Unit 4.3: ECG & the Cardiac Cycle

Question 1

How many leads do you use in an ECG? What do you form?

Answer 1

3 leads to make up “Einthoven’s triangle”

Question 2

How many ECG leads do we use now?

Answer 2

12

Question 3

What are the 2 components of an ECG?

Answer 3

1. Waves

2. Segments

Question 4

What are the waves in an ECG?

Answer 4

1. P wave: depolarization of atria
2. QRS complex: ventricular depolarization
3. T wave: repolarization of ventricles

Question 5

What are the segments of an ECG?

Answer 5

P-R segment: atrial contraction

S-T segment: ventricular contraction

Question 6

What information does an ECG provide?

Answer 6

Info such as heart rate (p wave to p wave)

Question 7

What is systole and diastole?

Answer 7

Systole: contraction
Diastole: relaxation

Question 8

What are the steps to the cycle?

Answer 8

P. 62

Question 9

when do the lub dub sounds of the heart manifest?

Answer 9

Lub - closing of AV valves

Dub - closing of semi-lunar valves

Question 10

What is the end diastolic volume?

Answer 10

maximum volume in ventricle (end of ventricular filling)

Question 11

What is the end systolic volume?

Answer 11

minimum volume in ventricle (end of ventricular contraction)