BioScience Dictionary

 
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Ot.

Found Heart 7 times.

Displaying results 1 to 10.

1. Heart
A muscular organ found in most animals with circulatory systems which pumps blood throughout the body. The hearts of fish have two chambers, the hearts of amphibians and reptiles have three, and the hearts of crocodilians, birds, and mammals have four.

2. Heart block
A heart block is an abnormality of conduction of the electrical heart impulse. Both anatomic or functional imapirment of atrial-ventricular (AV) conduction is contributory. Types: * first degree AV block: P-R interval longer than 0.21 seconds in adults; all supraventricular impulses are conducted * second degree AV block: Mobitz type I (Wenckebach) block: conduction time (P-R interval) is progressively prolonged prior to dropped beats. Mobitz type II conduction time (P-R interval) is not prolonged prior to dropped beats. * third degree AV block: no impulses are conducted.

3. Heart murmurs
Heart murmurs are heart sounds that are heard by auscultation of the chest. Some believe that turbulence of blood flow accounts for the formation of murmurs, others believe that vortex formation being the cause. Nonetheless, everybody seem to agree that they are associated with either abnormal valves (regurgitation or stenosis) or abnormal blood flow (hyperdynamic circulation producing functional murmur). A murmur is characterized by the following: * the location where it is heard loudest: e.g. left sternal border, pulmonic area, aortic area; * the timing of the cardiac cycle when the murmur is present: systolic ejection murmur (pansystolic), diastolic filling murmur, systolic regurgitant murmur, diastolic regurgitant murmur; * the intensity of the murmur: ranges from grade I indicating a murmur not readily audible to Grad VI indicating a murmur audible with the stethoscope removed from the chest; * radiation: the area along the surface of the chest where the murmur continues to be audible.

4. Heart
The multicellular, chambered, muscular structure that pumps blood through the circulatory system by alternately contracting and relaxing.

5. Heartburn
Heartburn is a sensation of burning or warmth that is behind the middle of the chest; a symptom of gastric acid reflux .

6. Heartburn
Heartburn is a sensation of warmth or burning behind the sternum or in the epigastrium. Sometimes there is a acidic taste associated with heartburn.

7. Heartwood
Inner rings of xylem that have become clogged with metabolic by-products and no longer transport water; visible as the inner darker areas in the cross section of a tree trunk.

View web definitions »

Learn more about Heart »