Tissues A group of cells that work together

2 main parts to tissues 1.Living- cells 2.Nonliving- noncellular -intracellular space called matrix

Types of tissues 1.Epithelium 2.Connective 3.Muscle 4.Nervous

Epithelial Tissue Functions 1.Protection 2.Control Permeability/absorption 3.Secretion 4.Surface Transportation 5.Sensation

Epithelial characteristics Cells are packed and held together with desmosomes Cells are attached to basement membrane Basement membrane and ET are avascular!!

Cell arrangement Single layer, called SIMPLE Many layers, called STRATIFIED Looks layered but really just a single layer, called PSEUDOSTRATIFIED

Cell Shapes Based on OUTER LAYER ONLY!!! 1.Flat= squamous 2.Rounded= cuboidal 3.Tall= columnar

Simple Squamous “fried egg” shape Found lining tubules and capillaries

Simple Cuboidal Found in ducts of glands, in ovaries, and capsule surrounding lens of eye

Simple Columnar Often specialized for protection, secretion or absorption May contain goblet cells which produce mucus May contain cilia – in respiratory tract, uterine tubes May contain microvilli – appears as “brush border”, found in small intestine and kidney tubules

Simple Columnar

Stratified Squamous Function in protection from “mechanical stress” Found in skin, oral cavity, esophagus, and vagina May be keratinized(skin) or not(inside of mouth, vagina)

Stratified Cuboidal Found in ducts of sweat gland of skin

Stratified Columnar Functions in protection and secretion Found in urethra

Pseudostratified Columnar Staggered nuclei give appearance of more than 1 layer Often contain goblet cells Ciliated( respiratory tract and middle ear) and nonciliated (in urethra and parotid gland)

Transitional Surface cells may be binucleate Cells are loosely packed which gives elasticity Found in bladder, ureters and kidneys

Glandular epithelium Function in secretion 1.EXOCRINE- secrete product into a duct system or onto a free surface ex- enzymes, sweat, milk, sweat 2. ENDOCRINE- secrete a product directly into bloodstream ex.- hormones

Exocrine Gland 1.Size- a. Unicellular- ex. Goblet cell b. Multicellular 2.Shape a. Tubular, acinar/alveolar, tubuloalveolar 3.Type of Secretion- a. Serous- watery w/ enzymes b. Mucous c. mixed

4. Method of secretion a. Merocrine- expel only secretion by exocytosis - ex. sweat, salivia, mucus b. Aprocrine- release portion of cell with secretory product - ex. mammary glands, underarm sweat c. Holocrine- a whole cell is secretory product - ex. Sebaceous or oil glands, testes and ovaries