Human Anatomy: Chapter 1 and 3

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Introduction

cells are the basic unit of life

the human body contains about 75 trillion calls

cells carry out activities essential to life or move specific specialized functions

Cytology

is the scientific study of cellular structure and function

fundamental unit of all living things

cell, tissue, system, organism; in order to function properly, cells must function properly

cellular function = METABOLISM

many body dysfunctions and diseases originate in the cells

proper functioning cell breakdown is the basis of disease

aging occurs at a cellular level

Cell Theory

every living organism is made of cells

cells arise only through the division of pre-existing cells rather than springing spontaneously from nonliving matter

all cells have the same basic chemical components

Microscopy

Three Basic Categories

Light Microscope (LM)

Transmission Electron Microscope (TEM)

Scanning Electron Microscope (SEM)

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Cell Shapes and Sizes

Squamous

thin, flat, scaly shape

(ex. line of esophagus and form surface layer of skin)

Cuboidal

squarish, about equal in height and width

(ex. liver cells)

Columnar

distinctly taller than wide

(ex. inner lining of intestines)

Polygonal

irregular angular shapes with four or more sides

squamous, cuboidal, and columnar cells often look like these when viewed from above rather than from the side

Stellate

multiple pointed processes give cells a somewhat starlike shape

(ex. cell bodies of nerve cells)

Spheroid

round to oval

(ex. egg cells and white blood cells)

Discoid

disk-shaped

(ex. red blood cells)

Fusiform

spindle-shaped; elongated with a thick middle and tapered ends

(ex. smooth muscle cells)

Fibrous

long, slender, and thread-like

(ex. skeletal muscle cells and the axons (nerve fibers) of nerve cells)