Yan Repro and Hormonal Functions of Male Flashcards
how many seminiferous tubules are there?
900
Are the epididymis long?
sort of, 6m long
When does puberty start?
around 12-14 years of age
What are the three phases of psermatogenesis?
1) mitotic of spermataogonia to spermatocytes
2) meiosis turning spermatocytes into spermatids
3) haploid differentiation and morphogenesis of spermatids to spermatazoa
Where do spermatagonia hang out?
on the basal membrane waiting to undergo mitosis
So you have PGCs that turn into spermatogonia and wait on the basal membrane until puberty, where they will begin to undergo mitosis to turn into (blank)
spermatocytes and then eventually become sperm
What 2 things do sperm need to be effective?
flagella and acrosome
What is the acrosome filled with?
enzymes to penetrate the shell of the egg
What three hormones stimulate spermatogenesis?
LH
FSH
Testosterone
What secretes testosterone and thus helps with the meiotic and haploid phases of spermatogenesis?
Leydig cells
What is secreted by the anterior ptituitary gland and stimulates the leydig cells to secrete testosterone?
LH
What is secreted by the anterior pituitary gland and stimulates the sertoli cells to secrete growth factors to maintain quantitiave spermatogenesis?
FSH
How do you make estrogen?
by aromatizing testosterone in Sertoli cells
What does estrogen do in men?
it allows for the reabsorption of fluid from the epididymis to allow for concentrated sperm
Beta estrogen receptors on spermatogonia, spermatocytes and sertoli cells may mediate the actions of (blank)
xenoestrogens (estrogenic endocrine disrupters; mimc estrogen)
What is secreted from sertoli cells or germ cells and can as effectors of major hormonal signals?
growth factors
Paracrine and autocrine regulation of growth hormone is under the control of (Blank)
endocrine signals
Do males need estrogen?
yes, without it they will become infertile
What binds to sertoli cells to make it produce growth factors and inhibin?
FSH
How does a sperm become motile?
it gains motility as it moves from the head (caput) of the epididymis to the tail (cauda) of the epididymis.
At what point in the epididymis does the sperm become motile?
at the middle (corpus) of epididymis (in the head the are not motile)
Where is the majority of sperm stored and are they motile here?
in the vas deferens and no, motility is suppressed here
Since sperm is not motile in the vas deferens when do they become motile again and describe this motility?
upon ejaculation they become motile and when they enter the female they swim all crazy so they can penetrate the egg.
How do the sperm start swimming all crazy in the female reproductive tract?
via ion channels
Where do sperm survive longer, the epididiymis of female reproductive tract?
epididymis can last greater than 1 month
in female reproductive tract 1-2 days
What kind of microenvironment do you need to have motile sperm?
alkaline
acidic is loss of motility
What do seminal vesicles secrete and what do they empty into?
mucoid material w/ fructose, citric acid, prostaglandins, fibrinogen, and others
empty into ejaculatory duct
What do the seminal vesicle secretions provide the sperm?
nutrition and the prostaglandins aid fertilization
What does the prostate gland do?
An acidic secretion w/ calcium, citrate ion, a clotting enzyme and profibrinolysin.
What does the prostate gland do during emission?
contract together with the vas deferens to add fluid to the semen
Why is the prostate gland secretion acidic?
to neutralize the fluid from the seminal vesicles
secretions from what make up the semen and in what quantities?
Vas deferens (10%) -> sperm and fluid Seminal vesicle (60%) Prostate gland (30%) bulbourethral glands (small amount)
What are the characteristics of sperm?
ph of 7.2-8
milk appearance
clotting enzyme (gets dissolved by profibrinolysin from the prostate gland)
How long does semen stay in the vas deferens and epididymis? How about in the female tract?
1 month
1-2 days
Can you freeze sperm?
yup for years!
