Tissues and Tissues Types AI FLASHCARDS

VOCABULARY-style flashcards covering key terms and concepts from tissue biology.

Tissues

A group of cells that usually have a common origin in an embryo and function together to carry out specialized activities.

Histology

The science that deals with the study of tissues.

Pathologist

A physician who specializes in laboratory studies of cells and tissues to assist diagnoses.

Epithelial tissue

Tissue that covers body surfaces, lines hollow organs and ducts, and forms glands.

Connective tissue

Tissue that binds, supports, protects organs; stores energy; transports substances.

Muscular tissue

Tissue composed of cells specialized for contraction and generation of force.

Nervous tissue

Tissue that detects changes and responds by generating electrical signals.

Cell junctions

Contact points between the plasma membranes of tissue cells.

Tight junction

Occluding junction that seals passageways between adjacent cells.

Adherens junction

Junction with a plaque that attaches membrane proteins to microfilaments; cadherins link cells.

Cadherin

Transmembrane glycoproteins that participate in adherens junctions.

Desmosomes

Junctions with plaques that connect intermediate filaments; resist tearing.

Intermediate filaments

Cytoskeletal fibers (e.g., keratin) attached to desmosomes.

Hemidesmosomes

Junctions that anchor cells to the basement membrane via integrins.

Integrin

Transmembrane glycoprotein in hemidesmosomes that links to the basement membrane.

Gap junctions

Intercellular channels formed by connexins/connexons allowing cell-to-cell communication.

Connexin

Transmembrane proteins that form gap junction channels.

Connexon

Hexameric channel formed by connexins in gap junctions.

Apical surface

Free, exposed surface of epithelial cells.

Basal surface

Surface that adheres to the basement membrane.

Basement membrane

Thin layer separating epithelium from underlying connective tissue.

Simple epithelium

Single layer of cells; functions in diffusion, osmosis, filtration, secretion, or absorption.

Pseudostratified epithelium

Epithelium that looks multi-layered due to nuclei at different levels; often ciliated.

Stratified epithelium

Two or more cell layers; provides protection against wear and tear.

Squamous epithelium

Flat, scale-like epithelial cells.

Cuboidal epithelium

Cube-shaped epithelial cells.

Columnar epithelium

Tall, column-like epithelial cells.

Transitional epithelium

Epithelium that changes shape (squamous to cuboidal) to stretch in organs like the urinary bladder.

Keratinized stratified squamous

Stratified squamous epithelium with surface keratin that is dead and protective.

Nonkeratinized stratified squamous

Stratified squamous epithelium with living surface cells; moist.

Simple squamous epithelium

Single layer of flat cells; suitable for diffusion/filtration.

Simple cuboidal epithelium

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

Simple columnar epithelium (nonciliated)

Single layer of nonciliated columnar cells with microvilli and goblet cells; secretes/absorbs.

Goblet cells

Unicellular glands that secrete mucus onto epithelial surfaces.

Microvilli

Finger-like extensions that increase surface area for absorption.

Cilia

Hair-like projections that move mucus or particles along surfaces.

Pseudostratified ciliated columnar epithelium

Pseudostratified epithelium with cilia and goblet cells; secretes mucus.

Pseudostratified nonciliated columnar epithelium

Pseudostratified epithelium without cilia or goblet cells; absorption.

Glandular epithelium

Epithelium that forms the secreting portions of glands.

Endocrine glands

Glands that secrete hormones directly into the bloodstream (ductless).

Exocrine glands

Glands that secrete products into ducts onto surfaces.

Goblet cell (unicellular gland)

Unicellular exocrine gland secreting mucus onto epithelia.

Multicellular glands

Glands composed of many cells forming ducts and secretory portions.

Unicellular glands

Glands composed of a single cell, such as goblet cells.

Glandular epithelium

Epithelium specialized for secretion in glands.

Mucous membranes

Lining of cavities that open to the exterior; contain epithelium and lamina propria.

Lamina propria

Areolar connective tissue underlying mucous membranes.

Serous membranes

Membranes lining cavities not open to exterior; consist of areolar tissue and mesothelium.

