01 - Cardiac Anatomy

Question 1

Where is the mediastinum

Answer 1

thorax region

resides between the sternum and vertebrae, the two pleural cavities nad between the first rib and diaphragm

Question 2

What does the mediastinum contain

Answer 2

pericardial cavity that surrounds the heart

Question 3

What does the outer layer of the pericardium fuse to

Answer 3

the fibrous pericardium fuses with the central tendon of the diaphragm

Question 4

What are the four regions of the mediastinum

Answer 4

anterior
superior
posterior
middle

Question 5

What does the anterior mediastinum contain

Answer 5

thymus: organ responsible for production and maturation of immune cells

Question 6

What does the superior mediastinum contain

Answer 6

aortic arch: major BV
esophagus: deliver food
trachea: deliver air

Question 7

What does the posterior mediastinum contain

Answer 7

descending aorta
esophagus: deliver food
lymph nodes: assesses infections
vagus nerves: to innervate structures of abdominal cavity
thoracic duct: transports lymph

Question 8

What does the middle mediastinum contain

Answer 8

heart
great vessels (aorta & pulmonary trunk): outflow from heart
phrenic nerves: innervates muscles of diaphragm

Question 9

What are the layers of the heart

Answer 9

epicardium (outermost)
myocardium (thickest - contractile tissue/muscle)
endocardium (innermost)

Question 10

What are the layers of the pericardium

Answer 10

fibrous pericardium (outermost layer) - limites stretching
parietal pericardium (middle layer)
visceral pericardium (epicardium

Question 11

What do the sulci (grooves) on the heart do

Answer 11

protect blood vessels which are also surrounded by adipose (fat)

Question 12

What are the different sulci on the heart

Answer 12

right coronary sulcus (between right atrium and ventricle)

left coronary sulcus (between left atrium and ventricle)

interventricular sulcus (between the left & right ventricles)

Question 13

What do the coronary arteries do

Answer 13

perfuse the myocardium with blood

the left and right coronary arteries arise from the base of the ascending aorta
- branches form anastomoses

Question 14

When does blood flow occur

Answer 14

during diastole (when heart muscles relax)

Question 15

What do the coronary veins do

Answer 15

drain the myocardium and return the ‘spent’ blood to the right atrium
- drain into the coronary sinus on the posterior aspect the right atrium

Question 16

What is the path of blood flow in the heart

Answer 16

1. sup/inf vena cava
2. right atrium
3. tricuspid valve
4. right ventricle
5. pulmonary valve
6. pulmonary artery
7. lungs
8. pulmonary veins
9. left atrium
10. mitral valve
11. left ventricle
12. aortic valve
13. aorta
14. tissues of the body

Question 17

What does the right side of the heart handle

Answer 17

deoxygenated blood returning from the body tissues (systemic circuit)

Question 18

What does the left side of the heart handle

Answer 18

oxygenated blood returning from the lungs (pulmonary circuit)

Question 19

What do the four valves of the heart ensure

Answer 19

that blood flow occurs in one direction

useful when applying cardiac compressions

Two AV valves (left/right av valve)
Two semilunar valves (aortic-left/pulmonary-right semilunar valve)

Question 20

How the thicknesses of the left and right ventricles differ

Answer 20

left ventricle - thick, cylindrical shaped chamber
right ventricle - thin, crescent shaped chamber

Question 21

What does the left ventricle do

Answer 21

pumps blood under high pressure to all body systems (systemic circuit)

Question 22

What does the right ventricle do

Answer 22

pumps blood under low pressure to lungs (pulmonary circuit)

Question 23

What are the ventricles separated by

Answer 23

interventricular septum (wall)

Question 24

What is the function of the fibrous skeleton

Answer 24

dense connective tissue
- provides structural foundation for the heart valves
- maintains valve diameter (prevents overstretching)
- serves as an attachment site for muscle fibers
- electrically separates the atria from the ventricles

Question 25

What causes the opening and closing of heart valves

Answer 25

changes in pressure on each side of the valve

Question 26

What are the AV (atrioventricular) valves made of

Answer 26

valve leaflets attached to subvalvular apparatus (chordae tendinae & papillary muscles)

Question 27

What does the subvalvular apparatus do

Answer 27

prevent AV valve eversion (prolapse) during ventricular systole

Question 28

What can lead to AV valve insufficieny (regurgitation)

Answer 28

damage to papillary muscle (eg. heart attack)

Question 29

How do the subvalvular apparatus function during diastole

Answer 29

valve cusps open
- chordae tendineae = slack
- papillary muscles = relaxed

Question 30

How do the subvalvular apparatus function during systole

Answer 30

valve cusps close
- chordae tendineae = taut
- papillary muscles = contract

Question 31

What do the semilunar valves do

Answer 31

prevent backflow of blood from the great vessels (aorta & pulmonary trunk) back into the ventricles

Question 32

When and why is there backflow of blood in the heart

Answer 32

during atrial systole
because no valves guarding the venous entry points into the left and right atrium

Question 33

How does the heart prevent backflow during atrial systole

Answer 33

atrial muscles contract –> compresses/collapses the weak walls of the venous entry points to minimize backflow

Question 34

What is auscultation

Answer 34

listening to heart sounds

Question 35

How are heart sounds created

Answer 35

turbulent blood flow and the closure of heart valves

Question 36

What are the four heart sounds

Answer 36

2nd intercostal space (right) - aortic valve
2nd intercostal space (left) - pulmonary valve
left lower sternal border - tricuspid valve
5th intercostal space (left) - bicuspid valve/mitral

Question 37

Which heart sounds can you hear - what causes them
Where is the best spot to hear

Answer 37

S1 (lubb) - caused by the closure of av valves
S2 (dupp) - caused by closure of the semilunar valves

at locations that do not correspond to where the valves are located