Macro #4: Health and Diabetes Flashcards
Two hormones that control blood glucose levels at rest
- Insulin
- Glucagon
Insulin
Hormone that lowers blood glucose. Released from beta cells of the pancreas
Function of insulin
Binds to insulin receptor on the surface of skeletal muscle; causing a translocation of GLUT4 to the plasma membrane
Glycogenesis
The synthesis of glycogen from glucose
Glucagon
Hormone that raises blood glucose and is released from alpha cells from the pancreas. Stimulates breakdown of liver glycogen
Glucagon and gluconeogenesis
Glucagon stimulates gluconeogenesis (synthesis of glucose from non-CHO sources) because glucagon is trying to raise blood glucose levels so it will do it anyway it can
Glucogenic substrates
Pyruvate
Lactate
Amino acids
Glycerol from TG
Glucose breakdown at rest
At rest, output of glucose from the liver occurs from 60% glycogenolysis (breaking down glycogen to glucose) and 40% gluconeogenesis (creating glucose from not CHO sources)
How can gluconeogenesis increase?
- Starvation or skipping meals
- Prolonged low CHO intake
- During exercise when glycogen becomes depleted
All reasons why the body doesn’t use glucose and has to create glucose from non CHO sources
Acinar Cells
Exocrine functions that release pancreatic juices (95% of cells)
Islet of Langerhans
Endocrine functions that produce alpha and beta cells (2-5% of cells)
Beta Cells
Releases insulin (which has endocrine features)
Alpha Cells
Releases glucagon (which has endocrine features)
What type of reaction is insulin?
Anebolic reation (putting things together) when glucose enters the skeletal muscle
What type of reaction is glucagon?
Catabolic (taking things apart) by breaking down glycogen into glucose to put into the bloodstream
How is high blood glucose regulated?
Beta-cells release insulin into circulation, which then
1. increases glucose to be uptaken into cells through GLUT4 and 2. Glycogenesis (glucose is synthesized into glycogen in the liver/muscle)
All to reduces glucose from the blood
How is low blood glucose regulated?
Alpha-cells secrete glucagon into circulation, which then 1. causes glycogenolysis in the liver and muscle to increase (breaking down glycogen into glucose) and
2. increases gluconeogenesis (the creating of glucose from non CHO products) which deposits monosaccharides of glucose into the bloodstream
Diabetes Mellitus (DM)
A group of metabolic diseases characterized by high blood glucose (hyperglycemia)
Hyperglycemia
high blood glucose
Hypoglycemia
Low blood sugar that can cause loss of consciousness and even death
Type 1 Diabetes
Diabetes that you are born with (5% of diabetes cases)
How does Type 1 Diabetes occur
Beta cells are destroyed so they are not secreting insulin. This means that GLUT4 is not removing glucose from blood into muscle and glucose is not being synthesized into glycogen. Blood glucose gets too high and insulin isn’t there to bring it down
Type 2 Diabetes
Diabetes that is induced over time (90-95%)
How does Type 2 Diabetes to occur?
Glucose levels in the blood are chronically high so insulin is trying to bring it down but can’t because the insulin receptors are damaged and aren’t allowing the glucose to be absorbed into the blood
