Tissues and Epithelial/Connective Tissue - Vocabulary Flashcards

Vocabulary flashcards covering tissues, epithelia, and connective tissue concepts from the ANP1111 lecture notes.

Tissue

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

Homeostasis

Maintenance of a relatively constant internal environment through organized tissue function and integration.

Four primary tissue types

Epithelial, connective, muscle, and nervous tissues.

Epithelial tissue

A sheet of cells that covers body surfaces or lines cavities; forms boundaries and membranes.

Histology

The study of tissues and their cellular organization.

Basement membrane

Boundary layer that anchors epithelium to underlying connective tissue, consisting of basal lamina and reticular lamina.

Basal lamina

Glycoprotein-rich layer of the basement membrane that underlies epithelium.

Reticular lamina

Collagen-rich layer of the basement membrane lying beneath the basal lamina.

Polarity (epithelial)

Distinct apical and basal surfaces of epithelial cells, with specialized structures on the apical surface.

Tight junctions

Specialized contacts that seal neighboring cells together, limiting paracellular transport.

Desmosomes

Strong junctions that attach cells to each other, providing mechanical support.

Innervated but avascular

Epithelium has nerve supply but lacks blood vessels and is nourished by diffusion from underlying tissues.

Regeneration (epithelial)

High capacity for renewal and repair of epithelial tissue after injury.

Gland

One or more cells that secrete a product (hormones or other substances).

Endocrine gland

Ductless glands that secrete hormones directly into the bloodstream.

Exocrine gland

Glands with ducts that secrete onto surfaces or into cavities (e.g., mucous, sweat, salivary).

Unicellular exocrine gland

Gland consisting of a single cell, such as goblet cells, that secretes onto surfaces.

Multicellular exocrine gland

Gland with duct and secretory units; supported by connective tissue.

Merocrine secretion

Secretory products released by exocytosis; most common type.

Holocrine secretion

Secretory cells rupture to release product; whole cell destroyed (e.g., sebaceous glands).

Apocrine secretion

Apical portion of the cell pinches off with secretory product; cell repairs itself.

Simple squamous epithelium

Thin, permeable epithelium; functions in filtration and diffusion (e.g., endothelium, kidney, lungs).

Simple cuboidal epithelium

Cube-shaped cells specialized for secretion and absorption (e.g., kidney tubules, small glands).

Simple columnar epithelium

Tall, column-like cells specialized for secretion and absorption (e.g., GI tract).

Pseudostratified ciliated columnar epithelium

Single layer that appears stratified; often with cilia and mucus secretion (e.g., respiratory tract).

Stratified squamous epithelium

Multiple cell layers; basal cells cuboidal, apical cells flattened; provides protection (skin is a common example).

Transitional epithelium

Stratified epithelium that lines the bladder; apical cells flatten as the organ stretches.

Cell shape

One criterion for epithelial classification: squamous, cuboidal, or columnar.

Number of cell layers

Second criterion for epithelial classification: simple (one layer) vs stratified (multiple layers).

Ground substance

Amorphous matrix in connective tissue that binds fibers and cells; contains interstitial fluid and proteoglycans.

Fibers

Structural proteins in connective tissue: collagen (tension), elastic (stretch/recoil), and reticular (fine supportive network).

Collagen fibers

Thick, strong fibers with high tensile strength; main structural protein in CT.

Elastic fibers

Elastin-containing fibers that allow stretch and recoil.

Reticular fibers

Thin collagen fibers that form a supportive mesh in soft tissues and organ stroma.

Ground substance function

Hydrated gel that fills the extracellular matrix and acts as a molecular sieve.

Blast vs cyte (connective tissue cells)

Blasts are actively dividing/synthesizing cells; cytes are mature cells that maintain the matrix.

Mesenchyme

The first connective tissue from the mesoderm; source of all other CT types.

Connective tissue proper

Main CT category including loose and dense connective tissues.

Areolar connective tissue

Loose CT with gel-like matrix; cushions and nourishes epithelia; site of edema during inflammation.

Adipose tissue

Loose CT specialized for nutrient storage in adipocytes; insulates and protects organs.

Reticular connective tissue

Loose CT with reticular fibers forming a supportive internal skeleton for lymphoid organs.

Dense regular connective tissue

Dense CT with parallel collagen fibers; provides strong attachment (tends/ligaments).

Dense irregular connective tissue

Dense CT with irregularly arranged collagen fibers; resists tension from many directions.

Elastic connective tissue

Dense CT rich in elastic fibers; highly flexible (e.g., certain ligaments).

Cartilage

A type of supportive connective tissue with a resilient, gel-like matrix.

Bone

Hard connective tissue that supports, protects, and stores minerals.

Blood

Fluid connective tissue that transports nutrients, gases, and wastes.

Fibers as main component of CT

Fibers (collagen, elastic, reticular) are the primary structural elements of connective tissue.

Connective tissue functions

Binding and supporting, protecting, insulating, and transporting substances.