Chapter 4 Flashcards
epithelial tissue
covers body surfaces and line hollow organs, body cavities and ducts; also form glands
connective tissue
protect and support the body and its organs. bind organs together, store energy reserves as fat, help provide the body with immunity to disease- causing organisms
muscular tissue
composed of cells specialized for contraction and generation of force. (heats and warms the body)
nervous tissue
detects changes in a variety of conditions inside and outside the body and responds by generating electrical signals called nerve action potentials that activate muscular contraction and glandular secretions
cell junction
contact points between the plasma membranes of tissue cells
tight junction
consist of weblike stands of transmembrane proteins that fuse together the outer surfaces of adjacent plasma membranes to seal off passageways between adjacent cells.
location: cells of epithelial tissues that line the stomach, intestines and urinary bladder
- watertight seal!!!!!!!!
adherens junctions
contain plaque - a dense layer of proteins on the inside of the plasma membrane that attaches both to membrane proteins and to microfilaments of the cytoskeleton. Transmembrane glycoproteins called cadherins join the cells
- help epithelial surfaces resist separation during various contractile activities
Desmosomes
contain plaque and have transmembrane glycoproteins (cadherins) that extend into the intercellular space between the adjacent cell membranes. Attaches to intermediate filaments
location: among cells that make up the epidermis and among cardiac muscle cells
Hemidesmosomes
resemble desmosomes. They don’t link adjacent cells
Gap Junctions
membrane proteins (connexins) form tiny fluid filled tunnels called connexons that connect neighbouring cells
Epithelial Tissue/ Epithelium
consists of cells arranged in continuous sheets in either single or multiple layers
basement membrane
a thin extracellular layer that commonly consists of two layers: the basal lamina and reticular lamina
basal lamina
(lamina = thin layer) is closer to and secreted by the epithelial cells. Contains proteins
reticular lamina
closer to underlying connective tissue and contains proteins (i.e. collagen produced by connective tissue cells called fibroblasts)
simple epithelium
- Single layer of cells, centrally located nucleus
Function: diffusion, osmosis, filtration, secretion or absorption
Pseudostratified epithelium
a type simple epithelium that appears to have multiple layers of cells because the nuclei lie at different levels.
stratified epithelium
consists of two or more layers of cells; cells that do extend to the apical surface may contain cilia
Function: protect underlying tissues in locations where there is considerable wear and tear
squamous cells
thin; allows for rapid passage of substances through them
cuboidal cells
shaped like cubes/hexagons; function in secretion or absorption
columnar cells
shaped like columns, may have cilia or microvilli at apical surface; protect underlying tissues
transitional cells
change shape!!! from squamous to cuboidal and back in organs that stretch to a larger size and the collapse (i.e. urinary bladder)
glandular epithelium
function: secretion