Hormone Regulation - Female Flashcards
FSH
stimulates growth and maturation of follicles within follicles
secretes oestrogen
LH
induces ovulation, transforms ruptured follicles into corpus luteum - produces progesterone
what happens during childhood
small amount of oestrogen is secreted, hypothalamus is very sensitive to oestrogen
prevent the release of GnRH
what happens at puberty
hypothalamus becomes less sensitive to oestrogen releases GnRH which acts on the pituitary gland causing the secretion of LH&FSH
what induce menarche
FSH & LH
what does high oestrogen cause
during puberty it causes physical and physiological changes, the reproductive organs begin to support pregnancy
causes the epiphyses in the long bones to fuse
what might delay menarche
extreme activities, low body fat
blocks hypothalamic activity - responsible for converting adrenal androgens to oestrogen
persistent blocking can cause low oestrogen level which causes loss of bone and osteoporosis
what is menopause
a year without a period
what happens to the oestrogen at menopause
the ovarian oestrogen function continues for a while but the ovaries stop functioning as endocrine organs
what happens as oestrogen is lost
pubis hair is lost
breast and repro organs begin to atrophy
ovarian cycle
series of events associated with the maturation of ovum
uterine cycle
series of events in which the endometrium undergoes each month, in response to ovarian hormones
what is gestation
time of prenatal development
what does oestrogen induce
growth and development of breasts
increased deposits of sebaceous glands
widening of pelvis
growth of auxiliary and pubic hair
(O)esterone
androgenic precursors are converted by aromatase into esterone by adipose cells
AROMATASE = produce by adipose tissue
(O)estrdiol
in reproductive years
(o)estriol
during pregnancy
important roles of oestrogen
maintains low levels of cholesterol
facilitating Ca uptake: helps sustain bone density
memory and libido
maintain skin and anti aging
lack of oestrogen
gradual thinning of skin
irritability and mood swings
loss of bone mass
risk of depression
memory function is impaired
intense vasodilation of skin blood vessels causing hot flushes
rising blood cholesterol
post menopausal women at higher risk of cardiovascular disease
menstrual phase
ovum is not fertilised, CL degenerates
if fertilised hCG would support this
PR + OE falls causing the menstruation to shed
flow consists of secretion from the endometrial cells, blood from degenerating capillaries and unfertilised ovum
proliferative phase
ovarian follicle is stimulated by FSH, becomes mature producing OE which stimulates the proliferation of endometrium functional layer, ready for the fertilised ovum
endometrium thickens, becoming more vascular and rich in mucus secreting glands
high levels of OE causes an increase in LH levels causing ovulation
secretion phase
after ovulation
LH from the ant pituitary gland stimulates the growth of the CL, producing progesterone, some OE and some ibhibin
PR causes the endometrium to become oedematous, mucus is secreted which aids the passage of sperm through the uterus to the UT
OE + PR + inhibin suppresses the hypothalamus after ovulation and the pituitary so LH & FSH fall
low FSH prevents further follicles from developing, if there is no fertilisation, the falling LH causes the CL to degenerate
A steady decrease of these hormones causes the uterine lining to degenerate, initates a new cycle
what happens if a ovum is fertilised
hCG keeps the CL in tact, allowing PR + OE to be produced, inhibiting maturation of other follicle
1st trimester
embryonic and early foetal development
rapid cell division, embryo is formed and cell mass is organised into three germ layers:
outer ectoderm: skin and nervous tissue
middle ectoderm: connective tissue
inner ectoderm: epithelium + digestuve system
2nd trimester
development of organs and systems
3rd trimester
major organs and systems fully functional
what determines whether or not RT is given
diagnosis, type, stage, trimester
not recommended in first trimester, should delay to late 2nd or early 3rd trimester if possible
