What artery supplies the:
- SA node
- AV node
- AV bundle
SA node - 60% of ppl right coronary, 40% of ppl left coronary
AV node - left coronary
AV bundle - left coronary
How are isolated dextrocardia and dextrocardia associated with situs inversus distinguished?
Isolated dextrocardia is a when the placement of the heart is completely reversed so that the apex is misplaced to the right instead of the left.
In dextrocardia with situs inversus, there is a general transposition of the thoracic and abdominal viscera which is usually associated with fewer accompanying cardiac defects compared to isolated dextrocardia.
Identify structures labeled A through D in the image below.
What is unique about structure D?
Structure D (apex of heart) is also the auscultation site for the mitral (bicuspid) valve.
Identify structures labeled A through C in the image below.
What are auricles, where can they be found, and what do they do?
Auricles are two pouch-like projections from the atria of the heart that increase atria capacity.
The right auricle overlaps the ascending aorta and the left auricle overlaps the pulmonary trunk.
Identify structures A through E in the radiograph below.
What can affect the size of structure B?
Structure B (arch of aorta aka "aortic knob") often increases in size when there is an increase in blood flow or it can decrease in size when there is a decrease in blood flow.
Identify structures A through D in the image below.
What is the main vein of the heart, and where does it empty into?
The coronary sinus is the main vein of the heart, and it empties into the right atrium along with the IVC and SVC.
Which portion of the interior wall of the right ventricle is smooth, which is rigid, what makes it rigid and why?
the outflow portion of the interior wall of the right ventricle is smooth
the inflow portion is rigided by cardiac muscle
Identify structures A through E in the image below.
Also, define the function of structure C.
Stucture C (fibrous chordae tendineae) are responsible for connecting the free ends of the three cusps of the tricuspid valve to the papillary muscles (structures E & F).
They act as cords attaching to a parachute and during systole, papillary muscle contraction tenses the cords to insure tight closure of the cusps thereby preventing retrograde flow in to the right atrium.
What is cor pulmonale and what causes it? Why are shortness of breath and cyanosis during physical activity often the first symptoms?
What is the major difference between the left atrium and the right atrium?
What is the major difference between the left ventricle and the right ventricle?
The interior wall of the left atrium is completely smooth while the anterior aspect of the interior wall of the right atrium has a rigid portion full of cardiac muscle.
The left ventriclular wall is nearly double the thickness of the right ventricular wall due to the drastic increase in systemic pressure compared to pulmonary pressure.
What structure can be found immediately posterior to the left atrium (starred region in the image below)
Where can ridged cardiac muscle be found within the left ventricle? What added function does this cardiac muscle have besides contraction?
Rigid cardiac muscle can be found all over the interior wall of the left ventricle except for near the smooth outflow portion.
This muscle also prevents suction that would otherwise occur with a flat surface and would impair pumping efficiency.
Of the four valves of the heart, which lack chordae tendineae?
Explain when and how the remaining valves close?
The pulmonary and aortic valves lack chordae tendineae so they are reliant on pressure gradients to open and close.
The mitral and tricuspid valves possess chordae tendineae that are attached to papillary muscles which contract during systole to tightly close these valves, ensuring that there is no retrograde flow of blood during the chamber's contraction.