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.