BIO 502, Lecture 16: Cardiopulmonary

  1. What is the function of the serous fluid found on the superficial surface of the parietal pluera?
    It doesn't have a function b/c that is not where the serous fluid is located. It is located between the layers of the visceral and parietal pleura. There it creates a frictionless environment to facilitate the movement of the lungs.
  2. What are the pleural recesses and what is their function?
    The pleural recesses are spaces in the pleural cavities that the lungs can expand into during inhalation. There are two of them: a smaller costomediastinal recess, located medially, posterior to the body of the sternum, and a larger costodiaphragmatic recess, located inferior to the inferior margin of the lungs. When the lungs are not occupying the space, the recesses exist as a double lining of parietal pleura. When the lungs move into the recesses, the parietal pleura opposes the visceral pleura.
  3. Which lung is larger than the other and why?
    The right lung is larger than the left. This is because the left lung has to "share" the left side of the body wit the heart.
  4. What is the difference between the root and the hilum of the lung?
    The root of the lung is the collection of structures passing between the heart and each lung (i.e., the pulmonary arteries ad veins, the bronchi, the bronchial arteries and veins, the pulmonary plexus, lymphatics). The hilum of the lung is the opening allowing the passage of those structures. This is also where the parietal pleura transitions into the visceral pleura.
  5. Why is it possible to remove portions of the lung without affecting function of the rest of the lung, and what are these portions called?
    Bronchopulmonary segments. It is possible to remove them because they are the smallest functional divisions of the lungs and as such they operate entirely independently of one another. Each segment has its own segmental bronchus and all of the bronchial vessels down to the alveoli.
  6. In the lungs, what would occur if the right vagus nerve were cut?
    The vagus nerve carries visceral (parasympathetic)  efferent and afferent fibers to the lungs. If the right nerve were cut anywhere the ability to constrict the bronchioles on the right side would be lost. And technically, this would affect the heart, as well. It would be very very bad.
  7. If there is an infection in the superior mediastinum, would the posterior mediastinum be affected, as well? Why or why not?
    Yes, because the divisions between the posterior and superior mediastinum are descriptive only. There are no actual barriers between the regions.
  8. What is wrong with this pulmonary impulse pathway?

