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where is the dartos muscle contained?
in the superficial fascia of the scrotum
what are the layers that surrounds the testes?
- tunica vaginalis (outer layer from peritoneum)
- tunica albugnea (inner, dense fibrous capsule that folds in to divide testis
where does the testicular arteries arise from?
what is the purpose of the pampiniform venous plexus?
- testicular veins arise from
- surrounds each testicular artery to cool artery going to the testes
how does the teste migrate to the scrotum during fetal development?
from abdominal to inguinal canal (development as ligament that gets pulled down)
what is the condition where there is an abnoraml descent of the testes?
what may happen to a male's fertilitiy is cryptorchidism is not corrected?
- sperm can't be produced b/c the temperature is too warm.
- prepenile: outside the ouside layer (tunica vaginalis)
where does sperm production occur?
in the seminiferous tubles; thick, stratified epithelium surrounding central fluid-containing lumen
what kind of cells squeeze sperm, testicular fluids out of testes?
what kind of cells does the seminiferous tubles contain?
- nurse cells that support spermatogenesis
- interstitial endocrine cells that produce androgens (secrete hormones)
what is the progression of the sperm cells?
spermatocytes to spermatids to spermatozoa
what is spermatogenesis?
- production of sperm in the seminiferous tubles
- begins at puberty
- each division produces a daughter cell that is pushed toward the lumen of the tuble
what occurs in spermatogenesis?
- spermatogonia (stem cells) in contact with epithelial basal lamina
- each mitotic division yields one type A and one type B daughter cell (primary spermatocyte)
- meiosis I and II
what happens in meiosis I?
primary spermatocyte (2n) goes to form secondary spermatocyte (n)
what happens in meiosis II
secondary spermatocyte (n) forms two spermatids (small, nonmotile cells close to lumen of the tuble
what is spermiogenesis?
- final stage in sperm production
- spermatids elongate; lose excess cytoplasm, form a tail, become spermatozoon
what are the parts of a sperm?
- head (genetic region) nucleus and helmet like acrosome (contains hydrolytic enzymes that enable sperm to penetrate egg)
- midpiece: metabolic region; mitochondra which gives ATP to move tail
how is the blood testis barrier formed?
tight junctions divide tubule into two compartments, prevent sperm from getting into the blood
what is the role of the nurse cells?
- provide nutrients and signals to dividing cells
- move cells along to lumen
- secrete testicular fluid into lumen for sperm transport
- phagocytize germ cells and excess cytoplasm
- make sure sperms don't get out of the testes and into blood (body would amount immune response otherwise)
what is the movement of the sperm after seminiferous tubules
straight tubule then the rete testis then the efferent ductules then epididymis
what is the epididymis?
- where sperm is stored, the beginning of the male reproductive tract
- supply nutrients to the spermatoza
- takes two weeks for the sperm to travel through, after which they are physically mature (learned to swim)
- ajusts fluid produced by seminiferous tubules with microvilli
- contracts to produce ejaculation, expelling sperm to ductus deferens
what happens at the duct of the epididymis
micorvilli absorb testicular fluid (establish concentration inside tubule) and pass nutrients to stored sperm
how does the sperm migrate after the epididymis?
ductus deferens, ejaculatory duct, urethra
how does the ejaculatory duct form?
vas deferens passes through inguinal canal to pelvic cavity, which joins duct of seminal vesicle
what conveys both urine and semen through the prostate gland and the penis?
what are the accessory glands?
- seminal gland
- prostate gland
- bulbo-urethral glands
what is the function of the seminal glands?
- contributes 60-70% of the semen fluid
- constricts like vas deferens and epididymis to ensure fluid gets into uretha as well
- prostaglandins stimulate smooth muscle to help sperm move up the reproductive tract
- fibrinogen forms semen clot in vagina
- slightly alkalin to buffer acid environments
- provide fluid that initiates capacitation (development of motility)
what is the role of the prostate gland?
- secretes milky, slightly acidic fluid (20-30% of semen volume)
- seminalplasmin: antibiotic properties, appears to help prevent UTIs
what happens in ejaculation?
sperm is forced up into the vas deferens, which goes up, around the front of, over the top of, and behind the bladder
what will happen when the prostate gland enlarges?
interferes with urination by constricting the urethra
what is the function of the bulbo-urethral glands?
produce thick, clear mucus during sexual arousal to lubricate penis and neutralize traces of acidic urine in uretha
what are the three regions of the penis?
- root (bulbo-urethral gland)
what does the cylindrical bodies of the erectile tissue consists of?
spongy network of connetive tissue and smooth muscle with vascular spaces
where does the erectile tissues arise?
- corpus spongiosum: surrounds urethra and expands to form glans and bulbs
- corpora cavernosa: paired dorsal erectile bodies
what happens in the penis during resting state?
arterial branches of corpus spongiosum constricted, little blood flow
what happens in the penis during an erection?
- parasympathetic neurons release NO, a vasodilator
- causes vascular smooth muslce relaxation
- arterioles dilate, corpora cavernose expand, blocks venous drainage
- engorgment of erectile tissues with blood (enlargement and stiffening of the penis)
what happens in ejaculation?
- a sympathetic spinal reflex where ducts, bulbospongiosus muscles and accessory glands contract and empoty their contents
- bladder sphincter muscle constricts, preventing expulsion of urine
what are the causes of erectile dysfunction?
- too little NO from parasympathetic stimulation (alcohols, drugs)
- incompetent venous valves
what is the HPG axis?
- regulates production of gametes and sex hormones through 3 interacting sets of hormones
- GnRH indirectly stimulates testes via FSH and LH
- FSH and LH direcly stimulates testes
what is the role of FSH in males?
targets nurse cells to trigger spermatogenesis
what is the role of LH in males?
- causes interstitial cells to secrete testosterone
- testosterone and inhibin (negative feedback on hypothalamus and anterior pituitary)