Adult Heart

Question 1

where are the 4 borders of the heart found in relation to the ribs?

Answer 1

right top border of R atrium: 3rd costal cartilage

right bottom border of R ventricle: 6th costal cartilage

left top border of L atrium: 2nd costal cartilage

left bottom border of L ventricle (apex): 5th intercostal space

Question 2

what structure of the heart makes up most of the right border?

Answer 2

right atrium

Question 3

what structure of the heart makes up most of the left border?

Answer 3

left ventricle

Question 4

what structure of the heart makes up most of the anterior side?

Answer 4

right ventricle

Question 5

what structure of the heart makes up most of the posterior surface?

Answer 5

left atrium

Question 6

the ascending aorta and pulmonary trunk each originate from which heart structure, respectively?

Answer 6

ascending aorta comes from L ventricle (left side of heart is systemic)

pulmonary trunk comes from R ventricle (right side of heart is pulmonary)

Question 7

the superior and inferior vena cava both drain into the

Answer 7

right atrium

Question 8

what are the right and left valves of the heart? which are AV and which are outflow (semilunar)?

Answer 8

right: tricuspid (AV) and pulmonic (outflow/semilunar)

left: mitral/bicuspid (AV) and aortic (outflow/semilunar)

[“tri” before you “bi”]

Question 9

which heart valves are open during systole? during diastole?

Answer 9

AV valves open during diastole (passive filling)

outflow valves are open during systole (—>lungs and body)

auscultation is the sound of closure

Question 10

what is the significance of the shape of the outflow heart valves? (hint: it’s in the name)

Answer 10

outflow valves = semilunar valves because of convex shape (half-moon)

semilunar nodule between valves prevents hole between convex shapes when valves are closed

Question 11

where is each valve sound best auscultated in relation to the valve?

Answer 11

aortic valve: @ ascending aorta, above and right of heart (patient’s right), 2nd intercostal

pulmonic valve: pulmonic trunk, above and left of heart, 2nd intercostal

tricuspid: @ 5th intercostal at sternal border left of midline (so sternum is not in the way)

mitral: @ L 5th intercostal at mid clavicular line, at apex (inferior heart is more anterior, so sound is best at apex)

Question 12

murmur vs bruit

Answer 12

murmur: turbulence in heart
bruit: turbulence in peripheral vessels

caused by blood passing through narrow opening (stenosis or insufficiency)

Question 13

stenosis vs incompetence/insufficiency

Answer 13

stenosis: valve doesn’t open as fully as normal

incompetence/insufficiency: valve doesn’t close as fully as normal, causing regurgitation

Question 14

when would you hear a murmur caused by stenosis and insufficiency, respectively, of the AV (tricuspid and mitral/bicuspid) valves?

Answer 14

AV valves open in diastole

stenosis —> diastolic murmur
lub dub shhh

insufficiency —> systolic murmur
lub shhh dub

[lub = systole, dub = diastole]

Question 15

when would you hear a murmur caused by stenosis and insufficiency, respectively, of the outflow/semilunar valves?

Answer 15

outflow valves open in systole

stenosis —> systolic murmur
lub shhh dub

insufficiency —> diastolic murmur
lub dub shhh

[lub = systole, dub = diastole]

Question 16

understanding that regurgitation causes backwards blood flow and that heart sounds are best heard downstream of valves, where can regurgitation of each valve be auscultated best?

Answer 16

[outflow valves open in systole]
- aortic regurgitation (diastolic): apex of heart (L ventricle feeds aorta)
- pulmonic regurgitation (diastolic): R ventricle, left of sternal border (feeds pulmonary trunk)

[AV valves open in diastole]
- tricuspid regurgitation (systolic): R ventricle, right of sternal border
- mitral regurgitation (systolic): L atrium, radiates in L axilla

key is to remember that downgrade is retrograde in regurgitation murmurs

Question 17

where would you find the following:
a. pectinate muscle
b. crista terminalis
c. sinus venarum

Answer 17

found in heart atrium

a. pectinate muscle: rough myocardium
b. crista terminalis: separates rough and smooth muscle
c. sinus venarum: smooth myocardium (embryonic origin)

Question 18

where would you find the following:
a. infundibulum
b. chordate tendinae
c. septomarginal trabecula
d. papillary muscle
e. trabeculae carnae

Answer 18

found in heart ventricle

a. infundibulum: smooth muscle
b. chordate tendinae: attaches papillary muscle to valve cusps
c. septomarginal trabecula: moderator band
d. papillary muscle: contracts in systole to prevent valve prolapse
e. trabeculae carnae: rough muscle

[valve prolapse is like a door opening from the wrong way]

Question 19

describe how the aortic sinuses function to close the aortic semilunar valve?

