Cardiovascular Flashcards
The region between the two pleural cavities that contains the heart and great vessels is called the ___.
mediastinum
Which layer of pericardium touches the heart?
visceral pericardium
Cardiac muscle tissue cells have ____.
intercalated discs
Why is the left ventricle more muscular than the right ventricle?
It contracts with force sufficient to push blood through the systemic circuit
Where is the ANS headquarters for cardiovascular control?
medulla oblongata
What is the importance of the 100-msec delay at the AV node?
Atria must contract to fill the ventricles with blood
Why is resting HR somewhat slower than the 80-100 bpm set by the SA node?
Parasympathetic effects dominate in a resting individual
How is cardiac output (CO) calculated?
CO mL/min = (EDV - ESV) x HR
CO mL/min = HR bpm x SV mL/beat
During ventricular systole of the cardiac cycle, all of the following would occur EXCEPT ____.
pressure in ventricles would force the semilunar valves closed
When during the cardiac cycle do ventricles contain their maximal amount of blood? What is this quantity called?
- at the end of atrial systole; EDV
- at the end of ventricular diastole; EDV
On an ECG reading, what does the P wave indicate?
atrial depolarization
What event is taking place during the Q-T interval?
a single cycle of ventricular depolarization and repolarization
What factor could cause an increase in the size of the QRS complex of an electrocardiogram recording?
an increase in heart size
What condition contributes to a reduction in the size of the T wave?
coronary ischemia
Why is there no wave corresponding to atrial repolarization on an ECG reading?
It is masked by the QS complex
What affects the rate of venous return?
cardiac output, stroke volume, and heart rate
How is eversion of the AV valves and backflow of blood into the atria prevented?
tightening of chordae tendineae and contraction of papillary muscles
Doris was born with a malformed pulmonary valve. How will that affect her circulation?
Blood will flow back into her right ventricle
Grandpa has developed a radiating pain in his chest upon raking leaves. What medication might be given to offer prompt relief?
nitroglycerin, which is a vasodilator of coronary vessels
How does damage to the cardioinhibitory center of the medulla affect heart rate? Why?
Heart rate increases; sympathetic dominance
What blood vessels bring blood back into the right atrium?
superior and inferior venae cavae and coronary sinus
What is the effect of NE binding to adrenergic receptors?
increases vasoconstriction and increases heart rate
Benjamin has an EDV of 120 mL and an ESV of 45 mL, which gives him an SV of 75 mL. What is his ejection fraction?
60%
Frank has just run a marathon and his heart is beating extremely rapidly. What happens to the length of diastole and filling time?
both decrease
Why is ESV lower when you are actively exercising?
EDC increases and ventricular muscle produces more forceful contractions ejecting more blood
What is the most important factor in considering cardiac function over time?
cardiac output
