Lecture 62 - Endocrine 4 Flashcards
what do pancreatic islets look like on histology
small areas of diluted stain
what are the four types of cells within pancreatic islets
- alpha cells
- beta cells
- D cells
- F cells
what do alpha cells produce? what is its job?
glucagon; increase blood glucose
what do beta cells produce? what is its job?
insulin; decrease blood glucose
what do D cells produce? what is its job?
somatostatin; increases blood glucose
what do F cells produce? what is its job?
pancreatic polypeptide; increases blood glucose
describe the structure of insulin
2 chains - A (short) and B (long) - connected by disulfide bonds
feline insulin is most similar to ____
bovine
“cats are like cows”
canine insulin is most similar to ____
porcine
“pups are like pigs”
summarize insulin control of blood glucose in 5 steps
- eat food
- blood glucose increases
- insulin released from the pancreas
- glucose uptake by cells
- blood glucose decreases
acute phase refers to
release of stored insulin
chronic phase refers to
release of newly synthesized insulin
what are the two theories of insulin secretion
- glucose interacts with cell surface receptors and triggers the intracellular secondary messenger system for exocytosis
- the above process is done intracellularly after glucose is in the cell
what is C-peptide
byproduct of insulin when proinsulin is split
what is the most common cell type in the pancreatic islet?
beta
T/F: canine and bovine insulin are most similar to each other
FALSE
T/F: insulin is an anabolic hormone
TRUE
define anabolism
creation of larger molecules from smaller ones
why is the liver important in the anabolic process
close proximity to the pancreas via the portal vein
what is the storage form of glucose
glycogen
what is the storage form of fatty acids
triglycerides
what is the storage form of amino acids
protein
what does insulin initiate (“GO”)
- glucose uptake by cells
- glycolysis
- glycogen synthesis
- protein synthesis
- intracellular ion movement
what does insulin inhibit (“STOP”)
- gluconeogenesis
- glycogenolysis
- lipolysis
- ketogenesis
- proteolysis
protein hormones are composed of ___ and their receptors are at the ____
amino acids; cell surface
what are GLUTs
glucose transporters that facilitate glucose uptake
an 8y/o spayed female mini schnauzer presents to the clinic for PU/PD, weight loss but good appetite. what is a good differential?
diabetes mellitus
presence of glucose in the blood is
hyperglycemia
presence of glucose spillover in the urine is
glucosuria
absolute deficiency of insulin is similar to what in humans
type I diabetes
insulin resistance (insulin produced but cells don’t respond) is similar to what in humans
type II diabetes
T/F: insulin has a biphasic release pattern
TRUE
what effect does insulin have on ketone synthesis
decreases
what are the counter-regulatory hormones to insulin
- progesterone
- growth hormone
- epinephrine
- cortisol
- glucagon
what other diseases could increase counter-regulatory hormones and lead to insulin resistance
- pancreatitis
- Cushing’s
- diestrus or pregnancy
- acromegaly
what are the 4 functions of glucagon?
- decreased glycogen synthesis
- increased glycogenolysis
- increased gluconeogenesis
- increased lipolysis
factors affecting insulin stimulation
- high blood glucose
- amino acids
- fatty acids
- glucagon
- incretins
factors affecting insulin inhibition
- low blood glucose
- catecholamines
- somatostatin
- pancreatic polypeptide
T/F: counter-regulatory hormones have a blood glucose-lowering effect
FALSE
The most important insulin secretagogue in cats is
protein
