Metabolic States of the body

(T or F) - Our bodies sense the nutrient stores in our bodies and control the uptake of disaccharides, amino acids, monoglycerides and free fatty acids accordingly

False; Our bodies have evolved to absorb all nutrients that enter our body

Absorption Pathway (slide 5) for Amino acids, glucose, and fatty acids

Amino acids

• Catabolic

  • body proteins → amino acids

  • amino acids → urea → urinary excretion

  • metabolic fuel

• Anabolic

What do brains primarily use for fuel and what is the exception?

• can only really use glucose for fuels

• only exception is ketoacids during “starvation”

• brain cannot store glucose reserves

What is the importance of food intake being intermittent?

• body shuttles energy stores between ingested nutrients, stored forms, and circulating fuels

  • for - maintaining relatively constant supply of energy for all the cells of the body and especially for the brain

What are the two metabolic states of the body and their features?

Absorptive

• anabolic rxns> catabolic rxns

• Fed state (eating)

• Glucose is plentiful and serves as main energy source

Postabsorptive state

• Catabolic rxns >anabolic reactions

• Fasting state

• Endogenous energy stores mobilized to provide energy

Describe the glucose reactions in the body

Anabolic

• Glycogenesis

  • glucose → glycogen

  • decrease blood glucose

Catabolic

• Glycogenolysis

  • glycogen → glucose

  • increase blood glucose

• Gluconeogenesis

  • amino acids → glucose

  • increase blood glucose

Describe the protein reactions in the body

Catabolic

• Protein synthesis

  • amino acids → proteins

  • decrease blood amino acids

Anabolic

• Protein degradation

  • proteins → amino acids

  • increase blood amino acids

Describe the fat reactions in the body

Catabolic

• Fat synthesis

  • fatty acids and glycerol → triglycerides

  • decrease blood fatty acids

Anabolic

• Fat breakdown (lipolysis or Fat degradation)

  • triglycerides → fatty acids and glycerol

  • increase blood fatty acids