Chapter 4 Body Tissues and Membranes tissue specialized

Chapter 4 Body Tissues and Membranes

* tissue = specialized cells of one type that performs a common function * study of tissues = histology * four major tissue types : epithelial – coverings and linings connective - support muscular - movement nervous - control

4. 1 Epithelial Tissue * protection, secretion, absorption * easily regenerates (makes new cells) * cells are tightly packed together (sheets) * always has a free surface * other surface is attached to the basement membrane

* classified according to # of cell layers : simple = one layer stratified = more than one layer

Classification of Epithelia Simple or stratified

* classified according to shape of cells: squamous = flattened cells cuboidal = cube-shaped cells columnar = elongated (tall) cells

A. Squamous Epithelium

1. simple squamous epithelium * F – allows passage of materials * L – kidneys, lungs, blood vessels, heart

Simple Squamous Epithelium Top View

#11

2. stratified squamous epithelium * F - protection * L – skin, oral cavity, pharynx, urinary and reproductive tracts

Epithelia: Stratified Squamous

#13

B. Cuboidal Epithelium

1. simple cuboidal epithelium * F – secretion, absorption * L – kidney tubules, ducts of glands, ovaries

C. Columnar Epithelium

1. simple columnar epithelium * F – secretion (mucus), absorption * L – digestive tract, ducts of glands

Simple Columnar Epithelium

D. Pseudostratified Columnar Epithelium * single layer (simple), cells differing heights

* may have cilia = pseudostratified ciliated columnar epithelium * F – protection, secretion * L – respiratory and reproductive tracts

E. Transitional Epithelium * stratified (looks like cuboidal/squamous)

* F – stretches * L – urinary bladder, ureters

Epithelia: Transitional

Transitional Epithelium (Ureter) 3 apical (free) surface