B8.005 Male Reproductive Tract Flashcards
how are pelvic features used forensically for aging
Y shaped growth plate that separates 3 bones, the triradiate cartilage, starts fusing at ages 10-16
fusion ends around age 20
male vs female pelvis
sexual dimorphism occurs after puberty
subpublic angle is 90 deg in females and 70 deg in males
characterize pelvic fractures
automobile accident: displacement of the pubic symphsis posteriorly, breaking the superior and/or inferior rami
jumping: may lead to displacement of the head of the femur through the acetabulum
pelvis rarely fractures in a single place (it is a ring)
what is the pelvic diaphragm
muscular funnel that surrounds the anal canal and is formed by:
1) levator ani muscle
2) coccygeus muscle
where is the pelvic diaphragm located
stretches from the pubic symphysis anteriorly, to the coccyx posteriorly, and is laterally attached to the medial surface of the obturator internus muscle
portions of levator ani
3 parts innervated by S4, some S3 & S5 1. pubococcygeus 2. puborectalis 3. iliococcygeus
pubococcygeus
largest part of levator anu
attached from the body of the pubis to the coccyx
puborectalis
attached from the medial body of the pubis to form a U-shaped muscular sling around the anorectal junction
iliococcygeus
attached from a tendinous arch of fascia on top of the obturator internus muscles and the ischial spine to the coccyx
coccygeus muscles
attaches from ischial spine to the distal sacrum and coccyx
innervated by S4 (some S3, S5)
function of pelvic diaphragm
maintains the proper positioning of the pelvic organs and is essential for maintaining abdominal, and thus thoracic pressure, during micturation, defecation, parturition, and lifting heavy weights
what passes through the pelvic diaphragm
males: urethra and anus
females: urethra, vagina, and anus
relaxation of puborectalis
essential during defacation
what are kegels
isometric contraction of the pubococcygeus muscle and the pelvic diaphragm and pelvic diaphragm
function of kegels
help prevent urinary stress incontinence and fecal incontinence during and after pregnancy
prevent injuries during parturition and help prevent uterine prolapse after vaginal deliveries
perineal membrane
connective tissue membrane attaching laterally to the ischial tuberosities, and the ischiopubic rami
tough, connective tissue sheet which serves as a base for the external genitalia structures
spaces created by the perineal membrane
- superficial perineal space
2. deep perineal space
superficial perineal space
contains erectile tissues and muscles of the external genitalia in both male and female
deep perineal space
contains striated muscles of the urethra (sphincter and compressor) and a deep transverse perineal muscle that support the free edge of the perineal membrane
also contains nerves and arteries
superficial membranous fascia
superficial surface of the superficial perineal space
made of 3 differently named, but continuous membranes:
1. scarpas (anterior abdominal wall)
2. dartos (shaft of penis and scrotum)
3. colles (posterior to scrotum)
bleeding patterns of straddle injuries
bleed into superficial perineal space
blood is then limited in its diffusion by the superficial perineal membrane (scarpas, dartos, colles) and where it attaches to deep fascial planes
where does the superficial perineal membrane attach to deep fascia (outline of blood in straddle injuries)
superiorly: fascia surrounding anterior abdominal wall muscles
laterally: inguinal ligament and fascia lata of the thigh
posteriorly: posterior edge of perineal membrane
components of external anal sphincter
3 parts:
- deep external sphincter
- superficial external sphincter
- subcutaneous external sphincter
innervation of external anal sphincter
skeletal muscle under voluntary control
innervated by S4 through the inferior rectal/anal nerve (branch off the internal pudendal nerve)
internal anal sphincter
smooth muscle
more superior to external sphincter and directly under the mucosa
innervated by sym and parasym fibers from the pelvic splanchnic nerves
normally, tonically contracted, but relaxes to release gas and fecal material
importance of the pectinate line
separates visceral and parietal portions of anal canal
above pectinate line
nerves: visceral motor and sensory innervation
arteries: IMA
veins: to portal venous system
lymphatics: to internal iliac lymph nodes
below pectinate line
nerves: somatic motor and sensory innervation
arteries: internal iliac
veins: to caval venous system
lymphatics: to superficial inguinal lymph nodes
internal hemorrhoids
start superior to the pectinate line
generally painless, often grow quite large before being notices
external hemorrhoids
start inferior to pectinate line
generally quite painful and itch
hemorrhoids
