Chapter 4 Flashcards
What is a group of specialized cells that perform specific functions?
Tissue
What is the study of tissue called?
Histology
What are the four main types of tissue?
Epithelial, connective, muscle, nervous
What does epithelial tissue do?
Covers exposed surfaces, lines passages, forms glands
What does connective tissue do?
Fills internal spaces, supports other tissue, transports materials, stores energy
What does muscle tissue do?
Specializes in contraction
What does nervous tissue do?
Carries info through body via electrical impulses
Where are epithelial glands?
Surface of the skin, digestive, respiratory, reproductive, urinary
What do the epithelial glands do?
Physical protection from abrasions, dehydration, chemical and biological agents.. controls permeability, sensation, specialized secretions onto the epiderman surface
What are the characteristics of epithelial glands?
polarity, structure/function difference between apical and basal surfaces, cellularity, attachment to basement membrane, diffusional absorption, regenerates damaged/detached epidermal cells
What are stem cells?
Unspecialized general cells
What does apical mean?
Exposed
What does basal mean?
Attached
What are small finger-like projections of the plasma membrane?
Microvilli
What are small finger-like microtubules?
Cilia
What do microvilli do?
Absorption and secretion
What do cilia do?
Move fluids and secretions over epidermal surfaces
What does the ciliated epithelium do?
Lines the respiratory tract, moves mucus
What does mucus do?
Traps dust, pollen, and other foreign substances
What are cells firmly attached to?
Basement membrane and each other
What is a CAM?
Cell Adhesion Molecule
What are CAMs and what do they do?
Transmembrane protiens, attach opposing plasma membrane and to extracellular material (can attach by proteoglycans), prevent water loss
What is “intracellular cement” really called?
Proteoglycans
What are the three types of cell junctions?
Gap, tight, lumen
What does the gap cell junction do?
Holds cells together via interlocking transmembrane protiens
What are connexions and what do they do?
Transmembrane protiens, allow small molecules and ions to move between cells, common among epitheleal cells and cardiac muscle tissue
What does the tight cell juction do?
Lipid portions of two plasma membranes bound via interlocking junctional protiens, prevents water and solutes from passing between cells
What does the adhesion belt do?
Forms band to encircle cells, binds to cells
What does the lumen cell junction do?
Space inside tubular structures (ER, small intestine) in small intestine to keep enzymes, acid, and wastes in the lumen
What do desmosomes?
CAMs and proteoglycans link opposing plasma membranes, dense area connected to cytoskeleton
What are the two types of desmosomes?
Spot and hemi
What are spot desmosomes?
Small discs connected to intermediate filaments
What are hemi desmosomes?
Resemble half of a spot desmosome, attach cells to basement membrane
How is epithelia classed?
By number of layers and cell shape
Epithelium is thin and flat.
Squamous
Epithelium is like little boxes.
Cuboidal
Epithelium is tall and slender.
Columnar
Epithelium has only one layer.
Simple
Epithelium has multiple layers.
Stratified
What do simple epithelia do?
Thin and fragile, so they handle secretion and absorption
What do squamous epithelial cells look like?
Irregular in shape
Where are simple squamous epithelial cells found?
Alveoli, heart, blood vessels (reduces friction, in slick areas)
What are simple squamous epithelial cells called in the heart and blood vessels?
Endothelium
What are simple squamous epithelial cells called in the pleural, pericardial, and peritoneal cavities?
Mesothelium
What is the purpose of stratified squamous epithelial cells and where are they found?
Handle severe mechanical stresses, surface of skin and lining of mouth
What is the keratinized stratified squamous epithelium?
Superficial layers of epithelial cells packed with keratin filaments in exposed body surfaces