CHAP 4

Flashcards covering the tissue level of organization, microscopy techniques, epithelial tissue, intercellular connections, squamous, cuboidal, transitional, and columnar epithelia, glandular epithelia, connective tissue, muscle tissue, nervous tissue, inflammation, and regeneration in response to tissue injury.

Histology

The study of tissues.

Tissue

A collection of cells working together to perform specific functions.

Four Basic Tissue Types

Epithelial, Connective, Muscle, and Neural.

Microscopy

The use of microscopes.

Simple Microscope

Uses only one lens.

Compound Microscope

Uses more than one lens.

Electron Microscope

Can magnify over 1 million times.

Compound Light Microscope

Detects visible light through a thin section of tissue.

Two Lenses in Compound Light Microscope

Objective lens and ocular lens.

Total Magnification Calculation

Multiply the objective lens power by the ocular lens power.

Resolution

Ability to distinguish between two separate points.

Transmission Electron Microscope

Transmits electrons through specimen.

Scanning Electron Microscope

Uses electrons to produce a 3D image of the surface of a specimen.

Epithelial Tissue

Covers surfaces, lines cavities, and forms secretory glands.

Divisions of Epithelial Tissue

Epithelia and Glands.

Exocrine Glands

Secrete onto external surfaces or into ducts.

Endocrine Glands

Secrete hormones into interstitial fluid.

Functions of Epithelial Tissue

Physical protection, control of permeability, provision of sensation, and production of specialized secretions.

Apical Surface

Faces the exterior of the body or an internal space.

Base (Epithelial Tissue)

Attached to underlying tissues.

Basolateral Surface

Includes the base and sides attached to neighboring cells.

Polarity

Structural differences between exposed and attached surfaces.

Squamous

Thin and flat.

Cuboidal

Cube-shaped.

Columnar

Taller than they are wide.

Simple Epithelium

Single layer of cells.

Stratified Epithelium

Several layers of cells.

Epithelial Attachments

Attachments between adjacent cells and adjacent tissues.

Hemidesmosomes

Attach deepest epithelial cells to the basement membrane.

Tight (Occluding) Junctions

Interlocking membrane proteins bind adjacent plasma membranes together.

Adhesion Belts

Continuous band of membrane proteins that strengthens the apical region of cells.

Gap Junctions

Held together by interlocking transmembrane proteins (connexons) to assist chemical communication.

Desmosomes

Provide firm attachments by interlocking adjacent cells' cytoskeletons.

Squamous Epithelium

Thin, flat, irregularly shaped cells.

Simple Squamous Epithelium

Most delicate epithelium; functions in absorption, diffusion, and reduction of friction.

Mesothelium

Lining ventral body cavities.

Endothelium

Lining the heart and blood vessels.

Stratified Squamous Epithelium

Located where severe mechanical or chemical stresses exist; many layers of cells.

Keratinized Stratified Squamous Epithelium

Superficial layers packed with keratin; tough and water resistant.

Nonkeratinized Stratified Squamous Epithelium

Resists abrasion but can dry out.

Cuboidal Epithelium

Cells resemble hexagonal boxes; functions in secretion and absorption.

Simple Cuboidal Epithelium

Functions in secretion and absorption; lines exocrine glands and ducts.

Stratified Cuboidal Epithelium

Rare tissue; found in ducts of sweat and mammary glands.

Transitional Epithelium

Unusual stratified epithelium that can stretch and recoil without damage; found only in the urinary system.

Columnar Epithelium

Cells appear rectangular; elongated nuclei in a band close to the basement membrane.

Simple Columnar Epithelium

Found where absorption or secretion takes place; may have microvilli or cilia.

Pseudostratified Columnar Epithelium

Cells of varying shapes and functions; gives the appearance of being stratified but each cell contacts the basement membrane.

Stratified Columnar Epithelium

Rare tissue type; two or more layers of cells.

