Intro to Tissues Unit 2- Chapter 5

Introduction Histology = the study of tissues Tissues = layers or groups of similar cells with a common function Intercellular junctions connect cells together Tight junction Desmosome Gap junction

General Characteristics- Epithelial FunctionProtection Secretion Absorption Excretion LocationCover body surfaces Form inner linings of body cavities Lines and covers organs CharacteristicsFree surface exposed to outside Anchored to connective tissue by basement membrane Lack blood vessels Readily divide/replaced quickly Tightly packed ClassificationClassified by: 1) cell shape- squamous, cuboidal, columnar 2) number of cell layers- simple, stratified, pseudostratified

FunctionBind structures* Store fat Support and protection* Make blood cells Framework* Protect against infections Fill spaces* Repair tissue damage LocationThroughout body Fat Cartilage, ligaments, bone, blood CharacteristicsFarther apart, have extracellular matrix Can usually divide Vascular May be rigid or flexible Classification2 major categories: 1) connective tissue proper- (loose- areolar, adipose, reticular; dense- regular, irregular, elastic) 2) specialized connective tissue- cartilage, bone and blood General Characteristics- Connective

FunctionContraction Move bones Reflexes Pump blood LocationAttached to bones Walls of hollow organs (intestines) Heart CharacteristicsContract and relax in response to stimuli Can be voluntary or involuntary ClassificationClassified by location: 1) skeletal- voluntary; striated 2) smooth- involuntary; no striations 3) cardiac- involuntary; striated, branched General Characteristics- Muscle

FunctionConduct impulses Sensory Motor coordination Control center- communication, regulation, integration LocationBrain Spinal cord Nerves CharacteristicsPolarized (+ and – end) Basic cells are called neurons Dendrites/Axons Neuroglia cells support and bind nervous tissue General Characteristics- Nervous