    Anterior root @ T2 / spinal nerve / anterior ramus @ T2 / white ramus communicant / ganglion @ T2 / sympathetic chain / ganglion @ T4 / *synapse* / grey ramus communicant @ T4 / anterior ramus at T4 / sympathetic thoracic cardiac branches / posterior pulmonary plexus
    • One or two things, depending: 
    • 1) impulses originating from T1-T5 generally ascend rather than descend. So this may be right, but it may be wrong, too.
    • 2) impulses bound for thoracic viscera do not need to re-enter the anterior ramus. They simply synapse then continue via their relevant peripheral nerve to the target.
  9. If the fibrous pericardium were cut, would the heart remain in a frictionless environment? Why or why not?
    • Yes, if only the fibrous pericardium were cut, the heart would remain in a frictionless environment. This is because the serous fluid is located between the two layers of the serous pericardium: the visceral and parietal layers (which are deep to the fibrous pericardium). With the serous fluid, these two layers create the frictionless environment for the heart. So you'd be in bad shape, but your heart could still move about its friction-free space.
    • However, it would be exceedingly difficult to cut the fibrous pericardium without cutting the parietal pericardium, as well, since the latter adheres to the deep surface of the former.
  10. True or false (if false, please give the correct information):
    The superior and inferior vena cava carry de-oxygenated blood to the diaphragmatic surface of the heart.
    FALSE. The diaphragmatic surface of the heart is made up of the left ventricle and a small portion of the right ventricle. De-oxygenated blood is delivered to the right atrium of the heart, which is shared by the base of the heart and the anterior surface of the heart.
  11. True or false (if false, please give the correct information):
    the anterior interventricular branch of the left coronary artery travels with the great cardiac vein.
  12. True or false (if false, please give the correct information):
    the pulmonary arteries carry oxygenated blood from the lungs to the heart.
    FALSE. The pulmonary arteries carry de-oxygenated blood from the heart to the lungs.
  13. True or false: The coronary sinus drains into the superior vena cava and then into the right atrium.
    FALSE: the coronary sinus drains directly into the right atrium (into the sinus venae). The azygos vein drains into the superior vena cava.
  14. If the semilunar cusps of the pulmonary valves collapsed and were completely non-functional, what effect would this have on the right coronary artery?
    Well, you'd be in rough shape... But more specifically, if the semilunar cusps of the pulmonary valves were non-functional then a potentially large portion of deoxygenated blood would retreat back into the right ventricle at the end of or immediately following ventricular contraction. This would result in improper cardiac output to the lungs and eventually reduced oxygenated blood flow back into the left atrium. Reduced blood flow into the left atrium would mean reduced flow into the left ventricle and consequently, into the cusps of the aortic semilunar valve. Since the right coronary artery originates from the cusps of the aortic semilunar valve, over all inflow into the right coronary artery would be reduced, a potentially fatal disease. Similarly, blood flow to the left coronary artery would also be affected.
  15. If the excitation impulse somehow magically skipped over the atrioventricular node and moved on to the atrioventricular bundle, what may occur and why?
    The atrioventricular node serves to delay the  excitation signal coming from the sinu-atrial node to make sure that the atria finish contraction before the ventricles start contraction. If the AV node were "skipped over" the signal would not get slowed down and the ventricles may contract while the atria are still contracting. This may mean that the AV orifices and valves would be closed, cutting off the pathway of blood as it attempted to flow from the atria to the ventricles. Overall, it would be a huge mess
  16. Would the loss of the pectinate muscles directly affect the function of the mitral valve?
    the pectinate muscles do not directly act on the mitral valve. So other than the fact that heart function would be dramatically compromised which would affect everything, the loss of the pectinate muscles would not directly act on the function of the mitral valve.
  17. Describe how and when the aortic semilunar valve is closed.
    The aortic valve is closed after left ventricular contraction. The recoil of the blood that passed through the aortic valve fills the semilunar cusps of the aortic valve, causing them to close.
  18. If the left common carotid artery were 100% blocked, which muscles in the left arm would lose their primary blood supply? Explain your answer.
    Again, you'd be dead, but that notwithstanding, none of the muscles in the left arm would lose their primary blood supply because they are all supplied by branches of subclavian. The right and left coronary arteries supply the walls of the heart.
  19. If the parasympathetic innervation to the heart was accelerated are you likely to be in a state of agitation or relaxation? Explain your answer.
    You'd be relaxing, most likely. The parasympathetic system is responsible for decreasing the heart rate, reducing contraction force and constricting the coronary arteries, functions which are associated with a relaxed state.
  20. Which chamber of the heart receives the excitation impulses that travel in the septomarginal trabecula?
    The right ventricle
  21. Which ventricle pumps with greater force, the left or the right ventricle? Why?
    The left ventricle pumps with greater force than the right because it has greater muscle mass, needed to pump blood from the heart out to the body.
  22. Which pulmonary artery is longer and why?
    The right pulmonary artery is longer b/c the heart is situated on the left side of the body, so the right pulmonary artery has to travel across the midline of the body to enter the lung.
  23. Describe the relationship of structures deep to the sternal angle, traveling anterior to posterior.
    • Moving anterior to posterior, the following structures would be encountered:
    • 1) potentially the paricardium (fibrous, parietal and then visceral layers), if it extends up onto the ascending aorta that high)
    • 2) the aorta, ~ at the transition from the ascending aorta to the arch of the aorta
    • 3) the trachea, ~ at the level where it is bifurcating into the main bronchi
    • 3) the esophagus
    • 4) the anterior longitudinal ligament
    • 5) either the body of TIV or TV or the intervertebral disc between them
    • 6) the posterior longitudinal ligament
    • 7) the meninges (dura mater, arachnoid mater, pia mater), enclosing the spinal cord
    • 8) any variety of posterior structures, depending on the exact location (e.g., ligamentum flava, spinous process of TIV or TV, interspinous ligament, supraspinous ligament)
    • 9) Splenius capitus and cervicis
    • 10) rhomboid major
    • 11) trapezius

    The point is...there is a lot going on at the sternal angle
Card Set
BIO 502, Lecture 16: Cardiopulmonary