Reproductive System Flashcards
What hormone stimulates spermatogenesis?
During puberty, gonadotropic hormone from the anterior pituitary in seminiferous tubules.
Sertoli Cells
Surround developing spermatogonia.
Order of sperm in spermatogeneis?
Spermatogonia enlargenes–>primary spermatocyte 2n meiosis–>Secondary spermatocyte n–>spermatids n–>spermatozoa (sperm, x vs y) TO FERTILIZE OVUM.
Tricks: “Go” is first, see the 1st and 2nd “cytes”, until your tid-tired, and Z in zoa i last.
Components of a spermatozoa
Acrosome head: proteolytic enzymes and hyaluronidase (digests proteoglycan filaments of tissues). And Tail: Axoneme made of microtubules covered by thin cell membrane and lots of mitrochondria.
Where do sperm develop capability of motility?
Epididmymis
Growth Hormones function
Controls “background” metabolic functions, promots early division of spermatogonia themselves. W/o this= infertility
Estrogen
Formed from testoserone by Sertoli cells (stimulated by FSH).
Follicle Stimulating Hormone
where from? function?
From anterior pituitary gland, stimulates sertoli cells, helps convert spermatids to sperm.
LH
Leutenizing hormone from anterior pit, stimulates Leydig cells, which help secrete testosterone. Essential for growth/divison of germinal cells.
What is testosterone mainly converted to in target cells?
Dihydrotestosterone (more active).
What can testosterone be made from?
Cholesterol or acetyl Co-A
What does testosterone loosly/tightly bind to?
Loosly to plasma albumin, tightly to sex-hormone binding globulin
What if testoterone dosnt get used up?
Coverted in liver to androsterone and dehydroepiandrosteron, eventually excreted via liver bile or urine.
What enzyme converts testosterone into dihydrotestosterone? (Active in target tissues)
5 alpha reductase
Dihydrotestosteron binds to a recetpor, then what?
Goes to nucleus to manipulate DNA/RNA transcription/protein synth.
What produces androgen hormones?
Adrenal glands
What other hormone is needed to spermatogenesis/sertoli cell function and enzyme?
At low doses, estogren. Testosterone can be converted to this by aromatase.
What fetal week does testosterone work?
7th week. Male body characteristics/dscent of tests.
Testosterone does what to the pelvis?
Narrows pelvis outlet, funnel like shape, incs strength for load bearing
What does testoerone do in the kidneys?
Increase reabsorption of sodim in distal tubules= blood/ECF volumes of male in relation to body weight inc 5-10%.
What stage of life is testosterone at a low?
POST-newborn until puberty. Sperm production does not occur until puberty.
Where does Gonadotropin-releasing hormon (GnRH) come from? What 2 hormones does it release?
Hypothalmus; Stimulates release of LH (Testosterone/leydig cells) in* pulsatile fashion* and FSH (spermatogenesis/serotoli cells) from anterior pit gland.
What is the portal system in the pit called?
hypophyseal portal vascular system (GnRh getting from hypothal to ant pit).
What do LH and FSH have in common?
From gonadotrophs, and are glycoproteins–>activate cAMP.
Negative feedback loop testosterone?
Increase testosterone= shuts off GnRH which stops both LH and FSH hormones.
Negative feed back: Inhibin
Secreted by seroli cells, inhibits secretions of FSH from anterior pit gland. Decreases spermatogenesis.
Functions of sertoli cell
Takes care/nourishes of the sperm. Maintains blood-testis barrier, produces seminiferous tubular fluid, mades androgen-binding protein, removes damages cells, makes inhibin.
Leydig-Sertoli Germ Cell Crosstalk*
What type of recepors do sertoli cells have?
Sertoli Cells have androgen receptors, specifically estrogen receptors. Leydig cells bring in testosterone, which sertoli cells convert to estogen (via aromatase), which promotes spermtogenesis.
What do growth factors from sertoli cells do?
stimulated by FSH
increase LH receptors on leydig cells to increase testosterone production/ steroidogenesis.
What does T bind to in serotoli cells that those cells made?
Adrogen binding protein
Ovum at birth characteristics
thin layer of granulosa cells; ooxyte maturation inhibiting factors.
Ovum at puberty
stimulated by FSH/LH, additional layers of granulosa cells, and follicles are known as primary follicles.
FSH induces…
maturation of primary follicles. Gives rise to more layers and a “theca” forms around it.
Theca layers and functions
Theca Interna: steroid sex hormones (estrogen/progesterone)
Theca Externa: highly vascular CT–>capsule for developing follicle.
Follicular fluid,secreted by granulosa cells, are high in what? High fluid leads to what?
Estrogen; accumulation of fluid creates an “antrum”.
Primary hormone to take primary follicle to antral strage?
