growth
- currency of body?
hpa axis?
glucose = currency
hypo - GHRH
pit = GH
liver - insulin-like growth factor 1 (IGF-1) = somatomedin
what is function of somatomedin?
stimulate cell division
function of somatostatin?
inhibit GH and IGF-1 release.
do men or women have more growth hormone?
women. dont have T tho so dont get huge
prenatal stress and growth
- learn about world
- metabolic imprinting
learn conditions of world in womb.
when pregnant mom eats - broken down food goes into bloodstream. if not enough nutrition for fetus, it saves nutrients, hoards.
thrifty metabolism
- generational effects
conserving nutrients.
- not genetically. but mom with thrifty metabolism retains only what she needs = fetus learns that there isnt excess nutrients and develops thrifty metabolism as well.
dutch famine
- fetus at first trimester:
- fetus at 2/3 trimester
- 1st - more likley to develop heart disease & obesity
- 2nd/3rd - more like to have diabetes.
fetal origins of adult disease
FOAD - things from womb affect individual in adulthood
effects of prenatal stress
- glucocorticoid secretion
- excessive gluc = larger stress response = sluggish recovery.
- impact hippocampus development (important for negative feedback response)
- down regulate receptors for stress response in hippocampus. fewer receptors = higher [cortisol] needed for negative feedback
- demasculanize fetus. bc Gc & T are similar structurally.
offspring more anxious - amygdala has more cortisol in amygdala.
maternal separation (harlow) - orphanages?
separate fetus = issue with difficulty learning, chang in amygdala
romanian - low quality of care = higher bedtime cortisol.
stress dwarfism
-orphanages?
psychosocial: psychological stress caused stunted growth.
german orphanages: gov’t controlled. based on nun behaviour = determined growth.
grun - warm. high growth. shwartz - cold, low growth. grun move elsewhere - those kids grew more. shwartz went to grun’s old = kids stopped growing as well. X to shwartz - kids grew a bit better.
mechanisms of stress dwarfism
low levels of GH
inhibitory hormones secreted by hypothalamus = somatostatin.
less sensitive to circulating GH (Gc).
mind affects body -> GI doesnt absorb as many nutrients
active touching
premies - physical touch great positive effect on body. GH decreases if separated.
growth hormone in adults
bones: change shape to fit needs. storing, leaching.
resportion = ca back into bones. leach = from bone to body.
stress effects of GH in adult
increase bone breakdown.
Gc disrupt cell division, makes body less sensitive to GH and somatomedins.
osteoporosis = indicator of stress.
male reproductive HPA axis
Hypo = LHRH pit = LH, FSH testes = testosterone, FSH => sperm production
male reproductive system under stress
- effect on system? why does this happen?
system inhibited. less T, less sperm. = good for short term stress.
- endorphins and enkephalin (stress induced analgesia. endorphin - block release of LHRH.
- prolactin released by pit - acts to make it less sensitive
- Gc block testes from responding to LH
erections when stressed
erection need PNS
- stress = premature ejaculation: symp stimulated too soon.
- impotency: cant get it up. psychogenic => plaque build up due to psychogenic stress can lead to physical cause to impotence.
- erection during REM - test if psychogenic.. wrap a pack of stamps.
female repro HPA axis
Hypo - LHRH
pit - LH (stimulate E release form ovary), FSH (release egg)
FSH and twins
women w genes linked to more FSH production = more likely to release 2 eggs= more likely to have twins. skips male generation.
follicular phase
LHRH, LH, FSH and E rise.
E related to mood. sensitizes 5ht receptor.
luteal phase
P increase - build uterine lining.
sensitize GABA receptor.
high GABA = lower anxiety.
Low P = GABA doesnt work as well = higher anxiety
prolactin - bc and how it works
released during stress. maintain release due to breast feeding. nipple stimulation feeds to hypo to produce mroe prolactin ((needed for milk production)
prolactin in hibites hormonal cascade, including progesterone - uterine lining. needed for viable offspring to implant
female repro under sterss
androstenedione (A) - converted to E in fat cells.
not enough fat (anorexia, athletes) - sometimes wont get period.
endorphins & enkephalins = increase prolactin - less sensitive ovary to LH = less E = less ovulation.
