BIOL 2420 Lecture Notes - Lecture 4: Portal Vein, Adipose Tissue, Skeletal Muscle
26 Apr 2018
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Unit 10 – Lecture 4
Fed State Metabolism
- following ingestion of nutrients
- anabolic
o absorbed nutrients used for energy, synthesis, and storage
Carbohydrates Make ATP
- glucose
o primary substrate for ATP production
o absorbed from the intestine, enter the hepatic portal vein and is taken directly to the
liver
▪ about 30% of all ingested glucose is metabolized in the liver
▪ remaining 70% continues in the bloodstream for distribution to the brain,
muscles, and other organs and tissues
o moves from interstitial fluid into cells by membrane GLUT transporters
o most absorbed from a meal goes immediately into glycolysis and TCA cycle to make ATP
o some is used by the liver for lipoprotein synthesis
o glucose not required for energy synthesis is stored either as glycogen or fat
▪ ability of the human body to store glycogen is limited, therefore most excess
glucose is converted to triglycerides and stored in adipose tissue
Glucose Storage
- glycogen
o large polysaccharide
o main storage form of glucose in the body
o a glucose polymer
▪ created by linking many individual glucose molecules together into a branching
chain
o single glycogen particle in the cytoplasm can contain up to 55,000 linked glucose
molecules
o glycogen granules occur as insoluble inclusions in the cytosol of cells
o is found in all cells of the body
▪ exception: liver and skeletal muscles contain especially high concentrations
▪ in skeletal muscle
• glycogen provides a ready energy source for muscle contraction
▪ in liver
• glycogen acts as the main source of glucose for the body in periods
between meals
o in the fasted state
• estimated that the liver keeps ~4 hours supply of glucose stored as
glycogen
Amino Acids Make Proteins
- most amino acids absorbed from a meal go to the tissues for protein synthesis
- amino acids
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Fed state metabolism following ingestion of nutrients anabolic: absorbed nutrients used for energy, synthesis, and storage. Hdl level in plasma: used to predict risk of developing atherosclerosis, low hdl <40 mg/dl is associated with higher risk of developing chd, non-hdl cholesterol value (total cholesterol minus hdl) as a better indicator of chd risk. Improved diet, smoking cessation, exercise: very effective in improving lipid profiles, can be difficult for patients to implement and sustain. Drugs known as bile acid sequestrants: bind to bile acids in the intestinal lumen, prevent their reabsorption and increasing cholesterol excretion. In the absence of recycled bile salts, the liver increases bile acid synthesis from cholesterol, thereby decreasing plasma cholesterol when hepatic ldl receptors import cholesterol from the blood. Drug free way to accomplish the same result is to eat more soluble fiber (indigestible fiber found in oatmeal: soluble fiber traps bile salts and increases their excretion in the feces.