FSH
After antral stage, negative OR positive feedback to create what?
positive feeback to create larger follicles called vesicular follicles. Estrogen–>more FSH receptors–>more sensitive to FSH. Pit FSH and Estrogen combined–>LH receptors on granulosa cells–>increase in follicular secretions. Estrogen+ lh–> proliferation in thecal cells=hightens secretions.
How many follicles mature?
Only 1. Remaining undergo atresia. Eventually, high estrogen will stim a negative feedback to suppress fsh from ant.pit= leading to less maturatio of other follicles.
Before we were in follicular phase, Now were in “Ovulation” phase. Main hormone?
Follicular phase: FSH/estrogen, now it’s LH/progesterone. Rapid growth of follicle.
LH Surge leads to
follicle swelling and degeneration of stigma= follicle rupture.
a) Theca external releases proteolytic enzymes from lysosomes
b)rapid growth of new blood vessels into the follicle wall and prostaglandin (vasodilator) secretions into follicular tissues.
After ovulation, we have what phase?
Luteal phase. granlosa/theca cells converted to Lutein cells. LH is responsible for this. Corpus luteum.
What do grandulosa cells from corpus luteum release? And theca cells?
-Progesterone> estrogen
- theca=form androgens, aromatase
What does corpus luteum become?
Corpus albicans, 12 days, loses its secretory function
Involution of corpus luteum? What produces inhibin?
Corpus luteum secretes progesterone>estrogen and high conc inhibit FSH/LH. Lutein cells also produce inhibin, inhibits FSH secretions. This causes corpus luteum to degenerate= aka involution. 2 days before your period
Main hormon that contribute to secondary female traits?
Estrogen.
Estrogen does what to vaginal epithelium?
Cuboidal to stratified (more resistant to trauma/infections).
What hormone contributes to primary growth/function of breasts?
Prolactin (milk production) and progesterone (breast swelling due to lobules/alveoli breats=secretory). Converts breats into milk producing organs. (estrogen contibutes to GROWTH of milk producing appartus)
Estrogen’s effect on bones?
Stimulates bone growth: Osteoprotegerin/ osteoclastogenesis inhibitory factor.
ALSO stimulates uniting of epiphyses with the shafts of long bones. Girls will stop growing faster than guys in height due to this.
A deficiency= osteoporosis. High risk after menopause when estrogen production stops. Treated with estrogen replacemenets.
Is increased protein deposition higher with estrogen or T?
T
What hormone/thing affects hair development/dist?
Androgen secreted by female adrenal glands, not estrogen.
Estrogen’s affect on skin?
High vascularity, females will bleed more than men.
Estrogen is similar to what in terms of Na+ and H20 retainment?
Aldosterone
Progesterone’s effect in uterus? In fallopian tubes?
promotes secretory changes/ prepare uterus for implantation and also decreases intensity/freq of contractions to help prevent expulsion of implanted ovum. P wants a baby.
Also inc secretions for nutrition of fertilized ovum as it travels the F tube.
Three phases of endometrial cycle? and associted hormones?
1.Proliferation (estrogen induced) sets it up nice. thick.
2.Secretory changes (progesterone), stored nutrients
3.Desquamation (menstration), corpus luteum involutes, both hormones DECREASE, sheds, release of vasoconstrictors, endomed=vasospactic, blood vessel necrosis, loss of nutrients, uturine contractions
In regards to phase 2:
**Cytoplasm of the stromal cells increases, lipid and glycogen deposits **increase greatly in the stromal cells, and blood supply to the endometrium further increases in proportion to the developing secretory activity, with blood vessels becoming highly tortuous.
The purpose of these changes is to help provide large amounts of stored nutrients to provide appropriate conditions for the implantation of fertilized ovum.
How mnay blood and serous fluid is lost?
40 ml and 35 ml of serous fluid
Why is menstrual fluid nonclotting?
fibrinolysin. Too much bleeding=fibrinolysin may not be enough–>uterine dx.
In what way does the hypothalamus secrete GnRH?
Pulses.
lasting 5-25 minutes that occur every 1-2 hours
continuously=loss of function.
Where does the neuronal activity that causes pulsatile release of GnRH occur?
Arcuate Nuclei of Hypothalamus
What secretes inhibin again?
Corpus Luteum
Before ovulation, what type of feedback is estrogen participating in?
positive.
Before ovulation what hormone surges?
estrogen–positive fb—>LH.
Postovulatory secretion?
Negative fb loop, corpus luteum makes pogesterone,estrogen,inhibn.
Where is oxytocin produced?
Posterior Pit
Function of oxytocin?
Ejects milk from alveoli into ducts. Stimulated by suckling or hearing baby (suckling also stimulates prolactin)
What does prolactin go?
Lactation. Anterior pit gland. Conc rises from 5th week of pregnancy until birth.
