Male Reproduction Flashcards
Which 2 reproductive hormones are present in BOTH male and female?
FSH & LH
FOLLICLE-stimulating Hormone (FSH) does what for Ovarian FOLLICLES?
STIMULATES &
Nurtures
FSH does what for SERTOLI cells in males?
Nurtures sperm development
Lutenizing hormone (LH) does what in BOTH males and females?
Stimulates TESTOSTERONE production in:
- Leydig cells - males
- Thecal cells - females
FSH and LH are secreted by?
Anterior Pituitary
What stimulates the Anterior Pituirtary to release FSH and LH?
GnRH from Hypothalamus
T/F. Sex hormone FEEDBACK is always NEGATIVE.
False! Estrogen actually have a POSITIVE effect on the anterior pituitary, all other places is negative and testosterone always feedbacks negatively.
Main goal of FSH:
Gametogenesis
Main goal of LH:
Sex hormone secretion:
Females –> estrogen, progesterone, androgen precursors
Males –> testosterone
What is inhibin?
gives NEGATIVE FEEDBACK to anterior pituitary
Usually FSH > LH, there is one time period that LH dominates, what is it?
Adult Reproductive Period
In males, where does gametogenesis take place?
SEMINIFEROUS TUBULES in testes
Which trophin stimulates Sertoli cells in Semi tubules?
FSH
Which trophin stimulates Leydig cells in semi tubules?
LH
Development of sperm proceeds from Interstitium (where blood and Leydig are) to Lumen, carried by?
Sertoli cells. wrap around it and secrete substances to nuture it as it developments and moves it closer and closer to the lumen
What is the purpose of the TIGHT JUNCTIONS in the semi tubules?
Is like the Blood-Brain barrier. Very tight control of what’s going on in luminal/central compartment - not effected by things in the insterstitial fluid (alcohol, etc), can only bring in things that we want to nourish sperm
Mitosis occurs above/below the Tight Junctions?
Above (BASAL compartment)
What is the order/terminology associated with the progression of sperm development?
Spermatogonia –> Primary Spermatocyte –> 2 Secondarys –> 4 Spermatids –> Spermatozoa
Meiosis occurs in which compartment?
Central
Secondary spermatocytes is the first place we see a change in chromosome number, instead of 46, each will have how many?
23 (still have 2 chromatids per chromosome)
How many chromosomes and chromatids per chromosomes are present in spermatids?
23 : 1
How do LEYDIG cells cross the Tight junctions?
they are lipid soluble - therefore NOT a barrier to testosterone
Beside nurturing, the sertoli cells can secrete what else to help the process?
ABP - androgen binding proteins - helps capture testosterone and holds it close
Tip of the developed sperm is called what? and what does it have?
Acrosome - contains enzymes for penetrating the egg
Where is the mitochondria located in the sperm?
Midpiece
What is the purpose of the tail of the sperm (flagella)?
Power house for motion!
Who is in charge of QUALITY control of sperm?
Sertoli cells will auto digest any sperm that aren’t up to snuff!
What type of muscle in the epididymis and vas deferens help move sperm along?
smooth
T/F. Movement of sperm is BOTH passive and enhanced by smooth muscle contractions.
TRUE! Pressure created by continuous secretion of fluid rom Sertoli cells help
Describe the ANS domination from rest –> erection –> ejaculation
Rest = Sympathetic Erection = Parasympathetic Ejaculation = Sympathetic
Pharmacotherapy for ERECTILE DYSFUNCTION would focus on
- Sympathetic innervation
- Parasympathetic innervation
PARASYMPATHETIC - need to target cGMP to get desired response. Want it to stick around longer, so inhibit the enzyme that breaks down cGMP and remain ENGORGED longer.
NO (nitric oxide) stimulates _____ to vasoDILATE smooth muscle for erection.
cGMP
The vasodilation of erection is ended by breakdown of cGMP by PDE5, which med inhibits this enzyme?
VIAGRA - keeps boner
Which medication is CONTRAINDICATED with viagra?
Nitrates
What other medications should be monitored with Viagra?
alpha-blockers for HTN
Testosterone is important for spermatogenesis, but most tissues want to convert it to a more POTENT FORM:
Dihydrotestosterone (DHT)
Which enzyme converts Testosterone to DHT? and which medication inhibits this enzyme?
5a-reductase, inhibited by Finasteride for prostate and hair loss problems
T/F. GnRH has a pulsatile release from the HypoT
True - cycles every 90 minutes
In presence of FSH and ABSENCE OF LH, would you get NORMAL sperm?
NO - is collaborative
The Sertoli cells do A TON of things, can you list them all?
- Make tight Junctions
- Nourish developing sperm
- ABP
- Responds to T and FSH to stimulate sperm proliferation and differentiation
- Inhibin
- Phagocytize defective sperm
T/F. 98% of circulating testosterone is bound to plasma proteins including ABP.
TRUE - very little is actually solubulized in plasma, only released right at target tissues and then it moves right in to it
T/F. Androgens stimulate the synthesis of sex steroid-binding globulins (ABP)
False. brain can’t sense T, has no receptors for it, but does have it for ESTROGEN.
What enzyme creates estrogen from testosterone?
Aromatase
T/F. Gonads have the enzymes necessary to produce cortisol and aldosterone.
FALSE