What does capacitation do?
it makes sperm capable of fertilizing the egg
Where does capacitation occur and what does it do?
in the female reproductive tract
It washes off inhibitory factors (these suppressed sperm activity)
removed lipid/cholesterol vesicles and exposed acrosome to release acrosomal enzymes
Sperm membrane becomes permeable to calcium and increases sperm motility to penetrate zona pellucida
How do you make IVF work?
you wash sperm with HTF or capacitating medium
What is the acrosome reaction?
hyaluronidase and proteolytic enzymes dissolve connective tissue and zona pellucida
Where does the acrosome come for and what is it essential for?
comes from the golgi and is essential for sperm to fertilize egg
What dissolves connective tissues among multiple layers of granulosa cells?
hyaluronidase
What dissolves the zona pellucida?
proteolytic enzymes
How can you regulate the scrotum?
via sweat glands
countercurrent heat exchange
reflex regulation of surface area
reflex regulation of distance from abdomen
What temperature is required for normale spermatogenesisi and male fertility?
a temp. 2 degrees celsius below normal body temp
What is cryptorchidism?
when testes are inside body cavity (usually descend 1-3 before birth, if not usually descend within a couple months after birth)
During the first few months of life, the testes are inside the body, but upon release of (blank) from fetal leydig cells, the testes will descend. If not, you will have cryptorchidsm that needs surgicial help.
testosterone
Why is important to get the testes to descend?
because if you dont, you will get sterility or possible tumor
What is considered a low sperm count?
less than 2.5 ml
less than 20 million/ml is considered infertility
What can spermatogenic defects and genetic factors possible result in?
infertility or abnormal spermatogenesis
How can you have abnormal sperm motility?
if you structural have tail malformation or metabolic problems such as energy supply or messed up ion signaling
For the male sexual act to occur what do you need?
impulses from brain and sex organs integrated into sacral and lumbar spinal cord
Neuronal stimulus for performance of the male sexual act occurs due to sexual stimulation of the (blank).
male sex organs
What does this cause:
impulses-> pudendal nerve-> sacral plexus-> sacral portion of spinal cord
neuronal stimulus for male sexual act
How do you get a penile erection? (nerve wise)
parasympathetic impulses-> sacral portion of spinal cord-> pelvic nerves-> penis
How do parasympathetic nerve fibers cause erection?
parasympathetics release NO, VIP, Ach
Parasympathetic impulses releases NO which results in an erection, but how?
NO releaxes penile arteries and trabecular meshwork of SM fibers in corpora cavernosa and corpus spongiousm (this is what viagra does)
Is lubrication a parasympathetic process or sympathetic process?
parasympathetic
(blank) impulses stimulate secretion of mucus from the urethral glands and the bulbourethral glands. (lubrication)
parasympathetic
Is Emission and Ejaculation a parasympathetic or sympathetic process?
sympathetic
How do you get emission and ejaculation (nerve wise)?
reflex center of spinal cord emits sympathetic impulses at T12-L2-> hypogastric and pelvic sympathetic nerve plexuses-> genital organs-> emissions
For emission and ejaculation, after the nerves have fired, then what happens?
you get contractions that make sperm move through vas deferenes-> through internal urethra-> gain fluids from prostate gland-> gain fluids from seminal vesicles-> gain fluids from urethral glands and bulbourethral glands
During emission and ejaculation, what does filling of internal uretha do?
rhythmic contract of internal genital organs and pelvic muscles
thrusting movement of pelvis and penis
propels semen
The resolution of the male sexual act finishes after (blank) minutes after ejaculation
1-2 mins
Where do you get testosterone?
from leydig (interstitial cells) and adrenals (less than 5%)
What carries testosterone in the blood?
SHBG/ ABP and albumin
What secretes ABP/SHBG?
sertoli cells
How is testosterone converted to DHT?
by 5 alpha reductase in the liver (type 1) and in the tissues (type 2)
Is DHT high in the blood?
What does it have a high affinity for?
no only 5% of testosterine is converted to DHT in the blood
androgen receptors
Besides turning into DHT what else can testosterone do?
aromatize and turn into estrogen
When testosterone binds to androgen receptors, what happens?
you get transcription factors
How do you metabolize testosterone?
via reduction and conjugation in the liver and through excretion in kidneys or gut
Testosterone levels fluctuate throughout life, tell me about it?
increases in 2nd trimester than decreases until birth, increases at 1/2 a year then decrease until puberty, increases into 40 then slowly declines
During fetal development, T production starts at (blank) week.
7th
What does testosterone do during fetal development?
make male external and internal sex organs
descent of the testes
What does this:
Further development of external and internal genitalia
Development of 20 sexual characteristics
Distribution of body hair
Baldness: genetic background + large amount of androgen
Voice
Increased skin thickness: acne
Increased muscle development: abuse by athletes
Increased bone matrix and calcium retention
Increases basal metabolism
Testosterone in adults
maintenance of male features
In the adult: (blank) are no longer concerned with establishing the individual as a male or female; rather, they ensure that the reproductive system functions effectively.
gonadal steroid actions
In the male where does estrogen come from?
at the early follicular phase from leydig cells, sertoli cells, and developing germ cells and 2/3rds from peripheral conversion (skin, brain, fat liver)
(blank) regulates the re-absorption of luminal fluid in the head of the epididymis, allowing sperm to enter the epididymis concentrated rather than diluted.
