Reproductive L4 Flashcards
where are testes located in the adult male?
scrotum
Where are testes located in the early fetal developement?
abdomine
cryptorchidism
“hidden testes” or undescended testes
infertility
3% of term babies
Where does the sperm produced in seminiferous tubules move to?
rete testis
where does the sperm from rete testis move to?
epididymus
all sperm gets combined into 1 tube
Where does the sperm move to from epididymus?
Vas deferens
Eventually connects to urethra
Where do sperm mature?
occurs while sperm moves slowly through the epididymis
What does epididymis do?
reabsorbs liquid from around the sperm making it more concentrated
matures sperm
What is the major site of sperm storage in a male?
Vas Deferens
What is the position of vas deferens?
Pass from the testicles up and around the bladder, and come behind the bladder to join with seminal vesicles and prostate gland at the back of the prostate. The tubules then join with ejaculatory duct that passes through the prostate.
Seminal vesicles
join with the Vas deferens at the ejaculatory duct which passes through the prostate and then join to the urethra, which runs through the prostate to the penis
How long is urethra?
20 cm
how long does sperm mature in the epididymis ?
10 days -2 weeks
does sperm swim in the male reproductive tract?
no
where is most sperm stored?
ampulla of ductus(VAS) deferens
What are the accessory glands?
seminal vesicles
prostate gland
Seminal vesicles function
secrete mucoid(sticky) substance, which is alkaline, contains fructose-source of energy for sperm, contains prostaglandins(important for smooth muscle contractions- in the female to push sperm through), and clotting proteins
-The contents of the seminal vesicles are emptied into the ejaculatory duct directly after the sperm is ejected from the vas deferens and washes sperm down the ejaculatory duct. Last component
The prostate gland
-doughnut-shaped organ. The urethra passes through the hole in the prostate which secretes prostatic fluid into the urethra ahead of sperm during ejaculation.
What is the order of fluid ejaculation?
Prostatic fluid-> sperm-> seminal fluid
The prostate secretion
-Slightly acidic( pH 6.5)-> combined with alkaline seminal fluid to create a neutral buffer
-contains citrate( for ATP)
-milky color
-contains phosphate and calcium
-Prostate Specific Antigen(PSA) and other enzymes
(breaks down coagulant)
what is the function of Prostate Specific Antigen(PSA)?
breaks down the coagulant
Why does the semen have both coagulant and anti-coagulant properties?
coagulant properties of seminal fluid allow it to stick to the vagina and not be removed during intercourse
The anti-coagulant properties allow it to move further into the uterus
What is the composition of semen-ejaculated fluid
- sperm 10%
- seminal vesicle fluid 60%
- prostatic fluid 30%
- other secretions small amounts
what is the ph of semen?
~7.5 with prostatic fluid and seminal fluid neutralizing each other.
how much sperm is in human ejaculate?
20 million/ml
~2-5 ml
Benign prostatic hyperplasia
excess growth of the prostate
- Causing difficulty in voiding the bladder
- weakening of the bladder
- can cause UTI, and kidney problems
what is the distribution of Benign Prostatic hyperplasia by age?
Incidence of men requiring treatment (USA)
– <40 rare
– 50-59 17%
– 60-69 27%
– 70-79 35%
90% of men over 85
Over 300,000 corrective operations/year 2nd most
common surgical procedure in men (after cataract)
– Costs >2 Billion dollars/year
treatment for prevention or reduction of benign prostatic hyperplasia?
Selective 5 α-reductase inhibitor(s) – Finasteride – dutasteride( longer half life) • Stop the prostate from enlarging or shrink it. • Requires long-term therapy. • Surgery
How does the therapy work?
testosterone is converted to dihydrotestosterone through 5 α-reductase
5 α-reductase is inhibited by the drugs Finasteride and Dutasteride
which reduces the hormonal stimulus for overgrowth
Prostate cancer
causes ~ 1/3 of all cases of cancer in men
how is prostate cancer detected?
PSA testing, registering elevated levels of PSA in the blood
How many men who died WITH prostate cancer did not know they had it?
2/3 or 66%
What is autopsy cancer?
men who died WITH prostate cancer did not know they had
how many men >50 found to have prostate cancer at autopsy?
~30%
only 9.5% have been diagnosed with prostate cancer
did the mortality rates change after introduction of PSA testing?
not much
what are some treatments for prostate cancer?
-watch and wait
-androgen depletion
– 5 α−reductase inhibitors (finasteride)
– castration(chemical)
– Inhibitors of androgen synthesis
• Inhibition of testosterone action- block the androgen receptor.
• Surgery – prostatectomy(removal of prostate gland)
What is the accuracy of the PSA screening?
Of 1000 men (55-69) screened for PSA
– 136 will be positive but
– 95 will have a false positive test result i.e. no cancer!
Risks of prostatectomy
For every 100 men undergoing prostatectomy
– 1 will die as a consequence of the operation
– 20-80 men will have erectile dysfunction
– 4-21 will have urinary incontinence as a result of the operation.
What are the main structures of the penis?
1) corpora cavernosa (x2)
-The main erectile tissues.
2) corpus spongiosum
-surrounds the penile urethra and prevents
occlusion during erection.
3) penile urethra
- conducts semen (and urine)
What happens during erection?
-erection occurs in response to sexual stimulation
-Release of Nitric Oxide( NO) and Prostaglandin E1 causes the smooth
muscle of the corpora cavernosa to relax.
*NO& Prostaglandin E1-vasodilators
– Blood fills the cavernous spaces of the corpora cavernosa
• The erect penis contains about 8 times the blood volume of the
flaccid penis
– The engorgement of the corpora reduces the venous outflow
adding to the engorgement.
What is the function of corpus spongiosum?
when the corpus cavernosa expands corpus spongiosum also fills with blood and prevents the corpus cavernosa from extending inwards and closing off the urethra
Viagra mechanism of action
Relaxation of the smooth muscle in the corpora cavernosa
requires Guanosine Monophosphate (cGMP)
– (2nd messenger reduces intracellular calcium)
• The enzyme phosphodiesterase breaks down GMP
• Viagra inhibits phosphodiesterase (type 5), leading to
increased GMP, relaxation of the arteries supplying the corpora
cavernosa and erection
