- | Page
ECG CPO EXAM QUESTIO NS AND
ANSWERS
Question :What is the pattern of blood flow through the
heart?
Correct answer:Right atrium - Tricuspid valve - Right
Ventricle - Pulmonic Valve - Pulmonary Arteries - To the Lungs - Pulmonary Veins - Left atrium - Mitral Valve - Left ventricle - Aortic valve - Aorta
Question :What is the atrial kick?
Correct answer:This is atrial systole - The atrial kick
delivers 20-30% of the blood volume from the atria to the ventricles. The atria is contracting in response to the SA node
Question :What is the pericardial cavity?
Correct answer:Between the parietal and visceral layers of
the heart is a potential space. It contains serious fluid (pericardial fluid) which reduces friction.
- | Page
Question :What is the epicardium?
Correct answer:It is the outer surface of the heart or inner
serous layer of the pericardial asc
Question :What is the myocardium?
Correct answer:It is the middle layer of the heart and it is
the muscular layer
Question :What is the endocardium?
Correct answer:It is the inside layer that is nice and
smooth. It helps the blood to flow smoothly.
Question :What are the five unique properties of
myocardial tissue?
Correct answer:1) Automaticity
2) Rhythmicity 3) Conductivity 4) Contractility 5) Excitability
- | Page
Question :What does 'automaticity' of cardiac cells refer
to?
Correct answer:It refers to their ability to initiate an
impulse without an external source of stimulation It works without your brain instructing it to
Question :How is the action potential generated?
Correct answer:Phase 4: Resting membrane potential.Inside the cell is a high concentration of K+. In this stage, K+ gates open and it starts to leak out.
Phase 0: Depolarization phase. Na+ enters the cell via fast
sodium channels - making the inside of the cell positive.K+ gates close.
Phase 1: Early repolarization - fast sodium channels close
Phase 2: Plateau phase - calcium moves into the cell,
causing the cardiac contraction along with the sodium.The influx helps to maintain the positive charge over this time period.
Phase 3: Repolarization - K+ moves into the cell via the
pump and the RMP is re-established
- | Page
Question :What does the 'rhythmicity' of the cardiac cells
refer to
Correct answer:It means that impulses are formed at
regular intervals. The sodium and potassium move at regular rates and then the cycle is repeated - its regular
Question :What does the 'conductivity' of the cardiac cells
refer to?
Correct answer:Electrical impulses travel quickly through
the heart. Intercalated discs contain gap junctions that speed up the conduction.
Question :What does the 'contractility' of the heart refer
to?
Correct answer:The cardiac fibers are arranged in a
circular pattern. Shortening of them reduces the chamber size and increases chamber pressure. The contraction action produces the pumping effect of the heart. To increase the force of contraction, fibers must shorten even more.