Topic 9 Heart and Circulatory System- 9.0 Heart

What is the main function of erythrocytes in the blood?

Erythrocytes are the oxygen carriers of the blood.

What are the two major circuits of the human circulatory system?

The pulmonary circuit and the systemic circuit.

What do leukocytes do?

Leukocytes provide the body’s front line of defense against disease.

What is plasma primarily composed of?

Plasma is an aqueous solution of proteins, ions, nutrient molecules, and gases, with 91% water.

What is the role of platelets in the blood?

Platelets induce blood clots that seal breaks in the circulatory system.

Where do human blood cells develop?

Human blood cells develop in red bone marrow of the vertebrae, sternum, ribs, and pelvis.

What is the hematocrit?

The volume percentage of red blood cells in blood, normally around 45% for men and 40% for women.

What is the difference between systole and diastole?

Systole is when the ventricles contract, while diastole is when they relax and fill with blood.

What factors affect cardiac output?

Cardiac output can be affected by heart rate and stroke volume.

What is stroke volume?

The amount of blood ejected per beat from the left ventricle, calculated as SV = EDV - ESV.

How does the pressure in the systemic circulation compare to the pulmonary circuit?

Systemic circulation has high blood pressure, while the pulmonary circuit has lower pressure.

What does the term 'afterload' refer to?

Afterload is the systemic vascular resistance that the heart must overcome to eject blood.

Define preload in the context of cardiac function.

Preload is the left ventricular end-diastolic pressure, indicating the amount of stretch in the ventricles before contraction.

What is the normal range for systolic blood pressure in a healthy individual?

The normal systolic blood pressure range is 110-140 mmHg.

What happens when the radius of a blood vessel increases?

Increasing the radius by a factor of 2 increases fluid flow by a factor of 16.

What is the cardiac cycle?

The sequence of events consisting of systole (ventricular contraction) and diastole (ventricular relaxation).

What components make up the cardiac output formula?

Cardiac Output (CO) is calculated using the formula CO = Stroke Volume (SV) x Heart Rate (HR).

What is the primary role of cardiac muscle?

Cardiac muscle contracts to pump blood throughout the circulatory system.

What is the main advantage of having separate pulmonary and systemic circuits?

It prevents excessive pressure in the lungs and allows efficient gas exchange.

What is the relationship between stroke volume and exercise intensity?

Stroke volume increases proportionally with exercise intensity.