1. Male repro. Flashcards
why do the testes hang outside the body
cooler temp. (35 degrees) required to maximise spermatogenesis
describe sperm’s journey in the testes
i. sperm produced in seminiferous tubules…
2. collect in rete testes…
3. mature in epididymis…
4. transported in vas deferens (final maturation) to urethra
label
which type of cells make up the seminiferous tubules and the interstitium between them - what is their function
SERTOLI CELLS:
- make up walls of seminiferous tubules
- support sperm cell production from primary spermatocytes (from primordial germ cells)
- form blood-testis barrier via tight junctions
LEYDIG CELLS:
- contained in intersitial tissue separating tubules
- synthesise androgens, inc. testosterone (in response to LH)
describe the tissues layers enclosing the testes
- tunica albuginea: fibrous capsule enclosing testes and dividing parenchyma into lobules.
- tunica vaginalis: covers anterior and lateral surfaces of each testicle. Derived from abdominal peritoneum - as processus vaginalis - so has parietal and visceral layers.
describe the vasculature of the testes
arterial supply: via paired testicular aa. - arise directly from abdominal aorta and pass into scrotum through inguinal canal, contained within spermatic cord
venous drainage: pampiniform plexus (wrapped around testicular a.) drains into testicular vein. Acts as heat exchanger, cooling arterial blood before it reaches testes.
L testicular v. drains into L renal v. whilst R testicular v. drains directly into IVC.
describe the lymphatic drainage of the testes and scrotum
- testes: lumbar and para-aortic nodes (L1)
- scrotum: superficial inguinal nodes
describe the course of the spermatic cord
begins at deep inguinal ring… passes through inguinal canal… enters scrotum via superficial inguinal ring to reach posterior testes
describe the 3 layers of the spermatic cord - where does each derive from
- external spermatic fascia (from external oblique aponeurosis)
- cremasteric muscle (from internal oblique aponeurosis) - acts to alter testes height for temp. regulation
- internal spermatic fascia (from transversus abdominins)
describe the cremasteric refex arc
i. stroke superior-medial part of thigh… sensed by ilioinguinal n. (afferent limb)…
ii. impulse along genital branch of genitofemoral n. (efferent limb)…
iii. cremaster muscle contraction and testis elevation on ipsilateral side
describe the contents of the spermatic cord
- 3 arteries: testicular a., cremasteric a., a. to vas deferens
- 3 veins: pampiniform plexus/testicular v., cremasteric v., v. to vas deferens
- 3 nerves: ilioinguinal n., genital branch of genitofemoral n. (to cremaster), sympathetic testicular nn.
3 other: lymphatics (drain into para-aortic nodes), cremaster muscle, vas deferens
how does the vas deferens transport sperm
persistaltic contraction (sympathetic innervation) of 3 SM layers in wall
describe the anatomical course of the vas deferens
epididymis tail… inguinal canal… lateral pelvic wall (in close proximity to ischial spine)… turns medially to pass between bladder and ureter… joins seminal duct to form ejaculatory duct
where is the bulbourethral gland located
posterolateral to membranous urethra in EUS
describe the anatomical relations of the prostate gland
- inferior to neck of bladder
- supperior to EUS
- anterior to ampulla of rectum
describe the 3 histological zones of the prostate - what are the clinical features of these
- central zone
- surrounds ejaculatory ducts
- embryologically derived from mesonephric duct - transitional zone
- surrounds urethra
- embryologically derived from UGS
- undergoes hyperplasia in BPH - peripheral zone
- located posteriorly (can be felt against rectum in DRE)
- embryologically derived from UGS
- origin of most prostate cancers
label these regions of the prostate
label these regions of the penis
describe the 3 main parts of the penis
- ROOT:
- located in superficial perineal pouch of pelvic floor (not visible externally)
- contains 3 erectile tissues: 2 crura and bulb - BODY:
- composed of 3 cylinders of erectile tissue: 2 corpus cavernosa and corpus spongiosum - GLANS:
- distal expansion of corpus spongiosum containing exerternal urethral orifice
describe the attachments of the root of the penis
attached to pubic bone and 2 muscles:
- bulbospongiosus - associated with bulb, contracts to empty urethra of any residual semen and urine
- ischiocavernosus - surround crura, contract to force blood from cavernous spaces in crura into corpus cavernosa to maintain erection
describe the vasculature of the penis
- arterial supply: via branches of internal pudendal a. (arises from internal iliac a.) - dorsal aa. of penis, deep aa. of penis and bulbourethral a.
- venous drainage: deep dorsal v. of penis drains cavernous spaces (empties into prostatic venous plexus) and superficial dorsal vv. drain superficial structures
describe the innervation of the penis
S2-S4 spinal cord segments and spinal ganglia:
- branch of pudendal n. (dorsal n. of penis) - sensory and sympathetic innervation to skin and glans penis
- cavernous nn. from prostatic n. plexus - parasympathetic innervation for vascular changes which cause erection
how is the cylindrical nature of the penis maintained during erection
TUNICA ALBUGINEA: collagen fibres arranged at right angles (can rupture in broken penis)
