Pancreas Flashcards
Human metabolic processes outside cell vs inside cell
Outside the cell:
Keep blood glucose levels within a constant range during the fed, fasted, and starved state.
- Inside the cell:
Maintain intra-cellular ATP and provide energy for high energy requiring tissues and anabolic processes
Normal fasting BG: 70-100 mg/dl
Normal BG 2h after meal:
Normal fasting BG: 70-100 mg/dl
Normal BG 2h after meal: <139 mg/dl
Blood glucose is kept within a narrow range via
Blood glucose is kept within a narrow range via tight hormonal regulation
glucose pathway after a meal
- glucose enters blood through intestine
- insulin is secreted
- glucose uptake by liver, adipose , and skeletal m.
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explain cahilll diagram based on phases
When awake, we eat approx. every 4 hours. We keep ourselves in Phase I of the Cahill Diagram.
Glucose supply between 4 – 12 hours (i.e during the last half of nocturnal sleep) comes from glucose stored as glycogen from the liver (Phase II), Glycogenolysis.
Beyond 12 hours, glucose has to be newly made by mobilizing stored energy rich substrates. This occurs mainly in the liver (Phase III), Gluconeogenesis.
The main hormone regulating metabolism during fasting is
The main hormone regulating metabolism during fasting is Glucagon
Main energy carriers in nutrition
Carbohydrates: approx. 4.7 kcal/g, main source of nutritional energy
50% of all calories in diet
Lipids: approx. 9 kcal/g, 20-30% or all calories in diet
Proteins: approx. 4.7 kcal/g, 20-30% of all calories in diet
Nucleotides: have potential caloric value, but do not significantly contribute to energy (ATP) production.
Ethanol: approx. 7 kcal/g
Digestive phase: Metabolism orchestrated almost entirely by
Digestive phase: Metabolism orchestrated almost entirely byinsulin.
Fating phase metabolism is regulated by
Glucagonandcatecholamines(epinephrine, norepinephrine)
what two hormones PARTIALLY contribute to fasting phase/
Growth hormone and cortisol also contribute somewhat to fasting-phase metabolism.
alphas and beta cells of pancreas
Beta cells produce insulin which induces uptake of blood glucose
Alpha cells produce glucagon (counter-regulation) which induces gluconeogenesis and glycogenolysis, leading to secretion of glucose and increase blood glucose
delta cells of pancreas
Delta cells produce somatostatin which inhibits the influx of glucose and amino acids; and decrease gastric secretion
insulin action in the liver
Insulin action promotes nutrient storage.
In the liver.
Insulin signaling through Akt2 activates glycogen synthase
decreases the transcription of gluconeogenic enzymes via inactivation of FOXO1.
Insulin effect on skeletal muscle,
In skeletal muscle, insulin activates glucose uptake and glycogen synthesis.
Skeletal muscle will also take up FAs for oxidation.
insulin effect on adipose tissue
In adipose tissue, insulin inhibits lipolysis & promotes glucose uptake.
