Endocrine Pancreas Flashcards
What are the three main cell types in the pancreas
alpha, beta and delta cells
alpha cells in the pancreas secrete ______
glucagon
beta cells in the pancreas secrete
insulin and amylin
delta cells in the pancreas secrete
somatostatin
All the cells of the exocrine pancreas are located in which area
Islets of Langerhans
alpha cells are situated mainly in which area of the Islets of Langerhans
Core
Which glucose transporter is insulin dependent
GLUT4
Which glucose transporter is insulin independent
GLUT2
What effect does insulin have in the liver
- increased glycolysis
- increased protein synthesis
- increased amino acid uptake
What effect does insulin have in adipose
- inhibits hormone sensitive lipase
- promostes lipogenesis through lipoprotein lipase
- inhibits ketogenesis
What effect does insulin have in muscle
- increased glucose uptake
- increased glycogenesis
- increased protein synthesis
- increased amino acid uptake
What effect does glucagon have in the liver
- increased gluconeogenesis
- increased glycogenolysis
What effect does insulin have in adipose
-increases lipolysis
Effects of insulin deficiency on protein metabolism
- Less protein synthesis hence blood amino acid levels rise
- Amino acids catabolism is increased.
- Increased gluconeogenesis
Effects of insulin deficiency on fat metabolism
- Liver and other tissues the fatty acids are catabolized to acetyl-CoA.
- Some acetyl-CoA are catabolized (supply is ˃ than utilization)
- Excess acetyl-CoA is converted to ketone bodies
- Plasma concentration of TG, chylomicrons and FFA ↑and plasma is lipemic
- Plasma cholesterol level is ↑
How does insulin deficiency on fat metabolism
Increase in ketone bodies causes ketoacidosis
Characteristics of Type I diabetes mellitus
- insulin dependent
- destruction of beta cells
- usually starts in childhood
Characteristics of Type II diabetes mellitus
- insulin independent
- decreased secretion of insuiln
Why can obesity lead to Type II disbetes mellitus
Excess in take of food cause a continuous increase in insulin secretion which causes a down regulation of insulin receptors
What is the main stimulus for insulin release
glucose
Incretin has an effect on which organ
Intestine
Proinsulin is composed of what
An A chain, B chain and a C peptide
What is the clinical significance of C-peptide in insulin
It allows us to get an estimate of how much insulin in secreted from the beta cells
The B chain in insulin has receptor tyrosine kinase activity that leads to activation of which two second messenger pathways
PI3K and MAPK
Akt (PKB) activates what
- GLUT4 translocation
- protein phosphatases
- SREBP1C
How does amylin aid in Type II diabetes mellitus
amylin builds up in the beta cells and causes destruction of the cells
Proglucagon is converted into which two substances
Glucagon and Glucagon-like-peptide 1
Which stimulus increases Glucagon-like-peptide 1
Increased intestinal glucose
Glucagon is inhibited by
- hyperglyemia
2. somatostatin
Glucagon is activated by
- hypoglycemia
- epinephrine
- vagal stimulation
