🧬| Chapter 4: Tissue Level of Organization

A comprehensive set of vocabulary flashcards covering key terms from the lecture on tissue types, their structures, and functions.

Histology

The study of tissues.

Tissue

A group of similar cells and extracellular products with a common function.

Epithelial Tissue

Tissue that covers surfaces, lines cavities, and forms glands.

Connective Tissue

Tissue that fills spaces, supports, and stores energy.

Muscle Tissue

Tissue for contraction and movement; includes skeletal, cardiac, smooth.

Nervous Tissue

Tissue that conducts electrical impulses and carries information.

Epithelium

A sheet of epithelial cells covering or lining a body surface or cavity.

Basement Membrane

Non-cellular layer anchoring epithelial cells, from epithelium and connective tissue.

Apical Surface

The free surface of an epithelial cell exposed to the body exterior or cavity interior.

Microvilli

Microscopic, non-motile apical projections for increased absorption surface area.

Cilia

Motile, hair-like projections on apical surfaces that move fluid or mucus.

Basolateral Surface

The sides and base of an epithelial cell that attach to neighbors and the basement membrane.

Tight Junction

Intercellular junction that seals adjacent cells to prevent passage of water and solutes.

Gap Junction

Intercellular junction allowing ions and small molecules to pass between cells.

Desmosome

Strong intercellular junction that resists stretching and twisting stresses.

Simple Epithelium

Epithelium with one layer of cells.

Stratified Epithelium

Epithelium with two or more layers of cells.

Squamous Cell

Epithelial cell wider than tall; plate-like.

Cuboidal Cell

Epithelial cell as tall as wide; cube-shaped.

Columnar Cell

Epithelial cell taller than wide; column-shaped.

Simple Squamous Epithelium

Single layer of flat cells; permits diffusion/filtration and secretes lubricants.

Mesothelium

Simple squamous epithelium lining pericardial, pleural, and peritoneal cavities.

Endothelium

Simple squamous epithelium lining heart and blood vessels.

Simple Cuboidal Epithelium

Single layer of cube-like cells; functions in secretion and absorption.

Simple Columnar Epithelium

Single layer of tall cells; involved in absorption and secretion; ciliated form propels mucus.

Goblet Cell

Unicellular exocrine gland that secretes mucin to form mucus.

Pseudostratified Ciliated Columnar Epithelium

Appears stratified but all cells touch basement membrane; cilia move mucus.

Stratified Squamous Epithelium

Multiple layers of cells; protects against severe mechanical or chemical stresses.

Keratinized Epithelium

Stratified squamous epithelium with surface layers packed with keratin, making it tough and water-resistant.

Nonkeratinized Epithelium

Stratified squamous epithelium lacking surface keratin; must remain moist.

Transitional Epithelium

Stratified epithelium that stretches; lines urinary bladder, ureters, and proximal urethra.

Glandular Epithelium

Epithelial tissue specialized for secretion forming exocrine and endocrine glands.

Exocrine Gland

Gland that releases secretions into ducts leading to epithelial surfaces.

Endocrine Gland

Ductless gland that releases hormones into the bloodstream.

Connective Tissue Proper

Connective tissue with diverse cells, fibers, and syrupy ground substance.

Areolar Tissue

Loose connective tissue with all cell types; widely distributed packing material.

Adipose Tissue

Loose connective tissue of adipocytes that stores fat and insulates the body.

Reticular Tissue

Loose connective tissue with reticular fibers forming a stroma in lymphoid organs.

Dense Regular Connective Tissue

Connective tissue with parallel collagen fibers; forms tendons and ligaments.

Dense Irregular Connective Tissue

Connective tissue with thick, interwoven collagen bundles; found in dermis and organ capsules.

Elastic Tissue

Connective tissue rich in elastic fibers; allows stretch and recoil in arteries and ligaments.

Plasma

Fluid blood matrix suspending formed elements.

Cartilage

Supporting connective tissue with chondrocytes in lacunae and a firm, avascular matrix.

Chondrocyte

Mature cartilage cell occupying a lacuna.

Lacuna

Small cavity in cartilage or bone matrix housing a cell.

Perichondrium

Dense irregular connective tissue membrane surrounding cartilage.

Hyaline Cartilage

Common, stiff-flexible cartilage; reduces joint friction.

Elastic Cartilage

Cartilage with abundant elastic fibers; tolerates distortion and returns to shape.

Fibrocartilage

Cartilage with dense collagen; resists compression and limits movement.

Bone (Osseous Tissue)

Supporting connective tissue with calcified matrix and collagen fibers.

Osteoblast

Bone-forming cell that secretes bone matrix.

Osteocyte

Mature bone cell residing in a lacuna; maintains bone matrix.

Osteoclast

Large, multinucleated cell that resorbs bone matrix.

Periosteum

Dense connective tissue membrane covering bone surfaces except at joints.

Muscle Fiber

Elongated muscle cell capable of contraction.

Skeletal Muscle

Striated, multinucleated voluntary muscle attached to bones.

Cardiac Muscle

Striated, branched involuntary muscle of the heart with intercalated discs.

Intercalated Disc

Specialized junction of cardiac muscle; synchronizes contraction.

Smooth Muscle

Non-striated involuntary muscle in walls of hollow organs and blood vessels.

Neuron

Excitable cell that transmits electrical impulses.

Soma

Cell body of a neuron containing the nucleus.

Dendrite

Branched neuronal process that receives signals.

Axon

Long neuronal process that conducts impulses away from the soma.

Neuroglia (Glial Cells)

Supporting cells nourishing, protecting, and insulating neurons.