Cardiac cycle and ECG

Question 1

Electrocardiogram

Answer 1

Is a test to check for difficulties with the electrical activity of your heart

Question 2

P wave

Answer 2

on the graph, it looks like a small bump from the baseline. It represents the depolarization of the atria. This happens right before the atria contract and push blood into the ventricles.

Question 3

QRS complex

Answer 3

is a much larger wave than the P wave, and it represents the depolarization of the ventricles.

Impulse spread through the ventricles from the AV node to the purjinke fibers.

Question 4

PQ segment

Answer 4

AV nodal delay

Question 5

QT segment

Answer 5

Ventricular contraction, where ventricular pressure is high in the ventricles, as it pumps blood out of the aortic valve and to the rest of the body.

Question 6

TQ interval

Answer 6

Ventricular relaxation

Question 7

RR interval

Answer 7

time between heart beats

Question 8

A condition of the heart in which the heart beat is fewer than 60 beats per minute is called

Answer 8

bradycardia

Question 9

Tachycardia

Answer 9

A condition to describe a rapid heart rate of greater than 100 beats per minute

Question 10

arrhythmia

Answer 10

deviation from a normal heart rhythm

Question 11

Myocardial ischemia

Acute myocardial infarction

Answer 11

is inadequate delivery of oxygenated blood to the heart tissue. This can lead to death of heart muscle clles when a blood vessel supplying that rea of the heart becomes blood or ruptured. This can lead to a heart attack (acute myocardial infarction)

Question 12

Systole

Answer 12

is the period of the heart cycle where the ventricles are contracting

Question 13

dystole

Answer 13

is the period of ventricular relaxation

Question 14

Cardiac cycle

Answer 14

is the mechanical events of the heart associated with blood flow during a single heartbeat. The cycle is divided into systole and diastole. It can also be divided into four phases.

Question 15

end-diastolic volume

Answer 15

the volume of blood in the ventricle at the end of diastole an average of 135 millilitres.

Question 16

Ventricular filling

Answer 16

a phase in the cardiac cycle where the pressure in the atria is greater than the pressure in ventricles.

Initially, during the passive phase, all four chambers are momentarily relaxed, and the AV valves are open due to greater Atria pressure.

During the active phase, the atria contract

Question 17

Isovolumetric ventricular contraction

Answer 17

is the event occurring in early systole, the ventricles contracts without corresponding volume change (isovolumetrically). This brief moment in time within the cardiac cycle takes place when the heart valves are closed because the onset of ventricular contraction forces apply a backward pressure that forces the AV valves to close.

Question 18

Ventricular ejection phase

Answer 18

In this phase of the cardiac cycle, the pressure of the ventricles is greater than the pressure in the atria, and the semilunar valves open as the blood is pumped out of the ventricles

Question 19

Describe the two phases of the Ventricular Diastole during a cardiac cycle

Answer 19

Ventricular diastole= Phase 4, and phase 1:
In phase 4, The pressure in the ventricle decreases to below that of the aorta and the aortic valve closes

In Phase 1: ventricular filling begins once the pressure in the ventricle is less than that of the atria, and the AV valves open. In the beginning, the ventricle fills passively as the AV valves are open … and then the atria contracts, and actively fill the ventricle

Question 20

Describe the phases in Ventricular Systole during a cardiac cycle

Answer 20

Ventricular systole occurs in phase 2 & phase 3
In phase 2: the increasing pressure within the ventricles causes the AV valves to close. This stage corresponds to isovolumetric ventricular contraction.

In Phase 3
The pressures in the ventricle exceeds those in the aorta, the aortic valve opens - blood is ejected out of the ventricles

Question 21

End systolic volume (ESV)

Answer 21

End systolic volume (ESV) - the volume of blood in the right/left ventricle at the end of contraction, or systole, and the beginning of filling or diastole. ESV is the lowest volume of blood in the ventricle at any point in the cardiac cycle.

Question 22

End diastolic volume (EDV)

Answer 22

End diastolic volume (EDV) - the volume of blood in the right or left ventricle at the end of filling.

Question 23

Stroke volume

How is it calculated?

Answer 23

is the volume of blood ejected from the heart during the cardiac cycle,
SV = EDV - ESV