脉搏

A pulse is a wave of expansion and recoil occurring in an artery in response to the heart's pumping action. It begins when the sinoatrial node creates electrical impulses that trigger ventricular contraction. The left ventricle then pumps a wave of blood called stroke volume into the aorta, creating the throbbing sensation felt when compressing an artery against a firm structure.

The average pulse rate for adults ranges from 60 to 100 beats per minute. Pulse rate quantifies the number of times the heart beats in one minute and reflects overall cardiovascular health. Deviations from this normal range can indicate various conditions such as dehydration and anemia, making it an important vital sign for healthcare assessment.

The heart's conducting system includes the sinoatrial node, atrioventricular node, bundle of His, and Purkinje fibers. The SA node initiates electrical impulses prompting atrial contraction. The AV node delays signal transmission to allow complete atrial filling before ventricular contraction. The bundle of His and Purkinje fibers coordinate efficient transmission, ensuring simultaneous and forceful ventricular contraction for optimal blood ejection.

Stroke volume is the volume of blood ejected by the left ventricle during a single contraction, measured in milliliters per beat. Cardiac output, the amount of blood pumped into systemic circulation per minute, is calculated by multiplying stroke volume by heart rate. Normal cardiac output ranges from 4 to 8 liters per minute in healthy adults at rest.

Pulse rate is influenced by stress, physical activity, hormonal changes, and other physiological factors. These same factors affecting heart rate directly impact cardiac output since it is calculated by multiplying heart rate and stroke volume. Understanding factors influencing heart rate helps healthcare providers assess cardiovascular health and identify potential abnormalities or conditions affecting circulation.

Stroke volume is calculated by subtracting end-systolic volume from end-diastolic volume. End-diastolic volume represents blood in the ventricles at the end of the filling phase, while end-systolic volume indicates blood remaining after contraction. This calculation reveals how much blood the ventricle effectively ejects with each heartbeat, a key measure of cardiac efficiency.

Pulse assessment provides critical information about the heart's ability to pump blood effectively and the overall health of the cardiovascular system. Measuring pulse rate, rhythm, and amplitude helps healthcare providers diagnose various conditions and monitor patient responses to treatment. Special considerations while measuring pulse ensure accurate assessment and reliable vital sign data for clinical decision-making.