Endocrine system Flashcards
what is the message detected by hormone receptors
hormone concentration
relative half lifes of hormones in blood
- monoamines (epinephrine): seconds
- peptides: minutes
- steroid hormones: hours
- thyroxine and triiodothyronine: days
2 ways to control secretion
- endogenous rhythm (ex. circadian)
- component of a negative feedback system
- gland is sensor, hormone is efferent path
- collaboration with nervous system
- collaboration with other endocrine organs
2 ways to control target cell sensitivity to hormones
- upregulation
2. downregulation
upregulation
- decreasing the number of receptors for the first message decreases the response of the target cell to the message
- cell surface receptors can be removed from the surface by endocytosis
- intracellular receptors can be degraded by proteases
- affinity of the receptors can be decreased by phosphorylation
upregulation
increasing the number of receptors increases the sensitivity
- cell surface receptors can be installed on the surface by exocytosis
- intracellular receptors can be produced by gene expression
- affinity of the receptors can be increased by phosphorylation
interactions of hormones: additive
a+b hormone add to combine strength and effect, do same thing
-independent functions still, but do same thing
synergistic
a+b add together for huge effect, work better together
permissive
a, b by themselves=nothing
-a+b combined you get response. only if a+b together
antagonistic
A and b do opposite things
-get lesser response with a+b
another name for posterior pituitary
neurohypothesis
posterior pituitary
neuron controlled from hypothalamus
- doesnt make hormones
- secretes 2 peptides: ADH and oxytocin
anterior pituitary
- stimulated by hypothalamic releasing hormones
- has endoderm cells-make hormones
- releasing hormones find target cell, releases an. pit, hormones
2 hormones that do not use cAMP as a secondary messenger
TRH, GnRH
use phosphatidyl inositol
thyroglobulin is what?
a protein made in the follicular cells of the thyroid gland containing large amounts of the amino acid TYROSINE
-made by the RER in follicular cells and secreted into the colloid by exocytosis
what does iodine have to do with the process
iodine is actively transported into the follicle cells, then diffuses into the colloid
-thyroglobulin in the colloid is iodinated by addition of iodine to the tyrosine rings
what does TSH do to the thyroid
acts via cAMP to do the following coordinated responses in the follicle cells
- causes increased secretion of thyroglobulin
- causes an increased active transport of iodine
- increases growth and division of thyroid follicle cells
- causes endocytosis of iodinated thyroglobulin into follicular cells
- causes secretion of T3 and T4
how are thyroxine and triiodothyronine synthesized
by combining two of the iodinated tyrosines from thyroglobulin
T3 and T4 overall effect
increase basal metabolic rate
-increase heat
study negative feedback loop for thyroid
s
release of TRH from hypothalamus involves
its a peptide, so transcription, translation, exocitosis
TRH reaches ant. pit
trh-trh receptor-Gp=phospholipase C-etc
Male reproductive system: leydig cells
make testosterone
sertoli cells
help sperm develop and nourish
2 gonadotropin hormones from pituitary
- FSH-promotes sperm development
2. LH-testosterone inducing hormone
Study male gonadotrophin feedback system
s
study female gonadotrophin system
s