Glands

Collections of epithelial cells that produce secretions.

Endocrine Glands

Release secretions into interstitial fluid.

Exocrine Glands

Release secretions into ducts onto an epithelial surface.

Merocrine Secretion

Product released from secretory vesicles by exocytosis.

Apocrine Secretion

Apical cytoplasm packed with secretory vesicles is released along with the secretory product.

Holocrine Secretion

Entire cell bursts, releasing secretions and killing the cell.

Simple Duct Structure

Single duct that does not divide.

Compound Duct Structure

Duct divides one or more times.

Tubular Secretory Area

Glandular cells form tubes.

Alveolar or Acinar Secretory Area

Glandular cells form sacs.

Unicellular Exocrine Glands

Mucous (goblet) cells.

Basic Components of Connective Tissue

Specialized cells, extracellular protein fibers, and ground substance.

Matrix

Extracellular fibers and ground substance.

Subdivisions of Connective Tissue

Connective tissue proper, fluid connective tissue, and supporting connective tissue.

Connective Tissue Proper

Contains many types of cells and extracellular fibers in a syrupy ground substance.

Fluid Connective Tissue

Watery matrix with distinctive group of cells.

Supporting Connective Tissue

Less diverse cell population and more densely packed matrix.

Loose Connective Tissue Proper

Fibers create a loose, open framework.

Dense Connective Tissue Proper

Fibers are densely packed.

Extracellular Protein Fibers

Reticular, collagen, and elastic fibers.

Ground Substance

Clear and colorless; viscous due to proteoglycans and glycoproteins.

Classes of Cells in Connective Tissue Proper

Fixed and Wandering.

Fixed Cells

Stationary and involved with maintenance, repair, and energy storage.

Wandering Cells

Move throughout tissue; function in defense and repair.

Melanocytes

Synthesize melanin pigment.

Fixed Macrophage

Engulfs cell debris and pathogens.

Mast Cells

Stimulate inflammation and mobilize defenses.

Fibroblasts

Synthesize extracellular fibers.

Adipocytes

Store lipid reserves.

Fibrocytes

Differentiate from fibroblasts and maintain extracellular fibers.

Plasma Cells

Immune cells producing antibodies.

Mesenchymal Cells

Stem cells that aid in tissue repair.

Neutrophils and Eosinophils

Phagocytic blood cells.

Types of Loose Connective Tissue

Areolar, adipose, and reticular tissue.

Areolar Tissue

Most common connective tissue proper; packing material of the body.

Adipose Tissue

Found deep to skin in various areas of the body; cells (adipocytes) account for most of tissue volume.

Reticular Tissue

Found in liver, kidney, spleen, lymph nodes, and bone marrow; provides support and resists distortion.

Dense Connective Tissues

Most volume occupied by extracellular fibers.

Types of Dense Connective Tissue

Dense regular, dense irregular, and elastic tissue.

Dense Regular Connective Tissue

Found in cords (tendons, ligaments) or sheets; collagen arranged in parallel bundles.

Dense Irregular Connective Tissue

Fibers arranged in a meshwork to resist tension in many directions.

Elastic Tissue

More elastic fibers than collagen; is springy and resilient.

Fluid Connective Tissue

Fluid matrix with many suspended proteins.

Types of Fluid Connective Tissue

Blood and Lymph

Blood

Watery matrix called plasma.

Formed Elements of Blood

Red blood cells, white blood cells, and platelets.

Lymph

Watery matrix called lymph; collected from interstitial fluid.

Cartilage Matrix

Firm gel containing chondroitin sulfates.

Chondrocyte

Type of cell found in cartilage.

Lacunae

Small chambers where chrondrocytes are located.

Types of Cartilage

Hyaline cartilage, elastic cartilage, and fibrocartilage.

Hyaline Cartilage

Found between ribs and sternum, covering bones in mobile joints, part of nasal septum, supporting respiratory passageways; provides stiff but flexible support.