Lect 26 Flashcards
What hormone secretion is very low during prepubertal phase? Why?
- LH and FSH low
- due to active neural inhibition of GnRH release
What hormones are secreted during puberty
- increased secretion of GnRH -> LH and FSH
- stimulation in spermatogenesis and testosterone production
What happens to testosterone during senescence
- senescence: the condition or process of deterioration with age.
- decrease in production of sperm and testosterone
What are the signs of androgen deficiency in aging males (ADAM)
- decrease in
- bone formation
- muscle mass
- libido
- hematocrit
- increase in
- facial hair
- changes in appetite
What glands/organs are responsible for ejaculate (semen) production
- accessory glands (90%)
- Seminal vesicles: 60%
- prostate: 20%
- Bulbourethral gland: 10%
- sperm compose remaining 10%
Where are the seminal vesicles
- there are two
- empty into last portion of the ductus deferens, one on each side
Where are the Bulbourethral gland
- pair
- empty into urethra, just before urethra enters penis
function of prostate gland
- secretes alkaline fluid that neutralizes the acidic vaginal secretions
take home point: what is the function of seminal fluid
- help support and maintain sperm function in the female reproductive tract
prostate disease are common at what age
after age 50
what is benign prostatic hyperplasia
- enlarged prostate, which may cause dribbling after urination or a need to go often, especially at night
cause of male erection
- arterioles in penis dilate
- penis engorges with blood
penile erectile tissue is composed on three erectile tissues. name them
- 2 corpora cavernosa
- 1 corpus spongiosum
explain the erection reflex in males
- basic spinal reflex
- mechanoreceptors stimulated in glans penis
- parasympathetic innervation of arterioles in penis
- can be facilitated or inhibition by higher brain centers
Explain the erect state (tumescence) of erectile response
- relaxation of helicine arteries by NO
- blood flows into cavernous spaces -> engorgement and erection
Explain the flaccid state of erectile response
- blood flow into cavernous space is limited by contraction of helicine arteries
ejaculation is stimulated by what
SNS
ejaculation is composed of what two phases
-
Emission (SNS impulses from L1 and L2)
- semen enters urethra
- SNS stimulation of smooth muscle and contraction of accessory glands
-
Expulsion
- filling of urethra triggers SNS which activated skeletal muscles at base of penis
list the ejaculation pathway
- vas deferens -> ampulla -> urethra -> outside
what contracts to prevent retrograde ejaculation into bladder
internal urethral muscle
Male sexual response: Psychic stimuli causes activation in brain at what centers
- cortex
- limbic
- hypothalamus
Male sexual response: PNS arterial dilation via NO and Ach causes what 3 things
- vasocongestion
- engorgement of genitalia
- stimulation of bulbourethral glands
Male sexual response: SNS impulses lead to
- emission and expulsion of sperm
- contraction of pelvic musculature to enhance sperm motility
Most common tx options for erectile dysfunction
- phosphodiesterase inhibitors (PDE5)
- enhance effect on NO on penis in smooth muscle
- Sildenafil (viagra)
- Tadalafil (Cialis)
- Vardenafil (Levitra)
MOA of phosphodiesterase inhibitors (PDE5)
prevent cGMP degradation so that cGMP can activate myosin phosphatase in smooth muscle -> promotes relaxation
Mechanism of Vasectomy
- surgical cut of each vas deferens
- prevents sperm migration along ejaculatory track
- sperm are discharged by phagocytosis
- *does not interfere with testosterone activity
can vasectomy be reversed
yes, with 70% effectiveness -> vasovasostomy
MOA of the male contraception: Desotrogestrel and Etonogestrel
- synthethic progestin given in combo with testosterone IM
- produces severe oligoazoospermia
- not currently available on local market
side effects of Desotrogestrel and Etonogestrel
- acne
- increased body weight
- decreased HDL
MOA of IVD: intra vas device
- new male contraceptive
- inserted into scrotum and blocks vas deferens
- in pilot studies
