Pulse in animals

Pulse in animals

Pulse in animals is a wave of expansion and elongation followed by recoiling of the arterial walls and due to the forceful entry of the blood from the aorta during each heart beat. It originates from aorta spreads throughout arterial system and disappears at the arterioles.

Systolic rush of blood into aorta causes steep increase in the distension of the arterial walls represents anacrotic limb of the pulse wave, whereas the elastic recoiling of the distended arteries causes a drop in the declining slope in the pulse wave, referred as catacrotic limb.

During the end of systole and the beginning of isometric relaxation phase of cardiac cycle, there will be drop in the intra-ventricular pressure causes the back flow of blood in to the aorta. This results in closure of the aortic valve and the distension of the root of the aorta. This creates a drop in the intra-arterial pressure characterized by dicrotic notch or incisura of the pulse.

Velocity of pulse wave

Pulse wave is greater than blood velocity Rigid vessels have more velocity than elastic arteries. Velocity is less in large central arteries than in small peripheral arteries

Venous pulse

Venous pulse is the pulsation seen in the large veins near the heart.

• Venous pulse is of two types-
  1. If the wave travels towards heart it is referred as positive venous pulse. Downward movement of AV valves, lengthening of the atrium followed by a drop in the intra atrial pressure, gradual atrial filling (v wave of the atria), all result in positive venous pulse.
  2. Bulging of AV valves during ventricular systole causes negative venous pulse (away from heart) in the jugular vein.