ECG and pressure graph

Question 1

ECG

Answer 1

Electrocardiogram. Measures the electrical pulse of the heart by sensors/electrodes on the chest.

Question 2

P wave

Answer 2

Atrial systole the depolarization phase. The end of the wave is were the AV valve opens.

Question 3

Depolarization

Answer 3

It is a change within a cell, during which the cell undergoes a shift in electric charge distribution, resulting in less negative charge inside the cell. Electrical impulse causes ions to cross the cell membrane and an action potential takes place.

Question 4

Repolarization

Answer 4

It is the return of the ions to their previous resting state, which corresponds with relaxation of the myocardial muscle. Ions return to the normal side ready for the next action potential.

Question 5

QRS complex

Answer 5

Ventricular systole and at the end of the wave atrial diastole. At the peak of the Q wave the AV valve shuts.

Question 6

T wave

Answer 6

Ventricular diastole and repolarization of the heart muscle.

Question 7

Tachycardia

Answer 7

Fast heart rate

Question 8

Bradycardia

Answer 8

Slow heart rate

Question 9

Atrial pressure

Answer 9

Least change in pressure. Always quite low because the walls are thin so can’t exert a huge pressure. As the atria fills with blood there is a slight increase.

Question 10

Ventricular pressure

Answer 10

Starts low but has a huge pressure change. The AV valve shuts and the pressure rises due to the thick muscular walls. The semilunar valve opens and the pressure lowers as blood leaves the heart.

Question 11

When are the semilunar valves open?

Answer 11

When the ventricular pressure is higher than the aortic pressure.

Question 12

When are the AV valves open?

Answer 12

When the atrial pressure is higher than the ventricular pressure.