BIOL 2443 Lecture Notes - Lecture 3: Stereocilia, Cell Junction, Microvillus
Document Summary
Intro: this chapter concentrates on tissues, there are approximately 200 types of cells, all cells can be placed into one of the four tissue categories. Polarity: apical surface, basal surface, surfaces are structurally and functionally different. Functions: provides protection from abrasion, dehydration and destruction, controls permeability, provides sensations, produces secretions. Apical surface in urinary and digesive tracts. Long microvilli, commonly found in the inner ear and male reproductive tract: ciliated epithelium. Intracellular connections: extensive connection between the cells. Prevents the passage of chemicals and pathogens: cell junctions, cams, intracellular cement gives the epithelium strength and stability. Maintenance and renewal: must be replaced frequently. Found in protected areas such as the internal compartments of the body: stratified. Found in areas where there are mechanical chemical stresses. Thin, flat cells/ squished nuclei right in the middle. Located in the heart and blood vessels: cuboidal cells. Simple cuboidal- found in the kidneys: columnar cells. Longer than they are wide/ nucleus near the base.