hormonal communication Flashcards
glands in endocrine system
pancreas, adrenal glands, pituitary gland
roles of hormones
.chemical messengers
.bind to specific receptor on target cells to stimulate it to produce a response
how hormones act as chemical messengers
.produced by endocrine glands
.when stimulated, release hormones into the blood stream
.blood carries hormones to the target cells
.they attach to receptors on or inside target cells
.cells respond to hormone
non-steroid vs steroid hormone
.non-steroid is water soluble(hydrophilic) where as steroid are lipid soluble(hydrophobic)
.non-steroid cannont travel through phospholipid bilayer
.non-sterioid bind to suface membrane to activate second messenger
.steroid bind to receptor in the cytoplasm or nucleus forming a hormone-receptor complex that acts as a transcription factor
non = adrenaline
steroid = oestrogen
hormonal vs neuronal
.endo is slow, widespread and lasts long
.neuro is fast, localised and short lasting
adrenal glands
.in the kidney
.consists of the adrenal cortex(outer) and medulla(inner)
.cortex produces glands for steroid hormones
.medulla produces glands for non-steroid hormones
hormones produced by adrenal cortex
glucocorticoids-
.regulate metabolism via converting fats, protein and carbs into energy
.control blood pressure
.regulate immune response
.e.g. cortisol
mineralocorticoids-
.maintain blood pressure via balancing salt and water in blood
.e.g. aldosterone
androgens-
.regulation of sexual charateristics and cell growth
.e.g. testosterone
hormones produced by adrenal medulla
catecholamines-
.prepare body for stressful/dangerous situations
.e.g. adrenaline and noradrenaline
adrenaline effects
.increases heart rate , blood pressure and blood flow
.increases blood glucose levels, breathing rate and dilated bronchioles
noradrenaline
.increases heart rate
.expands air passages
.dilates pupils
.narrows blood vessels in organs
role of pancreas as endocrine gland
.contains islet of langerhans which contains alpha and beta cells
.beta scretes insulin
.alpha scretes glucagon
why is maintaining glucose important
.essential for respiration
.extreme levels cause osmotic imbalanced and cause cell death
when glucose levels are high
.inhibition of alpha cells
.beta cells release insulin
.insulin increase permeability of cells to glucose
.increased glucose breakdown for energy production
.glycogenesis occurs
when glucose levels are low
.inhibition of beta cells
.decrease in glucose breakdown
.glycogen is conveted back into glucose in liver cells
.glucose is produce from amino acids and fats in liver
control of insulin secretion
.glucose enter beta cell via transport proteins
.increased respiration produces more ATP
.ATP cause potassium ion channels to close
.causing increase in potassium ion conc inside cell
.rise in potassium levels lead to depolarisation opening calcium ion channels
.calcium ion influx stimulates insulin release via exocytosis
type 1 diabetes
.autoimmune disease destroying beta cells
.leads to no insulin production
.and so high glucose concentration
type 2 diabetes
.when beta cells dont produce enough insulin or cells resist insulin
fight or flight response
.autonomic NS detect threat and sends signal to hypothalamus
.hypothalamus activates sympathetic NS sending electrical impulses to glands and muscles
.sympathetic NS triggers secretion of adrenaline and noradrenaline fron adrenal medulla
.hypothalamus triggers the release ACTH
.ACTH travels via bloodsteam to adrenal cortex stimulating it to release other hormones
adrenaline as and example of the second messenger model
.adrenaline bind to complementary receptor on liver cell surface membrane
.causing the protein to change shape activating G protein
.G protein activates adenyl cyclase
.adenyl cyclase converts ATP into cAMP
.cAMP acts as an second messenger activating proteins to activate enzymes that catalyse the breakdown of glycogen into glucose
