Skip to main content
Medicine LibreTexts

Chapter 3: Digestion, Absorption and Transport of Nutrients

  • Page ID
    21472
    • 3.1: Basic Biology, Anatomy, and Physiology
      The cell is the basic structural and functional unit of life. Cells are independent, single-celled organisms that take in nutrients, excrete wastes, detect and respond to their environment, move, breathe, grow, and reproduce. The macromolecules carbohydrates, proteins, lipids, and nucleic acids make up all of the structural and functional units of cells. In complex organisms, cells are organized into five levels so that an organism can conduct all basic processes associated with life.
    • 3.2: Digestion and Absorption
      The breakdown of complex macromolecules in foods to absorbable components is accomplished by the digestive system. These components are processed by cells throughout the body into energy or are used as building blocks. The digestive system is composed of the mouth, pharynx, esophagus, stomach, small intestine, large intestine (or colon), rectum, and anus. There are four steps in the digestion process: ingestion, the breakdown of food, nutrient absorption, and elimination of indigestible food.
    • 3.3: Nutrients Are Essential for Organ Function
      Metabolic homeostasis occurs when the amount of nutrients consumed matches the energy required to carry out life’s biological processes. The circulatory system transports nutrients to cells and transports wastes from them. The essential minerals sodium, potassium, calcium, and chloride, and the macronutrients protein and carbohydrates, are required for central nervous system function. Fat is also critical for central nervous system function (see the Discussion Starter below).
    • 3.4: Disorders That Can Compromise Health
      Unbalanced diets can cause diseases and, conversely, certain disorders and diseases can cause an inadequate intake and absorption of nutrients simulating the health consequences of an unbalanced diet. Unbalanced, high-fat diets can exacerbate the symptoms of GERD and IBS. Celiac disease and anorexia can lead to nutritional deficiencies, which compromise functioning of the organ systems and decrease health.
    • 3.E: Exercises

    • Was this article helpful?