Intro to TissuesUnit 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

Function •Protection•Secretion•Absorption•Excretion

Location •Cover body surfaces•Form inner linings of body cavities•Lines and covers organs

Characteristics •Free surface exposed to outside•Anchored to connective tissue by basement membrane•Lack blood vessels•Readily divide/replaced quickly•Tightly packed

Classification •Classified by: 1) cell shape- squamous, cuboidal, columnar 2) number of cell layers- simple, stratified, pseudostratified

Function •Bind structures * Store fat•Support and protection * Make blood cells•Framework * Protect against infections•Fill spaces * Repair tissue damage

Location •Throughout body•Fat•Cartilage, ligaments, bone, blood

Characteristics •Farther apart, have extracellular matrix•Can usually divide•Vascular•May be rigid or flexible

Classification •2 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

Function •Contraction•Move bones •Reflexes •Pump blood

Location •Attached to bones•Walls of hollow organs (intestines)•Heart

Characteristics •Contract and relax in response to stimuli•Can be voluntary or involuntary

Classification •Classified by location: 1) skeletal- voluntary; striated 2) smooth- involuntary; no striations 3) cardiac- involuntary; striated, branched

General Characteristics- Muscle

Function •Conduct impulses•Sensory•Motor coordination•Control center- communication, regulation, integration

Location •Brain•Spinal cord•Nerves

Characteristics •Polarized (+ and – end)•Basic cells are called neurons•Dendrites/Axons•Neuroglia cells support and bind nervous tissue

General Characteristics- Nervous