Unit 4-Histology Flashcards
Tissue
A group of cells that have a common origin in the embryo and carryout special actions
Histology
The study of tissues
Pathologist
a PHYSICIAN who studies cells and tissues to help other MDs make diagnoses
Types of Tissues
Epithelial, Connective, Muscular, Nervous
Epithelial Tissue
Covers body surfaces and inner surfaces; forms glands; provides interaction of inner and outer environments
Looks like structured, organized cells, whether flat (squamous), cubed (cuboidal), layered (stratified), or simple (and pseudostratified), or columnar.
Found in: heart, vessels, lymph linings; serous membranes; lung sacs, kidneys, inside tympanic membrane; lines lens in eye, retina; secreting surfaces; digestive tract; some sinuses; spinal canal; ventricles of brain
Connective Tissue
Protects and supports, binds, stores energy fat, provides immunity
Looks like epithelium but with extracellular matrix (fluid).
Found in: blood, some blood vessels, umbilical cord, fat, bone marrow, tendons, ligaments, pericardium, periosteum of bone, joints, lung tissue, elastic arteries, vocal chords, cartiledge, and bone
Muscular Tissue
Contraction and force, also produces heat when used.
Looks like striated rows, organized, long.
Found: attaching bones, in heart wall (remember intercalated discs!), and smooth muscles
Nervous Tissue
Detects changes and responds to signals to activate muscles and glands
Looks like big nucleus with long extensions, called axons and dendrites.
Found in nervous system.
Cell junction
contact points between plasma membrands of tissue cells
Types: tight, adherens, desmosomes, hemidesmosomes, and gap
Epithelial vs. Connective tissue
- -E. have little to no matrix between cells, C. cells have ample space between each cell.
- -E. almost always IS the surface (not blood vessel epithelium, though) where C. layers over other tissues.
The Basement Membrane
thin extracellular layer of 2 layers, to attach cells to the membrane, as well as maintain filtration and protection.
Membranes
flat sheets of pliable tissue that line a part of the body
Effects of aging on tissues
They thin and become fragile.
