Chapter 4. Tissues and Histology Practice Flashcards

Comprehensive vocabulary flashcards covering the four primary tissue types (Epithelial, Connective, Muscle, and Nervous) including their characteristics, categories, and specific cell types.

Histology

The study of tissues.

Tissues

Collections of specialized cells and cell products that perform specific functions.

Epithelia (epithelium)

Layers of cells covering external surfaces or lining internal surfaces.

Glands

Structures primarily composed of epithelia that produce and release fluid secretions.

Avascularity

A characteristic of epithelial tissue meaning it lacks blood vessels, though it is innervated.

Microvilli

Projections on the apical surface of epithelial cells that increase absorption.

Cilia

Projections that move fluids across apical surfaces through ciliary action.

Cell adhesion molecules (CAMs)

Transmembrane proteins that help cells stick to each other and to their surroundings.

Gap Junctions

Specialized contacts held together by transmembrane proteins called connexons that allow rapid communication and passage of small molecules and ions.

Tight Junctions

Junctions between two plasma membranes that prevent the passage of water and solutes, keeping enzymes and acids in the lumen of the digestive tract.

Desmosomes

Junctions where CAMs link opposing plasma membranes; spot desmosomes tie cells together.

Hemidesmosomes

Structures that attach cells to the basement membrane.

Basal lamina

The portion of the basement membrane closest to the epithelium, produced by epithelial cells.

Reticular lamina

The deeper portion of the basement membrane, produced by connective tissue.

Mesothelium

Simple squamous epithelium that lines body cavities.

Endothelium

Simple squamous epithelium that forms the inner lining of the heart and blood vessels.

Simple columnar epithelium

A single layer of tall cells with round to oval nuclei; nonciliated type lines most of the digestive tract.

Goblet cells

Unicellular glands that secrete mucin, which combines with water to form mucus.

Pseudostratified columnar epithelium

A single layer of cells of differing heights with nuclei seen at different levels, giving the appearance of multiple layers; lines the trachea and most upper respiratory tract.

Keratinized stratified squamous epithelium

Epithelium where surface cells are dead and full of keratin; forms the epidermis of the skin.

Transitional epithelium

Epithelium that stretches readily and permits distension; lines the ureters, bladder, and part of the urethra.

Endocrine glands

Glands that release hormones directly into the bloodstream.

Exocrine glands

Glands that discharge secretions through ducts onto epithelial surfaces, having local effects. Think sweat, salivary,sebaceous

Extracellular matrix

The part of connective tissue outside of cells, composed of extracellular protein fibers and ground substance.

Collage fibers

The most common and abundant fibers in connective tissue proper; long, straight, unbranched, and resist force in one direction.

Reticular fibers

Fibers made of type III collagen that form interwoven networks called stroma; they resist forces in many directions.

Elastic fibers

Branched and wavy fibers containing elastin that return to their original length after stretching.

Fibroblasts

The most abundant cell type in connective tissue proper that produces the extracellular matrix.

Mesenchymal cells

Stem cells that respond to injury or infection by differentiating into fibroblasts, macrophages, or other cells.

Adipocytes

Fat cells that each store a large fat droplet.

Mast cells

Cells that stimulate inflammation after injury or infection by releasing histamine and heparin.

Mesenchyme

The common embryonic origin for all classes of connective tissue.

Areolar connective tissue

Loose connective tissue with a gel-like matrix and all three fiber types; wraps and cushions organs.

Hyaline cartilage

Cartilage with an amorphous but firm matrix and an invisible network of collagen fibers; covers the ends of long bones.

Osseous tissue

Hard, calcified matrix containing collagen fibers and osteocytes in lacunae; well vascularized and supports/protects.

Hematopoiesis

The site for blood cell formation, which occurs in the marrow inside bones.

Superficial fascia

Connective tissue that separates the skin from underlying tissues.

Serous membranes

Membranes that line the closed pleural, pericardial, and peritoneal cavities.

Skeletal muscle tissue

Tissue consisting of long, thin, multinucleate cells that are striated and voluntary.

Cardiac muscle tissue

Tissue found only in the heart, consisting of branched, striated cells interconnected by intercalated discs.

Smooth muscle tissue

Tissue with small, spindle-shaped, non-striated cells found in the walls of contracting organs; involuntary.

Neurons

Specialized cells in nervous tissue for conducting and transmitting electrical impulses.

Neuroglia

Specialized cells in nervous tissue that support neurons.