BIOL 212 Lecture Notes - Lecture 3: Elastin, Merocrine, Apocrine
Document Summary
4 types of tissues: epithelial tissue covers, connective tissue connects, muscular tissue contracts, nervous tissue conducts. Epithelial tissue: there are two main divisions, those that cover the surfaces and line cavities, tubes. Increase cancer rates with this tissues because of the regeneration of cells: these cells are avascular which have no blood vessels. These are usually near connective tissue that has blood vessels: show polarity as the top is apical and bottom is a basal surface. Apical is on top like atic that have cilia or microvilli, basal is the bottom: they are underlain with basal lamina (like glue) Function: physical protection, from abrasion, dehydration, toxins, and pathogens, control permeability, many epithelia are basically impermeable or have regulated permeability, junctions between cells can prevent substances from passing adjacent cells. This allows us to control what goes through: provide sensation, most is highly innervated as they have neurons and neuroepithelium, produces specialized secretions, gland cells (sweat glands, mamatory glands)
