Final answer:
Heart rate, stroke volume, and cardiac output define the cardiac performance in pumping blood; these factors are influenced by both positive (like sympathetic stimulation) and negative factors (like parasympathetic stimulation) that affect the heart's contractility and overall function.
Step-by-step explanation:
The responses of the following cardiac terms are defined as:
- Heart rate is the number of times the heart beats per minute.
- Stroke volume is the amount of blood pumped by one ventricle with each beat.
- Cardiac output is the volume of blood pumped by the heart in one minute, calculated as a product of heart rate multiplied by stroke volume.
Positive factors affecting heart contractility, which can increase cardiac output, include sympathetic stimulation and hormones such as epinephrine, norepinephrine, and thyroid hormones. Negative factors, which can decrease cardiac output, include parasympathetic stimulation and electrolyte imbalances such as high or low potassium and low calcium levels. Variations in blood flow and pressure elicit a cardiac response where the heart adjusts its rate and stroke volume to maintain adequate circulation and blood pressure.