Hormonal communication 5.4 Flashcards
describe what is the endocrine system
made up of endocrine glands and hormones and made up of non-steroid and steroid hormones
what are hormones
released into blood directly and travel around the whole body and bind to specific receptors on target cells to produce a response
what are non-steroid hormones
proteins like insulin that cant pass through the cell membrane so bind to receptors on the cell surface of target cells
what are steroid hormones
lipids that can pass through cell membrane of target cells
produced by adrenal cortex
describe the secretion and detection of hormones
hormone is the first messenger and binds to specific receptors on cell surface
membrane of target cells
activates adenyl cyclase an enzyme
cAMP activates a cascade of enzyme controlled reactions
what are the two parts of the adrenal gland
adrenal cortex
adrenal medulla
describe the adrenal cortex
secretes steroid hormones - like cortisol when stressed
inc the uptake of Na+ and H2O by kidneys
suppress immune system
describe the adrenal medulla
secretes adrenaline- when stressed
inc. heart rate and breathing rate
breaks down glycogen into glucose
vasoconstriction so blood is diverted from brain and muscles
describe the pancreas
made of Islets of Langerhans
B-cells: secrete insulin
a-cell: secrete glucagon
acinar cells: release hydrolytic enzymes
what are acinar cells
produce digestive enzymes into the small intestine
what does sodium hydrogencarbonate do
neutralise stomach acid in the pancreas
when does blood glucose conc. increase
when eating food containing carbohydrates
when does blood glucose conc. fall
after exercise , more glucose used in respiration during exercise to release energy
when glucose conc. is too high what happens
insulin binds to specific receptors on liver and muscle cells
inc. permeability –> cells take up more glucose
glycogenesis - glucose to glycogen
glycogen stored as an energy source
inc. rate of respiration
when glucose conc. is too low what happens
glucagon binds to receptors on liver cells only
glycogenolysis - glycogen to glucose
gluconeogenesis - glycerol and AA to glucose
decreases rate of respiration
how is insulin regulated
B-cells contain insulin in vesicles
when blood glucose conc. is high, more glucose enters the B-cells by facilitated diffusion
more ATP made, triggers K+ channels in plasma membrane to close
inside is more -ve than outside
depolarisation triggers Ca2+ channels to open, Ca2+ diffuse into B-cell
causes vesicles to fuse with B-cell plasma membrane releasing insulin via exocytosis
what is Type 1 diabetes and who can get it
autoimmune disease where body cells attack B-cells
insulin not produced
young adults or children
higher risk with family history
with type 1 diabetes what happens after you eat
blood glucose conc. stays high
with type 1 diabetes what happens to the kidneys
cant reabsorb all glucose
excreted as urine
symptoms of type 1 diabetes
thirsty
frequent urination
weight loss
treatments for type 1 diabetes
insulin injections regularly
islet cells transplant
insulin pump
what is type 2 diabetes and who can get it
B-cells dont produce enough insulin or body cells dont respond to insulin because insulin receptors dont work properly
blood glucose conc. is higher than normal
obesity or from african/asian ethnic groups or family history
symptoms of type 2 diabetes
hypoglycemia - low blood sugar
hyperglycemia - high blood sugar
weight gain
frequent thirst and urination
treatments for type 2 diabetes
low sugar and salt diet
exercise
medication like metformin
what other ways can you obtain insulin from to cure diabetes
genetically modified bacteria or stem cells
benefits of using GM bacteria to cure diabetes
cheaper
make large amounts
make human insulin instead of animals which for vegans/vegetarians or religious ppl they prefer this
why is it beneficial that GM bacteria can produce human insulin
less likely to be rejected rather than animal insulin
vegetarians and vegans prefer using human insulin
religious reasons
what are the benefits of using stem cells to cure diabetes
- pluripotent
- produce B-cells
describe the structure of the adrenal glands
- adrenal medulla :
. secretes adrenaline - adrenal cortex:
Secretes aldosterone
what does aldosterone help regulate
helps the kidneys regulate blood pressure