Hormones Flashcards
define the term endocrine glands
groups of cells that are specialised to secrete hormones
what are hormones
chemical messengers
what are the specific receptors that hormones bind to
target cells
why is a hormone called a first messanger
it carries the chemical message from the endocrine gland to the receptor on the target cell
why is the signalling molecule called a second messenger
carries the chemical message from the receptor to other pars of the cell
describe the effect of adrenaline when it is released
adrenaline is a first messenger
binds to target cells
activates enzyme called adenylyl cyclase
this catalyses the production of the second messenger called cAMP from ATP
this activates a cascade of enzyme reactions
what type of hormones does the cortex of the adrenal glands secrete and what do they do
steroid hormones (cortisol and aldosterone)
breakdown of proteins and fats into glucose, increases blood volume and pressure , suppresses the immune system
what type of hormones does the medulla of the adrenal glands secrete and what is their effect
catecholamine hormones, increase breathing and heart rate so cells break down glycogen
describe the histology of the pancreas
the areas of the pancreas that contain endocrine tissue are called the islets of Langerhans, made up of alpha and beta cells
how would you identify islets of Langerhans on a microscope
paler patches amongst other cells
what endocrine gland controls blood glucose conc
pancreas
what secretes insulin
beta cells in the Islets of Langerhans
what secretes glucagon
alpha cells in the Islets of Langerhans
how does insulin lower blood glucose conc
increases permeability of liver and muscle cells to glucose
activates enzymes that convert glucose into glycogen in a process called glycogenesis
how does glucagon increase blood glucose conc
activates enzymes that breaks down glycogen called glycogenolysis
also promotes the formation of glucose from glycerol and amino acids in a process called gluconeogenesis
