GI 3 Flashcards
What two forms of energy can the brain use?
Glucose
Ketone bodies
4 types of cells in the endocrine pancreas and what they release
Beta cells: insulin Alpha cells: glucagon Delta cells: somatostatin PP cells: pancreatic polypeptide Epsilon cells: ghrelin
Actions of insulin
Increases uptake of glucose by target cells (muscle, adipose)
Promotes formation of glycogen in muscle and liver
Inhibits glycogenolysis
Normal blood glucose level
About 90 mg/100mL
Fasting must be above 60ml/100mL
Must be below 110mg/100mL
Type 1 diabetes
Autoimmune destruction of pancreatic cells
What causes the desensitization of the insulin receptors in T2D?
Inflammation in obesity
Why does the beta cell fail?
Chronic hyperglycemia and high circulating free fatty acids can cause glucotoxicity and lipotoxicity
There is also an oversecretion of insulin to compensate for insulin resistance
Macrovascular complications of diabetes
Stroke Heart disease Hypertension Peripheral vascular disease Foot problems
Microvascular complications of diabetes
Diabetic eye disease
Renal disease
Erectile dysfunction
Peripheral neuropathy
Generally, what are incretins?
Released from the small intestine
Cause more release of insulin in response to glucose
GLP-1
Incretin hormone Released from L cells in ileum and colon Stimulates insulin from beta cells in a glucose-dependent manner Inhibits gastric emptying Reduces food intake and body weight Inhibits glucagon secretion from alpha cells Deficient in T2D Promotes beta cell mass
GIP
Incretin hormone
Released from K cells in duodenum
Stimulates insulin from beta cells in a glucose dependent manner
Minimal effects on gastric emptying
No significant effects on satiety or body weight
Does not appear to inhibit glucagon secretion from alpha cells
Normal levels by decreased responsiveness in T2D
What enzyme degrades GLP-1?
DPP-4
Exenatide
Very similar to GLP-1 but is not degraded by DPP-4
Stimulates insulin secretion only when blood glucose concentrations are elevated
Suppression of postprandial glucagon secretion
Slowing of gastric emptying
DPP4 inhibitors
Good because they only block this one enzyme that does one function
Reduces fasting and postprandial glucose
Decrease glucagon response to ingested meal
