Lecture 16: Endocrine Pancreas Flashcards
what are the 4 musketeers of glycemic control
- Liver
- Adipose tissue
- pancreas
- muscle
all work together to regulate blood glucose levels
islands of endocrine cells in a sea of exocrine tissue
Islets of langerhans
main endocrine cell types
- β cells (60%)
- α cells (25%)
- δ (10%)
- gamma
- epsilon
Beta cells secrete what hormones
insulin and Amylin
alpha cells secrete what hormone
glucagon
increased blood glucose casuses a decrease in __________ and an increase in ___________
decreased glucagon
increased insulin
decreased blood glucose levels cause a ________ in glucagon and a ______ in insulin
increased glucagon
decreased insulin
amylin is a hormone secreted by _____ that acts on the CNS to ……
B cells, suppresses appetite
delta cells secrete what hormone and what does it do
Somatostatin, it inhibits digestive function, inhiits α and β cells
gamma cells secrete what and what does it do
Pancreatic polypeptide, inhibits gastric juices, appetite and food intake
Epsilon cells secrete what and what does it do
Ghrelin, appetite stimulating hormone
C-peptide is a marker of _____ production and ______ cell function
Insulin production and β cell function
food intake leads to an increase in….
- blood glucose concentration
- increased blood amino acid concentration
- increased GI hormones
- increased parasympathetic stimulation
sympathetic stimulation (and epinephrine) block ____ cells via α-adrenergic stimulation
β cells
insulin secretion leads to…
- decreased blood glucose
- decreased blood fatty acids
- decreased blood aas
- increased protein synthesis
- increased fuel storage
proinsulin is cleaved into ____ and _____
insulin and C-peptide
how does glucose stimulate insulin release?
excitation-secretion coupling in βcells
what are the steps of Excitation-secretion coupling in βcells
- glucose depolarizes cell membrane
- Glu enters via GLUT2
- Glucose+PO43- –> Glucose-6-phosphate
- G6P oxidation –> ATP
- ATP closes K channel
- decreased K flux depolarizes cell membrane
- Voltage gated Ca channels open
- Ca enters β cell
- Ca triggers exocytossi of insulin vesicles
- insulin is secreted into circulation
what are some other humor factors that stimulate insulin release (besides glucose)
- other sugars (fructose, mannose, ribose)
- amino acids (leucine, arginine)
- hormones (glucagon, secretin)
- drugs (sulfonylurea, theophylline)
- short chain fatty acids
- ketone bodies
carbohydrates ____ blood glucose and ____ storage
decrease blood glucose
increase storage
Lipids ____ blood fatty acids and ____ storage
decrease fatty acids
increase storage
proteins ____ blood amino acids and _____ storage
decrease, increase
GLUT____transports glucose across the BBB
GLUT 1
GLUT_____transports glucose in kidney and intestine
GLUT2
GLUT____transports glucose into neurons
GLUT3