In this phase of male growth, secretion of LH and FSH is low due to hippocampal inhibition of GnRH
prepubertal phase
In this phase of maturation, ithere is an increased secretion of GnRH leading to increased LH and FSH
puberty
This phase of male maturation is marked by a decreased production of testosterone and sperm
senescence
50% of hypogonadism occurs in males over the age of…
80
A patient presents with the following sxs, what are you concerned for?
- decreased bone and muscle
- decreased sex dive
- decreased body height
- decreased Hct
- decreased facial hair
-increased CVD
changes to mood/energy/appetite
androgen deficiency (ADAM)
4 endocrine consequences to testosterone replacement…
- reduced LH, FSH
- Reduced sperm production
- increased free estrogens
- increased peripheral conversion of T to estrogen
What hormone from the adrenal cortex stimulates public and axial hair growth?
DHEA
This hormone stimulates hair growth in men and causes male pattern hair loss…
DHT
Beard growth is stimulated by synergism between what two hormones?
DHT and IGF-1
Scalp hair growth is attenuated by what substances?
DHT and TGF-B1
this enzyme causes miniaturization of the hair follicle by converting T to DHT
5 alpha reductase
This drug has the following mechanism:
-irreversibly binds 5-a-reductase preventing conversion of T to DHT
Finasteride
What are the SFx of finasteride?
ED
loss of libido
reduced ejaculate
Which accessory organ?
- responsible for 60% of ejaculate
- contains fructose to nourish sperm
- releases prostaglandins to stimulate male/female reproductive tract
- contains clotting factors
seminal vessicles
This accessory organ…
responsible for 20% of ejaculate
-secretes alkaline fluid to counter acidic vaginal environment, trigger clotting of sperm
prostate
This accessory organ:
- responsible for 10% of ejaculate
- lubrication
bulbourethral glands
Collectively, which three glands produce 90% of semen volume…
seminal vesicles
prostate
bulbourethral glands
Is there a relationship between BPH and prostate cancer?
no
The male erection occurs due to _________ of the penis with blood
vasocongestion
What tissues fill with blood allowing erection?
2 corpora cavernosa and 1 corpus spongiosum
________ become dilated during sexual arousal
arterioles
What areas of the brain are stimulated when thinking about sex that coordinately facilitate erection?
amygdala
MPOA
paraventricular nucleus
periaqueductal gray matter
Higher brain activity stimulates has what effects on the PNS?
PNS penile arteriolar dilation
PNS supply to bulbourethral/urethral glands
Mechanoreceptor stimulation of the penis has what effects on the SNS?
inhibits SNS constriction of penile arterioles
Mechanical stimulation of the ______ provides sensory feedback to the sacral erection generating center in S2-4
glans
Vasodilation of the penis arterioles by PNS stimulates the release of ______
NO
NO activates ______ and produces ______ which lowers intracellular calcium causing mechanical compression of veins by skeletal muscle at base of penis
NO actuvates guanylyl cyclease
produces cGMP
cGMP activates what in smooth muscle, which decreases intracellular calcium and promotes relaxation
myosin phosphatase
In the flaccid state, blood flow to the penile tissue is limited by contraction of what two things?
helicine arteries
trabecular smooth muscle
In the erect state, helicine arteries are relaxed by ______ which is released from nerve terminals to allow blood flow into cavernous spaces
NO
compression of the _______ venules reduce venous outflow
subtunical
What are the two phases of ejaculation and what part of the nervous system is responsible for each?
emission (L1/L2 SNS) and expulsion (Somatic)
Which phase of ejaculation?
- SNS from L1-L2
- Semen enters urethra from accessory gland contraction
- SNS stimulation of smooth muscle
Emission
Which phase of ejaculation?
- urethral filling triggers somatic nervous impulses
- rhythmic activation of skeletal muscles at base of penis
- ejaculate volume: 2-6 mL total after several days of abstinence
expulsion
how many sperm per ml of ejaculate
100M
What muscle contracts to prevent retrograde ejaculation into bladder?
internal urethral sphincter
What is the ejaculation pathway?
vas deferens to ampulla to urethra
This occurs as a result of a failure of the internal urethral sphincter, causing semen to enter the bladder
retrograde ejaculation
Proper erectile function requires coordinated involvement of what 4 factors?
- CNS/PNS
- Corpora cavernosa and spongiosum
- normal blood supply
- normal venous drainage
________s sustain NO stimulated cGMP levels in the penis
Phosphodiesterase inhibitors
–afil suffix
What degrades cGMP?
phosphodiesterase
Blocking ________ causes increased relaxation and blood flow in sinusoidal cavernous spaces, leading to erection.
PDE5
What are the three forms of male birth control are available?
condoms, withdrawal, vasectomy
In a vasectomy, is accessory gland function affected?
no
In a vasectomy, are testosterone levels affected
no
What removes sperm after vasectomy?
phagocytosis