Physiology Flashcards
What is the endocrine system?
communication between glands and other tissues by secretion of hormone into the blood stream
Name the 7 major endocrine glands?
thyroid gland pituitary gland hypothalamus parathyroid gland adrenal glands gonads pancreas
Name 2 modified amino acids?
andrenaline
thyroid hormone
Name 3 steroids?
progesterone
cortisol
testosterone
What are progesterone, cortisol and testosterone derived from?
cholesterol
Name 3 peptides?
ACTH
ADH
oxytocin
Name a protein?
insulin
What are thyroid hormones derived from?
tyrosine
tryptophan
What type of signalling is exhibited by autocrine cells?
cell signals to itself
What type of signalling is exhibited by paracrine cells?
cell signals to nearby cells
What type of signalling is exhibited by endocrine cells?
cell signals through signalling molecules transported via the blood to target distant cells
Describe the action of complementary hormones?
action of several hormones regulates many complex functions
Give an example of complementary hormones?
adrenaline
cortisol
glucagon
Describe the action of antagonistic hormones?
occurs through the balance of opposing influences
Give an example of antagonistic hormones?
insulin
glucagon
Describe the synthesis, storage, transport and release of amines?
pre synthesised
stored in vesicles
transported mainly in free plasma
released by Ca dependant exocytosis in response to stimuli
Are amines hydrophillic or hydrophobic?
hydrophilic
Give an example of an amine?
tyrosine -> adrenaline
Describe the synthesis, storage, transport and release of peptides and proteins?
pre synthesises at the ribosomes of rough ER
stored in vesicles
transported mainly in free plasma
released by Ca dependant exocytosis in response to stimuli
Are peptides and protiens hydrophobic or hydrophilic?
hydrophillic
Describe the synthesis, storage, transport and release of steroids?
synthesised on demaned
when stimulated, there is an increased uptake and avaliability of cholesterol and increase in the rate limiting step of transforming cholesterol to pregnenolone
transported mainly bound to plasma proteins
Are steroids hydrophobic or hydrophilic?
hydrophobic
Is steroid hormone signalling faster or slower than protien, amino acid or peptide signalling?
SLOWER
What type of signalling uses carrier proteins?
steroids
What is the role of carrier proteins?
increase the amount of hormone in the blood and provie a resevoir of free lipophilic hormone
extend the half life of hormone
Name 3 specific carrier proteins?
cortison binding gobulin
thyroxine binding gobulin - binds T4 mainly, a bit of T3 too
sex steroid binding gobulin - bind testosterone and oestradiol
Name 2 general carrier proteins?
albumin - binds steroids and thyroxine
transthyretin - binds thyroxine and some steroids
How is the free:bound hormone equilibrium kept?
when free hormone concentration falls, the bound hormone unbinds and becomes free which maintains ths equilibrium
What rhythm does hormone secretion have?
diurnal rhythm
What are the 3 groups of hormone receptors?
G protein coupled
Receptor kinases
Nuclear receptors
Describe G protein coupled receptors?
cell surface receptors that activate a signalling cascade
activated by some amines, protiens and peptides
ligand = hydrophilic
Describe receptor kinases?
intracellular receptor
ligand is lipophilic so can difuse accross the membrane
activated by proteins and peptides
Describe Class 1 nuclear receptors?
activated by steroids
located in the cytoplasm bound to heat shock proteins and move to nucleus when activated and forms a dimer by binding to hormone response elements in DNA resulting in a CHANGE OF GENE EXPRESSION
ligand is lipophillic
Describe Class 2 nuclear receptors?
activated by lipids (glucocorticoid)
present in the nucleus
ligand is lipophilic
Describe hybrid nuclear receptors?
activated by thyroid hormone
intracellular receptor
ligand is lipophilic
