Tissue Level of Organization

Flashcards covering the topic of Tissue Level of Organization, including Epithelial, Connective, Muscle, and Nervous Tissues. Also includes microscopy techniques, intercellular connections, gland types, and responses to tissue injury.

Epithelial Tissue

Covers exposed surfaces, lines internal passageways and chambers, and forms secretory glands.

Connective Tissue

Fills internal spaces, provides structural support, and stores energy.

Muscle Tissue

Contracts to produce movement, including skeletal muscle, cardiac muscle, and smooth muscle.

Nervous Tissue

Conducts electrical impulses and carries information.

Histology

The study of tissues.

Microscopy

The use of microscopes to study cells and tissues.

Simple Microscope

Microscope that uses only one lens.

Compound Microscope

Microscope that uses more than one lens.

Electron Microscope

Microscope capable of magnifying over 1 million times.

Compound light microscope

Detects visible light through a thin section of tissue, using two lenses to magnify the specimen.

Transmission electron microscope

Transmits electrons through the specimen using magnets to direct a beam of electrons.

Scanning electron microscope

Uses electrons, but bounces them off a metal-coated specimen to produce a 3D image of the surface.

Epithelia

Layers of avascular tissue that cover exposed surfaces and line internal cavities and passageways.

Glands

Structures derived from epithelia, predominantly made of secretory cells.

Exocrine Glands

Glands that secrete onto external surfaces or into ducts.

Endocrine Glands

Glands that secrete hormones into the interstitial fluid, which are then distributed by the bloodstream.

Apical Surface

Faces the exterior of the body or an internal space.

Base

Attached to underlying tissues and the basolateral surface.

Basolateral Surface

Includes the base and sides (lateral surfaces) attached to neighboring cells.

Squamous Epithelium

Thin and flat epithelial cells.

Cuboidal Epithelium

Cube-shaped epithelial cells.

Columnar Epithelium

Epithelial cells that are taller than they are wide, resembling slender rectangles.

Simple Epithelium

Single layer of epithelial cells.

Stratified Epithelium

Several layers of epithelial cells.

Hemidesmosomes

Attach deepest epithelial cells to the basement membrane.

Tight Junctions

Interlocking membrane proteins that bind adjacent plasma membranes together to prevent passage of water and solutes between cells.

Adhesion Belts

A continuous band of membrane proteins that strengthens the apical region of cells and reinforces tight junctions.

Gap Junctions

Interlocking transmembrane proteins (connexons) that assist chemical communication to help coordinate functions.

Desmosomes

Provide firm attachments by interlocking adjacent cells’ cytoskeletons, resisting stretching and twisting.

Simple Squamous Epithelium

Epithelium that is thin, flat, irregularly shaped cells adapted for absorption, diffusion, and reduction of friction.

Simple Squamous Epithelium Locations

Locations include peritoneum, capillary walls, inside the eye, lung alveoli.

Stratified Squamous Epithelium

Epithelium characterized by many layers of cells in areas with mechanical or chemical stresses, with the superficial layer flattened.

Stratified Squamous Epithelium Locations

Located where severe mechanical or chemical stresses exist, such as the surface of skin and lining the mouth, throat, esophagus, rectum, anus, vagina.

Keratinized Stratified Squamous Epithelium

Stratified squamous epithelium, where superficial layers are packed with keratin, making it tough and water resistant

Nonkeratinized Stratified Squamous Epithelium

Stratified squamous epithelium that resists abrasion but can dry out, found lining the oral cavity, pharynx, esophagus, anus, vagina.

Simple Cuboidal Epithelium

Epithelium in which cells resemble hexagonal boxes, functioning in secretion and absorption, and lines the exocrine glands and parts of kidney tubules and thyroid gland.

Transitional Epithelium

Transitional epithelium, found only in the urinary system, that can stretch and recoil without damage.

Columnar Epithelium

Epithelium comprised of rectangular cells, taller and more slender than cuboidal, absorbing substances and protecting the body.

Simple Columnar Epithelium Locations

Simple columnar epithelium is commonly found lining the stomach, intestine, gallbladder, uterine tubes, kidney ducts.

Pseudostratified Columnar Epithelium

A columnar epithelium composed of cells of varying shapes and functions that appear layered due to the varying location of nuclei.

Glands

Collections of epithelial cells (or derived structures) that produce secretions.

Endocrine Glands

Glands that release secretions into interstitial fluid.

Exocrine Glands

Glands that 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, released along with the secretory product.

