armadillos, beavers
- Some bring testes down seasonally= rodents, insectivores, bats
What affects testes function?
-temperature affects both the endocrine and exocrine function
Capsule of testis
-Visceral peritoneum (visceral vaginal tunic)
-Tunica albuginea containing blood vessels, septa, lobules, and a mediastinum
Testis parenchyma components
1.seminiferous tubules
2.Interstitial tissue
Descent of testes
-occurs through gubernaculum which extends from the fetal testis through the inguinal canal to scrotum
>testis migrate along the gubernaculum within the fold of the peritoneum through canal and brings peritoneum layers with it and will become the vaginal tunic
Vaginal tunic
-peritoneal outpouching (visceral and parietal layers) through canal (vaginal ring, deep inguinal ring, superficial inguinal ring) and around the gubernaculum
What happens when testicular descent is complete?
-gubernaculum shrinks; irreversible
Testicular descent timing
**Very important, as poor timing can result in abnormalities
-Ruminants: mid-gestation
-Pigs, horses: near term
- Dogs: 1-3 weeks after birth
Descent abnormalities
-cryptorchidism
Spermatic Cord parts
-has visceral and parietal layers of vaginal tunic
>vaginal canal separates the layers
-testicular artery (long and convoluted) and veins (pampiniform plexus around the artery)
-lymph drains to nodes near bifurcation of aorta
-nerves with sympathetic fibers
Mesorchium
anything that connects the parietal and visceral parts of testes
Layers of the scrotum
1.Skin
2. Dartos
3.External spermatic fascia
4. Internal spermatic fascia
5. Parietal vaginal tunic
6. Visceral vaginal tunic
Dartos
-inseparable from skin
-elastic and smooth muscle
External spermatic fascia
-loose CT
-easily broken down
-separated in closed castration approach
Internal spermatic fascia and Parietal vaginal tunic
-inseparable layers
-tough CT lined by serous membrane
Visceral vaginal tunic
-inseparable from tunica albuginea