Chapter Questions The Cardiovascular System
The heart is in the mediastinum. Just what is the mediastinum?
Medial cavity of the thorax within which the heart, great vessels and the trachea are found
From inside to outside, list the layers of the Heart wall and the coverings of the heart.
•Endocardium – inside layer of the heart wall, sheet of endothelium, lines the heart chambers and covers the fibrous skeleton of the valves
•Myocadium – middle layer of heart wall, composed mainly of cardiac muscle, the layer that pumps
•Epicardium – Viseral layer of the Serous Pericardium that lines the external heart surface
•Pericardial Cavity – cavity between the serous pericardium that’s filled with serous fluid
•Parietal Layer – lines the internal surface off the fibrous pericardium and attaches to the large arteries exiting the heart.
•Fibrous Pericardium – superficial part of pericardium, protects, anchors and prevents the heart from overfilling
What is the purpose of the serous fluid inside the pericardial cavity?
The slippery fluid allows the membranes to glide past one another, allowing the mobile heart to work in relatively frictionless environment
What is the function of the papillary muscle and the chordae tendineae?
Keep the AV valve flaps from reverting into the aorta
Which side of the heart acts as the pulmonary pump? The systemic pump?
The right side of the heart acts as the pulmonary pump and the left side acts as the systemic pump
Which of the following statements are true?
a)The left ventricle wall is thicker than the right ventricle wall.
b)The left ventricle pumps blood at a higher pressure than the right ventricle
c)The left ventricle pumps more blood with each beat than the right ventricle.
a)The left ventricle wall is thicker than the right ventricle wall.
•True
b)The left ventricle pumps blood at a higher pressure than the right ventricle
•True -the left ventricle supplies the whole body and the right ventricle only the lungs
c)The left ventricle pumps more blood with each beat than the right ventricle.
•False
Name the two main branches of the right coronary artery.
•Right Marginal Artery – serves the myocardium of the lateral side of the heart
•Posterior interventricular Artery – runs to the heart apex and supplies the posterior ventricular walls
For each of the following, state whether it applies to skeletal muscle, cardiac muscle, or both
a)Refractory period is almost as long as the contraction
b)Source of Ca2+ for contraction is only SR
c)AP exhibits a plateau phase
d)Has troponin
e)Has triads
a)Cardiac Muscle - Refractory period is almost as long as the contraction
b)Skeletal Muscle - Source of Ca2+ for contraction is only SR
c)Cardiac Muscle - AP exhibits a plateau phase
d)Both - Has troponin
e)Skeletal Muscle - Has triads
Cardiac muscle cannot go into tetany. Why?
Because the absolute refractory period is almost as long as the contraction
Which part of the intrinsic conduction system directly excites ventricular myocardial cells? In which direction does the depolarization wave travel across the ventricles
purkinje fibers; the wave travels upwards from apex towards atria
Describe the electrical events in the heart that occurs during each of the following
a)The QRS wave of the ECG
b)The T wave of the ECG
c)The P-R interval of the ECG
a)The QRS wave of the ECG - ventricular depolarization
b)The T wave of the ECG - ventricular repolarization
c)The P-R interval of the ECG - atrial depolarization and the conduction of the AP through the rest of the intrinsic conduction system
The second heart sound is associated with the closing of which valve(s)?
semilunar valves
If the mitral valve were insufficient, would you expect to hear the murmur (of blood flowing through the valve that should be closed) during ventricular systole of diastole
ventricular systole
During the cardiac cycle, there are two periods when all four valves are closed. Name these two periods
isovolumetric contraction phase and the isovolumetric relaxation phase
After running to catch a bus, Josh noticed that his heart was beating faster than normally and was pounding forcefully in his chest. How did his increased HR and SR come about?
Exercise activates the SNS, which increases heart rate and ventricular contraction, which increases stroke volume
What problem of cardiac output might ensue if the heart beats far too rapidly for an extended period, that is, if tachycardia occurs? Why
the amount of time for ventricular filling between contractions is decreased, which decreases EDV, SV, and therefore CO
Name the two components of the fetal heart that allow blood to bypass the lungs
foramen ovale and the ductus arteriosus
In the past decade, many people over 70 have competed in the Ironman World Championships in Hawaii. In what way might age-related changes of the heart limit the performance of these athletes?
Sclerosis and thickening of heart valve flaps, a decline in cardiac reserve, fibrosis of cardiac muscle, and atherosclerosis
Sclerosis and thickening of heart valve flaps, a decline in cardiac reserve, fibrosis of cardiac muscle, and atherosclerosis