UG-male Reproduction Flashcards
What are the 3 differences of the male pelvis?
- heart shaped linea terminalis
- subpubic arch 50-60 degrees
- ilia project less laterally
What does the pelvic floor separate?
Perineum from the pelvis
What are the two triangles of the pelvic floor?
Urogenital triangle
Anal triangle
What are the two main muscles that make up the pelvic floor?
- Levator ani (pubococcygeus/ iliococcygeus/ puborectalis)
- coccygeus
Which nerve innervates the levator ani muscles?
pudendal S2-4
What does the puborectalis act as?
Sling between the rectum and anus
What angle does the puborectalis create?
80 degree
What is the role of the puborectalis?
- Prevents and controls defecation
- increase angle to relax internal and external anal sphincters allowing defecation
What is the difference between male and female urethral sphincters?
Male: internal (autonomic) and external urethral sphincter (somatic)
Female: 3 sphincters
- compressor urethrae
- sphincter urethrovaginalis
- external urethral sphincter
What are the three tubes of the penis?
2 corpora cavernous
1 corpus spongiosum
What are the three parts of the penis?
Root
Bulb
Body
What does the root of the penis contain?
Proximal parts of corpora cavernous (Pubic arch)
What does the bulb of the penis contain?
Proximal parts of corpus spongiosum anchored to perineal membrane
What does the body of the penis contain?
Tethers free parts of corpora cavernosa and corpus spongiosum
In what process does corpora cavernosa have a role in?
Erection
How many parts are there to the urethra?
4
What are the 4 parts of the urethra?
- pre prostatic
- prostatic
- membranous
- spongy
What nerve stimulates an erection?
Parasympathetic fibres of pelvic splanchnic nerves s2-4
How do the parasympathetic nerves stimulate an erection?
Release ACh which stimulates the release of nitric oxide from endothelial cells of trabecular arteries which diffuse into the smooth muscle causing vasodilation
How does vasodilation lead to an erection?
As the arteries dilate the corpus spongiosum and corpora cavernosa fill with blood and the muscles compress the veins of corpora cavernosa limiting venous drainage
Is the temperature of the testis the same as the rest of the body?
No
3 degrees cooler
Where does spermatogenesis occur?
Seminiferous tubules
What are the two cell types in the testis?
Leydig
Sertoli
Where are leydig cells located?
Loose tissue surrounding the seminiferous tubules
Can the epididymis be palpated?
Yes
Where does the right testis drain into?
inferior vena cava
Where does the left testis drain to?
left Renal vein
describe the pathway of sperm
1-Spermatogenesis occurs in the seminiferous tubules
2 – rete testes (network of tubules)
3-efferent ducts - stored and gains motility in head of the epididymis – epididymis has a head, body and tail and the tail which thickens to form vas deferens
4-Vas deferens joins up with the seminal vesicles to form the ejaculatory ducts which penetrates the prostate and drains into the prostatic urethra – seminal vesicles and prostate release seminal fluid into prostatic urethra
What are the 3 accessory sex organs?
Seminal vesicles, Prostate gland, Bartholin’s glands
what substances does the seminal vesicles contain?
- fructose
- citric acid
- lots of prostaglandins and fibrinogen
what does the prostate gland contain?
- zinc rich to stabilise DNA
- fructose for nutrition
- alkaline to neutralise vaginal acid
what does the bartholins gland contain?
- alkaline fluid to protect sperm during arousal
- mucus that lubricates the end of the penis and the lining of the urethra
what is the difference between spermatogenesis and spermiogenesis?
Spermatogenesis is producing sperm while spermiogenesis is where spermatids develop a tail and head
describe Spermatogenesis
- spermatogonia migrate from the basement membane, between sertoli cells, through the tight junctions of the blood-testis barrier
- they differentiate into diploid primary spermatocytes
- each primary spermatocyte replicates its DNA and meiosis I begins forming 2 haploid secondary spermatocytes which then form 4 spermatids after meiosis II
describe spermiogenesis
In the final stage, each spermatid develops a flagellum and acrosomal head to become spermatozoa
when does sperm gain motility?
when stored in the epididymis (head)
what does fluid from leydig cells do?
fluid from the leydig cells pushes sperm into the rete testes which drains sperm into the efferent ducts which join the head of the epididymis
what are the roles of sertoli cells (4)?
- surround the proliferating and differentiating germ cells forming pockets and providing nutrients
- phagocytose excess spermatid cytoplasmic material
- secrete ABP - ensure sperm remain in the adluminal compartment
- secrete anti-mullerian hormone - breaks down the mulerrian duct
what are leydig cells also known as?
interstitial cells
what do leydig cells contain?
many cholesterol lipid droplets-cholesterol convert to testosterone
where are leydig cells situated?
between seminiferous tubules in interstitium
describe the emission stage of ejaculation
Sperm moved from testes and epididymis to beginning of the urethra due to contraction of muscles around the epididymis and ductus deferens, pushing the sperm into the prostate and urethra
what is the ejaculatory proper?
semen expelled by strong spasmodic contractions of the bulbospongiosus and ischiocavernosus muscles
once ejaculation has started it becomes a reflex reaction triggered by which nerve?
pudendal nerve
WHAT DIFFERENTIATES INTO A SPERMATOZOA? SPERMATOGONIUM OR SPERMATID?
spermatid
WHICH CELL AIDS SPERMATOGENESIS
sertoli
which cell secretes testosterone
leydig
what % of seminal fluid is found in the prostate?
25%
what % of seminal fluid is found in the seminal vesicle?
70%
how many lobes does the prostate have?
5
-anterior/ posterior/ medial/ 2x lateral
which 3 muscles make up the levator ani?
- pubococcygeus
- iliococcygeus
- puborectalis
