Conducting system of the heart
Conducting system of the heart: the impulse for cardiac contraction is transmitted through the conduction system of the heart. This system is made of :
- Sino atrial node (SA-node)
- Atrioventricular node (AV-node)
- Bundle of his
- Purkinje fibers.
Heart sounds:
Totally 4 sounds are produced by the heart. The first sound as LUB and the second sound as DUB can be heard with a stethoscope. The third and fourth sounds cannot be heard. The “ lub” is the first heart sound, commonly termed S1, and is caused by turbulence caused by the closure of mitral and tricuspid valves at the start of systole. The second sound, “dub” or S2, is caused by the closure of aortic and pulmonic valves, marking the end of systole. Heart Murmurs. The most common abnormal heart sound is a heart murmur. A murmur is a blowing, whooshing, or rasping sound that occurs during your heartbeat.
Pulse: its throbbing sensation felt over the walls of arteries. It’s defined as the pressure difference transmitted in the form of a wave over the arterial walls.
Heart Rate:
the normal resting heart rate for adults ranges from 60 to 100 beats a minute. The wrist is the common site where the pulse is usually felt. At this site, the radial artery is very superficial. This pulse is called as a radial pulse. Other arteries where a pulse can be felt are a carotid artery. Facial artery and temporal artery. In case of fever, the rate of pulse increases at the rate of 10 per every rise of 1F.Generally, veins don’t exhibit pulsation. The only vein which exhibits pulsation is jugular vein which is nearer to the heart.