Epithelial and Connective Tissue - Vocabulary Review

Vocabulary flashcards covering key terms from epithelial and connective tissue biology, including basement membranes, ECM components, cell types, and gland types.

Epithelial tissue

A sheet of cells lining surfaces and cavities; can be simple (one layer) or stratified (multiple layers); rests on the basement membrane.

Basal membrane (basement membrane)

Thin layer between epithelium and connective tissue, composed of basal lamina and reticular lamina, anchoring the epithelium to the connective tissue.

Basal lamina

Part of the basement membrane produced by epithelial cells; rich in collagen IV and laminin; supports the epithelium.

Reticular lamina

Part of the basement membrane produced by connective tissue; contains reticular (collagen type III) fibers.

Desmosomes

Intercellular junctions that tightly link adjacent epithelial cells, contributing to tissue cohesion.

Microvilli

Tiny finger-like projections on the apical surface of some epithelia to increase surface area for absorption.

Brush border

The dense appearance of microvilli on the apical surface, especially in the intestine, seen with light microscopy.

Cilia

Hair-like projections on some epithelial cells that move mucus or fluids along the surface.

Goblet cell

Unicellular gland within epithelium that secretes mucus; common in the GI and respiratory tracts.

Mucous gland

Exocrine gland that produces mucus; can be unicellular (goblet cells) or multicellular.

Serous gland

Exocrine gland that secretes a watery, protein-rich (serous) fluid; cytoplasm appears eosinophilic.

Exocrine gland

Gland that releases secretions onto an epithelial surface via ducts.

Endocrine gland

Gland that releases hormones directly into the bloodstream (ductless).

Connective tissue

Tissue that connects, supports, and protects; composed of cells, fibers, and ground substance; main cell type is the fibroblast.

Fibroblast

Primary cell of connective tissue; elongated nucleus; synthesizes fibers and ground substance; can be active or inactive.

Ground substance

Gel-like component of the extracellular matrix surrounding fibers and cells; rich in water, proteoglycans, and glycosaminoglycans.

Extracellular matrix (ECM)

Non-cellular framework outside cells, consisting of fibers and ground substance.

Collagen

Most abundant ECM protein; forms fibrils and fibers; provides tensile strength; produced by fibroblasts.

Collagen type I

Major fibrillar collagen type forming thick, strong fibers in many connective tissues.

Collagen type III (reticular fibers/reticulin)

Delicate, supportive network forming reticular fibers; important in liver, spleen, lymph nodes; visualized with silver stain.

Reticular fibers

Fibers made of collagen type III forming a supportive mesh in organs like liver.

Elastic fibers

ECM fibers that provide elasticity; composed of elastin reinforced by fibrillin microfibrils.

Elastin

Protein giving tissues the ability to stretch and recoil.

Fibrillin

Glycoprotein that associates with elastin to form elastic fibers; helps stabilize elasticity.

Proteoglycans

Core protein with glycosaminoglycan chains; highly negatively charged; attracts water in ground substance.

Glycosaminoglycans (GAGs)

Long polysaccharide chains attached to proteoglycans; contribute to the gel-like ECM and water binding.

Endothelial cells

Cells lining the interior of blood vessels; form the vascular endothelium.

Blood vessel

A tubular structure carrying blood; lumen is lined by endothelium.

Basal membrane components

Basal lamina (epithelial origin) and reticular lamina (connective tissue origin) forming the basement membrane between epithelium and connective tissue.

Stratified squamous epithelium, keratinized

Multilayered epithelium with a keratinized surface; provides robust protection, typical of skin.

Squamous epithelium (light microscopy)

Flat, scale-like epithelial cells; appears as light/white lines under light microscopy.

Silver stain

Histological stain that highlights reticular fibers (collagen type III) in tissues like liver, spleen, and bone marrow.

Invasive squamous cell carcinoma (SCC)

Malignant tumor arising from squamous epithelium that invades surrounding tissues.