Human Physiology Final - Glucose Homeostasis

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(Anabolic/Catabolic) pathways predominate during the absorptive state

Anabolic
Major hormones during absorptive state
- Insulin
- Growth hormone
(Anabolic/Catabolic) pathways predominate during the post absorptive state

Catabolic
The majority of ingested CHO is digested and absorbed in ______________________

Upper 20% of small intestine
Digestion of CHO begins where?

Mouth (salivary amylase)
3 Glut transporters expressed in GI epithelial cells
- SGLT 1
- Glut 5
- Glut 2
SGLT 1
- Luminal membrane of GI epithelial cells
- Co-transport Na and glucose or galactose into epithelial cell
Glut 5
- Luminal membrane of GI epithelial cells
- Transports fructose into epithelial cells
Glut 2
- Basal membrane of GI epithelial cells
- Transports monosaccharides out of GI epithelial cells into interstitial space
Glucose enters liver by facilitated transport through ________

Glut 2 transporters
Increase in plasma blood glucose --> Pathway in liver
- Increased glucose
- Enters hepatocytes through GLUT2 transporters
- Glucose ---(glucokinase)---> G6P
- 2 fates of G6P: G6P ---> glycogen synthesis (enhanced by insulin); G6P ---> triglyceride storage
Increase in plasma blood glucose --> Pathway and effects in beta cells of pancreas
- Glucose enters beta cells through GLUT2
- Glycolysis + krebs cycle, etc.
- Increased ATP
- ATP sensitive K channels close --> membrane depolarization
- V-gated Ca channels open
- Influx of calcium into the cell; calcium induced calcium release
- Fusion of insulin containing secretory vesicles to membrane
- Insulin released
Most potent stimulator of insulin secretion?

Glucose
Insulin (stimulates/inhibits) hepatic gluconeogenesis and glycogenolysis and (stimulates/inhibits) glycogenesis
- Inhibits
- Stimulates
Insulin (stimulates/inhibits) glycogen synthesis by (activating/deactivating) glucokinase and glycogen synthase
- Stimulates
- Activating
Insulin (stimulates/inhibits) glycogen phosphorylase activity

Inhibits
Insulin (stimulates/inhibits) G-6-phosphatase

Inhibits
Insulin (stimulates/inhibits) glucose uptake into skeletal muscle cells and adipocytes

Stimulates
Insulin stimulates glucose uptake into skeletal muscle cells and adipocytes via _______ transporters

GLUT4
GLUT4 Translocation Pathway in skeletal muscle cells and adipocytes
- Insulin binds to its protein kinase receptor
- Recruits and phosphorylates IRS
- IRS stimulates PI3K
- PI3K converts PIP2 to PIP3
- PIP3, with PDK, activates Akt (protein kinase B)
- Akt phosphorylates AS160
- This inhibits AS160, allowing GLUT4 to move to the membrane and bring glucose into the cell
Muscle contraction (exercise) (stimulates/inhibits) GLUT4 translocation into muscle membrane

Stimulates
Mechanism by which exercise stimulates glucose uptake
- Exercise stimulates AMPK (AMP activated kinase)
- AMPK stimulates phosphorylation of AS160
- Promotes GLUT4 translocation
Fat digestion and absorption occurs almost entirely in _________

the small intestine
Chylomicrons

Lipoproteins that transport dietary triglycerides and cholesterol from small intestine to body's cells
_______ breaks down chylomicrons

lipoprotein lipase (LPL)
VLDL

Transport triglycerides and cholesterol from liver to body's cells
VLDL degraded into ______, which is degraded into ________
- IDL
- LDL
LDL

lipoproteins that carry cholesterol to the body's cells
HDL

lipoproteins that carry cholesterol back from tissues and organs to the liver where it will be degraded or recycled
Major hormones of post absorptive state
- Glucagon
- Cortisol
- Epinephrine
- NE
- GH
Goal of post absorptive state

Increase blood glucose and spare it for the brain

Author

jdwein39

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Card Set

Human Physiology Final - Glucose Homeostasis

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Updated

2014-05-05T00:26:27Z

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