Exam 4: Male Reproductive System Flashcards
general functions of reproductive system (3)
production of sex cells (ovum females, sperm males)
secretion of hormones (cyclical in females, constant males)
support of developing fetus
what does the male reproductive system consist of (5 or 8)
testes epididymis ductus deferens (aka vas deferens) accessory glands (seminal vesicles, prostate, bulbourethral) penis
why are the testes outside the body
if inside the germ cells would not be able to produce sperm and abnormalities can happen with mitotic division and can be a cancer risk
- germ layer producing sperm needs to be ~10 degrees less than the core body T
epididymis
stores sperm once they are produced
sperm not active yet but they have been produced and left the testes
ductus deferens (vas deferens)
goes through spermatacord
eventually carries sperm out of epididymis and gets them ready for ejaculation
what do all of the accessory glands ensure
the sperm make it out of the male reproductive system tract with enough energy and semen that they could survive in the female system
not destroyed on the way out through the urethra
penis
copulatory organ for the male
when do he testes descend into the scrotum
the third trimester
scrotum
protects the testes and regulates temperature
divided into 2 cavities by a septum - raphe
what are the 2 layers of muscle in the scrotum
dartos muscle
cremaster muscle
dartos muscle
in scrotum
- compresses around testes or relaxes it, controls shape of scrotum around teste
- little T regulation
cremaster muscle
most T regulation
- if contracts: pulls testes up towards body
- if relaxes: moves testes away from body - T regulation
the double layer in addition to the scrotum
tunica vaginalis
- parietal and visceral layers
parietal: capsule you can take off
visceral: on top of teste
tunica albuginea
deeper into the testes
composed of tissue
divides into lobes with each lobe getting a seminiferous tubule
each seminiferous tubule has
germ cells that go through mitosis, one cell stays behind to maintain germ layer other goes and is guided by Sertoli cells or sustenacular cells - bind testosterone and make sure you go through meiosis to get 4 haploid sperm
sperm go through lumen of seminiferous tubules, not active still
move into reet testes and then epididymis for storage, stay here for weeks
what cells do seminiferous tubules have
germ (spermatogenic) cells and Sertoli (sustenacular) cells
what do germ cells produce
spermatids
Sertoli cells
direct maturation of sperm
surround sperm producing blood-testes barrier
bind testosterone
secrete inhibin
blood testes barrier
produced by sertoli cells
prevent testes from interacting with cells in blood , since they are haploid you do not want them exposed to immune cells due to inactivation or making antibodies against the sperm - infertility
myoid cells
outer layer of contractile cells that move the sperm into the rete testes by peristalsis (thickens with age)
what happens as males age
get less gem cells, dec ability to make sperm, errors and abnormal sperm taken out by sertoli cells
basement membrane of myloid cells gets thicker, dec diameter in seminiferous tubules, dec testosterone
Leydig (interstitial) cells
produce testosterone
- active for dvelopment and then inactive from 5 months development until puberty
spermatogenesis cycle
takes ~74 days
sperm survive in male system for weeks but only last 2-3 days in female, max of 5 days in female
newly mature sperm are non-motile and are moved by peristalsis
acrosome
head of sperm
has enzymes for penetrating the ovum - specific receptors on ovum, has proteins to form actin strands that push the nuclear material into the ovum
-make sure do not do this too soon
what does the sperm mebrane have to prevent the sperm from carrying out fertilization
glycoconjugates
this way sperm cannot do fertilization until 10-15 min in female that is going through capacitation
glycoconugates removed in female system during capacitation
avg ejaculate has how much sperm
15-200 million
less than 15 million sperm - infertility issues
epididymis
stores sperm
maintains fluid environment
carries out phagocytosis of cell debris/recycled sperm
ductus deferens
continuous with epididymis; lower region stores sperm
moves sperm for ejaculation by peristaltic waves
seminal vesicles
secrete majority of the seminal fluid
secretions:
-fructose: energy
-prostaglandins: create smooth muscle contraction in female system to propel spem up through system
-semenogelin: critical for capacitation
with coagulate all sperm stay together giving sperm time to wear off and get rid of inhibitors
prostate
valve - prevents urine and ejaculation from occurring at same time
inner lining makes up prostatic urethra
secretes 20-30% seminal fluid
secretion has enzymes for liquidifying sperm coagulum
- later breaks down semenogelin to fertilize the egg
bulbourethral gland
secretes thick alkaline mucus to neutralize pH in urethra and lubricate the glans penis
pre-ejaculate - when erection happens, triggers these glands to secrete fluid before the sperm and seminal fluid. Lubricates inside of spongy urethra and glans penis
membranous portion that includes the external sphincter
penis
body has 2 types of erectile tissue
corpus cavernosa
corpus spongiosum
corpus cavernosa
erectile tissue
fills with blood during ejaculation
-has helicine arteries that fill with blood
-elongation and thickening of penic in erection
corpus spongiosum
erectile tissue
surrounds urethra and extends to form the glans
-ensures that when you get an erection and the erectal tissue fills with blood that you do not close off the urethra, you keep it open
prepuce
fold of skin that covers the glans
contains gland that produce smegma (protective lubricant fluid)
3 steps of male sexual act
erection
emission
ejaculation
erection process
- vascular event regulated by autonomic nervous system
- stimulation of mechanoreceptors (or CNS) initiates PARASYMPAHETIC dilation of helicine arteries (begins with Ach, progresses with NO)
- blood flow results in expansion of erectile tissue that compresses veins (corporal occlusive mechanism)
- parasympathetic impulses trigger bulbourethral glands
emission
sympathetic response results in peristaltic movement of sperm and gland secretions into the urethra
ejaculation
sympathetic impulses in skeletal muscle at base of penis result in expulsion of semen and orgasm
sympathetic impulses contract the helicine arteries, dec P in erectile tissue, allows erection to be resolved
