Lecture Notes Video: Tissue Biology and Epithelial Membranes - Vocabulary Flashcards

Vocabulary-style flashcards covering extracellular/intracellular materials, cell adhesion, signaling, epithelial/muscle/nerve tissues, glands, membranes, and tissue repair.

Intracellular materials

Materials found within cells; includes cytoplasm, organelles, and inclusions.

Extracellular materials

Materials found outside of cells; intercellular material in tissue or body cavities.

Intercellular (interstitial) fluid

Fluid found between cells in a tissue.

Plasma

The extracellular fluid of blood.

Matrix

Proteins and polysaccharides secreted by cells that determine tissue properties and support structure.

Fibers

Structural components of the matrix, including collagen, elastic, and reticular fibers.

Collagen fibers

Fibers that provide high tensile strength in tissues.

Elastic fibers

Fibers that provide elasticity, composed of elastin.

Reticular fibers

Fine collagenous fibers forming supportive networks (stroma).

Attachment proteins

Noncollagen proteins that organize the matrix and help cells attach.

Cell adhesion molecules (CAMS)

Membrane proteins that mediate cell–cell and cell–matrix adhesion and guide movement.

Tight junctions

Adjacent cell membranes fuse to form a barrier, creating impermeable seals.

Desmosomes

Junctions with cadherins and cytoplasmic plaques; keratin filaments anchor cells and resist pulling forces.

Gap junctions

Distinct junctions where cells are connected by channels for direct chemical/electrical exchange.

Connexon

A hollow channel formed by connexin proteins that creates a gap junction.

Contact-dependent signaling

Signaling requiring direct contact between cells (membrane-bound signals).

Ligands

Soluble signaling molecules produced by cells that bind receptors.

Hormones

Endocrine ligands secreted into the bloodstream to act on distant targets.

Paracrine signaling

Local signaling where factors diffuse to neighboring cells.

Neurotransmitters

Ligands released by neurons that diffuse across synapses to target cells.

Receptors

Proteins that bind ligands to elicit a cellular response; may be catalytic or GPCRs.

Tyrosine-kinase receptor

Catalytic receptor with intrinsic tyrosine kinase activity; ligand binding activates signaling.

Catalytic receptors

Receptors that function as enzymes or activate enzymes upon ligand binding.

Chemically gated (ligand-gated) ion channel

Receptor that opens an ion channel in response to ligand binding.

G protein-coupled receptor (GPCR)

Receptor that activates a G protein, triggering intracellular cascades via second messengers.

cAMP

A second messenger produced by adenylyl cyclase in GPCR signaling.

Basement membrane

Thin layer attaching epithelium to connective tissue; composed of basal lamina and reticular lamina.

Basal lamina

Glycoprotein-rich layer secreted by epithelial cells.

Reticular lamina

Layer of collagen fibers produced by connective tissue, beneath the basal lamina.

Epithelium

Tissue that covers surfaces, lines cavities, and forms glands; avascular but innervated; regenerates well.

Polarity

Distinct apical (surface) and basal (basement) surfaces in epithelial cells.

Avascular

Lacking blood supply.

Simple epithelium

Single cell layer; functions include diffusion, absorption, and secretion.

Stratified epithelium

Multiple cell layers; basal cells are active; apical cells are protective.

Squamous epithelium

Flat, scale-like epithelial cells.

Cuboidal epithelium

Cube-shaped epithelial cells.

Columnar epithelium

Tall, column-like epithelial cells; nuclei near the base.

Keratinized epithelium

Stratified squamous epithelium with surface keratinized cells (dead cells at surface).

Simple squamous epithelium

One layer of flat cells; permits diffusion and filtration.

Simple cuboidal epithelium

One layer of cube-shaped cells; functions in secretion and absorption.

Simple columnar epithelium

One layer of tall cells; often with goblet cells and sometimes cilia.

Pseudostratified columnar epithelium

One layer with nuclei at different levels; often ciliated and with goblet cells.

Stratified squamous epithelium

Many layers; protects underlying tissues; keratinized or nonkeratinized.

Transitional epithelium

Epithelium that stretches and changes shape as organs distend.

Glandular epithelium

Epithelium forming glands; secretory tissue.

Exocrine gland

Gland that secretes onto a surface or into ducts.

Endocrine gland

Gland that secretes hormones into the bloodstream.

Multicellular exocrine glands

Glands with ducts and secretory units; classified by structure and function.

Simple vs compound glands

Glands with unbranched vs branched ducts.

Tubular vs alveolar (acinar)

Secretory units that are tubular (tube-shaped) or alveolar (sac-like).

Merocrine glands

Glands that secrete by exocytosis without cell loss.

Holocrine glands

Secretions released when the secretory cell ruptures and dies.

Apocrine glands

Secretions accumulate at the apex and are released when the apex pinches off.

Mesenchyme

Embryonic connective tissue; star-shaped cells that give rise to all connective tissues.

Areolar (loose) connective tissue

Gel-like matrix with all three fiber types; wraps/cushions organs.

Adipose tissue

Loose connective tissue with adipocytes for fat storage and insulation.

Reticular connective tissue

Network of reticular fibers forming internal skeleton for lymphoid organs.

Dense regular connective tissue

Parallel collagen fibers with fibroblasts; withstands pull in one direction (tendons/ligaments).

Dense irregular connective tissue

Irregular collagen fibers with fibroblasts; withstands tension in many directions (dermis).

Elastic connective tissue

Dense connective tissue rich in elastic fibers; great elasticity.

Cartilage

Firm connective tissue; types include hyaline, elastic, and fibrocartilage.

Hyaline cartilage

Firm matrix with imperceptible collagen network; supports and cushions.

Elastic cartilage

Cartilage with numerous elastic fibers; maintains shape with flexibility.

Fibrocartilage

Dense collagen in matrix; absorbs shock in joints and intervertebral discs.

Ground substance

Amorphous matrix filling spaces between cells; enables diffusion.

Extracellular matrix (ECM) components

Ground substance, fibers (collagen, elastin, reticular), proteoglycans, glycoproteins (fibronectin, laminin).

Proteoglycans

Glycosaminoglycans bound to protein; contribute to ECM viscosity and hydration.

Laminin

ECM glycoprotein aiding cell adhesion to the matrix.

Fibronectin

ECM glycoprotein that binds cells to extracellular matrix components.

Basement membrane (concept)

Structure anchoring epithelium to connective tissue; includes basal lamina and reticular lamina.

Basement membrane sublayers

Basal lamina (epithelial secretions) and reticular lamina (connective tissue).

Epithelial membranes

Membranes comprised of epithelial layer with underlying connective tissue: serous, mucous, and cutaneous.

Serous membrane

Membrane with mesothelium and areolar tissue; secretes lubricating serous fluid.

Mucous membrane

Membrane with epithelium and lamina propria; secretes mucus.

Cutaneous membrane

Skin; stratified squamous epithelium with underlying connective tissue.

Tissue repair

Healing process: inflammation, organization, and regeneration or fibrosis.

Inflammation

Initial response with increased vascular permeability and clot formation to isolate injury.

Granulation tissue

Delicate connective tissue with capillaries, macrophages, and fibroblasts replacing a clot.

Regeneration

Replacement of damaged tissue with the original tissue architecture.

Fibrosis

Replacement with fibrous connective tissue (scar formation) when regeneration is limited.