Anatomy Lecture Ch 4 Review Questions Flashcards
What are the four basic tissue types?
epithelial, muscular, connective, nervous
What does epithelial tissue do?
covers body surfaces; lines hollow organs, body cavities and ducts; forms glands; allows body to interact with internal and external environments
What does connective tissue do?
protects and supports the body and its organs, binds organs together, stores energy reserves as fat, helps provide the body with immunity to disease-causing organisms
What does muscular tissue do?
composed of cells specialized for contraction and generation of force which generates heat that warms the body
What does nervous tissue do?
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 contractions and glandular secretions
What is a biopsy?
the removal of a sample of living tissue for microscopic examination
What are cell juntions?
contact points between the plasma membranes of tissue cells
What are the five main types of cell junctions?
tight junctions, adhering junctions, desmosomes, hemidesmosomes, and gap junctions
What is the structure of tight junctions?
consist of weblike strands of transmembrane proteins
What do tight junctions do?
inhibit the passage of substances between cells and prevent the contents of these organs from leaking into the blood or surrounding tissues
Where are tight junctions located?
stomach, intestines, and urinary bladder
What is the structure of adhering 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
What are cadherins?
transmembrane glycoproteins that insert into the plaque of adhering junctions, partially crossing the intercellular space, and connects to cadherins of an adjacent cell
What are adhesion belts?
extensive zones formed from adhering junctions that encircle the cell
What do adhering junctions do?
help epithelial surfaces resist separation during various contractile activities, such as food moving through the intestines
What is the structure of desmosomes?
contain plaque and have cadherins that extend into the intercellular space between adjacent cell membranes and attach cells to one another; plaque does not attach to microfilaments but instead to intermediate filaments
What are intermediate filaments made of?
the protein keratin
Where are desmosomes most common?
cells that make up the epidermis and among cardiac muscle cells
What is the function of desmosomes?
prevent epidermal cells from separating under tension and cardiac muscle cells from pulling apart during contraction
How are hemidesmosomes different from desmosomes?
they do not link adjacent cells
What are the transmembrane glycoproteins in hemidesmosomes called?
integrins
What do hemidesmosomes do?
anchor cells to the basement membrane but not to one another
What is the structure of gap junctions?
membrane proteins called connexins form tiny fluid-filled tunnels called connexons that connect neighboring cells
What do gap junctions do?
allow ions and small molecules to diffuse from the cytosol of one cell to another through connexons while preventing the passage of large molecules; allow the cells in a tissue to communicate with one another; enable nerve or muscle impulses to spread rapidly among cells