sinoatrial node

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Related to Atrial sinus: SA node

node

 [nōd]
a small mass of tissue in the form of a swelling, knot, or protuberance, either normal or pathological. adj., adj no´dal.
node of Aschoff and Tawara atrioventricular node.
atrioventricular node (AV node) a collection of cardiac fibers at the base of the interatrial septum that transmits the cardiac impulse initiated by the sinoatrial node.
Bouchard's n's cartilaginous and bony enlargements of the proximal interphalangeal joints of the fingers in degenerative joint disease; such nodes on the distal joints are called Heberden's nodes.
Delphian node a lymph node encased in the fascia in the midline just above the thyroid isthmus, so called because it is exposed first at operation and, if diseased, is indicative of disease of the thyroid gland.
Flack's node sinoatrial node.
Heberden's n's nodular protrusions on the phalanges at the distal interphalangeal joints of the fingers in osteoarthritis. Similar nodes on the proximal joints are called bouchard's nodes.
Comparison of Heberden's nodes (seen in patients with osteoarthritis) with Bouchard's nodes (seen in patients with rheumatoid arthritis). From Copstead and Banasik, 2000.
hemal n's nodes with a rich content of erythrocytes within sinuses, found near large blood vessels along the ventral side of the vertebrae and near the spleen and kidneys in various mammals, especially ruminants, having functions probably like those of the spleen; their presence in humans is doubtful.
Keith's node (Keith-Flack node) sinoatrial node.
Legendre's n's Bouchard's nodes.
lymph node see lymph node.
Osler's n's small, raised, swollen, tender areas, bluish or sometimes pink or red, due to inflammation around the site of lodgement of small infected emboli in distal arterioles; they occur commonly in the pads of the fingers or toes, in the palms, or in the soles and are practically pathognomonic for subacute bacterial endocarditis.
Parrot's n's bony nodes on the outer table of the skull of infants with congenital syphilis.
n's 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 into which the nucleus pulposus of the intervertebral disk herniates.
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. If this node is negative for malignancy, others “upstream” from it are usually also negative.
signal node an enlarged supraclavicular lymph node; often the first sign of a malignant abdominal tumor.
singer's n's vocal cord nodules.
sinoatrial node a collection of atypical muscle fibers in the wall of the right atrium where the rhythm of cardiac contraction is usually established; therefore also referred to as the pacemaker of the heart. Called also SA node.
syphilitic node a swelling on a bone due to syphilitic periostitis.
node of Tawara atrioventricular node.
teacher's n's vocal cord nodules.
Troisier's node (Virchow's node) sentinel node.

sin·u·a·tri·al node

[TA]
the mass of specialized cardiac muscle fibers that normally acts as the "pacemaker" of the cardiac conduction system; it lies under the epicardium at the upper end of the sulcus terminalis.

sinoatrial node

n.
A small mass of specialized cardiac muscle fibers located in the posterior wall of the right atrium of the heart that acts as a pacemaker by generating at regular intervals the electric impulses of the heartbeat. Also called sinoauricular node, sinus node.

sinoatrial node

sinoatrial node

SA node, sinuatrial node, sinus node, heart's pacemaker Anatomy A knot of specialized, spontaneously depolarizing cells located at the posterior wall of the upper right atrium, in the sulcus terminalis at the junction between the superior vena cava and right atrium, the heart's natural pacemaker Normal rhythm 70/min; conducts impulses via 3 Purkinje fiber tracts: (1) anterior internodal tract of Bachman; (2) middle internodal tract of Wenckebach; (3) posterior internodal tract of Thorel to AV node–normal rhythm, 45/min–in right posterior portion of interatrial septum; it is continuous with bundle of His–normal rhythm, 35/min Blood supply Rt coronary–65%, circumflex–25%, both in remainder Flow of impulse From the SN through right atrium to AV node in low septal right atrium. See Conduction system. Cf Atrioventricular node.

sin·u·a·tri·al node

, sinoatrial node (sin'yū-ā'trē-ăl nōd, sī'nō-) [TA]
The mass of specialized cardiac muscle fibers that normally acts as the "pacemaker" of the cardiac conduction system; it lies under the epicardium at the upper end of the sulcus terminalis.

sinoatrial node

A small area of specialized muscle cells in the upper right chamber of the heart (right atrium) that acts as the natural pacemaker of the heart, setting the rate in conjunction with other controlling influences, and transmitting impulses throughout the heart muscle.

sinoatrial node (SAN)

see HEART.

sinoatrial node

; atriculoventricular node; AV node area of muscle (within right atrial wall of heart) that contracts spontaneously; links to all other areas of heart muscle (via Purkinje fibres) allowing all areas of heart muscle to contract synchronously and regularly

sin·u·a·tri·al node

, sinoatrial node (sin'yū-ā'trē-ăl nōd, sī'nō-) [TA]
The mass of specialized cardiac muscle fibers that normally acts as the "pacemaker" of the cardiac conduction system; it lies under the epicardium at the upper end of the sulcus terminalis.

sinoatrial

pertaining to the sinus venosus and the atrium of the heart or to the sinoatrial node; abbreviated S-A, SA.

sinoatrial block
an absence of a discharge from the sinoatrial node. The heart is regular unless there is an underlying atrial arrhythmia. Considered to be within the limits of normality provided it disappears with exercise.
sinoatrial node
a collection of atypical muscle fibers and nerve endings in the wall of the right atrium, adjacent to the sulcus terminalis, where the rhythm of cardiac contraction is usually established; therefore also referred to as the pacemaker of the heart. Called also sinoatrial bundle, Keith's node, Keith-Flack node.