swollen (redundant) veins within the anal canal that are thought to be due to increased venous pressure caused by: portal HTN, excessive straining (constipation), excessive weight gain
prevalence of hemorrhoids
4% of US pop
1 mil new cases per year
degrees of internal hemorrhoids
1st: bulges into anal canal during BMs
2nd: bulges from the anus during BM, then goes back in
3rd: bulges from anus during BMs and must be pushed back in with a finger
4th: protrudes from anus all the time
treatment for internal hemorrhoids
rubber band ligation, takes 7-10 day for necrotic hemorrhoid to fall off
infrared coagulation for small and medium internal hemorrhoids
anal fissues
most common cause of BRBPR at any age
breaks or tears in the skin of the anal canal
generally self healing, but can become chronic
epidemiology of anal fissures
1 in 350
most often ages 15-40
90% located in the midline, posterior to the anus, anterior to the coccyx
chronic anal fissures
can lead to spasm of the internal anal sphincter, which impairs blood flow to the region, slowing healing
treatments for anal fissures
dietary fiber
careful anal hygiene after defecation
placing a cotton ball at anus to keep tissue dry
nitroglycerin or Ca2+ channel blockers, injection of botox
scrotum
sac containing testicles and epididymises
keeps cooler than abdominal temperature
testis
produce sperm and androgens
epididymis
- sperm maturation
- sperm storage
- sperm disposal
- absorption of fluid
- secretion of proteins
vas deferens
connects epididymis to urethra
thick walled
peristaltic contractions of the smooth muscle wall move sperm along the vas
penis
common outlet for both urine and semen
scrotal components of the male after the seminiferous tubules
- tubulus rectus
- rete testis
- ductuli efferentes
- epididymis
- vas deferens
tubulus rectus
link seminiferous tubule to rete testis
rete testis
network of spaces contained within the connective tissue of the mediastinum
ductuli efferentes
12 spiral winding tubes arising from the rete testis
become confluent with a single epididymal duct coiled into a compact structure
seminiferous tubules
continuous loops with a lumenal fluid/sperm filled space; about a meter long
seminiferous epithelium cell types
- spermatogenic cells
2. sertoli cells (support cells)
structure of seminiferous epithelium
from outside to inside:
- peritubular (myoid) cells outside of BM
- basal lamina
- spermatogonium (stem cells) with interspersed sertoli cells
- spermatocytes
- early spermatid
- late spermatid
sertoli cell overview
nonproliferating cells which support spermatogenic cells
contact 3-5 other sertoli and 30-50 spermatogenic cells
receptors on sertoli cells
FSH and androgen receptors
both FSH and androgens are required to maintain highly differentiated nature of the cells
proteins secreted by sertoli cells
MIS/AMH transferrin ceruloplasmin androgen binding protein (ABP) kit ligand/ steel factor inhibin B
AMH/MIS
inhibits mullerian duct development into female repro organs
transferrin
transports iron into spermatogenic cells
ceruloplasmis
transports copper into spermatogenic cells
androgen binding protein (ABP)
high affinity for T and DHT
essential for proper epididymal function
kit ligand/ steel factor
required for spermatogenic cell survival (membrane bound)
inhibin B
inhibits pituitary FSH release
marker of sertoli cell function
blood testis barrier
formed at puberty
tight junctional complex between adjacent sertoli cells
creates a compartment hidden from the immune system
function of meiosis
produces 4 unique haploid cells
stages of spermatogenesis
- spermatogonia stage
- primary spermatocyte stage
- secondary spermatocyte stage
- spermatid development
spermatogonia stage
2 weeks
mitotically dividing stem cells
primary spermatocyte stage
4 weeks meiotically dividing cells 1. preleptotene 2. leptotene 3. zygotene 4. pachytene 5. diplotene
secondary spermatocyte stage
8 hours
quick division
spermatid development stage
3 weeks
haploids cells undergoing dramatic shape change from round cell to a sperm
spermiogenesis*
total time for spermatogenesis
74 days (2.5 months)
sperm structures
acrosome (secretory granule) head connecting piece middle piece of tail principal piece of tail end piece of sperm tail
why are sperm immunologically foreign
- genetic recombination during meiosis creates new combination of maternal and paternal genes
- haploid gene expression includes numerous genes products that are unique to spermatogenesis
- initiates long after immunological self has been determined (aka during puberty, long after birth)
Leydig cell overview
interstitial cells
have LH receptors and produce androgens
function of T produced by leydig cells
stimulate spermatogenesis
inhibit HP axis at hypothalamus and anterior pituitary
receptors on spermatogenic cells
dont have any!!!
