Tissue Level of Organization

Comprehensive vocabulary flashcards covering tissue types, epithelial membranes, cell junctions, glandular secretions, connective tissue components, cartilage, muscle, and nervous tissue based on lecture slides.

Histology

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

Epithelial tissue

Tissue type that covers internal and external body surfaces.

Connective tissue

Tissue type that protects, supports, and integrates body parts.

Muscle tissue

Excitable tissue type that contracts to move.

Nervous tissue

Excitable tissue type that communicates between body regions.

Mucous membrane (mucosa)

Epithelial membrane lining internal cavities and passageways that open externally, producing mucus and supported by an underlying lamina propria connective tissue.

Serous membrane (serosa)

Epithelial membrane lining cavities and organs that do not open externally, producing serous fluid.

Cutaneous membrane

Epithelial membrane (skin) covering the external body surface, containing keratinized cells to protect from desiccation and pathogens.

Synovial membrane

Connective tissue membrane lining the internal cavity of moveable joints and producing synovial fluid.

Apical surface

The free surface of epithelial tissue that interacts with the external environment.

Basement membrane

Permeable material composed of reticular and basal laminae that links epithelial tissue to underlying connective tissue.

Desmosomes

Anchoring junctions where cadherin adhesion proteins link adjacent cell membranes.

Hemidesmosomes

Anchoring junctions where integrin adhesion proteins link cells to the basal lamina.

Adherens junctions

Anchoring junctions where actin contractile proteins link cell patches or form a belt inside cells, influencing tissue shape and folding.

Tight junctions

Cell junctions with no extracellular space that prevent substances from moving between cells and separate apical and basal compartments.

Gap junctions

Cell junctions forming intercellular passageways between membranes of adjacent cells, allowing quick, direct movement between cytoplasm.

Simple squamous epithelium

Single layer of flattened and thin cells specialized for absorption and secretion, lining alveoli, heart, blood, and lymphatic vessels.

Simple cuboidal epithelium

Single layer of boxy cells specialized for absorption and secretion, lining kidney tubules, glands, and ducts.

Simple columnar epithelium

Single layer of tall, rectangular cells specialized for absorption and secretion, lining bronchi, uterine tubes, uterus, and digestive tract.

Stratified squamous epithelium

Multiple layers of cells with flattened top cells providing protection, lining skin, esophagus, mouth, and vagina.

Stratified cuboidal epithelium

Multiple layers of cube-shaped cells providing protection, lining sweat, salivary, and mammary glands.

Stratified columnar epithelium

Multiple layers of tall cells providing protection and secretion, lining the male urethra and glandular ducts.

Pseudostratified columnar epithelium

Single layer of cells appearing stratified, involved in secretion, lining the trachea and upper respiratory tract.

Transitional epithelium

Unique stratified epithelium (urothelium) that stretches and changes shape, allowing urinary organs like the bladder, urethra, and ureters to expand.

Exocrine glands

Glands whose secretions (such as mucus, sweat, saliva, and milk) leave through a duct opening to the external environment.

Endocrine glands

Ductless glands that release secretions (hormones) directly into surrounding tissues and fluids.

Merocrine secretions

Secretions enclosed in vesicles and released by exocytosis with minimal damage to the cell.

Apocrine secretions

Secretions released together with a pinched-off portion of the cell membrane, causing little damage to the cell.

Holocrine secretions

Secretions released when the mature cell bursts, rupturing and destroying the entire gland cell.

Fibroblast

The most common cell type in connective tissue proper; an active cell that secretes polysaccharides and proteins.

Fibrocyte

The second most common cell type in connective tissue proper; a less active, mature form of fibroblast.

Adipocyte

Connective tissue cell specialized for storing lipids in its cytoplasm.

Mesenchymal cell

Multipotent adult stem cell in connective tissue involved in repair and healing.

Macrophage

Phagocyte in connective tissue that secretes cytokines to recruit other immune cells.

Collagen fibers

Long, straight connective tissue fibers consisting of fibrous protein subunits that are flexible with great tensile strength.

Elastic fibers

Connective tissue fibers containing elastin protein and glycoproteins that return to original shape after being stretched or compressed.

Reticular fibers

Branching connective tissue fibers with collagen-like subunits that anchor and structurally support soft organ parenchyma.

Dense regular connective tissue

Dense connective tissue with fibers arranged parallel to each other, providing high tensile strength in one direction.

Dense irregular connective tissue

Dense connective tissue with fibers arranged in random directions, providing strength in all directions.

Areolar tissue

Loose connective tissue containing all cell types and fibers randomly arranged to fill spaces and support organs.

Reticular tissue

Loose connective tissue providing a mesh-like, supportive framework for soft organs like the spleen, liver, and lymphatic tissue.

Chondrocytes

Less active and mature cartilage cells located within lacunae.

Lacunae

Spaces within the matrix of cartilage or bone occupied by chondrocytes or osteocytes.

Perichondrium

Layer of dense irregular connective tissue encapsulating cartilage.

Hyaline cartilage

Most common cartilage type, containing short, dispersed collagen fibers and proteoglycans to provide strong but flexible support.

Elastic cartilage

Cartilage containing elastic fibers along with collagen and proteoglycans, providing rigid support and elasticity.

Fibrocartilage

Cartilage containing thick bundles of collagen fibers dispersed in matrix to provide tough shock absorption.

Skeletal muscle

Voluntary muscle tissue consisting of long, cylindrical, striated fibers with multiple peripheral nuclei.

Cardiac muscle

Involuntary muscle tissue found in the heart, consisting of short, branched, striated cells with a single central nucleus.

Smooth muscle

Involuntary muscle tissue consisting of short, spindle-shaped cells without striations and with a single central nucleus.

Neurons

Nervous tissue cells that propagate information via electrochemical impulses (action potentials) and release neurotransmitters.

Neuroglia

Nervous tissue cells that play an essential role in supporting neurons and modulating their information propagation.