quiz 4 Flashcards
Atrial fibrillation is a dysrhythmia that causes uncoordinated atrial excitation and contraction - the atrial cardiomyocytes are not synchronized and there is essentially no atrial systole. How would you expect atrial fibrillation to impact ventricular filling?
Question 1 Answer
a.
The ventricles are dependent on atrial contraction to fill - without a pacemaker, this would be a fatal dysrhythmia.
b.
There would be a small reduction in ventricular filling at rest, which would be more prominent with exercise.
c.
Ventricular filling would be significantly reduced, to below 50% of normal in most people.
d.
Passive ventricular filling would compensate for the loss of atrial contraction and it would be unlikely to be reduced at rest or during exercise
b.
There would be a small reduction in ventricular filling at rest, which would be more prominent with exercise.
How is ejection fraction calculated? Use the following abbreviations: EF = ejection fraction; ESV = end systolic volume; EDV = end diastolic volume, SV = stroke volume
Question 2 Answer
a.
EF = (EDV - ESV)/SV
b.
EF = (EDV - ESV)/EDV
c.
EF = SV X EDV
d.
EF = EDV/SV
b.
EF = (EDV - ESV)/EDV
Which of the following NEVER increases stroke volume?
Question 3 Answer
a.
Increased contractility
b.
Increased afterload
c.
Increased chronotropy
d.
Increased preload
b.
Increased afterload
Which valves would you expect to be open during isovolumetric contraction?
Question 4 Answer
a.
The semilunar valves are open, but the atrioventricular valves are closed.
b.
Both the atrioventricular and semilunar valves are closed.
c.
The atrioventricular valves are open, but the semilunar valves are closed.
d.
Both the atrioventricular and semilunar valves are open.
b.
Both the atrioventricular and semilunar valves are closed.
Choose the TRUE statement about the force of contraction in a cardiac myocyte.
Question 5 Answer
a.
Greater cardiomyocyte force development is due to greater intracellular calcium levels during contraction.
b.
Greater cardiomyocyte force development is due to greater sodium entry during the action potential.
c.
It is rare for the force of contraction to change in a cardiomyocyte - most variation in blood flow is due to changes in heart rate.
d.
The shorter a cardiomyocyte prior to contraction, the greater the force of contraction that can develop since actin and myosin exhibit maximal overlap.
a.
Greater cardiomyocyte force development is due to greater intracellular calcium levels during contraction.
How does the role of the sarcoplasmic reticulum differ between a cardiac myocyte and a skeletal muscle cell?
Question 6 Answer
a.
In a cardiac cell the sarcoplasmic reticulum conducts the action potential deep into the cell. Skeletal muscle cells depend on the plasma membrane for action potential conduction.
b.
In a cardiac cell the sarcoplasmic reticulum is the major source of calcium ions that are essential for binding to troponin. Skeletal muscle cells depend more on extracellular calcium.
c.
In a cardiac cell the sarcoplasmic reticulum is responsible for rapidly repolarizing the cell. Skeletal muscle cells undergo tetany so they do not rely on the sarcoplasmic reticulum for rapid repolarization
d.
Cardiac muscle cells store large quantities of ATP in the sarcoplasmic reticulum, which aids continual cardiomyocyte activity. This is not an essential feature of skeletal muscle cells.
a.
In a cardiac cell the sarcoplasmic reticulum conducts the action potential deep into the cell. Skeletal muscle cells depend on the plasma membrane for action potential conduction.
What is the cardiac event that occurs during the P-wave of the ECG?
Question 7 Answer
a.
Ventricular contraction
b.
Atrial depolarization
c.
Ventricular depolarization
d.
Atrial contraction
b.
Atrial depolarization
Which of the following will decrease chronotropy?
Question 8 Answer
a.
Increased activation of beta-1 receptors
b.
Increased concentrations of thyroid hormone
c.
Increased activation of muscarinic receptors
d.
Increased stretch of the right atrium
c.
Increased activation of muscarinic receptors
ACETYLCHOLINE IS PNS rest and digest
chronotropy= rate of contraction, heart rate
Which chamber are you auscultating (listening to) when you place your stethoscope over the left sternal border at the 4th intercostal space?
Question 9 Answer
a.
The left atrium
b.
The left ventricle
c.
The right atrium
d.
The right ventricle
d.
The right ventricle
Which of the following statements are TRUE regarding the coronary circulation?
Question 10 Answer
a.
The left coronary artery usually supplies the SA node
b.
The left coronary artery usually supplies the anterior interventricular artery
c.
The right coronary artery usually supplies the left circumflex artery
d.
The left coronary artery usually supplies the posterior interventricular artery
b.
The left coronary artery usually supplies the anterior interventricular artery
What type of folding in the trilaminar germ disc is responsible for the final position of the heart?
Question 11 Answer
a.
Head folding
b.
Lateral folding
c.
Coelom folding
d.
Tail folding
a.
Head folding
Which of the four components below is usually poorly-formed in an atrial septal defect?
Question 12 Answer
a.
septum primum
b.
foramen primum
c.
foramen secundum
d.
septum secundum
d.
septum secundum
