Physiology: Chapter 4 - Tissues/Histology

Absorption

The intake of fluids or other substances such as digested food from the intestinal tract.

Adherens Junctions

Contains plaque, a dense layer of proteins on the inside of the plasma membrane that attaches both to membrane proteins and to microfilaments of the cytoskeleton.

Apical Surface

Faces the body surface, a body cavity, the lumen (interior space) of an internal organ, or a tubular duct that receives cell secretions of an epithelial cell.

Avascular

Relying on the blood vessels of the adjacent connective tissue to bring nutrients and remove wastes.

Basal Surface

The opposite of the apical surface of an epithelial cell.

Basement membrane

A thin extracellular layer that commonly consists of two layers, the basal lamina and reticular lamina.

Cell Junctions

Contact points between the plasma membranes of tissue cells.

Chondrocyte

The cells of mature cartilage which occurs singly or in groups within spaces called lacunae in the extracellular matrix.

Collagen Fibers

Very strong and resist pulling or stretching, but they are not stiff, which allows tissues flexibility.

Connective Tissue

Protects and supports the body and its organs.

Desmosomes

Contains plaque and have transmembrane glycoproteins that extend into the intercellular space between adjacent cell membranes and attach cells to one another.

Elastic Fibers

Smaller in diameter than collagen fibers, branch and join together to form a fibrous network within a connective tissue.

Endocrine gland

Called hormones, enter the interstitial fluid and then diffuse into the bloodstream without flowing through a duct.

Epithelial Membrane

A body covering made of two tissue layers working together: an epithelial layer on top and a connective tissue layer underneath.

Epithelial Tissue

Covers body surfaces and lines hollow organs, body cavities, and ducts; it also forms glands which allows the body to interact with both its internal and external environments.

Exocrine Gland

Secretes their products into ducts that empty onto the surface of a covering and lining epithelium such as the skin surface or the lumen of a hollow organ.

Extracellular Matrix (ECM)

The material located between its widely spaced cells.

Fibrosis

The process by which fibroblasts synthesize collagen fibers and other extracellular matrix materials that aggregate to form scar tissue.

Gap Junctions

Aggregates of intercellular channels that permit direct cell

Goblet Cell

A goblet-shaped unicellular gland that secretes mucus; present in epithelium of the airways and intestines.

Ground Substance

The component of a connective tissue between the cells and fibers.

Hemidesmosomes

Resembles desmosomes, but they do not link adjacent cells.

Intercalated Discs

An irregular transverse thickening of sarcolemma that contains desmosomes, which hold cardiac muscle fibers (cells) together, and gap junctions, which aid in conduction of muscle action potentials from one fiber to the next.

Keratin

An insoluble protein found in the hair, nails, and other keratinized tissues of the epidermis.

Lateral Surface

Faces the adjacent cells on either side, may contain tight junctions, adherens junctions, desmosomes, and/or gap junctions of an epithelial cell.

Lymph

Fluid confined in lymphatic vessels and flowing through the lymphatic system until it is returned to the blood.

Microvilli

Microscopic, fingerlike projections of the plasma membranes of cells that increase surface area for absorption, especially in the small intestine and proximal convoluted tubules of the kidneys.

Muscle Tissue

Consists of elongated cells called muscle fibers or myocytes that can use ATP to generate force.

Mucosa/Mucus Membrane

A body cavity that opens directly to the exterior.

Nervous Tissue

Detects changes in a variety of conditions inside and outside the body and responds by generating electrical signals called nerve action potentials (nerve impulses) that activate muscular contractions and glandular secretions.

Neuron (nerve cells)

Sensitive to various stimuli.

Reticular Fibers

Consisting of collagen arranged in fine bundles with a coating of glycoprotein, provide support in the walls of blood vessels and form a network around the cells in some tissues.

Secretion

The production and release of substances such as mucus, sweat, or enzymes.

Serosa/Serous Membrane

A body cavity that does not open directly to the exterior (thoracic or abdominal cavities), and it covers the organs that are within the cavity.

Stem Cells

Immature, undifferentiated cells that divide to replace lost or damaged cells.

Synovial Membrane

Lines the cavities of freely movable joints (joint cavities).

Tight Junctions

Consists of weblike strands of transmembrane proteins that fuse together the outer surfaces of adjacent plasma membranes to seal off passageways between adjacent cells.