Final answer:
Cardiac output (CO) is the volume of blood pumped by the heart per minute, calculated as heart rate multiplied by stroke volume. It is influenced by heart rate and stroke volume, and factors such as sympathetic stimulation, parasympathetic stimulation, and various hormone levels can affect CO.
Step-by-step explanation:
Cardiac Output Explanation
Cardiac output (CO) is the measurement of blood flow from the heart through the ventricles, which is expressed in liters per minute. To calculate CO, the formula CO = HR × SV is used, where HR represents heart rate (beats per minute) and SV represents stroke volume (the amount of blood pumped by each ventricle per beat). Factors that influence cardiac output can either increase or decrease it. Increasing factors include sympathetic stimulation, catecholamines (epinephrine and norepinephrine), thyroid hormones, and increased calcium ion levels.
Decreasing factors are parasympathetic stimulation, variations in potassium ion levels, decreased calcium levels, anoxia, and acidosis. Major influencers of heart rate (HR) consist of autonomic innervation and endocrine control, while environmental aspects such as electrolytes, metabolic products, and temperature also play a role. Stroke volume (SV) is primarily controlled by preload, contractility, and afterload, with electrolytes affecting contractility as either positive or negative inotropic agents.