controlled by nearby sertoli cells via direct cell cell interactions
regulation of heat in testes
normally 2 deg cooler than abdominal temps
result of scrotal location and the counter current heat exchanger from the cooler blood within the pampiniform plexus to the testicular artery
result of increased heat in testes
seminiferous tube atrophy
leydig production of T decreased over the long term
what is klinefelters
XXY hypogonadism
extra X chromosome caused testicular failure of both spermatogenesis and androgen production
symptoms of klinefelters
decreased T levels small penis generally azoospermic 33-50% have breast development high FSH and LH (trying to increase T) trouble w language skills
diagnosis of klinefelters
1 per 600 male births
generally not detected until puberty, unless genetically tested at birth
most common chromosomal abnormality in humans
epidemiology of testicular cancer
1-2% of male cancers
second most frequent cancer of 20-29 year old males
germ cell tumors most common
treatable
structure of the epididymis
highly tortuous duct, 6 meters long
takes sperm 3-8 days to travel its length
sperm maturation in epididymis
nonmotile sperm obtain the ability to swim
takes place in head and body
sperm storage in epididymis
100 million in each
70% of sperm stored here
a portion released with ejaculation
sperm disposal in epididymis
after abstinence, a higher percentage of infertile sperm are released
sperm do “age” within the male repro tract
motility and morphology of sperm depressed after 7 days of abstinence
absorption of fluid in epididymis
most of the fluid produced by sertoli cells is absorbed in the caput
secretion in the epididymis
secretes a number of proteins which alter the sperm surface
epithelium of epididymis
columnar epithelium with variable height (star shaped lumen): 1. principal cells and 2. basal cells
height rises and then falls toward the vas deferens
amount of smooth muscle cells surrounding the epithelium increased caudally toward the vas deferens
portions of the epididymis length
- head/caput
- body/corpus
- tail/cauda
- continuous with vas deferens
principal cells of epididymal epithelium
long microvilli on apical surface
structure of vas deferens
35 cm long, 3 mm in diameter
pseudostratified columnar epithelium with short microvilli
surrounded by 3 layers of smooth muscle (inner and outer longitudinal, middle circular)
ampulla
lies just superior to the seminal vesicles, before the ejaculatory ducts
stores sperm
congenital absence of vas deferens
CF gene
vasectomy
ligation and/or removal of a segment of the vas deferens
spermatogenesis continues at normal or slightly reduced rates
FSH, LH, T unchanged
96% of sperm broken down within epididymis
sperm granuloma
can develop post vasectomy at site of sperm leakage
macrophages and other WBCs attack the sperm as foreign bodies
very painful in 4% of men who have gotten vasectomies
procedure of vasectomy
simple, outpatient, performed by many family practice physicians
< 60 min
no sutures required
vasovasectomy
reversal of vasectomy; reanastomosis & opening of cut and sealed vasal ends
pregnancy rates are lower than expected, probably due to antisperm Abs which develop after vasectomy
what is cryptorchidism
undescended testicle
congenital malposition resulting in retention of the testes anywhere along the route of descent
prevalence of cryptorchidism
2-5% of boys under 1
15-20% in premature boys
10% bilateral
treatment of cryptorchidism
HCG treatment (stimulates Leydig cells to produce androgens) may stimulate descent
otherwise, early surgery (before 6 mo)
reduction in fertility if not treated
pampiniform plexus
veins that wrap around the tortuous testicular artery
cools the coiled testicular arterial blood with countercurrent heat exchange
varicocele
insufficient or congenital absence of valves within the spermatic/ pampiniform plexus veins, causing blood reflux within the pampiniform plexus
occur in 10% of men
where does varicocele commonly occur
L side
due to return of the left testicular vein to the L renal vein (higher pressure vein) than the R testicular vein which drains into the IVC
consequences of varicocele
reduced fertility (count) treatment often increases sperm production