Answer 19

ascending aorta is elastic artery - stretches in systole, recoils in diastole…

retrograde blood flow during diastole fills the aortic sinuses and pushes cusps back to the center to close the semilunar valves (right, left, and posterior)

Question 20

what is different about the coronary arteries compared to other arteries?

Answer 20

coronary arteries - only branches of the ascending aorta, therefore fill during diastole due to elastic recoil of ascending aorta (opposite of other arteries)

this makes sense because you would want to push blood through the heart wall when muscles are relaxed!

Question 21

what does the right coronary artery supply? (think about the anatomical path it follows)

Answer 21

R coronary artery follows the AV sulcus, therefore it supplies R atrium and R ventricle

Question 22

what are the branches of the R coronary artery and what do they supply?

Answer 22

1. SA nodal artery: supplies SA node
2. marginal artery: supplies R ventricle
3. posterior IV artery/ PDA (posterior descending artery): follows posterior IV sulcus

Question 23

what are the branches of the L coronary artery and what do they supply?

Answer 23

1. circumflex artery (LCx): follows coronary sulcus, supplies L atrium and L ventricle
2. anterior IV artery/ LAD (left anterior descending) - most common to be occluded in MI

*3. in left heart dominance (10% population), posterior IV artery arises from circumflex artery instead of R coronary

Question 24

where are the 2 major anastomoses found in the heart?

Answer 24

1. R coronary artery + L coronary artery (circumflex branch)
2. LAD (left anterior descending) + posterior descending artery

*note that in left dominance, the second anastomose would be a L/L anastomose (likely less favorable)

Question 25

how is blood supply to the ventricular septum divided between the R and L coronary artery?

Answer 25

anterior 2/3: left coronary artery
posterior 1/3: right coronary artery

Question 26

which vein runs parallel to the LAD (left anterior descending artery) of the heart in the AV sulcus?

Answer 26

great cardiac vein - empties into coronary sinus, which empties in R. atrium

Question 27

function of Thebesian veins of heart

Answer 27

most venous blood enters R. atrium via coronary sinus, some enters via anterior cardiac veins

then small percentage in least cardiac veins (aka Thebesian veins) drain directly into underlying chamber (L/R ventricle) —> small amount of deoxygenated blood drains into left side of heart, which is why O2 saturation is ~98% in ascending aorta

Question 28

what are the 3 layers of the pericardial cavity?

Answer 28

1. visceral pericardium: aka epicardium, on surface of heart, serous membrane
2. parietal pericardium: also serous membrane
3. fibrous pericardium: collagenous and non-elastic, fused with parietal pericardium

Question 29

pericardiocentesis

Answer 29

removal of fluid in pericardial cavity (with syringe)

Question 30

what are the transverse and oblique sinuses of the heart?

Answer 30

where the visceral pericardium reflects to become the parietal pericardium (they are continuous)

oblique sinus: dead-end
transverse sinus: not dead-end, in front is outflow vesicles, behind is inflow vesicles

Question 31

how do each of these function in depolarization of myocardium?
a. fibrous skeleton
b. SA node
c. AV bundle (bundle of His)
d. AV node
e. septomarginal trabecula

Answer 31

a. fibrous skeleton: prevents electrical communication between myocardium of separate chambers (if 1 depolarizes, they all do)
b. SA node: as the fastest myocardium, it sets the pace (pacemaker cells)
c. AV bundle: allows pathway for depolarization from atrium to ventricle (through fibrous skeleton)
d. AV node: slowest myocardium, so allows atrium to contract before ventricle before depolarization can reach AV bundle (like a gate keeper)
e. septomarginal trabecula: aka moderator band, shortcut to anterior papillary muscle so it doesn’t lag