BIO 181 Lecture Notes - Mitosis, Epithelial Polarity
Document Summary
Tissue: cells grouped together with the same characteristics or specializations: four basic types of tissue: epithelial, muscle, connective, nervous. Organ: composed of tissues, usually of several different types. Epithelial tissues: are sheets of tightly connected cells that cover body surfaces and line hollow organs. Connective tissues: support & reinforce other tissues. Muscle tissues: three types (skeletal, cardiac, smooth) Nervous tissues: two types (neurons: generate and transmit electrochemical signals, glial cells: provide supporting functions for neurons) Cover the body surfaces & line hollow internal body organs (ex: the gut, bladder, blood vessels, etc. ) Some comprise a barrier between the body & the environment. Rest upon a secreted layer of extracellular protein termed the basement membrane. Cells display polarity (distinct inner & outer surfaces) Surfaces differ in both structure and function. Apical surfaces: face either the environment or the lumen. Different proteins are expressed in apical or basolateral membranes. Specialized for connecting, anchoring, cushioning, and support of other tissues;
