Cardiac function does not require intact innervations. Frog's heart removed from the body, and in human beings who have transplanted heart, the heart continues to function. The perfusion of the isolated heart in the laboratory will also continue to beat at regular intervals. In a frog's heart when the chambers are separated, each of the chambers shows regular contractions on [...]
The following points highlight the top eight factors affecting venous return. The factors are: 1. Pressure Gradient 2. Vis-a-Tergo 3. Vis-a-Fronte 4. Skeletal Muscle Pump 5. Thoracic Pump 6. Abdominal Pump 7. Venomotor Tone 8. Posture and Gravity. Factor # 1. Pressure Gradient: The pressure in the right atria (central venous pressure) into which the superior and inferior vena cavae [...]
Normal heart rate is about 60-90 beats per minute. On an average, the rate at which the heart beats is about 75 per minute. It depends on the balanced activity between the sympathetic and parasympathetic nerve influence that are acting on it. Heart rate can be increased because of either an increased activity of sympathetic nerve fibers or a decreased [...]