Chapter 5 Tissues

Introduction Tissue: groups of cells with similar function Histology: study of tissues Tissue types Epithelial, connective, muscle, nervous

Epithelial Tissue

Introduction Protects underlying tissues Absorbs nutrients Secretes hormones, mucus, enzymes Excretes waste

Introduction (cont’d.) Basement membrane: anchor Named according to shape, arrangement, function Cells are closely packed

Classification Based on Shape Squamous: flat (protection) Cuboidal: cube shaped (protection and secretion) Columnar: tall and rectangular (secretion and absorption)

Classification Based on Shape (cont’d.) Squamous epithelial cells (Photo © Robert Knauft/Biology Pics/Science Source)

Classification Based on Shape (cont’d.) Cuboidal epithelial cells (Photo © Biophoto Associates/Science Source)

Classification Based on Shape (cont’d.) Columnar epithelial cells (Photo © Biophoto Associates/Science Source)

Classification Based on Arrangement Simple: one cell layer Stratified: several layers Pseudostratified: appears to be several layers but is not Transitional: several layers of easily stretched cells

Classification Based on Arrangement (cont’d.) Pseudostratified ciliated, columnar epithelium (Photo © Steve Gschmeissner/Science Source)

Classification Based on Arrangement (cont’d.) Transitional epithelium (Photo © Biophoto Associates/Science Source)

Classification Based on Function Mucous membrane: mucus production Exocrine glands: simple and compound Endocrine: hormone secretion Endothelium: lines vessels Endocardium Mesothelium (serous): lines great cavities

Connective Tissue

Introduction Cells with large amount of intercellular material Matrix embedded with: Collagen Elastin Subgroups: loose, dense, specialized

Loose Connective Tissue Fills space between and penetrates organs Areolar: injury repair, phagocytosis, inflammatory response Fibroblasts, histiocytes, mast cells Adipose: fat storage Reticular: framework

Loose Connective Tissue (cont’d.) Areolar (loose) connective tissue (Photo © Biophoto Associates/Science Source)

Dense Connective Tissue Regular arrangement Tendons, ligaments, aponeuroses Irregular arrangement Muscle sheaths, joint capsules, fascia

Dense Connective Tissue (cont’d.) Tendon (dense) connective tissue (Photo © Biophoto Associates/Science Source)

Specialized Connective Tissue Cartilage Cells called chondrocytes Found in lacunae Types Hyaline: ribs, nose, trachea Fibrocartilage: intervertebral disks Elastic: ears, auditory tubes, epiglottis

Specialized Connective Tissue (cont’d.) Bone Compact Cancellous Mineral salts: especially calcium and phosphorus Teeth Dentin Enamel

Specialized Connective Tissue (cont’d.) Bone (osseus tissue) (Photo © Michael Ross/Science Source)

Specialized Connective Tissue (cont’d.) Blood: fluid portion and formed elements Lymphoid: antibody production and disease protection Reticuloendothelial system: phagocytosis Kupffer cells in liver Macrophages Neuroglia Synovial: lines joints

Connective Tissue Functions Support Bones, cartilage Nourishment Blood Transportation Connection Tendons, ligaments

Connective Tissue Functions (cont’d.) Movement Bones, tendons Protection and insulation Bones, blood, fat Storage Bone, fat Attachment and separation Attaches skin to muscle

Muscle Tissue

Muscle Tissue (cont’d.) Smooth Spindle-shaped, single nucleus Not striated Involuntary Digestive tract, arteries and veins, ureters Peristalsis

Muscle Tissue (cont’d.) Smooth (nonstriated involuntary) muscle (Photo © Biophoto Associates/Science Source)

Muscle Tissue (cont’d.) Striated (skeletal) Long thin cells Multinucleated and striated Actin and myosin Voluntary Movement by pulling on bones

Muscle Tissue (cont’d.) Skeletal (striated voluntary) muscle (Photo © Eric V. Grave/Science Source)

Muscle Tissue (cont’d.) Cardiac Only in the heart Uninucleated and striated Involuntary Cylindrical shape Connected to other cardiac muscle cells by intercalated disks

Muscle Tissue (cont’d.) Cardiac muscle (Photo © Biophoto Associates/Science Source)

Nervous Tissue

Nervous Tissue (cont’d.) Neurons Conducting cells Very long: called nerve fibers Parts Cell body: contains nucleus Dendrites: rootlike extensions that receive stimuli Axons: long thin extensions that transmit impulse

Nervous Tissue (cont’d.) Neuroglia: supporting cells Nervous tissue Makes up brain, spinal cord, and nerves Is most highly organized tissue of the body Controls and coordinates body activities Allows perception Controls emotion and reasoning Stores memories

Nervous Tissue (cont’d.) Motor neuron (Photo © Biophoto Associates/Science Source)

Summary Introduced the concept of tissues and how to classify tissues Classified epithelial tissue based on shape and arrangement Described the three major types of connective tissue Described the three types of muscle tissue Discussed nervous tissue and its functions