Human Anatomy & Physiology - Chapter 4: Tissue: The Living Fabric

A comprehensive collection of vocabulary flashcards covering basic tissue types, epithelial features, glands, connective tissue components, muscle and nervous tissues, body membranes, tissue repair, and germ layers from Chapter 04.

Histology

The study of tissues.

Epithelial tissue

A sheet of cells that covers a body surface or lines body cavities, functioning in protection, absorption, filtration, excretion, secretion, and sensory reception.

Apical surface

The upper free side of an epithelial cell or tissue exposed to a surface or body cavity.

Basal surface

The lower attached side of an epithelial tissue that faces inward toward the body and attaches to the basal lamina.

Basal lamina

An adhesive sheet at the basal surface of epithelial cells that holds them to underlying cells.

Reticular lamina

A layer deep to the basal lamina consisting of a network of collagen fibers.

Basement membrane

A boundary structure composed of the basal lamina and reticular lamina that reinforces the epithelial sheet and resists stretching and tearing.

Simple epithelia

Epithelial tissues consisting of a single cell layer, located where thin barriers are needed for absorption, secretion, or filtration.

Stratified epithelia

Epithelial tissues consisting of two or more cell layers, located in high-abrasion areas where protection is the primary role.

Endothelium

A specialized simple squamous epithelium that lines lymphatic vessels, blood vessels, and the heart.

Mesothelium

A specialized simple squamous epithelium found in serous membranes lining the ventral body cavity.

Simple squamous epithelium

A tissue composed of a single layer of flattened cells with disc-shaped central nuclei and sparse cytoplasm, specialized for rapid diffusion and filtration.

Simple cuboidal epithelium

A single layer of cubelike cells with large spherical central nuclei, functioning in secretion and absorption in kidney tubules and small gland ducts.

Simple columnar epithelium

A single layer of tall cells with round to oval nuclei, involved in absorption and secretion of mucus, enzymes, and other substances.

Pseudostratified columnar epithelium

A single layer of cells of differing heights that give a false appearance of being multi-layered, specialized for secretion and ciliary propulsion of mucus.

Stratified squamous epithelium

A thick tissue composed of several cell layers with flattened surface cells, protecting underlying tissues in areas subject to abrasion.

Transitional epithelium

A tissue resembling stratified squamous and stratified cuboidal epithelia with dome-shaped surface cells that stretch readily to allow distension of urinary organs.

Endocrine glands

Ductless glands that secrete hormones by exocytosis directly into surrounding interstitial fluid to enter the lymph or blood.

Exocrine glands

Glands that secrete their products through ducts onto body surfaces or into body cavities.

Mucin

A complex sugar-protein produced by unicellular exocrine glands that dissolves in water to form mucus.

Merocrine glands

Exocrine glands that secrete products by exocytosis as they are produced, without altering or damaging the cell.

Holocrine glands

Exocrine glands that accumulate their products within their cells until the cells rupture to release the product.

Apocrine glands

Exocrine glands that accumulate products within their cells until the apex ruptures, after which the cell repairs itself.

Mesenchyme

An embryonic tissue from which all classes of connective tissue originate.

Ground substance

An unstructured gel-like material filling the space between cells in connective tissue, composed of interstitial fluid, cell adhesion proteins, and proteoglycans.

Collagen fibers

The strongest and most abundant connective tissue fibers, providing high tensile strength to resist pulling forces.

Elastic fibers

Networks of long, thin elastin fibers in connective tissue that allow for stretching and recoil.

Reticular fibers

Short, fine, highly branched collagenous fibers that form mesh-like networks to support soft organs and blood cells.

Fibroblasts

Immature cell types in connective tissue proper that actively secrete ground substance and matrix fibers.

Areolar connective tissue

The most widely distributed loose connective tissue, serving as a universal packing material that supports and binds other tissues.

Adipose tissue

A loose connective tissue composed primarily of adipocytes that stores energy, insulates against heat loss, and absorbs shock.

Reticular connective tissue

A loose connective tissue containing reticular fibers and reticular cells that form a mesh-like stroma supporting blood cells in lymphoid organs.

Dense regular connective tissue

A connective tissue containing closely packed parallel bundles of collagen fibers that offer high resistance to tension in one direction.

Dense irregular connective tissue

A connective tissue with thick, irregularly arranged collagen fiber bundles that can withstand tension exerted in multiple directions.

Hyaline cartilage

The most abundant type of cartilage, featuring packed collagen fibers and chondrocytes in lacunae with a shiny bluish glass appearance.

Elastic cartilage

Cartilage that is similar to hyaline cartilage but contains significantly more elastic fibers, providing flexibility in the ear and epiglottis.

Fibrocartilage

A tough cartilage with properties between hyaline cartilage and dense regular connective tissue, found in intervertebral discs and knees.

Osteons

Individual structural units of compact bone tissue.

Blood

An atypical fluid connective tissue consisting of blood cells surrounded by fluid plasma matrix, which carries $O_2$, $CO_2$, nutrients, and wastes.

Skeletal muscle tissue

Voluntary muscle tissue composed of long, cylindrical, multinucleate, striated cells attached to bones.

Cardiac muscle tissue

Involuntary muscle tissue found only in the walls of the heart, containing branching, striated, uninucleate cells joined by intercalated discs.

Smooth muscle tissue

Involuntary muscle tissue consisting of non-striated, spindle-shaped, uninucleate cells located in the walls of hollow organs.

Intercalated discs

Specialized junctional sites where adjacent cardiac muscle cells connect.

Neurons

Specialized cells of nervous tissue that receive input via dendrites and transmit electrical signals along axons.

Neuroglia

Nonexcitable supporting cells in nervous tissue that support, protect, and insulate neurons.

Cutaneous membrane

A dry organ membrane consisting of a keratinized stratified squamous epithelium (epidermis) attached to a thick layer of connective tissue (dermis).

Mucous membranes

Moist membranes lining body cavities that open to the exterior, composed of an epithelium over a loose connective tissue layer called lamina propria.

Serous membranes

Moist membranes lining closed ventral body cavities, composed of simple squamous epithelium (mesothelium) resting on thin areolar connective tissue.

Regeneration

A repair mechanism in which destroyed tissue is replaced with the same kind of tissue, fully restoring original function.

Fibrosis

A repair mechanism in which destroyed tissue is replaced by dense connective tissue, forming scar tissue and causing loss of original function.

Granulation tissue

A delicate, capillary-enriched tissue that replaces a blood clot during the organization step of tissue repair.