Chapter 4: The Tissue Level of Organization

Vocabulary practice flashcards covering Chapter 4: The Tissue Level of Organization, including epithelial, connective, muscle, and nervous tissue properties, classifications, cellular structures, and embryonic origins.

Tissues

A group of cells that have a similar embryological origin and are specialized for a particular function.

Histology

The science that studies tissues.

Pathologist

A physician who specializes in studying cells and tissues to help make diagnoses and perform autopsies.

Biopsy

A sample of living tissue removed for microscopic examination.

Ectoderm

The outer embryonic layer forming skin, nervous system, and pigment cells.

Mesoderm

The middle embryonic layer forming muscles, bones, and blood.

Endoderm

The inner embryonic layer forming respiratory and digestive linings.

Epithelial Tissue

A major tissue type found on internal and external body surfaces, formed primarily of tightly packed cells, that forms glands and functions in protection, absorption, or secretion.

Connective Tissue

A major tissue type made mostly of non-cellular matrix material that connects, binds, and supports other body tissues.

Muscle Tissue

A major tissue type that contracts to produce body movement.

Nervous Tissue

A major tissue type composed of neurons and neuroglia that allows for electrochemical communication between body regions.

Avascular

Lacking a direct blood supply, requiring nutrients to diffuse from underlying tissues.

Goblet Cells

Unicellular glands that produce mucus to lubricate luminal surfaces of the epithelium and protect underlying tissue layers.

Simple Epithelium

Epithelial tissue consisting of a single layer of cells attached directly to the basement membrane, optimized for absorption and secretion.

Stratified Epithelium

Epithelial tissue consisting of two or more layers of stacked cells, specialized for protecting underlying tissues.

Pseudostratified Epithelium

Epithelial tissue consisting of a single layer of cells that appears layered, though all cells touch the basement membrane.

Squamous Cells

Flattened, scale-like epithelial cells.

Cuboidal Cells

Cube-shaped epithelial cells featuring a round/circular nucleus.

Columnar Cells

Tall rectangular epithelial cells featuring an oval or elliptical nucleus.

Transitional Epithelium

Epithelial tissue with variable, stretch-adaptable cell shapes that lines the urinary bladder.

Cilia

Contractile hair-like appendages on apical surfaces that propel mucus across epithelium, such as in the respiratory tract.

Microvilli

Finger-like projections on apical cell surfaces that increase surface area to optimize absorption and secretion in the GI tract and kidneys.

Simple Squamous Epithelium

A single layer of flattened cells in direct contact with the basement membrane, functioning in diffusion, excretion, and absorption in locations such as lung alveoli and capillaries.

Simple Cuboidal Epithelium

A single layer of cube-shaped cells resting on the basement membrane, functioning in excretion and absorption in the kidney and thyroid.

Simple Columnar Epithelium

A single layer of tall rectangular cells in direct contact with the basement membrane, functioning in secretion and absorption in the gastrointestinal tract.

Stratified Squamous Epithelium

Epithelium composed of several layers of flattened cells at the apical surface, existing in keratinized and non-keratinized forms to protect against abrasion and desiccation.

Gap Junctions

Cell junctions made of connexons that provide passageways for chemical movement between cells.

Tight Junctions

Cellular junctions formed by strands of transmembrane proteins that prevent the movement of material between adjacent cells.

Desmosomes

Cellular junctions that link epithelial cells to surrounding structures, found in skin and heart tissues.

Adherens Junctions

Cell junctions made of plaque that form an adhesion belt around cells to resist separation during contraction.

Hemidesmosomes

Cellular junctions that connect epithelial cells to the underlying basement membrane.

Exocrine Glands

Epithelial glands that possess a duct to carry secretions onto a body surface, such as sweat and sebaceous glands.

Endocrine Glands

Ductless epithelial glands that secrete hormones directly into the bloodstream or bodily fluids.

Merocrine Glands

The most common exocrine glands that release products via secretory vesicles without loss of cell material, such as salivary and sweat glands.

Apocrine Glands

Glands that release secretions by pinching off the apical portion of the cell, found in mammary, axillary, and pubic glands.

Holocrine Glands

Glands whose cells accumulate secretory products and entirely rupture/die upon release, such as sebaceous glands.

Fibroblasts

Connective tissue cells that produce the matrix and secrete protein fibers.

Collagen Fibers

The most abundant connective tissue fibers; rope-like structures that resist tensile forces and give high strength to tendons and ligaments.

Elastic Fibers

Bungee-cord-like connective tissue fibers that allow stretching and recoiling, found in blood vessels and the dermis.

Reticular Fibers

Branching connective tissue fibers that anchor and hold cells in place within filtering organs like the liver, spleen, and lymph nodes.

Areolar Tissue

Loose connective tissue containing loosely packed collagen, elastic, and reticular fibers that supports, nourishes, and provides loose packing in the upper dermis.

Adipose Tissue

Specialized loose connective tissue composed of lipid-filled cells that provides cushioning, insulation, and fat storage for energy.

Dense Regular Connective Tissue

Avascular connective tissue with collagenous fibers packed into parallel bundles, granting high tensile strength to tendons and ligaments.

Dense Irregular Connective Tissue

Connective tissue with an interwoven, mesh-like network of collagenous fibers located in the lower dermis and submucosa of the GI tract.

Compact Bone

Smooth, dense osseous tissue on the exterior of bones composed of osteons, osteocytes in lacunae, and Haversian canals.

Spongy Bone

Porous bone tissue composed of trabeculae located beneath compact bone, containing red bone marrow for blood cell production.

Hyaline Cartilage

The most common cartilage type, featuring a glassy matrix; located in the nose, trachea, larynx, ribs, and articular ends of long bones.

Elastic Cartilage

Flexible cartilage rich in elastic fibers and abundant chondrocytes, found in the external ear, epiglottis, and Eustachian tube.

Fibrocartilage

Cartilage filled with parallel collagen fibers that acts as an exceptional shock absorber in intervertebral discs, the pubic symphysis, and joint menisci.

Osteon

The functional structural unit of compact bone tissue.

Chondrocytes

Mature cartilage cells located within lacunae.

Neurons

Nervous tissue cells specialized for receiving and transmitting impulses.

Neuroglia

Supportive glial cells in nervous tissue that protect and assist neurons.

-blast

Connective tissue cell suffix denoting a cell that produces matrix.

-cyte

Connective tissue cell suffix denoting a cell that maintains matrix.

-clast

Connective tissue cell suffix denoting a cell that destroys or breaks down matrix.