cardiac cycle and disease Flashcards
(13 cards)
When do AV valves open?
When the pressure in the atria is greater than the pressure in the ventricles
When do the AV valves close?
As the ventricles contract, preventing back-flow of blood into the atria
When do semi-lunar valves open?
When the pressure in the ventricles is greater than the pressure in the arteries
When do the semi-lunar valves close?
As the ventricles relax, preventing back-flow of blood into the ventricles
What is cardiac output?
The volume of blood pumped out of one ventricle per minute
What is the equation for cardiac output?
Cardiac output = stroke volume x heart rate
What are the units for stroke volume?
cm³
What are the units for heart rate?
min⁻¹
What is stroke volume?
The volume of blood expelled from the left ventricle of the heart per contraction
What is heart rate?
Number of contractions per minute
What happens to stroke volume during exercise?
Increased blood flow causes the heart to contract more strongly, pumping out an increased volume of blood so it increases
Why does regular exercise cause resting heart rate to decrease?
The heart muscles produce stronger contractions, so the ventricles become larger in size and volume
What are some of the risk factors for cardiovascular disease?
Smoking, high blood pressure, high blood cholesterol levels, prolonged stress, genetic factors, lack of exercise