grading of varicocele
bag of worms
- seen only on US
- smallest, not visible, but felt w valsalva
- not visible, but felt
- visible
congenital hydrocele
congenital, processes vaginalis remains open to peritoneal cavity
most resolve spontaneously during first year of life without intervention
appearance of hydroceles
scrotum rapidly fills with fluid when straining or sitting up
6% of term males
acquired hydrocele
abnormal accumulation of serous fluid in the sac of the tunica vaginalis; most often noncommunicating with peritoneal cavity
can also be result of plugged inguinal lymphatic system from repeated, chronic infection
testicular torsion
sudden twisting of spermatic cord resulting in strangulation of the blood vessels serving the testis and epididymis
normally prevented by gubernaculum remnant
painful, EMERGENCY, must be treated in 4 hours
parts of the male urethra
prostatic membranous (intermediate) penile
penis
common outlet for both urine and semen
erect in anatomical position
structure of penis
3 cylinders of erectile tissue
- 2 corpora cavernosa on the dorsal surface formed of erectile tissue
- single corpus spongiosum contains the urethra
- tunica albuginea connective tissue layer surrounds each cylinder
penile ligaments
- fundiform
2. suspensory
fundiform ligament
attaches from the deep fascia of the penis to the linea alba superiorly
sling-like structure
more superficial than suspensory
suspensory ligament
attached from the deep fascia of the penis to the pubic symphysis
deep to fundiform
circumcision
release and/or removal of a portion of the foreskin and is performed for both hygiene and religious regions
purpose of circumcision
religious (jewish, islamic)
prevents smegma accumulation (cheesy accumulation of dead skin and sebaceous gland secretions)
muscles of the root of the penis
bulbospongiosus
ischiocavernosus
contract to help restrict venous blood flow out from the penis and can cause transient increase in internal penile pressure above arteriolar pressure
function of bulbospongiosus
expels both semen and urine from the base of the penile urethra
dorsal penile arteries
deep to Buck’s fascia outside the corpora cavernosa
deep penile (cavernous) arteries
center of each corpora cavernosa
main source of blood to erectile tissue
artery of the bulb of the penis
to bulb of penis and to bulburethral glands
somatic innervation to the penis
pudendal nerve
S2-4
becomes dorsal nerve of the penis
autonomic innervation of the penis
cavernous nerves
- from inferior hypogastric plexus
- run next to central cavernous artery within corpora of the penis
- has sym and para
what is required for successful erection and ejaculation
vascular system smooth and skeletal muscles urethral sphincters para and sym ANS bulbospongiosus muscle
erection
parasympathetic stimulation (S2-4) through pelvic splanchnic, inferior hypogastric, and prostatic nerve plexuses and the cavernous nerves results in vasodilation of the helical arteries allowing more blood flow (5-10x) and enlargement and erection
emission
delivery of sperm via vas deferens, prostatic secretions, and seminal secretions into the prostatic urethra
requires sym innervation (L1-2) to smooth muscle in walls of vas deferens, prostate, and seminal vesicle
ejaculation
forceful removal of semen from the urethra
internal urethral sphincter (smooth muscle, sym) must remain CLOSED
external urethral sphincter (skeletal) must OPEN
bulbospongiosus muscles contract (pudendal S2-4) forcing semen from the penis base
detumescence
loss of an erection
follows sym discharge required for emission
causes constriction of helical arteries, reducing blood flow into the cavernous tissue
retrograde ejaculation
semen redirected towards the urinary bladder
internal smooth muscle sphincter does not function properly
causes of retrograde ejaculation
trans-urethral resection of the prostate
diabetes (neuropathy)
WBCs in ejaculate
<1 million is a normal component
if infected with HIV, prostatic secretions appear to aid the transmission/ spread of HIV from contact with semen
black light glow of semen
PSA from prostate
semenogelins from seminal vesicle
WHO sperm guidelines
1.5-6 mL volume
15-200 million per mL
4-44% normal morphology
55% motility (mean)
7.4 pH