Estrogen
How is estrogen involved in negative feedback?
estrogen inhibits hypothalamic GnRH
What role does estrogen play in men?
pubertal growth spurt
epiphyseal closure
maintenance of bone mineralization and integrity
Beta estrogen receptors on spermatogonia, spermatocytes, and sertoli cells may mediate the actions of (blank)
xenoestrogens (estrogenic endocrine disrupters)
If you have deprivation in testosterone what will happen to your LH levels?
they will increase
The site of (blank) negative feedback is both at the level of the pituitary gland (decreasing pulse amplitude) and at the hypothalamic GnRH pulse generator (decreasing LH pulse frequency).
Testosterone
(blank and blank) are secreted by gonadaotropes of the anterior pituitary.
FSH and LH
What is the mechanism of action of LH?
LHR-> cAMP-> PKA
What is the mechanism of action of FSH?
FSHR-> cAMP-> PKA
What does LH do in the male?
influences leydig cells to make testosterone which will make sertoli cells release growth factors and increase spermatogenesis
What does FSH do in the male?
targets sertoli cells to allow them to grow and differentiate so that it can secrete growth factors AND increased LHR on leydig cells
What sort of fashion do sertoli cells secrete growth factors?
in a paracrine fashion
Besides testosterone, what else inhibits FSH secretion and what secretes this?
inhibin secreted by sertoli cells
If you have really high levels of FSH in males, it is indicative of what?
cryptorchidism
Summarize the hypothalmo-pituitary-gonadel axis in the male
Hypothalamus releases GnRH which secretes FSH and LH, LH makes leydig cells secrete testosterone which will make external and internal genitalia and make sertoli cells secrete inhibin. Inhibin will inhibit the anterior pituitary. FSh secreted by anterior pituitary will stimulate the sertoli cells to proliferate and differentiate.
Prolactin released from anterior pituitary makes leydig cells make more LH receptors thus increase its ability to make testosterone
(blank) increases the response of Leydig cells to LH by increasing the number of LH receptors expressed on Leydig cells.
Prolactin (PRL)
Male do not have menopause but instead have (blank) which is when testosterone levels start dropping off at age 40
andropause “male climacteric”
What are these symptoms of:
hot flashes, suffocation, and psychic disorders, similar to those of menopause syndrome
andropause “male climacteric”
What is a Orchidectomy?
removal of a testicle or both testicles
What happens to your body when you have an orchidectomy?
Accessory organs shrink and lose seminal plasma
decrease muscle mass
decreased libido
decreased baldness, kidney and liver weight and erythropoiesis
increase in thymus weight
What is the Nocturnal penile tumescence (NPT) test (stamp test, or rigidity test)?
Testing is usually repeated for at least two nights. If good erections occur during sleep, the major cause of the erection problems probably is not physical.
The NPT test determines whether a man is having normal erections during sleep. This test can be done at home or in a special sleep lab via a snap gauge or electronic monitoring device.
Checked for 2 nights
What is the normal number of erections a male should have during sleep?
3 to 5
Men who are unable to have an erection because of a psychological problem still have erections during deep sleep.
T or F
T
Occasionally some sleep disorders or serious depression can prevent these nighttime (nocturnal) erections.
T or F
T
What is adiposogenital syndrome (Frohlich’s syndrome. hypothalamic enuchism)?
Hypothalamic deficiency in GnRH that results in abnormalities in the feeding center of the hypothalamus: overeat-> obesity
What is hirsuitism and virilization?
Facial hair, temporal balding, muscle development, male type pubic hair, clitoromegaly.
Also discuss the effects of estrogens in males and the need for orchidectomy for near-complete development of female secondary sexual characteristics.
(blank) is the excessive hairiness on women in those parts of the body where terminal hair does not normally occur or is minimal - for example, a beard or chest hair.
Hirsutism
What is this:
Possession of mature masculine somatic characteristics by a girl, woman, or prepubescent male; may be present at birth or may appear later, depending on its cause; may be relatively mild (e.g., hirsutism) or severe and is commonly the result of gonadal or adrenocortical dysfunction, or of androgenic therapy
virilization
