Cardiac Lecture 5 Flashcards
The right vagus nerve innervates the ______ node
SA
Sympathetic innervation is widespread and covers more of the ___________ than the vagus nerves
ventricle muscle
The left vagus nerve innervates the ______ node
AV
Which impacts the HR most, the vagus nerves or the sympathetic nerves?
vagus
The innermost layer of the pericardium is the ________
visceral layer of the serous pericardium
- stretchy and allows for heart movement
The outermost layer of the pericardium is the ________
fibrous pericardium
- rigid layer
What layer is between the visceral layer of the serous pericardium and the fibrous pericardium?
parietal layer of the pericardium
What ions can move through gap junctions in the heart?
Sodium and calcium
How do the ventricles contract to squeeze the most efficiently?
Wringing out a towel - endocardial and epicardial fibers
Another term for cusps is _______
leaflets
Cusps of heart valves are attached to the inside of ventricles via connective tissue called _________
chordae tendineae
Chordae tendineae attach cusps to ventricle muscle via _______
papillary muscles
What is the purpose of papillary muscles when ventricles contract?
Papillary muscles contract with ventricles and reinforce AV valves to protect them from high-pressure ventricles
normal EF?
70 mL ejected from starting volume of 120 mL = 70/120
Which AV valve is tricuspid vs bicuspid?
L - bicuspid
R - tricuspid
What are the different cusps called in the AV valves?
Bicuspid - anterior and posterior
Tricuspid - anterior, septal, and posterior
How many cusps do the pulmonary and aortic valves have? What are they called?
3 each
- pulmonary valve: right, left, and anterior
- aortic valve: left, right, and posterior
Which cusps are the coronary arteries attached to?
R and L cusps of the aortic valve
When are the coronary arteries perfused?
diastole - BP in aorta high, aortic recoil
What structure separates the electrical activity of the atria from the ventricles?
cardiac cartilaginous rings - insulator
Where is the bundle of his located?
a small opening in the cartilaginous rings
How is the bicuspid valve different from the other heart valves?
2 real cusps (bicuspid) and a “commissural cusp” which is part of the posterior cusp
The left coronary artery splits into the _______ artery and the ______ artery
LAD and circumflex
For most people, the PDA is fed by which coronary artery?
RCA - some people circumflex
Where is the great cardiac vein located? What does it empty into?
Posterior inferior heart, coronary sinus
What is the rate of coronary blood flow in a typical heart?
70 mL/min/100 grams muscle or 225 mL/min
Does the heart have more coronary blood flow during diastole or systole?
Diastole
What are the deep and superficial coronary blood vessels called?
Epicardial, endocardial, and subendocardial
In general, the LCA supplies ______ pressure areas of the heart, while the RCA supplies ______ pressure areas of the heart
high, low
When does coronary artery blood flow backward?
LCA flow back into the aorta during early systole
aortic pressure < LV pressure
What is the pressure that drives coronary artery blood flow?
aortic pressure
How is delta P calculated in coronary blood flow?
aortic pressure - wall (LV) pressure
Besides delta P, what else impacts coronary blood flow?
time - filling/diastole
If HR increases, which part of diastole would the healthy heart decrease? Why is this portion more important in unhealthy hearts?
middle 1/3 of diastole; needed for coronary artery blood flow in sick heart (decreases time with high wall pressures)
How would spinal anesthesia affect CO?
Spinal anesthesia wipes out SANS activity
- more circulatory than heart problem
- decreased Psf -> decreased CO
What are the 3 CVP/atrial waves?
A, C, and V
What causes the C wave in CVP/atrial pressure?
AV valves bulging backward when ventricle contracts during early systole
What causes the V wave in CVP/atrial pressure?
atrial filling while the AV valves are closed during late systole - blood returning from systemic circulation and filling the atria
What causes the A wave in CVP/atrial pressure?
atrial contraction at the end of diastole
What is the X descent in the CVP/atrial pressure graph?
after the c wave when the atria is empty and valves no longer bulging back (mid systole)
What is the Y descent in the CVP/atrial pressure graph?
after the v wave, when AV valves open and rapid filling of ventricle occurs (early diastole)
What is the normal range of pulmonary vascular resistance?
40-180 mmHg/L/min or cgs
What is the normal range of systemic vascular resistance?
800-1600 mmHg/L/min or cgs
What is the formula for SVR?
((MAP-CVP)/CO)*80
What is the formula for PVR?
((MPAP-PAWP)/CO)*80
What is a PRU? What is normal?
Peripheral resistance unit - 1
How do you convert PRUs to cgs?
PRU*1333 = cgs
What happens to CVP during inspiration? How would this affect CO?
decreases both
- negative pressure pulls on the walls of the veins, reducing preload
What happens to the preload and afterload of the RV during inspiration?
reduced preload - blood pulled out of RA into vena cava
reduced afterload - pulmonary veins are compliant
What happens to the preload and afterload of the LV during inspiration?
preload is decreased while afterload remains the same
During inspiration, which side of the heart has the greatest decrease in CO?
Left side - afterload stays the same since the aorta has thick walls and stays the same size
