Pancreas Flashcards
What is leptin
A hormone released by fat stores which depresses feeding activity
What is the normal range of blood glucose
4.6-6.3mM (80-120mg/dl)
What do alpha cells produce
Glucagon
what do Beta cells prduce
Insulin
What do gamme cells prduce
Somatostatin
What do F cells produce
pancreatic polypeptide
What stimulates insulin secretion
Glucose and amino acids
What often happens to excess protein
Stored as fat
What receptor type does insulin bind to
Tyrosine kinase
Where are GLUT-1 receptors typically found
Brain, kidney and red blood cells
Where are GLUT-2 receptors typically found
B-cells of pancreas and liver
What important ion channel plays a big role in insulin release
K+ atp channel
Where are GLUT-3 receptors typically found
Widespread
What enzymes does insulin activate/inhibit to alter glycogen stores
Activate - glycogen synthase
Inhibit - glycogen phosphorylase
What does insulin do in the liver?
inhibits gluconeogenesis
What are the stimuli for insulin release
Increased BG Increased AA Glucagon (say why) Incretin hormone (gastrin, CCK, GLP-1, GIP) Vagal nerve activity
What inhibits insulin release
Low BG
Somatostatin
Sympathetic effects
Stress (hypoxia)
Half life of insulin and where is it degraded
5 mins
liver and kidneys
What destroys the insulin receptors
Insulin protease
What glucose receptors does the liver have
Glut-2
Does insulin effect the glucose uptake by the liver
Yes - it enhances it but the tissue does not need it
What are the glucose counter-regulatory hormones
Glucagon
epinephrine
cortisol
growth hormone
What are the receptors for glucagon
Adenylate cyclase (g protein)
What are the 3 big effects fo glucagon
Increased glycogenolysis
Increased gluconeogensis
Formation of ketones
What effects does high levels of AA have on glucagon and why
increases it because if it didn’t then the insulin released because of the high AA content would take all the glucose aswell and the person would become hypoglycaemic
What are the stimulus that increases glucagon release
Low BG High AA sympathetic innervation and epinephrine Cortisol Stress (exercise/infection) Parasymphathetic (but less than insulin)
what are stimuli that inhibit glucagon release
High glucose
FFA ketones
Somatostatin and Insulin
What does epinephrine promote
Muscle glycogenolysis
Liver glycogenolysis
gluconeogenesis
lipolysis
What does cortisol promote
gluconeogenesis (using AA from protein catabolism)
Inhibition of glucose uptake
lipolysis
protein catabolism
What does GH promote
Gluconeogenesis
inhibition of glucose uptake
Lipolysis
What is the main pancreatic function of somatostatin
Slows down absorption of nutrients to prevent exaggerated peaks in plasma concentrations
What effect does somatostatin have on glucagon and insulin
Strongly suppresses them
