Types and Components of Tissues

Comprehensive vocabulary flashcards generated from the tissue study notes, covering tissue categories, intercellular connections, epithelial and connective tissue subtypes, secretion modes, and extracellular matrix components.

Tissue

A group of cells functioning together in the body.

Histology

The microscopic study of tissue appearance, organization, and function.

Pathology

The study of anatomical and physiological changes that occur during the course of disease.

Four Types of Tissues

The four primary categories of tissue in the body: epithelial tissue, connective tissue, muscle tissue, and nervous tissue.

Epithelial Tissue

Sheets of cells that cover exterior surfaces of the body, line internal cavities and passageways, and form certain glands.

Connective Tissue

The most diverse category of tissue that binds cells and organs together and functions in protection, support, and integration of body parts.

Muscle Tissue

Contractile tissue that provides movement, such as moving the skeleton or pumping blood through the heart.

Nervous Tissue

Tissue capable of short- and long-distance electrical communication throughout the body.

Extracellular Matrix

A network of substances that surround and support the cells in a tissue, varying from solid in bone to liquid in blood.

Collagen

The most abundant protein in the human body, formed from subunits woven into long, tough fibers that provide structure to the ECM.

Proteoglycans

Large, negatively-charged molecules composed of carbohydrates and proteins that attract $\text{Na}^+$ and water molecules into the extracellular matrix.

Tight Junctions

Protein complexes that fuse neighboring cell membranes tightly together, eliminating extracellular space to block substance leakage between cells.

Anchoring Junctions

Cell junctions, including desmosomes and hemidesmosomes, that structurally stabilize cells and provide strong yet flexible connections.

Desmosomes

Anchoring junctions that unite two neighboring cells together structurally.

Hemidesmosomes

Anchoring junctions that resemble half a desmosome and link cells to the underlying extracellular matrix.

Gap Junctions

Intercellular passageways between adjacent cell membranes that facilitate the movement of small molecules and ions to enable electrical and metabolic coupling.

Endothelium

Epithelial tissue lining inside body structures, such as blood vessels.

Epithelium

Epithelial tissue covering outside body structures, such as the skin.

Simple Squamous Epithelium

A single layer of flat cells with a 'fried egg' appearance, found in lung alveoli, segments of kidney tubules, and capillary linings.

Simple Cuboidal Epithelium

A single layer of boxlike cells that appear round, found in transport locations such as gland ducts.

Simple Columnar Epithelium

A single layer of tall, narrow cells active in absorption and secretion, lining sections of the digestive and reproductive systems.

Pseudostratified Columnar Epithelium

A single layer of irregularly-shaped columnar cells whose nuclear heights give the appearance of multiple layers, commonly found in the respiratory tract.

Transitional Epithelium

A specialized stratified epithelium found in the urinary bladder characterized by a scalloped pattern at its apical surface.

Goblet Cells

Unicellular exocrine glands located within simple and pseudostratified columnar epithelia that synthesize and secrete mucus.

Stratified Squamous Epithelium

Multiple cell layers featuring flat apical cells; can be keratinized (topped with dead, keratin-filled cells) or nonkeratinized (top layer consists of moist living cells).

Endocrine Gland

A ductless gland that releases secretions called hormones directly into the surrounding interstitial fluid and bloodstream.

Exocrine Gland

A gland that releases secretions through a duct onto an epithelial surface or to the outside of the body.

Merocrine Secretion

The most common exocrine secretion process, where products contained in vesicles are released at the cell surface via exocytosis.

Apocrine Secretion

A mode of exocrine secretion where material accumulates near the apical portion of the cell, which then pinches off and is released.

Holocrine Secretion

A mode of exocrine secretion involving the accumulation of secretory products followed by the total rupture and destruction of the gland cell.

Serous Glands

Glands that secrete watery fluids derived from blood plasma that are typically rich in enzymes.

Mucous Glands

Glands that secrete watery to viscous products rich in the glycoprotein mucin.

Ground Substance

The fluid or material component of connective tissue located between the cells and protein fibers.

Fibroblasts

The most abundant cells in connective tissue proper, responsible for producing protein fibers.

Adipocytes

Specialized connective tissue cells that store lipids as droplets filling most of their cytoplasm.

Areolar Tissue

A loose connective tissue resembling a web, consisting predominantly of collagen fibers with smaller amounts of elastin, underlying most epithelia.

White Adipose Tissue

The most abundant fat tissue in adults, which functions in lipid storage, thermal insulation, and physical shielding of organs.

Brown Adipose Tissue

A fat tissue common in infants that releases heat instead of ATP as it breaks down fats.

Reticular Tissue

A loose connective tissue framework of branching reticular fibers that provides structural support for immune cells in soft organs like the liver and spleen.

Chondrocytes

Cells embedded within cartilage matrix responsible for producing chondroitin sulfates, polysaccharides, and other matrix components.

Hyaline Cartilage

The most common cartilage type in the human body, featuring a smooth surface that covers bone joints and forms the rib cage.

Fibrocartilage

A tough cartilage containing thick bundles of collagen fibers, located in high weight-bearing areas like the knee joints and intervertebral discs.

Elastic Cartilage

A flexible cartilage containing collagen, proteoglycans, and abundant elastic fibers, providing rigid support and elasticity in structures like the external ear.