coagulates in seconds due to semenogelins from seminal vesicle
liquefaction occurs 10-60 min later caused by prostatic enzymes
normozoospermia
normal ejaculate
oligozoospermia
<15 mil per mL
asthenozoospermia
reduced sperm with forward progression
<32% progressive motility
teratozoospermia
sperm with abnormal morphology
<4% normal
azoospermia
no sperm in ejaculate
aspermia
no ejaculate
congenital bilateral absence of vas deferens
blockade of the transport of the spermatozoa from the testis or the epididymis to the distal genital tract
oligozoospermia
present in many males with CF
how to identify absence of vas deferens
fructose analysis of the semen
fructose is made in seminal vesicle, so CBAVD men are fructose negative
seminal vesicles
secrete 2 ml of viscous, slightly yellow fluid which is present in highest concentration in the last half of the ejaculate
helps wash sperm out of urethra
seminal vesicle epithelium
psuedostratified or simple low columnar
secretions from seminal vesicle
- fructose
- prostaglandins
- proteins responsible for semen coagulation: semenogelins
- slightly alkaline pH
fructose
energy source for sperm
prostaglandins
stimulate smooth muscle contraction in female repro tract, aiding in sperm dispersal
semenogleins
coagulate semen seconds after ejaculation
alkaline pH of seminal vesicle secretions
help neutralize acidity of vagina
function of prostate gland
secretes 0.5 mL of thin, opalescent fluid present in the first portion of ejaculate
zones of prostate
periurethral zone transitional zone
central zone
peripheral zone
anterior fibrous zone
periurethral zone
smallest region
immediately around urethra
resistant to inflammation and carcinoma
site of SPH
peripheral zone
70% of prostate
site of prostatic cancer
components of prostatic secretions
- prostatic acid phosphatase (PAP)
- prostate specific antigen (PSA)
- spermine
- fibrolysin
PAP
may enhance infectivity of HIV in semen
PSA
serine protease responsible for liquefaction of semen upon standing and liquefaction of cervical mucus
spermine
polyamine
antibacterial properties
musk odor of semen
fibrinolysin
liquefaction of semen
prostatic concretions
lumenal concretions which are thought to begin as protein and nucleic acid, but may calcify
occur in 20-30% of men over 50
may block ducts or appear in ejaculate
what is BPH
benign prostatic hyperplasia
obstructs the passage of urine, leading to increased retention and infections
increased difficulty urinating
BPH epidemiology
seldom seen before age 50
found in 75-80% of non asian men over 80
function of stromal cells of the prostate
have 5-alpha-reductase enzyme to convert T to DHT
diffuses from these cells into epithelial cells
function of DHT in the prostate
stimulates production of mitogenic growth factors to stimulate proliferation of both stromal and epithelial cells
treatment for BPH
a1 inhibitors (doxazosin) 5-alpha reductase type 2 inhibitors (finasteride)
a1 receptor inhibitors in BPH
relax contraction of smooth muscle in the stroma
increases urine flow
5-alpha reductase type 2 inhibitors in BPH
shrink size of the prostate by reducing androgen concentrations
difference in feel of BPH and prostate carcinoma
prostate cancer: lumps or bumps
BPH: general enlargement
prostate adenocarcinoma
3rd most frequent cause of cancer death in US males
PSA is used for monitoring
rectal exam used for screening
bulbourethral glands
compound tubuloalveolar glands that secrete clear mucus upon erotic stimuli
mechanism of penile erection
- nerves produce NO which diffuses into smooth muscle cells
- NO activates guanylate cyclase which converts GTP into cGMP
- cGMP triggers storage of Ca2+ within the cell (induces relaxation)
- relaxed smooth muscle presses against the small veins draining blood from the penis
erectile dysfunction
repeated inability to achieve and/or maintain penile erection and thus engage in intercourse
epidemiology of ED
more frequent in diabetic men
30 mil men in US
incidence increases with age
sildenafil mechanism
inhibits PDE5, an enzyme that promotes degradation of cGMP, which regulates blood flow in the penis
by inhibiting breakdown of cGMP, blood flow to the penis is increased, allowing maintenance of erection sufficient for intercourse