Holocrine Secretion

Destroys the gland cell, destroying the entire cell to release secretions, replacing cells via division.

Three Subdivisions of Connective Tissue

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

Ground Substance

Syrupy Clear and colorless substance due to the presence of proteoglycans and glycoproteins.

Reticular Fibers

Strong fibers that form a branching network.

Collagen Fibers

Thick and very strong fibers

Elastic Fibers

Slender and very stretchy fibers.

Fixed Cells

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

Examples of Fixed Cells

Melanocytes, Fixed macrophage, Mast cells, Fibroblasts, Adipocytes, Fibrocytes.

Wandering Cells

Move throughout tissue and function in defense and repair.

Examples of Wandering Cells

Plasma cells, Free macrophages, Mesenchymal cells, Neutrophils and eosinophils, Lymphocytes.

Areolar Tissue

Most common connective tissue proper found as the packing material of the body.

Adipose Tissue

Found deep to the skin and forms a layer of padding around the eyes and kidneys.

Reticular Tissue

Found in the liver, kidney, spleen, lymph nodes, and bone marrow, providing support and resisting distortion.

Dense Regular Connective Tissue

Collagen arranged in parallel bundles.

Dense Irregular Connective Tissue

Fibers arranged in a meshwork with no consistent pattern to resist tension in many directions.

Blood Components

Composed of watery matrix with formed elements suspended in plasma such as Red blood cells , White blood cells, Platelets.

Cartilage Matrix

A firm gel containing chondroitin sulfates.

Chondrocyte

Only one type of cell found in cartilage.

Lacunae

Small chambers where chondrocytes are located.

Hyaline Cartilage Locations

Found between ribs and sternum, covering bones in mobile joints, part of nasal septum, supporting respiratory passageways.

Elastic Cartilage

Distorts without damage and returns to its original shape; found in the external ear.

Fibrocartilage

Found in the knee joint, between pubic bones, and in intervertebral discs. It is durable, tough, and resists compression.

Perichondrium

Two layered structure that separates cartilage from other tissues.

Appositional Growth

Cartilage growth at the surface.

Interstitial Growth

Cartilage growth from within cartilage.

Osseous Tissue

Connective tissue with a solid, crystalline matrix mainly of calcium salts.

Osteons

Functional units of compact bone.

Osteocytes

Mature bone cells in lacunae.

Membranes

Line or cover body surfaces, typically consisting of epithelium supported by connective tissue.

Mucous Membranes

Line passageways open to the exterior of the body such as digestive, respiratory, reproductive, urinary tracts.

Serous Membranes

Composed of mesothelium supported by areolar connective tissue, line subdivisions of the ventral body cavity.

Cutaneous Membrane

Covers the surface of the body (skin), composed of stratified squamous epithelium.

Cutaneous Membrane Characteristics

Waterproof and dry membrane, typically covers the skin.

Synovial Membrane

Lines freely movable joint cavities.

Fasciae

Connective tissue layers that support and surround organs.

Superficial Fascia

Under the skin, consists of areolar and adipose tissue.

Deep Fascia

Continuous with capsules, ligaments, and other connective tissue structures, consisting of dense irregular connective tissue.

Subserous Fascia

Between serous membranes and deep fascia, consisting entirely of areolar tissue.

Relative body weight of Muscle Tissue

50 percent.

Relative body weight of Nervous Tissue

2 percent.

Muscle Tissue

Specialized for contraction to cause movement.

Skeletal Muscle Tissue Functions

Move and stabilizes skeleton, - Guard entrances and exits to digestive, respiratory, urinary tracts, - Generate heat, - Protect internal organs.

Cardiac Muscle Tissue Function

Functions to move blood and maintain blood pressure.

Smooth Muscle Tissue Functions

• Move food, urine, and reproductive secretions, - Control diameter of respiratory passageways and blood vessels

Nervous Tissue

Specialized for conduction of electrical impulses.

Neurons

Transfer information around the body and perform information processing.

Neuroglia or Glial Cells

Various supporting cells.

Dendrites

Receive information.

Axon

Conducts information to other cells.

Inflammation

Defense mechanism that leads to - Swelling, Redness, Warmth, PainMay result from injury or from infection (presence of pathogens within the tissue).

Mast Cell Activation

Activation process that produces indications of injury via inflammatory stimulation.

Regeneration

Fibroblasts produce collagen fibers to stabilize injury site, forming dense, collagenous framework called scar tissue.

Fibrosis

Permanent replacement of normal tissue by scar tissue.