BODY TISSUES HISTOLOGY NOTES in your notebook time

BODY TISSUES HISTOLOGY! NOTES in your notebook time! Yea!! I LOVE this stuff

We’re MOVING ON! TISSUES: groups of cells that are similar in structure & function HISTOLOGY: branch of anatomy dealing with the microscopic structures of tissues

4 main types of tissue: § 1) Epithelial § 2) Connective § 3) Muscle § 4) Nervous

EPITHELIAL TISSUE § Also known as EPITHELIUM § Location: Is the lining, covering, and glandular tissue of the body!

FUNCTIONS OF EPITHELIUM 1) Protection 2) Absorption 3) Filtration 4) Secretion

Each Epithelium has 2 names: First part of name = # of CELL LAYERS Second part of name = SHAPE

CLASSIFICATION OF EPITHELIUM FIRST NAME SIMPLE very thin – one layer of cells Functions: absorption, secretion, filtration

STRATIFIED Stratified two or more layers of cells * more durable Functions: protection

PSEUDOSTRATIFIED Pseudostratified false stratified; gives the impression that it is stratified but it is not Some cells are shorter than others so the nuclei do not all line up Really just one layer!

SECOND NAME SQUAMOUS Squamous flattened like fish scales Draw:

CUBOIDAL Cuboidal cube-shaped like dice Draw:

COLUMNAR Columnar shaped like columns Draw:

2 PART NAMES: STRATIFIED epithelia are named for the cells at the FREE SURFACE of the epithelial membrane!

CHARACTERISTICS of Epithelium 1) These cells form continuous sheets because they fit closely together (abut each other) 2) There is always one unattached surface (free surface) or edge. * called the APICAL SURFACE

Cont. 3) Lower surface of epithelial tissue rests on a basement membrane *Basement membrane thin layer of extracellular material to which epithelial cells are attached

Cont. 4) Epithelium is AVASCULAR – no blood supply of own blood gets to these cells by diffusion from capillaries 5) Epithelial cells regenerate themselves easily if well nourished (near blood)

Epithelial Tissue LOCATIONS

Simple Squamous Epithelium n. Location n Walls of blood vessels, air sacs in lungs n Lines ventral body cavity

Simple Cuboidal Epithelium n. Location n Glands, kidney tubules, covers ovaries

Simple Columnar Epithelium n Location n Lines digestive tract n Ciliated variety in respiratory tract

Pseudostratified Columnar Epithelium n. Location n Respiratory tract including trachea

Stratified Squamous Epithelium n. Location n Skin (has keratin), mouth & throat

Transitional Epithelium n. Location n Urinary bladder, ureters & urethra