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
the regulation of blood glucose conc,. is an example of what
negative feedback
when beta cells detect high blood conc. changes within the cell result in secretion of insulin how does this work
more glucose enters beta cells by facilitated diffusion
this causes rate of respiration to increase, making more ATP
potassium ion channels then close
the ions cant leave so the cell becomes less negative and membrane becomes depolarised
calcium channels then open and ions diffuse into cell
vesicles then fuse with membrane and releases insulin via exocytosis
what is type 1 diabetes
auto-immune disease where the body attacks beta cells so no insulin is produced and kidneys cannot reabsorb the glucose so some is excreted in the urine
how is type 1 diabetes treated
with insulin therapy, for some people this includes an insulin pump
some people have been treated with beta cell transplants
carefully planned diet and regular exercise
what is type 2 diabetes
when beta cells don’t produce enough insulin or cells do not respond properly to insulin
how is type 2 diabetes treated
regular exercise and a balanced healthy diet
or medication
why would treating diabetes with GM bacteria be more beneficial
cheaper, larger quantities can be produced, make human insulin rather than having to extract insulin from animals like pigs, ethically better due to religion/ eating preferences
how would stem cells be used to treat diabetes
stem cells could grow into beta cells which would then be implanted into the pancreas allowing them to produce insulin