Parietal serous membrane

Serous membrane attached to cavity walls.

Visceral serous membrane

Serous membrane covering organs within the cavity.

Pleura

Serous membrane lining the thoracic cavity and covering lungs.

Pericardium

Serous membrane lining the heart cavity and covering the heart.

Peritoneum

Serous membrane lining the abdominal cavity and covering abdominal organs.

Cutaneous membrane

Skin; the largest membrane, with epidermis and dermis.

Synovial membrane

Membrane lining joint cavities without epithelium; secretes synovial fluid.

Synoviocytes

Cells lining synovial membranes that secrete synovial fluid.

Ground substance

Material between cells and fibers; can be fluid, gelatinous, semifluid, or calcified.

Extracellular matrix

Material between cells and fibers secreted by connective tissue cells.

Proteoglycans

Glycosaminoglycan proteins that trap water in the matrix.

Glycosaminoglycans (GAGs)

Polysaccharides like hyaluronic acid, chondroitin sulfate, dermatan sulfate, keratan sulfate.

Hyaluronic acid

Viscous, slippery substance in ground substance; binds cells and lubricates joints.

Chondroitin sulfate

GAG providing support and adhesiveness in cartilage, bone, skin, and vessels.

Dermatan sulfate

GAG found in skin, tendons, vessels, and heart valves.

Keratan sulfate

GAG found in bone, cartilage, and cornea.

Fibronectin

Adhesion protein linking ground substance to collagen and cells.

Collagen fibers

Strong fibers resisting tension; provide tensile strength.

Elastic fibers

Fibers composed of elastin and fibrillin that allow stretch and recoil.

Reticular fibers

Fine collagen fibers forming networks to support organs.

Fibroblasts

Cells that synthesize fibers and ground substance.

Macrophages

Phagocytic cells derived from monocytes; engulf pathogens and debris.

Plasma cells

Cells derived from B lymphocytes that secrete antibodies.

Mast cells

Cells that release histamine and participate in inflammatory responses.

Adipocytes

Fat cells that store triglycerides.

Neutrophils

White blood cells that migrate to infection and perform phagocytosis.

Eosinophils

White blood cells active in parasitic infections and allergic responses.

Areolar connective tissue

Loose connective tissue that acts as packing material around other structures.

Adipose tissue

Loose connective tissue that stores fat; white and brown types exist.

Reticular connective tissue

Loose connective tissue with a reticular fiber network forming stroma.

Dense regular connective tissue

Dense connective tissue with collagen fibers aligned in parallel; forms tendons and ligaments.

Dense irregular connective tissue

Dense tissue with irregular collagen fiber arrangement; provides multi-directional strength.

Elastic connective tissue

Dense tissue with many elastic fibers; allows stretching and recoil.

Mesenchyme

Embryonic connective tissue; precursor to other connective tissues.

Mucous connective tissue

Embryonic connective tissue found in the umbilical cord.

Cartilage

Semi-rigid connective tissue with collagen and proteoglycans.

Hyaline cartilage

Glassy cartilage with fine collagen; most common cartilage.

Fibrocartilage

Strong cartilage with thick collagen fibers; lacks a perichondrium.

Elastic cartilage

Cartilage with elastic fibers; maintains shape.

Perichondrium

Dense irregular connective tissue surrounding cartilage.

Chondrocyte

Cartilage cell located in lacunae.

Lacuna

Small space containing a mature cell within cartilage or bone.

Osteon (Haversian system)

Basic unit of compact bone containing lamellae, lacunae, canaliculi, and a central canal.

Lamellae

Concentric sheets of extracellular matrix in osteons.

Lacuna (bone)

Small space housing an osteocyte within bone.

Canaliculi

Small channels that connect lacunae and allow nutrient/waste exchange.

Central (Haversian) canal

Passage for blood vessels and nerves through an osteon.

Osteocytes

Mature bone cells located in lacunae.

Endosteum

Membrane lining the inner surfaces of bone cavities.

Compact bone

Dense bone tissue organized into osteons.

Spongy bone

Bone tissue with trabeculae and spaces for red marrow.

Trabeculae

Bar-like structures in spongy bone forming a lattice.