Endocrine Control Of Fuel Delivery To Cells Flashcards
Why do we need food
Provide fuel to supply energy for work to perform biochemical reactions
To supply basic building blocks
How long will the total circulation concentration of glucose, fatty acids and tags in normal individual provide for energy requirements
1-2 hours
How long will an average individuals supply of glycogen stored in the liver and muscle ener for
8 hours
Why does the body proceed to break down other substances instead of glucose in starvation
To ensure the brain and heart maintain energy supply
When are these stores affected
Growth After feeding Between meals Starvation Disease Pregnancy
What endocrine structurs are imp for metabolic regulations
Pancreatic endocrine structures Anterior pituitary gland Liver Andrenal cortex Adrenal medulla Thyroid gland
What are islets of langehans
The endocrine sec part of the pancreas
Acinar cells
1-2% of pancreatic cells
3 types of sec cells
What are the 3 secretory cells of the islets of langehans
Alpha cells - glucagon
Beta cells - insulin
Alpha cells - somatostatin
What does insulin favour
Anabolism Stimulate conversion - Glucose to glycogen FFA to tags AAS to proteins
Is insulin a fed or hungry state hormone
Fed state when a lot of nutrients circulating
What does glucagon favour
Stimulating conversion of glycogen to glucose etc
Hungry state
What is insulin synthesised as and how is it converted to
Synthesised as pro hormone which is protealytic ally clipped to release mature peptide in secretion granules
What are he short lives of insuli and glucagon
Short
Insulin - 30 mins
Glucagon - 10 mins
What dos insulin stimulate
Glucose uptake by muscle and adipose tissue leading to reduction blood glucose levels
Causes GLUT4 transporters to be inserted in plasma mem from intracellular stores
What are the effects of insulin
Insulin activates the enzymes in liver and muscle which converts glucose to glycogen
In muscle and fat it stimulates the incorporation of amino acids into protein
Stimulates uptake of glucose from blood
Suppresses lipolysis while promote lipogenesis
Anabolic home one
What factors promote insulin secretion
Increase circulatory levels of plasma concentration of Glucose
Increase amino acids arginine and leu
Increase parasymp innervation
Increase glucagon
Increase of cck, gastric
What are the inhibiting factors of secretion of insulin
Decrease glucose
Increase symp activity
Increase somatostatin release
Increase cortisol
Does oral or intravenous infusion glucose induce a hater secretion of insulin
Oral
What are incretin hormones
Released form intestine
Glucose like peptide - 1
Glucose dept insulinotropic peptide
What do the incretin hormones do
Sec by intestine and stimulate insulin secretion of pancreatic cells
Feed forward mechanism
Regulate appetite
Only potentiate insulin release when plamsa glucose raised
Explain type 1 diabetes mellitus
Childhood onset
Little/no insulin
Affects 10-20% diabetics Defect beta cells function Ketosis develops Insulin injections Symptoms rapid development
Explain type 2 diabetes mellitus
Adult onset common children now too Insulin secretion may be normal Affect 80-90% Defect in insulin sensitivity Ketones rare Diet and exercise and oral drugs for treatment Symptoms slow development
How is lack of insulin or impaired cellular repsonse to insulin tested
Oral glucose tolerance test
What are the effects of severe diabetes
Very high plasma concentration of glucose after a meal
Glyosuria
Increased lipolysis to break fa for energy instead of glucose
Metab fa and generate a lot of acetyl coA gives ketone bodies and ketosis
Lower blood ph metab acidosis
What are the effects of glucagon
Increases hepatic glycogenolysis blood glucose rises
Decrease hepatic glycogen syn
Increases hepatic glycogenolysis
Decreases amino acid uptake in muscle increase as uptake by liver
Catabolic
What so the control of glucagon release
Decrease blood glucose increase glucagon secretion
Amino acids like arginine increase glucagon if protein high stim release of insulin and glucagon
If there is a decrease of fatty acid circulation there is an increase of glucagon secretion
Sympathetic nerve activity stimulates release during exercise
What are the effects of exercise
Increased sympathetic stimulation
Increases glucagon and decreases insulin
Increases adrenaline
Net effect to increase glucose and fuel output and suppress storage
What is metabolism
Refers to all the chemical reactions that occur in the body
Anabolism and catabolism and transformation of proteins carbs and fat
