reproduction

Question 1

female reproductive system ovulation

Answer 1

occurs at day 14 of cycle.
triggered by surge in LH.
finishes when egg releases to fallopian tube.

germinal epithelium [outer layer]: produce oogonia which divide mitotically to form primary oocytes.

primary oocyte divides meiotically into secondary oocyte and first polar body.[halted at metaphase until fertilised].

one ovum discharged at a time. ovum transferred to oviduct and fertilisation takes place at proximal part of oviduct.

Question 2

female reproductive cycles

Answer 2

menstrual cycle completes in 28 days.
divides into four phases
events involving ovaries -ovarian cycle
events involves uterus -uterine cycle

> follicular phase: follicle formation stimulated by FSH from anterior pituitary.FSH stimulate development of several primary follicles, one of them which is converted to graffian follicle.

> Ovulation: decrease in FSH and increase in oestrogen which;
1.stimulates endometrium and vascularisation
2.inhibits FSH secretion
decrease in FSH causes pituitary to release LH which induces ovulation by rupturing graffian follicle.

> luteal phase
ruptured follicle converted to corpus leuteum which secretes progesterone[maintains pregnancy] which;
1. develops endometrium receptive for implantation of zygote

> menstrual stage
if no fertilization occurs, coorpus leuteum degenerates, progesterone levels decrease causing endometrium to shed. mensturation starts.
lasts 3-7 days

MENOPAUSE: end of cycle