Intro To Tissues Flashcards
Cell shape
Cells take on a variety of shapes:
Cuboidal, columnar, spherical,
Squamous- flattened cytoplasm, they cover free surfaces (skin, blood vessels)
Spindle-shaped- roughly cylindrical with tapered ends
Stellate- cells with multiple branching extensions, characteristic of many cells in the central nervous system
Multi-nucleated cells
Arise from the fusion of multiple individual cells. They are not capable of cell division. Examples include skeletal muscle, placental cells
Extracellular matrix
Aqueous solution of electrolytes and macromolecules secreted by the cells in a tissue. It may be sparse and fluid as in epithelium, or it may be dense as in bone. Cells often establish connections with macromolecules in the ECM. In addition, the ECM May modify cell function, including the proliferation, development, migration, morphology and survival of cells
Epithelium
Most often functions as a barrier. Covers free surfaces of the body. Includes epidermis and as well as internal lining of the gut and blood vessels. Closely packed with tight intercellular connections and minimal ECM. It is avascular and separated from underlying connective tissue by basement membrane. May arise from any of the 3 germ layers
Connective tissue
Consists of cells scattered within an abundant ECM. Provides support for contractile and nervous tissue and underlies the epithelium. Blood vessels travel through connective tissue. It is classified as loose or dense according to the density of the ECM. Is of mesodermal origin
Loose connective tissue
Has abundant water and relatively sparse fibers. Underlies the lining of the gut
Dense connective tissue
Has masses of fibrous or crystalline material. Includes tendons, cartilage, and bone
Contractile tissue
Is specialized for movement to generate force. Three types of contractile tissue are skeletal, cardiac and smooth muscle, all of which rely on actin and myosin as contractile proteins. Skeletal and cardiac are striated (banding pattern within cell) and smooth is not.
Nervous tissue
Consists of neurons, cells specialized for rapid transmission of electrical signals, and glial small non-excitable supporting cells. Both may have extensive branching structure.
