Cardiovascular Physiology

Cardiovascular physiology is the branch of physiology related to the study of the cardiovascular system, addressing the function of the heart and blood vessels. The cardiovascular system is responsible for the circulation of blood throughout the body, delivering nutrients, oxygen, and hormones, and removing metabolic wastes like carbon dioxide.

Components of the Cardiovascular System

Heart: The heart is a muscular organ that pumps blood through the blood vessels. It has four chambers: two atria and two ventricles. The pumping action is regulated by electrical signals that create the heart's rhythmic contractions.
Blood Vessels: These include arteries, veins, and capillaries. Arteries carry oxygenated blood away from the heart, while veins return deoxygenated blood back to the heart. Capillaries facilitate the exchange of gases, nutrients, and waste products between the blood and tissues.

Key Concepts in Cardiovascular Physiology

Blood Circulation

Blood circulation can be categorized into two main circuits: the systemic circulation and the pulmonary circulation. The systemic circuit delivers oxygenated blood to the body, while the pulmonary circuit exchanges carbon dioxide for oxygen in the lungs.

Blood Pressure

Blood pressure is the force exerted by circulating blood on the walls of blood vessels. It is a critical parameter that influences cardiovascular health. Blood pressure is typically measured in millimeters of mercury (mmHg), with readings given as two numbers: systolic over diastolic.

Stroke Volume and Cardiac Output

Stroke volume is the amount of blood ejected by a ventricle with each heartbeat. Cardiac output is the total volume of blood pumped by the heart per minute, calculated as stroke volume multiplied by heart rate.

Regulation of the Cardiovascular System

The cardiovascular system is regulated by the autonomic nervous system and various hormones. The sympathetic nervous system generally increases heart rate and contractility, while the parasympathetic nervous system reduces them.

Role of Hormones

Hormones such as adrenaline and noradrenaline increase heart rate and cardiac output. The renin-angiotensin-aldosterone system regulates blood pressure and fluid balance, influencing vascular tone and sodium retention.

Pathophysiology

Diseases of the cardiovascular system can arise from disruptions in normal physiological processes. Common conditions include hypertension, atherosclerosis, heart failure, and arrhythmias.

Influential Figures in Cardiovascular Physiology

Pioneers like Arthur Guyton have made significant contributions to understanding cardiovascular physiology. His work laid the foundation for modern cardiovascular medicine and helped in developing educational resources such as the widely used "Guyton and Hall Textbook of Medical Physiology."