Tissues 4/9/2019

Cells Tissues Organs Organ systems Organisms 4/9/2019

Tissues Groups of cells with a common structure and function—similar cells work together at one job. 4/9/2019

Epithelial Tissues 4/9/2019

Introductory Questions What is the function of epithelial tissue? List some locations in which it is found. 4/9/2019

Epithelial Overview General definition Structure Function Types Simple Squamous, cuboidal, columnar Stratified Squamous, columnar, transitional 4/9/2019

Epithelial Tissues Structure Tightly-packed cells Little material between cells Cover or line organs or body cavities Has free side Basement layer—non-living and separates epithelial from underlying connective tissue 4/9/2019

Epithelial – Structure Classified by: 1) Number of layers Simple – single layer Stratified – multiple layers 4/9/2019

Epithelial – Structure Classified by: 2) Shape of cells Squamous – fried egg, tiles Cuboidal – cube Columnar - brick 4/9/2019

Epithelial Tissues Function --Secretion --Absorption Protective—Barrier to: -water loss -microbes -mechanical injury --Secretion --Absorption --Sensory reception --Movement -Cilia 4/9/2019

Types of Epithelial Cells 1) Simple A) Squamous Single layer Flat cells Passage ways such as lungs, arteries, mesentary Places of diffusion, filtration & secretion—alveoli, capillaries, lymph vessels 4/9/2019

Types of Epithelial—Simple B) Cuboidal Single layer Cube-shaped Covers and lines Forms tubes/glands Pancreas, kidney, salivary glands 4/9/2019

Types of Epithelial—Simple C) Columnar Single Layer – nuclei often on same level Tall, elongated cells Lining tissues Digestive, uterine Secretion – goblet cells secrete protective mucus 4/9/2019

Types of Epithelial 2) Stratified A) Squamous Layered Often keratinized (protein hardens—water stays inside & chemicals & microorg. kept out) – outermost skin, areas of high stress Non-keratinized -Mouth, rectum, vagina, esophagous Types of Epithelial 4/9/2019

Types of Epithelial—Stratified B) Transitional Many cells thick Elastic Bladder, ureters Appearance Stretched or relaxed 4/9/2019

Types of Epithelial—Stratified C) Columnar, pseudo- stratified Appears layered due to nuclei on multiple layers Often ciliated Moves product Respiratory tract Fallopian tubes Goblet cells secrete mucus & cilia sweeps away. 4/9/2019

The ink of tattoos must be injected below the basement membrane.   4/9/2019

Where does all the dead skin you shed go? It takes about 27 days for the outer layer of skin to shed and be replaced; that works out to 1.5 pounds of skin cells per year. Where does all the dead skin you shed go?

4/9/2019