Male GU Flashcards
what are the two main layers of the penis shaft?
corpora cavernosa and corpus spongiosum
what is the corpora cavernosa?
two left and right masses of tissue that fills with blood for an erection
what is the corpus spongiosum?
mass of tissue around the urethra opening that also fills with blood for an erection
what is the prepuce?
another name for foreskin
why are the testicles outside the body?
to keep them about 2 degrees colder than the internal temp (best sperm conditions)
what are the two main tunics covering the testes?
outer layer: tunica vaginalis(has visceral and parietal layers)
inner layer: tunica albuginea
what is genetic sex?
chromosome differentiation
XY for males and XX for females
what is gonadal sex?
sex based on gonads (testes for males and ovaries for females)
what two things are gonads comprised of?
germ cells and steroid hormone secreting cells
what are the germ cells for males and females?
males- spermatogonia
females- oogonia
what main hormone Sertoli cells make? what is this substance necessary for?
antimullerian hormone; need this to develop male reproductive structures
what two cells are found in the testes?
Sertoli and leydig
what two cells are associated with the ovaries?
granulosa and theca
what do granulosa cells (female) make?
estradiol (estrogen)
what do theca cells (female) make?
progesterone
what is the phenotypic sex?
defined by physical characteristics of internal genital tract and external genitalia
what are the 4 internal structures for males (for phenotypic sex)?
prostate, seminal vesicles, vas deferens, and epididymis
what are the 2 external structures for males (for phenotypic sex)?
scrotum and penis
what are the 3 internal structures for females (for phenotypic sex?
fallopian tubes, uterus, and upper third of the vagina
what are the 4 external structures for females (for phenotypic sex)?
clitoris, labia majora, labia minora, and lower two thirds of the vagina
describe the gonads at 5 weeks gestation
bipotential (have the ability to turn female or male)
when is the genetic sex determined?
at conception
describe the gonads at weeks 6-7 of gestation
in a genetic male, the testes start to develop
what does testosterone stimulate?
the growth and differentiation of the Wolffian ducts
what four structures do the Wolffian ducts give rise to?
epididymis, vas deferens, seminal vesicles, ejaculatory ducts
what do lydig cells secrete?
testosterone
what does anti Mullerian hormone inhibit?
development of the Mullerian ducts (would have been the internal female structures)
what happens at 9-10 weeks gestation in terms of sexual differentiation?
differentiation of external genitalia, penis, and scrotum
what two things does the growth of the external genitalia/penis/scrotum depend on?
testosterone converting to dihydrotestosterone AND presence of androgen receptors
where should the testes be at birth?
in the scrotal sac outside the body
at what lunar month do the testes start descending?
8
If the SRY gene is absent, what develops?
female reproductive organs (SRY is a testes determining factor gene that stimulates production of anti Mullerian hormone)
what are the two primary functions of the testes?
steroidogenesis and spermatogenesis
besides AMH and testosterone, what other two hormones do the testes produce?
dihydrotestosterone and androstenedione
what does the adrenal cortex produce? what is important about this?
produce androgens BUT not enough to promote sperm production (if testes cant make testosterone, adrenal cortex cant supply enough for the body’s needs)
what two hormones are secreted by the anterior pituitary gland?
LH and FSH
the hypothalamus secretes what hormone that acts on the ant pituitary?
GnRH
What does LH do?
regulates the production of testosterone by acting on the interstitial cells of leydig
what two places does testosterone provide negative feedback to?
anterior pituitary (dec LH secretion) and hypothalamus (dec GnRH)
what two things does FSH do?
initiates spermatogenesis and stimulates Sertoli cells
what three things does FSH cause Sertoli cells to produce?
androgen binding protein, plasminogen activator, and inhibin
what does inhibin do?
provide negative feedback on the anterior pituitary (inhibits FSH)
throughout adulthood, do the rates of FSH, LH, testosterone secretion, and spermatogenesis change?
