Male reproductive system Flashcards
Gonads
Gonads in both sexes begin to develop during the 5th week as masses of intermediate mesoderm called gonadal ridges, form bulges on dorsal AW
mesonephric duct = future male ducts
Development of external reproductive organs
genital tubercle enlarges ->penis, urethral folds fuse in the midline -> penile urethra,
labioscrotal swellings also join in the midline -> scrotum
Decent of testes
testes begin to move toward scrotum (inguinal region), and pull with them
their blood supply and innervation, & won’t descend any further until month 7, they should reach inguinal region at about 12 weeks
Decent of testes part 2
month 3- with the testes located towards scrotum, an increase in T encourages
gubernaculum to shorten and draw testis into scrotum, outpouching of peritoneal lining in abdomen called processus vaginalis pokes through layers of AW into
developing scrotum
Gubernaculum
fibrous cord that attaches to I portion of testis and floor of developing (outpouching of) scrotal sac
Decent of testes part 3
passage of testis from PAW into scrotum happens before birth in most cases.
The testis ‘pulling’ the layers of ABW with it, means that scrotum has same layers (different names) as ABW, there is no
layer of transversus abdominis in the scrotum, because layers are not I enough
Male ducts when testes decent
male ducts (transport for sperm upon
maturity) are present and arose from
degraded mesonephric duct, epididymis, ejaculatory duct and ductus deferens
Scrotal septum development
month 7 - testes enter scrotum, testis should maintain connection to gubernaculum, testis is securely anchored to I wall of scrotum
- A septum is maintained or developed separating testis from other testis and maintaining separate ‘compartments’ or ‘cavities’ for each testis within scrotum
Scrotum
sac of skin that extends external to the abdominopelvic cavity
- positioning provides an environment 3 ̊ cooler than body temp, for sperm production.
- 2 muscles in wall: dartos and cremaster muscles
Hernia
protrusion of abdominal contents out of AC through a weak point in muscles of AW
Sites: inguinal (above inguinal ligament)
- femoral (femoral canal)
- diaphragmatic
- lumbar (lumbar triangle)
- umbilical (omphalocele)
Common hernia (Indirect)
Inguinal: Viscera protrudes through AC at deep inguinal ring and inguinal canal
- Viscera pass L to I epigastric vessels, more common in younger patients
Uncommon hernia (direct)
1/3 to 1/4 of inguinal hernias - herniating bowel pushes through peritoneum and
transversalis fascia, typically traverses only M 1/3 of inguinal canal – a direct course through AW, rarely enters scrotum, viscera bulge M to I epigastric vessels
Testes structure
- Seminiferous tubules – sites of sperm production
- Epididymis – organ where sperm mature
Sperm path
seminiferous tubules → epididymis → ductus deferens → ejaculatory duct → urethra
Accessory sex glands
empty secretions into reproductive ducts along this path:
- seminal vesicles
- prostate gland
- bulbourethral glands
Vesicles
Elongated structures, lie between fundus of
bladder and rectum
- Secrete a thick alkaline fluid: mixes w/sperm as they pass into ejaculatory ducts and urethra, secretions contain:
- fructose and other nutrients nourish sperm.
- other substances to enhance fertilization
Ejaculatory ducts
Slender tubes, arise by union of duct of
seminal gland w/ductus deferens near neck of bladder.
- ducts run close together as they pass AI
through P part of prostate
Prostate
Prostate gland: encircles prostatic urethra.
- Prostatic secretions: 1/3 of semen volume and contain enzymes: enhance sperm
motility
Bulbourethral glands
I to prostate, secrete mucus: 2 pea-size bulbo-urethral (Cowper) glands situated PL to intermediate part of urethra
- their ducts pass through perineal
membrane w/intermediate urethra, open through very small apertures into proximal part of spongy urethra in bulb of penis.
- Secretions are mucus-like, enter urethra during sexual arousal, a basic solution that neutralizes traces of acidic urine
Penis
male urethra conveys urine and semen (at different times).
- Penile structure: 3 bodies of erectile cavernous tissue:
- CS and CC
- Glans penis - expanded tip of penis
surrounding opening, continuous w/CS
- Prepuce (foreskin) - loose fold of skin
surrounding glans to a variable extent
Internal structure of penis
- corpus spongiosum – surrounds urethra, enlarged proximally (root, covered by bulbospongiosus muscle), distally (glans).
- paired corpora cavernosa – covered by
ischiocavernosus muscles.
These muscles function in maintaining erection and emptying urethra
Erectile tissue
CS and CC both erect penis, anchored to BW by bulb and crus of penis (crus paired, bulb unpaired). Crus composed of CC while bulb is CS, penis is further attached to BW by both muscles BS and IC
Hypospadias
fusion of urethral folds incomplete, and abnormal openings of urethra occur along
I aspect of penis, usually near glans, along shaft, or near base.
- In rare cases, the urethral meatus extends along scrotal raphe
- When fusion of urethral folds fails, a wide sagittal slit found along entire length of penis and scrotum, 2 scrotal swellings then completely resemble labia majora.
- 3-5/1,000 births
Hydrocele and Hematocele
Fluid of blood accumulation in processus vaginalis. An open processus vaginalis necessary for this to occur, injury or infection/inflammation of epididymis may produce hydrocele of spermatic cord
