Tissues Tissue Histology Four Primary Types Epithelial Connective Muscular Nervous

Epithelial Tissue Functions *Covering or lining Protection Permeability control Secretion Absorption Excretion Sensory Function is determined by cell type & number of cell layers.

Structural Characteristics of Epithelia apical Cellularity Polarity Avascular Innervated Regeneration basal Basement Membrane

Polarity of Epithelial Cells

Classification of Epithelia The function of the epithelium determines which type. Classified according to 1. Number of cell layers Simple vs. Stratified 2. Shape of apical cell Squamous, cuboidal, columnar 3. Special features Cilia, villi End with epithelium to complete the naming

Arrangements Simple Stratified Pseudostratified Transitional

Shapes Squamous Cuboidal Columnar

Special Features Cilia Goblet Cells Villi Microvilli

Simple Squamous Epithelium Diffusion, filtration, secretion, absorption Location: Lining of blood vessels (endothelium) Peritoneum Alveoli

Lung

Simple Cuboidal Epithelium Functions Secretion Absorption Locations Lining of ducts Glands (salivary, pancreas, thyroid) Kidney tubules

Thyroid Follicle

Simple Columnar Epithelium Functions Secretion Absorption Locations GI tract Excretory ducts Reproductive tract Special Features

Pseudostratified Ciliated Columnar Epithelium Mixture of cell heights  nuclei located at various distances from surface. All cells touch basement membrane Functions Excretion Movement Locations Respiratory tract except for lungs Male reproductive ducts

Stratified Squamous Epithelium Function Protection (multiple layers = better protection) Keratinized vs. non-keratinized Location? Where we need protection! Skin surface Entrances/exits of body, e.g. mouth, vagina

Stratified cuboidal and columnar: quite rare, found in glands and ducts

Transitional Epithelium Layered appearance due to overcrowding. Function Extreme expansion Recoil Location Bladder Ureters

stretched

Locations in the Body

Oh…and this tissue type!

Connective Tissue: Supports, protects, binds tissues Structural characteristics: Specialized cells Extracellular matrix Protein fibers Ground substance (fluid-like) Mostly highly vascular Extracellular matrix – all non-living components

Functions Structural framework Transport Support and protection Energy storage

Classification of C.T. C.T. proper (viscous matrix with fibrous, insoluble proteins) Areolar (loose), reticular, dense, adipose Supporting C.T. (gelatinous or solid matrix) Cartilage, bone Fluid C.T. (watery matrix with dissolved proteins) Blood, lymph

Classification of Connective Tissues

Connective Tissue Proper Types: Areolar Dense regular Reticular Adipose Dense irregular Types of Fibers: Collagen Elastic Reticular Defense: Macrophages Plasma Cells Mast Cells Other WBC

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Fluid C. T. Blood Lymph

Supporting C.T. Cartilages Bone Hyaline Elastic Fibrocartilage Mineral matrix

Study individual types of c.t. in lab

Membranes = Combination of Epithelia & C.T. Mucous membranes Lining of cavities that communicate with exterior Serous membranes Lining of sealed, internal cavities Cutaneous membranes Skin Need to know membranes Parietal vs. visceral

Cutaneous & Synovial Membranes

C.T. Framework of Body Also: Hypodermis or subcutaneous layer

Muscle Tissue Skeletal Cardiac Smooth (not striated)

Skeletal Muscle Voluntary Heavily striated Multinucleated

Cardiac Muscle Heart (Only) Intercalated disks Heavily branched Involuntary Striated Intercalated disks Heavily branched Single central nucleus

Smooth Muscle Involuntary No striations Single central nucleus

Nervous Tissue Neurons Neuroglia Transmit electrical impulses Supportive cells of the nervous system

Neural Tissue