Tissue Basics: Epithelial, Connective, Muscular, Nervous

HUMAN ANATOMY AND PHYSIOLOGY LECTURE CHAPTER 4 – TISSUES • • • • TISSUE group of cells with similar structure and function plus extracellular substance (matrix) Histology - study of tissues Types of Tissues: o Epithelial o Connective o Muscular o Nervous EPITHELIAL TISSUES Location: o cover body (internal and external) o Ex. Skin, kidney, trachea, glands, etc. • • • • • GLANDS structures that secrete substances onto a surface, into a cavity, or into blood Exocrine glands: o glands with ducts o Ex. Sweat or oil glands Endocrine glands: o no ducts (directly into bloodstream) o ex. Thyroid, thymus, pituitary glands, etc. Types of Exocrine Glands: o Simple - no branches o Compound - many branches o Tubular - end of duct o Alveolus - sac-like structure CONNECTIVE TISSUES Classified based on type of extracellular matrix and function TYPES OF PROTEN FIBERS • • • Collagen fibers o look like ropes and are flexible but resist stretching Reticular fibers o supporting network that fills spaces between organs and tissues Elastic fibers o recoil after being stretched o Types of Cartilage ▪ Hyaline cartilage • covers ends of bones • some collagen fibers • reduces friction (cushion) ▪ Fibrocartilage • between vertebra • lots of collagen fibers • can withstand compression ▪ Elastic cartilage • ear and tip of nose • elastic fibers • can recoil Types of Ordinary Connective Tissue • Loose o Location: between organs, muscles, glands, skin o Structure: collagen fibers far apart o Function: support and protect • Dense o Location: tendons, ligaments, skin o Structure: collagen fibers packed close together o Function: connect and can withstand pulling forces • Adipose o under skin and around organs o collagen and elastic fibers, cells filled with lipids o storage, insulate, cushion • Cartilage o Type of connective tissue composed of chondrocytes o Contains collagen; Withstands compressions o Provides support, flexibility, strength • Bone o Hard connective tissue o 2 types: compact and spongy o Composed of osteocytes • • • • Blood Liquid connective tissue Erythrocytes, leukocytes, platelets Transport food, oxygen, waste, hormones • MUSCULAR TISSUE INTESTINE • • • • • • MUSCLE HEART NERVOUS TISSUE Consist of neurons or nerve cells Found in brain, spinal cord, and peripheral nerves Controls and coordinates body movements Includes axons, dendrites, cell bodies TISSUE REPAIR AND INFLAMMATION Tissue Repair o substitution of dead cells for viable cells o Regeneration - cells of same type develop (no scar) o Replacement - cells of a different type develop (scar) Inflammation o Occurs when tissues are damaged o Signals the body’s defenses (white blood cells) to destroy foreign materials and damaged cells so repair can occur. o Chemical mediators: ▪ released after injury ▪ cause dilation of blood vessels o Symptoms of Inflammation ▪ Redness - blood vessels dilate ▪ Heat - due to increased blood flow ▪ Swelling - from water and proteins ▪ Pain - nerve endings are stimulated by damage and swelling