aggregation

DEFINITION:

1. Massing of materials together as in clumping.

2. A clumped mass of material.

cells

DEFINITION:

See definitions for "cell."

connective tissue

DEFINITION:

See under tissue.

binds

DEFINITION:

1. To wrap with a binder or bandage.

2. To form a weak, reversible chemical bond, e.g., antigen to antibody or hormone to receptor.

fibroblasts

DEFINITION:

1. Connective tissue cells: flat elongated cells with cytoplasmic processes at each end, having flat, oval, vesicular nuclei. Fibroblasts, which differentiate into chondroblasts, collagenoblasts, and osteoblasts, form the fibrous tissues in the body including tendons, aponeuroses, supporting and binding tissues of all sorts.

2. Collagenoblasts.

fibroglia

DEFINITION:

Border fibrils in close relation to the surface of fibroblasts, and thought by some to be transformations of the ectoplasm.

collagen fibrils

DEFINITION:

Delicate fibrils of collagen in connective tissue, composed of molecules of tropocollagen in linear arrays. In Type I collagen, the most common type, the tropocollagen molecules are associated in periodic, staggered arrays that give the appearance of cross-banding, with a period of approximately 65 nm in the unit fibril (or microfibril); these unit fibrils are aggregated in bundles to form larger fibrils, with longitudinal striations, which may themselves be aggregated into fibers. Some other types of collagen also associate into fibrils (e.g., Types II, III, VI) but may not aggregate to show cross-banding or to form fibers. The terms fiber and fibril are sometimes interchanged loosely in descriptions of the hierarchy of collagen aggregation.

elastic fibrils

DEFINITION:

Fibrils which are susceptible of resisting and recovering from stretching, compression, or distortion applied by a force.

mesoderm

DEFINITION:

The middle layer of the three primary germ layers of the embryo, lying between the ectoderm and the entoderm. From it are derived the connective tissue, bone and cartilage, muscle, blood and blood vessels, lymphatics and lymphoid organs, notochord, pleura, pericardium, peritoneum, kidney, and gonads.

collagenous

DEFINITION:

Pertaining to collagen; forming or producing collagen.

mucous

DEFINITION:

1. Pertaining or relating to, or resembling mucus; mucoid.
2. Covered with mucus.
3. Secreting, producing, or containing mucus.

reticular

DEFINITION:

Pertaining to or resembling a net.

osseous

DEFINITION:

Of the nature or quality of bone; bony.

cartilaginous

DEFINITION:

Consisting of or of the nature of cartilage.

tissues

DEFINITION:

See definitions under "tissue."

connective tissue

DEFINITION:

See under tissue.

concentration

DEFINITION:

1. Increase in strength by evaporation.

2. The ratio of the mass or volume of a solute to the mass or volume of the solution or solvent.

areolar

DEFINITION:

Pertaining to or containing areolae.

interstitial tissue

DEFINITION:

Stroma. The matrix or supporting tissue of an organ, as distinguished from its parenchyma or functional element.

stroma

DEFINITION:

The matrix or supporting tissue of an organ, as distinguished from its parenchyma or functional element.

matrix

DEFINITION:

1. The intracellular substance of a tissue or the tissue from which a structure develops.

2. The groundwork on which anything is cast, or that basic material from which a thing develops.

3. A mold or a form for casting.

organ

DEFINITION:

A somewhat independent part of the body that performs a special function or functions.

effector organ - An organ that produces an effect, e.g., contraction or secretion, in response to nerve stimulation.

parenchyma

DEFINITION:

The essential elements of an organ; used in anatomical nomenclature as a general term to designate the functional elements of an organ, as distinguished from its framework, or stroma.

functional

DEFINITION:

1. Of or pertaining to a function.

2. Affecting the function but not the structure.

lymphoid tissue

DEFINITION:

A lattice work of reticular tissue the interspaces of which contain lymphocytes; lymphoid tissue may be diffuse, or densely aggregated as in lymph nodules and nodes.

reticular tissue

DEFINITION:

Connective tissue consisting of reticular cells and fibers.

lymphocytes

DEFINITION:

