atrioventricular node - definition of atrioventricular node in the Medical dictionary - by the Free Online Medical Dictionary, Thesaurus and Encyclopedia.

node (nōd) a small mass of tissue in the form of a swelling, knot, or protuberance, either normal or pathological.no´dal

atrioventricular node , AV node (AVN) a collection of Purkinje fibers beneath the endocardium of the right atrium, continuous with the atrial muscle fibers and atrioventricular bundle; it receives the cardiac impulses from the sinoatrial node and passes them on to the ventricles.

Bouchard's nodes cartilaginous and bony enlargements of the proximal interphalangeal joints of the fingers in degenerative joint disease.

Dürck's nodes granulomatous perivascular infiltrations in the cerebral cortex in trypanosomiasis.

Flack's node sinoatrial n.

Heberden's nodes small hard nodules, usually at the distal interphalangeal joints of the fingers, formed by calcific spurs of the articular cartilage and associated with osteoarthritis.

Hensen's node primitive node.

Keith's node , Keith-Flack node sinoatrial n.

lymph node any of the accumulations of lymphoid tissue organized as definite lymphoid organs along the course of lymphatic vessels, consisting of an outer cortical and an inner medullary part; they are the main source of lymphocytes of the peripheral blood and, as part of the reticuloendothelial system, serve as a defense mechanism by removing noxious agents, e.g., bacteria and toxins, and probably play a role in antibody formation.

Lymph node (nodus lymphoideus).

Osler's nodes small, raised, swollen, tender areas, bluish or sometimes pink or red, occurring commonly in the pads of the fingers or toes, in the thenar or hypothenar eminences, or the soles of the feet; they are practically pathognomonic of subacute bacterial endocarditis.

primitive node a mass of cells at the cranial end of the primitive streak in the early embryo.

nodes of Ranvier constrictions of myelinated nerve fibers at regular intervals at which the myelin sheath is absent and the axon is enclosed only by Schwann cell processes.

Schmorl's node an irregular or hemispherical bone defect in the upper or lower margin of the body of a vertebra.

sentinel node

1. the first lymph node to receive drainage from a tumor; used to determine whether there is lymphatic metastasis in certain types of cancer.

2. signal n.

signal node an enlarged supraclavicular lymph node; often the first sign of a malignant abdominal tumor.

singer's nodes vocal cord nodules.

sinoatrial node , sinuatrial node, sinus node a microscopic collection of atypical cardiac muscle fibers (Purkinje fibers) at the junction of the superior vena cava and right atrium, in which the cardiac rhythm normally originates and which is therefore called the cardiac pacemaker.

teacher's nodes vocal cord nodules.

Troisier's node , Virchow's node signal n.

atrioventricular node

A small mass of specialized cardiac muscle fibers, located near the ostium of the coronary sinus and giving rise to the atrioventricular bundle of the conduction system of the heart. Also called A-V node.

Atrioventricular node (AV node)

Highly specialized area of the heart muscle which transmits electrical impulses.

Mentioned in: Heart Block

atrioventricular (AV) node,

an area of specialized cardiac muscle that receives the cardiac impulse from the sinoatrial (SA) node and conducts it to the bundle of His and thence to the Purkinje fibers and walls of the ventricles. The AV node is located in the septal wall between the left and right atria.

atrioventricular

pertaining to an atrium and ventricle of the heart.

accessory tract atrioventricular conduction

see accessory tract atrioventricular conduction.

atrioventricular block

see atrioventricular heart block.

atrioventricular bundle

bundle of His.

common atrioventricular canal

a congenital cardiac defect in which both sides of the heart share the same atrioventricular orifice. Called also persistent atrioventricular canal, atrioventricularis communis.

atrioventricular node

a mass of cardiac muscle fibers (Purkinje fibers) lying on the right lower part of the interatrial septum of the heart. Its function is the transmission of the cardiac impulse from the sinoatrial node to the muscular walls of the ventricles. The conductive system is organized so that transmission is slightly delayed at the atrioventricular node, thus allowing time for the atria to empty their contents into the ventricles before the ventricles begin to contract.

partitioning atrioventricular canal

during embryological development partitioning of the cardiac chambers and their orifices may be incomplete, leading to fatal cardiac defects, e.g. persistent atrioventricular chamber.

persistent common atrioventricular canal

see atrioventricularis communis.

atrioventricular stenosis

left and right atrioventricular stenosis are recorded; the former is an acyanotic defect, the latter is more serious and a cyanotic defect.

atrioventricular trunk

see bundle of His.

atrioventricular valvular disease

may be identifiable on finding of systolic murmur (incompetent valve) or diastolic murmur (stenotic valve) over the apex of the heart with maximum audibility over the left or right sides, depending on the side involved.

Wenckebach atrioventricular block

see Mobitz atrioventricular heart block.