Chapter 4: Tissues – Human Anatomy & Physiology

Vocabulary flashcards summarizing key terms and definitions from Chapter 4 on tissues, covering epithelial, connective, muscle, and nervous tissues, their characteristics, classifications, and repair.

Tissue

Group of similar cells that perform a common or related function.

Histology

The study of tissues.

Epithelial Tissue

Sheets of cells that cover body surfaces or line cavities; functions include protection, secretion, absorption, filtration.

Connective Tissue

Most abundant primary tissue; supports, binds, protects, insulates, stores fuel, transports substances.

Muscle Tissue

Highly vascularized tissue whose cells (muscle fibers) contract to cause movement.

Nervous Tissue

Tissue specialized for internal communication via electrical impulses; composed of neurons and neuroglia.

Extracellular Matrix (ECM)

Non-living material (ground substance + fibers) surrounding connective-tissue cells; allows tissue to bear weight and tension.

Polarity (epithelium)

Property of epithelial cells having an apical (free) surface and a basal (attached) surface.

Apical Surface

The free, exposed surface of an epithelial cell facing the body exterior or cavity lumen.

Basal Surface

The lower, attached surface of an epithelial cell anchored to underlying connective tissue.

Basal Lamina

Thin adhesive sheet beneath epithelial cells that filters and anchors them to connective tissue.

Basement Membrane

Layer between epithelium and connective tissue composed of basal lamina + reticular lamina; reinforces epithelium.

Tight Junction

Intercellular junction that seals adjacent epithelial cells, preventing fluid leakage between them.

Desmosome

Anchoring junction that binds adjacent cells together through plaques and intermediate filaments; resists tearing.

Simple Epithelium

Epithelium composed of a single cell layer; specialized for absorption, secretion, filtration.

Stratified Epithelium

Epithelium with two or more cell layers; chiefly protective (e.g., skin).

Squamous Cells

Flat, scale-like epithelial cells.

Cuboidal Cells

Box-shaped epithelial cells approximately as tall as they are wide.

Columnar Cells

Tall, column-shaped epithelial cells.

Pseudostratified Columnar Epithelium

Single layer of height-varying cells that appears layered; often ciliated and mucus-secreting.

Transitional Epithelium

Stratified epithelium whose surface cells change shape to allow organ stretch (e.g., bladder).

Goblet Cell

Unicellular gland that secretes mucus in epithelial linings of intestines and respiratory tract.

Endocrine Gland

Ductless gland that releases hormones into blood or lymph for internal signaling.

Exocrine Gland

Gland that secretes products into ducts leading to body surface or cavities (e.g., sweat).

Unicellular Gland

Single secretory cell (e.g., goblet cell).

Multicellular Gland

Secretory epithelium composed of many cells, often with ducts (e.g., salivary gland).

Mesenchyme

Embryonic connective tissue from which all connective tissues arise.

Ground Substance

Gel-like material of ECM filling space between cells; contains fluid, adhesion proteins, proteoglycans.

Collagen Fiber

Thick, strong connective-tissue fiber providing high tensile strength.

Elastic Fiber

Long, thin fiber of elastin that stretches and recoils.

Reticular Fiber

Short, fine, branching collagen fiber forming supportive networks.

Fibroblast

Immature, matrix-secreting cell of connective tissue proper.

Chondroblast

Cartilage-forming, matrix-secreting cell.

Osteoblast

Bone-forming cell that secretes bone matrix.

Hematopoietic Stem Cell

Undifferentiated blood-forming cell in bone marrow.

Adipocyte

Fat cell that stores energy as triglycerides.

Mast Cell

Immune cell that releases histamine, heparin, and other mediators during inflammation.

Macrophage

Phagocytic cell that engulfs pathogens and debris; key player in immunity.

Areolar Connective Tissue

Loose CT that cushions organs, stores fluids, and plays a role in inflammation.

Adipose Tissue

Loose CT with closely packed adipocytes; stores fuel, insulates, supports organs.

Reticular Connective Tissue

Loose CT with reticular fibers forming an internal skeleton supporting blood cells.

Dense Regular Connective Tissue

CT with parallel collagen fibers; resists tensile stress; forms tendons & ligaments.

Dense Irregular Connective Tissue

CT with irregularly arranged collagen fibers; withstands tension in many directions.

Elastic Connective Tissue

CT rich in elastic fibers; allows recoil of arteries, lungs, and some ligaments.

Hyaline Cartilage

Most abundant cartilage; supports, cushions; found in nose, trachea, rib ends.

Elastic Cartilage

Flexible cartilage maintaining shape; found in external ear and epiglottis.

Fibrocartilage

Cartilage with thick collagen; absorbs compressive shock; intervertebral discs.

Perichondrium

Dense irregular CT membrane surrounding cartilage; supplies nutrients and houses chondroblasts.

Lacuna

Small cavity in cartilage or bone matrix housing a chondrocyte or osteocyte.

Osseous Tissue

Bone tissue; hard, vascular connective tissue that supports and protects.

Blood (as CT)

Fluid connective tissue with plasma matrix; transports gases, nutrients, wastes, hormones.

Skeletal Muscle

Voluntary muscle attached to bones; striated fibers move skeleton.

Cardiac Muscle

Involuntary, striated muscle of the heart; contains intercalated discs.

Smooth Muscle

Involuntary, non-striated muscle in walls of hollow organs (e.g., intestines, vessels).

Neuron

Excitable nerve cell that generates and transmits electrical impulses.

Neuroglia

Supporting, insulating, protecting cells of the nervous system.

Cutaneous Membrane

Dry membrane; the skin (keratinized stratified squamous epithelium atop CT).

Mucous Membrane

Moist membrane lining body cavities open to exterior; often secretes mucus.

Serous Membrane

Moist membrane lining closed ventral cavities; secretes lubricating serous fluid.

Regeneration (tissue)

Replacement of destroyed tissue with the same kind, restoring function.

Fibrosis

Replacement of destroyed tissue with scar (dense connective) tissue; function lost.

Granulation Tissue

Delicate connective tissue that replaces blood clot during healing and restores blood supply.