Physiology
Textbooks
Boundless Anatomy and Physiology
Physiology Textbooks Boundless Anatomy and Physiology
Physiology Textbooks
Physiology

Chapter 23

Nutrition and Metabolism

Book Version 29
By Boundless
Boundless Anatomy and Physiology
Physiology
by Boundless
View the full table of contents
Section 1
Nutrition
Thumbnail
Digestive Systems

Animals use the organs of their digestive systems to extract important nutrients from food they consume, which can later be absorbed.

Thumbnail
Carbohydrates: Sources, Uses in the Body, and Dietary Requirements

Carbohydrates, which break down to glucose, are a major source of energy for humans, but are not an essential nutrient.

Thumbnail
Lipids: Sources, Uses in the Body, and Dietary Requirements

Fats store energy, facilitate absorption of fat-soluble vitamins, aid brain growth and development, and protect against many diseases.

Thumbnail
Proteins: Sources, Uses in the Body, and Dietary Requirements

Proteins are composed of 20 different amino acids, about half of which are essential, meaning they must be obtained from the diet.

Thumbnail
Food Requirements and Essential Nutrients

Essential nutrients are those that cannot be created by an animal's metabolism and need to be obtained from the diet.

Section 2
Carbohydrates
Thumbnail
Carbohydrate Molecules

Carbohydrates are essential macromolecules that are classified into three subtypes: monosaccharides, disaccharides, and polysaccharides.

Thumbnail
Importance of Carbohydrates

Carbohydrates are a major class of biological macromolecules that are an essential part of our diet and provide energy to the body.

Section 3
Lipids
Thumbnail
Lipid Molecules

Fats and oils, which may be saturated or unsaturated, can be unhealthy but also serve important functions for plants and animals.

Thumbnail
Phospholipids

Phospholipids are amphipathic molecules that make up the bilayer of the plasma membrane and keep the membrane fluid.

Thumbnail
Steroids

Steroids, like cholesterol, play roles in reproduction, absorption, metabolism regulation, and brain activity.

Section 4
Proteins
Thumbnail
Types and Functions of Proteins

Proteins perform many essential physiological functions, including catalyzing biochemical reactions.

Thumbnail
Amino Acids

An amino acid contains an amino group, a carboxyl group, and an R group, and it combines with other amino acids to form polypeptide chains.

Thumbnail
Protein Structure

Each successive level of protein folding ultimately contributes to its shape and therefore its function.

Section 5
Metabolic Reactions
Thumbnail
Breakdown of Pyruvate

After glycolysis, pyruvate is converted into acetyl CoA in order to enter the citric acid cycle.

Thumbnail
Citric Acid Cycle

The citric acid cycle is a series of reactions that produces two carbon dioxide molecules, one GTP/ATP, and reduced forms of NADH and FADH2.

Thumbnail
Importance of Glycolysis

Glycolysis is the first step in the breakdown of glucose to extract energy for cellular metabolism.

Thumbnail
Electron Transport Chain

The electron transport chain uses the electrons from electron carriers to create a chemical gradient that can be used to power oxidative phosphorylation.

Thumbnail
ATP Yield

The amount of energy (as ATP) gained from glucose catabolism varies across species and depends on other related cellular processes.

Thumbnail
Control of Catabolic Pathways

Catabolic pathways are controlled by enzymes, proteins, electron carriers, and pumps that ensure that the remaining reactions can proceed.

Thumbnail
Transforming Chemical Energy

Cellular respiration is the process of transforming chemical energy into forms usable by the cell or organism.

Section 6
Metabolism of Nutrients
Thumbnail
Connecting Other Sugars to Glucose Metabolism

Sugars, such as galactose, fructose, and glycogen, are catabolized into new products in order to enter the glycolytic pathway.

Thumbnail
Connecting Proteins to Glucose Metabolism

Excess amino acids are converted into molecules that can enter the pathways of glucose catabolism.

Section 7
Metabolic Body States
Thumbnail
Catabolic-Anabolic Steady State

Catabolic reactions that break complex molecules provide the energy needed by anabolic reactions to produce complex molecules.

Thumbnail
Absorptive State

When the gastrointestinal tract is full, anabolism exceeds catabolism; this is the absorptive state.

Thumbnail
Postabsorptive State

The post-absorptive state occurs around three to five hours after a meal has been completely digested and absorbed.

Section 8
Metabolism and the Liver
Thumbnail
Cholesterol Metabolism

One quarter of body cholesterol is produced by the liver, and 50% of this is reabsorbed back into the circulation via the small intestine.

Thumbnail
Regulation of Blood Cholesterol Levels

Cholesterol is transported through the blood by lipoproteins which direct cholesterol to where it is needed.

Section 9
Metabolic Rate and Thermoregulation
Thumbnail
Homeostatic Process

Homeostatic processes ensure a constant internal environment by various mechanisms working in combination to maintain set points.

Thumbnail
Homeostasis: Thermoregulation

Animals use different modes of thermoregulation processes to maintain homeostatic internal body temperatures.

Thumbnail
Heat Conservation and Dissipation

Animals have processes that allow for heat conservation and dissipation in order to maintain a homeostatic internal body temperature.

Section 10
Diet, Digestion, and Energy Storage Regulation
Thumbnail
Hormonal Responses to Food

The endocrine system controls the release of hormones responsible for starting, stopping, slowing, and quickening digestive processes.

Thumbnail
Neural Responses to Food

All three phases of digestive responses to food (the cephalic, gastric, and intestinal stages) are managed through enzymatic neural control.

Thumbnail
Food Energy and ATP

Animals use energy for metabolism, obtaining that energy from the breakdown of food through the process of cellular respiration.

You are in this book
Boundless Anatomy and Physiology by Boundless
Previous Chapter
Chapter 22
Digestive System
  • Overview of the Digestive System
  • Nervous System of the Digestive System
  • The Peritoneum
  • The Alimentary Canal
  • Layers of the Alimentary Canal
and 9 more sections...
Current Chapter
Chapter 23
Nutrition and Metabolism
  • Nutrition
  • Carbohydrates
  • Lipids
  • Proteins
  • Metabolic Reactions
and 5 more sections...
Next Chapter
Chapter 24
Urinary System
  • Overview of the Urinary System
  • The Kidneys
  • Physiology of the Kidneys
  • Urine
  • Urine Transport, Storage, and Elimination
Subjects
  • Accounting
  • Algebra
  • Art History
  • Biology
  • Business
  • Calculus
  • Chemistry
  • Communications
  • Economics
  • Finance
  • Management
  • Marketing
  • Microbiology
  • Physics
  • Physiology
  • Political Science
  • Psychology
  • Sociology
  • Statistics
  • U.S. History
  • World History
  • Writing

Except where noted, content and user contributions on this site are licensed under CC BY-SA 4.0 with attribution required.