no
what is the primary inciting event of puberty?
the pulsatile secretion of GnRH (causes pulsatile secretion of FSH and LH)
besides differentiation of the Wolffian ducts, what else does testosterone do?
stimulates Sertoli cells to produce sperm
what is tanner staging used for?
to stage GU development of males and females (stage 1 is preadolescent and stage 5 is adult)
about what age does spermatogenesis start? what hormone primarily stimulates it? where does it occur?
age 13, stimulates by FSH; occurs in the seminiferous tubules of the testes
what three things are found in the seminiferous tubules?
spermatogonia, spermatocytes, and Sertoli cells
what do Sertoli cells do for spermatogenic cells? how about for the germ cells?
provide support and organizational structure; nutritional support
what do the tight junctions between Sertoli cells do?
provide a blood testes barrier
what does androgen binding hormone do?
provides high concentrations of testosterone to the spermatogenic cells
spermatogonial phase of spermatogenesis:
primordial germ cells undergo mitosis to become _______________. these cells then undergo mitosis to become ______________. then mitosis again to __________
spermatogonial stem cell; spermatogonium; primary spermatocyte
#2 phase of spermatogenesis: a primary spermatocyte undergoes \_\_\_\_\_\_\_\_\_\_\_\_\_ to turn into a \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
meiosis I; secondary spermatocyte
what happens in meiosis I?
go from 46 chromosomes to 23 chromosomes
#3 phase of spermatogenesis: secondary spermatocyte undergoes \_\_\_\_\_\_\_\_\_\_\_\_\_\_ to become a \_\_\_\_\_\_\_\_\_\_\_\_\_
meiosis II; early spermatid
what happens in meiosis II?
development of spermatids through dividing secondary spermatocytes
4 phase of spermatogenesis: an early spermatid differentiates into ________
sperm
how many sperm are made each day?
120 million
what part of the sperm is important in breaking through the egg for fertilization?
the acrosome on the head
what are the four parts of the sperm?
head (acrosome/nucleus), neck, midpiece (mitochondria), tail (plasma membrane)
where do mature sperm travel to from the seminiferous tubules?
epididymis (they mature and reside here)
how long can sperm last in the epididymis?
several months
during ejaculation, the epididymis ____________ and moves sperm to the ______ _________. sperm then travels to the __________ ______ and then to the _________ where it can also reside
contracts; ductus deferens (vas deferens); spermatic cord, ampulla
how long can the sperm live in the ampulla?
4-5 weeks
what is the prostate considered? what does it do?
accessory gland; secretes alkaline fluid (forms most of the ejaculatory fluid) that neutralizes the vaginal acidity (so sperm can easily travel)
what pH does sperm mobilization happen at?
6-6.5
what are the three accessory reproductive structures?
seminal vesicles, prostate, bulbourethral glands
what does the seminal vesicles do?
secrete fluid that supports the sperm
what two ingredients are in seminal fluid? how do each help the sperm?
fructose: provides energy for motility
prostaglandins: altering cervical mucosa to be more receptive to sperm and causes reverse peristalsis in the uterus
what do the seminal vesicles join to form the ejaculatory duct? where does this duct travel through?
vas deferens; travels through prostate
what % of the ejaculate comes from the seminal vesicles?
70%
what four things are in semen?
fructose, prostaglandins, sperm, alkaline fluid
what can bulbourethral glands hold? what does this account for?
sperm; accounts for occasional pregnancy when not using a condom/contraceptive
what do the bulbourethral glands do?
add fluid to the urethra pre-ejaculation
what ANS innervation does the penis have for an erection?
parasympathetic: release of nitric oxide
what is emission?
contraction of the vas deferens and ampulla with the release of sperm into the internal urethra
what ANS innervation is ejaculation?
sympathetic
what is detumescence? what ANS innervation does it have?
penile relaxation and outflow of blood from corpora cavernosa; sympathetic
when penile arteries are dilated, veins will be _____________
constricted
