chapter 67: metabolism of carbohydrates, and formation of atp guyton and hall, textbook of medical...

Unit Thirteen: Metabolism and Temperature Regulation

Chapter 67: Metabolism of Carbohydrates, and Formation of ATP

Guyton and Hall, Textbook of Medical Physiology, 12th edition

Metabolism of Carbohydrates

• Release of Energy from Foods and the Concept of“Free Energy”

a. Coupled reactionsb. Free energyc. ATP as the energy currency of the cell

Metabolism of Carbohydrates

• Release of Energy from Foods and the Concept of“Free Energy”

Fig. 67.1

Metabolism of Carbohydrates

• Release of Energy from Foods and the Concept of“Free Energy”

Fig. 67.2

Metabolism of Carbohydrates

• Central Role of Glucose in Cbh Metabolism

Metabolism of Carbohydrates

•Transport of Glucose Through the Cell Membrane

a. Via facilitated diffusionb. Active sodium-glucose co-transportc. Insulin increases the facilitated diffusion of glucosed. Immediate phosphorylation upon entry into cell

to form glucose-6-phosphatee. Can be used immediately or stored as glycogen in

the liver and skeletal muscle

Metabolism of Carbohydrates

• Glycogenesis-the Formation of Glycogen• Glycogenolysis-the Breakdown of Stored Glycogen

Fig. 67.4

Metabolism of Carbohydrates

• Release of Energy from Glucose by the GlycolyticPathway

Fig. 67.5 Glycolysis

Metabolism of Carbohydrates

• Conversion of Pyruvic Acid to Acetyl CoA

• Citric Acid Cycle

Fig. 67.6

Metabolism of Carbohydrates

• Formation of Large Quantities of ATP by Oxidationof Hydrogen-the Process of Oxidative Phosphorylation

Fig. 67.7

Metabolism of Carbohydrates

• Formation of Large Quantities of ATP by Oxidationof Hydrogen-the Process of Oxidative Phosphorylation

a. Chemiosmotic mechanism of the mitochondria toform ATP

b. Pumping of hydrogen ions into the outer chamber ofthe mitochondria, caused by the electron transportchain

c. Formation of ATP

Metabolism of Carbohydrates

• Energy Summary

a. During glycolysis, 4 ATPs are produced but a netgain of only 2 ATPs (two are needed to start the process); also generate 2 NADHs

b. During the transition rx, 2 NADHs are formedc. During each revolution of the citric acid cycle, one

ATP, 3 NADH, 1 FADH2

d. Generate a total of 38 ATP (3 per each NADH and 2 per each FADH2)

Metabolism of Carbohydrates

• Anaerobic Release of Energy (Fermentation)

a. Formation of lactic acidb. Reconversion of lactic acid to pyruvic acid when

oxygen becomes available again

Metabolism of Carbohydrates

• Release of Energy from Glucose by the PentosePhosphate Pathway

Fig. 67.8

Metabolism of Carbohydrates

• Gluconeogenesis- formation of carbohydrates fromproteins and fats

a. Regulation of gluconeogenesis

b. Effect of corticotropin and glucocorticoids

c. Blood glucose