Lecture 3

Question 1

What is excitation-contraction coupling?

Answer 1

A contraction of the cells is coordinated with an action potential

Question 2

Which molecules go in and out of the cell for a potential?

Answer 2

Sodium and calcium go into the cell
Potassium goes out of the cell

Question 3

What different types of refractory periods are there?

Answer 3

Absolute and the relative refractory period

Question 4

What does the contraction of myocytes start with?

Answer 4

With calcium

Question 5

What is order of conducting a signal in the heart?

Answer 5

The SA, then AV then the bundle fibers, then the purkinje fibers

Question 6

Which structure delays the signal in the heart?

Answer 6

The AV

Question 7

What happens during the P in an ECG?

Answer 7

This shows the AV node, thus the depolarization of the atria

Question 8

What happens during the Q in an ECG?

Answer 8

The spread of depolarization in the atria

Question 9

What happens during the T in an ECG?

Answer 9

This is the repolarization of the ventricles

Question 10

How long is the PR in an ECG?

Answer 10

it is 0.12-0.20 s (shows the conduction through the AV)

Question 11

How long is the QRS in an ECG?

Answer 11

0.07-0.10 s

Question 12

How long is the QT in an ECG?

Answer 12

0.3-0.4 s

Question 13

Which limbs are used when measuring lead I?

Answer 13

Left arm and right leg

Question 14

Which limbs are used when measuring lead II?

Answer 14

Right arm and left leg

Question 15

Which limbs are used when measuring lead III?

Answer 15

The left arm and left leg

Question 16

In which order do you look at an ECG?

Answer 16

Rhythm, frequency, conduction times, heart axis, P-wave, QRS wave and ST (ischemia)

Question 17

What causes fibrillation?

Answer 17

Myocarditis or heart failure

Question 18

What is comottio carditis and what causes this?

Answer 18

It is caused by a round object striking the chest at the start of the T wave. This increases the potassium current due to a cell membrane stretch and results in fibrillation

Question 19

What is an ICD and when is it used?

Answer 19

It is an internal defibrillator, which is only used in high risk patients

Question 20

Can you feel an AV block in the pulse?

Answer 20

Yes

Question 21

What is characteristic of a first degree AV block?

Answer 21

The PR-interval is longer

Question 22

What is characteristic of a second degree AV block?

Answer 22

Some signals are not passed on to the ventricles

Question 23

What is characteristic of a third degree AV block?

Answer 23

There is no conduction through the AV, other pacemaker cells take over (slower)

Question 24

How can an AV block be treated?

Answer 24

With the use of a dual chamber pacemaker

Question 25

What does a dual chamber pacemaker do?

Answer 25

It goes to the right atrium and ventricle to regulate the pace of the contractions

Question 26

What is long QT syndrome?

Answer 26

It is an inherited syndrome that results in a mutation in one of the ion channels that causes them to work less well (have a long QT interval)

Question 27

What is a risk factor for ventricular fibrillation?

Answer 27

The long QT syndrome

Question 28

What is long QT syndrome a common side effect of?

Answer 28

Of heart medication

Question 29

What happens during ST elevation?

Answer 29

The S is not fully down before the T, they flow into each other

Question 30

What happens with the T in ischemic tissue?

Answer 30

It is reversed, so the peak goes down.

Question 31

What does a reversed T peak indicate?

Answer 31

A heart attack

Question 32

What is done during heart catheterization?

Answer 32

A tube is put in the vessels in the arm to the heart. This is done to examine the heart valves, or take a sample of the blood/muscle

Question 33

What does a stent do?

Answer 33

It is inserted to open up the vessel

Question 34

Can hypertension be detected by an ECG?

Answer 34

No, but the consequences can be

Question 35

What does a higher workload of the heart lead to?

Answer 35

This leads to hypertrophy (when the cells that are already there grow)