W9- Lecture 45-Reproduction and Development Flashcards
when does testicular decent take place ?
Occurs during gestational development in humans.1st trimester
how and where are the Testis (& epididymis) anchored (pre decent)?
anchored anteriorly by the Diaphragmatic (cranial) ligament,
posteriorly by the Gubernaculum testis.
describe the decent of the testes
+ describe the impact of positional defects / why
Body grows,
gubernaculum shrinks,
diphragmatic ligament degenerates
descent through inguinal canal. (Gubernaculum degenerates.)
Positional defects ~2%. Cryptorchidism: links to testicular cancer.
due to temperature too hot for optimum
what 4 sections is the penis made of ?
root, shaft, neck & head
name two important spongy tissues found in the shaft of the penis
Corpus cavernosum & Corpus spongiosum (around urethra), which are erectile tissues.
where does the base of the the penis attach?
via what
Base, (root) attached below pubic symphysis.
Crura of corpora attached via ligament to bone.
name the structures in the head of the penis
prepuce(foreskin)
, glans penis(head)
& external meatus(external urethral orifice)
describe tumescence aka an erection
NO (nitric oxide secondary messenger )
arterial dilation
increased blood flow into Corpora cavernosa;
turgor (pressure.) reduces venous blood flow by constriction.
why is the Corpus spongiosum important?
allows sperm to exit during an erection
name two glands
location
and their role in the penus
Bulbourethral (Cowper’s) glands: at base of penis secreting alkaline mucus to lubricate and neutralise urinary acids.
Preputial glands: waxy secretion (smegma) between prepuce & glans.
what is the normal volume for the testes ?
what is this an indicator of ?
12 – 30ml vol. (mean 18ml).
indicator of sperm production
what is the Tunica albuginea ?
thick wall that encloses the testicular cavity
describe how the testicular cavity is divided
divided by septa, each containing coiled seminiferous tubules
what is the Pampiniform Plexus
+ the function
venous network - anastomosing veins wrap around the testicular artery
heat exchange mechanism
Seminiferous tubules (location of meiosis ) empty into a chamber what vessels do these go through ?
rete testis
efferent ducts
epididymis.