Bell Ringer: How are tissues and protection related? Objectives: Compare and contrast the types of epithelial tissues.   Standards Addressed: Protection, Support, Movement

Tissues Groups of specialized cells that carry out a specific function 4 Major Types: Epithelial Connective Muscle Nervous

Epithelial Tissues (General Characteristics) Functions Protection (underlying structures) Secretion Absorption Excretion *know these 4 *Epithelial tissues cover body surfaces and organs, line cavities, and compose glands

General (contd.) Basement membrane – thin, nonliving layer that anchors epithelial tissues to connective tissue *Epithelial tissue lacks blood vessels, but nutrients are diffused from connective tissue * Readily divide – injuries heal rapidly * Tightly packed *Classified according to shape and number of layers

Simple Squamous Structure – single layer of thin, flattened cells, nuclei – broad and thin *fit together like floor tiles Location – sites where diffusion and filtration take place

Simple Cuboidal Structure – single layer of cube shaped cells with a centrally located nucleus Location – covers ovaries, lines kidney tubules, lines salivary, pancreas, and thyroid glands Function: Secretion and Absorption

Simple Columnar Structure – resemble columns, single layer, may have cilia (free surfaces) Location – cilia – fallopian tubes (female reproduction) non-cilia – uterus, digestive tract Function – protection, absorption, secretion

Pseudostratified Columnar Structure – appear layered but are not (vary in shape and nuclei position), cilia are attached to free surface Location – lining of respiratory passages - goblet cells scattered through tissue secret mucous which the cilia sweep away (mucous traps dust and microorganisms to be removed from airways)

Stratified Squamous Structure – many layers of cells that divide in the deeper layers and push old ones outward Location – outer lay of skin (epidermis), oral cavity, esophagus, vagina, anal canal *as skin cells age they accumulate the protein keratin, harden and die – this process keeps nutrients in and harmful substances out

Transitional Epithelium Special Characteristic – changes in response to increased tension; prevents diffusion of contents of urinary tract back into internal environment *Forms the inner layer of the urinary bladder, ureters, and parts of urethra

Glandular Epithelium Specialized to produce and secrete substances into ducts or into body fluids Exocrine glands – secrete products into ducts that open onto surfaces (skin, digestive tract) Endocrine glands – secrete products into tissue fluid or blood *use table on page 101 to fill in types of exocrine glands in study guide