Introduction and reproductive physiology

Question 1

Describe anatomy of the male reproductive tract?

Answer 1

Testes-sperm production-vas deference passes up and around to back oh the prostate gland
Before prostate-seminal vesicles

Question 2

What are the key regulatory hormones for male reproduction?

Answer 2

In order of important
GnRH-pulsatile, in Hypothallamus
Acts on pituary glands

LH-anterior pituary-upregulate testosterone
FSH-anterior Pit-directy upregulate sperm (sertoli cells-adrogen binding protein)

Testosterone-upregulated by LH
Act on spermatogenic cells (increase) ONLY in testes
they produce inhbins that downregulates LH/FSH
Testo also has negative feedback on GnRH and LH/FSH
Testo also has other effects

doesnt stop with age-keeps working

Question 3

Describe process of spermatogenesis?

Answer 3

Primordial germ cells produce 4 sperm via mitosis and meiosis
happens in semniferous tubules-sertoli cells on the outside

Question 4

summarise male reproductive production of sperm

Answer 4

Starts at puberty-function all the time even with age
Sperm production is very rapid-
Quantity and quality generally decrease with age

LH stimulate testo
FSH and testo stimulate sertoli cells
Sertoli cells support spermatogensis

Question 5

summarise female reproductive production of sperm

Answer 5

Start at puberty and acts cyclically
Stops around 45 (can change)
Egg quality decrease with age-independent of menopause

FSH stimulate development of ovarian follicules and 17B estradiol
LH stimulates progesterone
Steroids regulate uterine endometrium

Question 6

Describe the female homromnal control of sex hormones?

Answer 6

Hypo-GnRH
upregulate LH and FSH in anterior PIT
target ovaries-produce estrogen and progesterone–downregulate GnRH and LH/FSH

in follicular phase-FSH/LH-produce estradiol-nromal downregulatory feedback
In midcycle-FSH/LH increase estradiol-UPREGULATORY FEEDBACK to LH/FSH => peaks just before midcycle (estradiol)
after ovulation-(peak of LH/FSH-Luteal phase-LH/FSH-increase progesterone-normal downregulatory feedback-high progesterone and estradiol

LH/FSH peak right at mid cycle just after the estradiol peaks => cause release of the egg

Question 7

What happens in the uterus during the menstrual cycle?

Answer 7

Start thin (2-4mm thick)-before ovulation, as the follicule develops-thicken slightly (1cm)-estrogen driven
At thay point, follicule produces estrogen
By end of midcycle-around 1cm-if implement, when itll be
After ovulation-estrogen and progesterone driven (The decline of proge is the signal for the shedding) causes breakdown of endometrium-back to thin 2-4mm
Follicule after ovulation-corpus luteum-idependent-produce esteogen and progesterone

Question 8

Describes the steps leading to an egg formation?

Answer 8

steps-primodrial follicule (with primary oocyte)->primary follicule->growing follicule-> antral follicule-> ruptured follicule-> corpus luteum-> degeneration (DOES NOT HAPPEN OVER 1 MONTH-THEY START EARLIER-about 3months early)

oogenesis does NOT mathc up with this-the first part happens in utero
The later part-Secondary oocytes and ovum-> after puberty
(possibly how long that gap is might cause degrading quality)

Question 9

Describe folliculogenesis?

Answer 9

Takes more than 2 cycles for a primordial follicule to become ready and ovulate
initiation is fast
antral phase goes all the way through1 cycle and some of the next one -> and selected partway through 3rd for the release

Happens in parrallel to other eggs. AND in both ovaries at the same time

Dominant is selected, but needs to be fertilised withing 24 after release

Question 10

Describe the process of fertilisation on molecular level?

Answer 10

Sperm must swim up the fallopian tube-very long
often malfunction-so most cant even make it up (takes hours-filters out the malfunctioning ones)-

Once sperm arrive, release enzymes (acrozome)-digest follicule cells left over, then through zona pellucida of the egg
Head of the sperm releases very condensed Chr-male pronucleus. also has female pronucleus DOES NOT COMBINE-

Question 11

How do Chromosomes behave in the egg during fertilisation?

Answer 11

Female and male pronucleus are present BUT DO NOT FUSE (23 chromatids)
1st meitoic division gave 1 polar body, second body is produced before male pronucleus happens (polar body-left over Chr)
immediatly duplicate and form mitotic spindles-seperate Chr from each other-> each of those clusters will become nuclei in the 2 daughter cells-identical –first cleavage division of embryo
very similar to mitosis-spereration