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
Stop
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