Any of the mononuclear, nonphagocytic leukocytes, found in the blood, lymph, and lymphoid tissues, that are the body's immunologically competent cells and their precursors. They are divided on the basis of ontogeny and function into two classes, B lymphocytes and T lymphocytes, responsible for humoral and cellular immunity, respectively.

lymphoid tissue

DEFINITION:

A lattice work of reticular tissue the interspaces of which contain lymphocytes; lymphoid tissue may be diffuse, or densely aggregated as in lymph nodules and nodes.

diffuse

DEFINITION:

1. Not definitely limited or localized; widely distributed.

2. To pass through or to spread widely through a tissue or structure.

aggregated

DEFINITION:

Crowded or clustered together.

lymph

DEFINITION:

A transparent, slightly yellow liquid of alkaline reaction, found in the lymphatic vessels and derived from the tissue fluids. It is occasionally of a light-rose color from the presence of red blood corpuscles, and is often opalescent from particles of fat. Under the microscope, lymph is seen to consist of a liquid portion and of cells, most of which are lymphocytes. Lymph is collected from all parts of the body and returned to the blood via the lymphatic system.

nodes

DEFINITION:

See definition for "node."

myeloid tissue

DEFINITION:

Medulla ossium rubra. Red bone marrow: marrow of developing bone, of the ribs, vertebrae, and many of the smaller bones; it is the site of production of erythrocytes and granular leukocytes.

medulla ossium rubra

DEFINITION:

Red bone marrow: marrow of developing bone, of the ribs, vertebrae, and many of the smaller bones; it is the site of production of erythrocytes and granular leukocytes.

bone marrow

DEFINITION:

Medulla ossium.

marrow

DEFINITION:

The soft organic material that fills the cavities of the bones; also called medulla .

ribs

DEFINITION:

1. Costae (singular costa) (def. 1).

2. Something resembling these bones.

vertebrae

DEFINITION:

Plural of vertebra.

site

DEFINITION:

A place, position, or locus.

erythrocytes

DEFINITION:

One of the elements found in peripheral blood; called also red blood cells or corpuscles . Normally, in the human, the mature form is a non-nucleated, yellowish, biconcave disk, adapted, by virtue of its configuration and its hemoglobin content, to transport oxygen.

nerve tissue

DEFINITION:

The specialized tissue making up the central and peripheral nervous systems; it consists of neurons with their processes, other specialized or supporting cells such as the neuroglia, and extracellular material.

peripheral

DEFINITION:

Situated away from a center or central structure.

neurons

DEFINITION:

Any of the conducting cells of the nervous system. A typical neuron consists of a cell body, containing the nucleus and the surrounding cytoplasm (perikaryon); several short radiating processes (dendrites); and one long process (the axon), which terminates in twiglike branches (telodendrons) and may have branches (collaterals) projecting along its course. The axon together with its covering or sheath forms the nerve fiber. Called also nerve cell .

supporting cells

DEFINITION:

Cells that serve to provide support and protection and perhaps contribute to the nutrition of principal or other cells of certain organs; such cells are found in the labyrinth of the inner ear, organ of Corti, olfactory epithelium, taste buds, and seminiferous tubules (Sertoli's cells). Called also sustentacular cells .

neuroglia

DEFINITION:

The supporting structure of nervous tissue. It consists of a fine web of tissue made up of modified ectodermal elements, in which are enclosed peculiar branched cells known as neuroglial cells or glial cells. The neuroglial cells are of three types: astrocytes and oligodendrocytes (astroglia and oligodendroglia), which appear to play a role in myelin formation, transport of material to neurons, and maintenance of the ionic environment of neurons; and microcytes (microglia), which phagocytize waste products of nerve tissue.

extracellular

DEFINITION:

Outside a cell or cells.

reticular tissue

DEFINITION:

Connective tissue consisting of reticular cells and fibers.

connective tissue

DEFINITION:

See under tissue.

reticular cells

DEFINITION:

The cells forming the reticular fibers of connective tissue; those forming the framework of lymph nodes, bone marrow, and spleen are part of the reticuloendothelial system and under appropriate stimulation may differentiate into macrophages.