Exam 1 - Cardiac Anatomy, CVP, Coronary Blood Flow Flashcards
What does the right and left vagus nerve innervate?
Right vagus = SA node
Left vagus = AV node
What is the name of the layer directly attached to the myocardium?
What is it’s function?
- The serous pericardium, visceral layer
- It’s very stretchy and allows for heart movement during the filling and ejection
What is the most superficial layer of the heart?
What are it’s characteristics?
Fibrous pericardium
Very tough and rigid
What is the name of the layer attached to the inside of the fibrous pericardium?
Serous pericardium, parietal layer
What is 1 and 2?
- Serous pericardium, parietal layer
- Fibrous pericardium
What are the 2 ions that move through gap junctions?
Na+ primarily, some Ca++
How are the epicardium and endocardium arranged?
Perpindicular to one another so that during contraction, they twist in opposite directions, like wringing out a towel
What are the other names for valves?
Cusps or leaflets
How are the AV valves connected to the heart?
Why is the purpose of these valve connections?
Valves are attached to chordae tendineae
Chaordae tendineae attach to papillary muscles that are a part of the ventricular muscle
The papillary muscles contract with the ventricle preventing displacement of the valves
What is a normal EF for our class?
SV/EDV
70mL/120mL = .58 or 58%
What is 1-3 in the picture below?
- Mitral Valve
- Anterior cusp
- Posterior cusp
What is 12 - 15 in the picture below?
- Tricsupid valve
- Anterior cusp
- Septal cusp
- Posterior cusp
What is 4-7 in the below picture?
- Pulmonary valve
- Right cusp
- Anterior cusp
- Left cusp
What is 8-11 in the below picture?
- Aortic valve
- Left cusp
- Right cusp
- Posterior cusp
Where do the coronary arteries attach to the aorta?
The right coronary artery branches off the right cusp
The left coronary artery branches off the left cusp
What is important about the shape of the aortic valves?
They are concave and act as “bowls” to direct blood that is in the aorta into the coronary arteries during diastole
What structure allows the atria and ventricular conduction to remain seperate?
The cardiac cartilagenous rings
How do impulses move from the atria past the cartilagenous rings?
There is an opening for the bundle of his
What is the name of the indicated structure?
Comissural cusp of the mitral valve
Name each of the labeled figures below?
- Right coronary artery
- Left coronary artery
- Circumflex artery
- Left anterior descending artery
Name each of the indicated structures?
- Circumflex artery
- Great cardiac vein
- Coronary sinus
- Posterior descending artery
- Right coronary artery
Where does the PDA branch from?
Most people, the right coronary artery
Sometimes branches from the circumflex artery
Where does the coronary sinus feed into?
The right atrium
How much blood flow does the heart require from the coronary arteries?
70 mL/min/100 grams of muscle
or
225 mL/min
Where is coronary blood flow continous during the entire cardiac cycle?
The right coronary artery which supplies the lower pressure areas of the heart: right ventricle and atrium
Describe what is happening in the circles portions?
During early systole, the endocardial vessels that are full of blood are squeezed tightly causing retrograde flow of blood from the coronary arteries back to the aorta.
What is the △P for coronary perfusion?
Aortic pressure - LV wall pressure
How could we calculate coronary perfusion?
△P (Aortic P - LV wall P) · Time in diastole
How does HR affect coronary perfusion?
The higher the HR, the less time spent in diastole, and the less time available for coronary perfusion
Why is coronary perfusion worsened by aortic stenosis?
Aortic stenosis creates increased LV pressure which makes it harder for the coronary arteries to perfuse the heart muscle
What causes the c wave on a CVP waveform?
When does this occur?
The tricuspid valve bulging backward into the atria during isovolumetric contraction
What causes the v wave on a CVP waveform?
Filling of the atria during systole
What is the x descent on a CVP waveform?
Occurs after the c wave, drop in pressure in the atria due to atrial relaxation during mid systole
What is the y descent on a CVP waveform?
Occurs after the v wave, due to drop in pressure in atria from ventricular filling in early diastole
What is normal SVR and PVR?
SVR: 800-1600 dynes·sec·cm-5
PVR: 40-180 dynes·sec·cm-5
What is the formula for SVR?
What are the units?
(MAP - CVP / CO) x 80
Dynes·sec·cm5
What is the formula for PVR?
Why is it overestimated?
(MPAP - PAWP / CO) x 80
Because PAWP is an estimate of LAP, but the pulmonary artery is much higher pressure than the LA
How can you calculate SVR using PRU’s?
△P/F = (100-0)/(~100 mL/s) = 1 PRU (mmHg/mL/s)
How can you convert PRU to cgs?
Multiply by 1333
How can you calculate PVR using PRU’s?
△P/F = (16-2 / 100) = .14 PRU (mmhg/mL/s)
Explain CO changes during inspiration for the right heart?
Decreased intrathoracic pressure creates a decreased pressure in the veins which may cause blood to be pulled from the right atria to the vena cava, reducing preload and CO. At the same time, the afterload of the right heart is also decreasing (pulmonary artery), so you could argue that they cancel each other out or CO increases slightly
Explain CO changes during inspiration for the left heart?
Decreased intrathoracic pressure decreases pressure in the pulmonary veins which decreases left heart preload. But because the aorta is very thick and resistant to changes in thoracic pressure, afterload is unchagned. This means preload is low and afterload is still high = low cardiac output initially.
