Chapter 1 - Introduction to PhysiologyOrganization of the BodyPhysiology is the study of the functions of organismsPathophysiology refers to what happens when normal body function is disrupted An organ system is a collection of anatomical structures that work together to carry out a specific functionThe brain contains billions of cells that are classified into four groups according to differences in their four general shapes (morphologies)oCells: smallest living unitsoAll cells in this category are specialized to transmit information in the form of electrical signals from one body location to anotherAll these cells are classified as neurons (or nerve cells)Cells, Tissues, Organs, and Organ SystemsThe four major classes of cells are neurons, muscle cells, epithelial cells, and connective tissue cellsoBased primarily on functional differencesOther rigorous ways to classify have been based on anatomical distinctions and embryological originsNerve cells or neurons are specialized to transmit information in the form of electrical signalsMuscle cells or muscle fibers are specialized to contract thereby generating mechanical force and movementoVoluntary control: (skeletal muscle such as muscles of the arms, legs, etc.) oInvoluntary control: (cardiac muscle such as the heart and smooth muscle such as blood vessels)Epithelial cells are found in tissues called epithelia (singular: epithelium) oConsists of a continuous, sheetlike layer of cells in combination with a thin underlying layer of noncellular material called a basement membrane Simple: cell layer may be one cell thickStratified: several cells thinkSquamous: cells may vary in shape from short and flattenedCuboidal: regular shapedColumnar: tall and oblongoCells join closely together to form a barrier that prevents material on one side of the epithelium from mixing freely with material on the other sideEpithelia are found wherever body fluids must be kept separate from the
You've reached the end of your free preview.
Want to read all 4 pages?
- Fall '08