Cardiovascular System

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BIOC33/CC4 Cardiovascular System (Lectures 1-4) Study Guide (2015)
Lecture 1: Electrical Conduction within the Heart
Topics
The Conduction System of the Heart
Pacemaker Potential
Sample Questions
1. What is the pathway of electrical conduction in the heart?
2. Which changes in ionic conductance (permeability) accompany the various phases of the pacemaker potential?

3.
1.

2.

4.

a) In zone 1, a decrease in PK and an increase in PNa: In zone 2, an increase in PCa
b) In zone 1, a decrease in PK and an increase in PCa: In zone 2, an increase in PNa
c) In zone 3, a large increase in PNa: In zone 4, an increase in PK and a decrease in PCa
d) In zone 3, a large increase in PCa: In zone 4, an increase in PK and a decrease in PNa
e) A and D

3.
The action potential that travels along the conduction pathway of the heart moves upward into the ventricles (from the apex of the heart) via the
?
a) AV node
b) SA node
c) Purkinje Fibres
d) Atrioventricular valves
e) Bundle of His

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Lecture 2: Cardiac Action Potential and the Electrocardiogram
Topics
The Cardiac Action Potential
Standard Bipolar Limb Leads and Einthoven’s Law
Components of the ECG Wave
Correlation of the ECT Components with the Electrical Conduction Through the Heart
Interpreting ECGs
Rate
Rhythm
Segments of the ECG Trace
Arrhythmia
Sample Questions
1. Which changes in ionic conductance (permeability) accompany the various phases of the cardiac action potential?
2. What do the different components of the ECG represent (i.e., T wave)?
3. Which changes in ionic conductance (permeability) DO NOT accompany the various phases of the cardiac action potential?

a) In zone 0, an increase in PNa
b) In zone 1, a decrease in PNa, a decrease in PK and an increase in PCa
c) In zone 2, a decrease in PNa and an increase in PCa
d) In zone 3, an increase in PK and a decrease in PCa
e) C and D
4. The P and T waves of the ECG represent

and

a) Ventricular repolarisation and atrial depolarisation.
b) Atrial depolarisation and atrial repolarisation.
c) Ventricular depolarisation and atrial repolarisation.
d) Atrial depolarisation and ventricular repolarisation.
e) Atrial depolarisation and ventricular depolarisation.

, respectively.

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5. The following ECG trace is representative of what cardiac disorder?

a) Atrial flutter.
b) Atrial fibrillation.
c) Ventricular fibrillation.
d) Wandering atrial pacemaker.
e) Second degree heart block.

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Lecture 3: ECGs, Electrical Axis of the Heart and the Cardiac Cycle
Topics
ECG and Arrhythmias Continued
Flutter
Fibrillation
Heart Block
Bundle Branch Block
The Electrical Axis of the Heart
Definition of the Electrical Axis
Diagnostic Uses of the Electrical Axis
Calculating the Electrical Axis
The Cardiac Cycle
Opening and Closing of Heart Valves
Heart Valve Disease
Pressure and Volume Changes during the Cardiac Cycle
Late Diastole (Ventricular Filling)
Early Systole (Isovolumetric Contraction)
Late Systole (Ventricular Ejection)
Early Diastole (Isovolumetric Relaxation and Ventricular Filling)

Sample Questions
1.
What are the characteristics of ventricular fibrillation?
2. Describe the changes in atrial pressure, ventricular pressure, aortic pressure and ventricular volume that occur during the various stages of the cardiac cycle. Illustrate when the various valves are open or closed.
3. In order for both of the semilunar valves to be open:
a) P (pulmonary artery) < P (right ventricle) and P (aorta) > P (left ventricle)
b) P (pulmonary artery) < P (right ventricle) and P (aorta) < P (left ventricle)
c) P (right ventricle) = P (aorta) and P (left ventricle) = P (pulmonary artery)
d) P (pulmonary artery) > P (right ventricle) and P (aorta) > P (left ventricle)
e) P (pulmonary artery) > P (right ventricle) and P (aorta) < P left ventricle
4. During Iso-volumetric contraction of the heart:
a) There is an increase in pressure without a change in volume.
b) The semilunar valves are closed.
c) The AV valves are closed
d) A and B
e) A, B and C

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5. Use the following information and diagrams to calculate the mean electrical axis of the heart.
Each division on the leads equals 1.
Magnitude of the QRS complex in lead I = 2
Magnitude of the QRS complex in lead II = 5
Magnitude of the QRS complex in lead III = 3
a) Approximately 33°
b) Approximately 43°
c) Approximately
67°
d) Approximately 90°
e) Approximately 115°

270
225

315

0

180

135

45
90

270
225

315

0

180
135

45
90

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Lecture 4: Cardiac Cycle Continued and Regulation of Cardiac Output
Topics
Cardiac Cycle
Aortic Pressure
Systolic and Diastolic Pressure
Pulse Pressure
Mean Arterial Pressure (MAP)
Stroke Volume
Ejection Fraction
Cardiac Output
Regulation of Heart Rate
Sympathetic Regulation of the Heart (Adrenergic Tone)
Parasympathetic Regulation of the Heart (Cholinergic Tone)
Effects of Adrenergic and Cholinergic Input on the Pacemaker Potential
Sample Questions
1. Cardiac output =

?

a) Blood pressure / Total peripheral resistance
b) Heart rate X stroke volume
c) Heart rate X EDV
d) Blood pressure X Total Peripheral Resistance
e) A and B
2. Use the following numbers to calculate stroke volume and pulse pressure.
Heart rate = 100 beats per minute
CO = 1 L/min
TPR = 0.1 mmHg min/ml
Diastolic pressure = 80 mmHg
a) SV = 10 ml; PP = 60 mmHg
b) SV = 10 ml/min; PP = 60 mmHg
c) SV = 100 ml: PP = 93 mmHg
d) SV = 80 ml; PP = 60 mmHg
e) SV = 10 ml; PP = 80 mmHg the heart rate because it would
3. An acetylcholinesterase inhibitor applied to the heart would the strength of signals. Note, within the synaptic cleft, acetylcholinesterase breaks down acetylcholine into choline and acetyl-CoA
a) Decrease…decrease…parasympathetic.
b) Decrease…increase…parasympathetic.
c) Decrease…decrease…sympathetic.
d) Increase…decrease…parasympathetic.
e) Increase…increase…sympathetic