01 - Cardiac Anatomy Flashcards
Where is the mediastinum
thorax region
resides between the sternum and vertebrae, the two pleural cavities nad between the first rib and diaphragm
What does the mediastinum contain
pericardial cavity that surrounds the heart
What does the outer layer of the pericardium fuse to
the fibrous pericardium fuses with the central tendon of the diaphragm
What are the four regions of the mediastinum
anterior
superior
posterior
middle
What does the anterior mediastinum contain
thymus: organ responsible for production and maturation of immune cells
What does the superior mediastinum contain
aortic arch: major BV
esophagus: deliver food
trachea: deliver air
What does the posterior mediastinum contain
descending aorta
esophagus: deliver food
lymph nodes: assesses infections
vagus nerves: to innervate structures of abdominal cavity
thoracic duct: transports lymph
What does the middle mediastinum contain
heart
great vessels (aorta & pulmonary trunk): outflow from heart
phrenic nerves: innervates muscles of diaphragm
What are the layers of the heart
epicardium (outermost)
myocardium (thickest - contractile tissue/muscle)
endocardium (innermost)
What are the layers of the pericardium
fibrous pericardium (outermost layer) - limites stretching
parietal pericardium (middle layer)
visceral pericardium (epicardium
What do the sulci (grooves) on the heart do
protect blood vessels which are also surrounded by adipose (fat)
What are the different sulci on the heart
right coronary sulcus (between right atrium and ventricle)
left coronary sulcus (between left atrium and ventricle)
interventricular sulcus (between the left & right ventricles)
What do the coronary arteries do
perfuse the myocardium with blood
the left and right coronary arteries arise from the base of the ascending aorta
- branches form anastomoses
When does blood flow occur
during diastole (when heart muscles relax)
What do the coronary veins do
drain the myocardium and return the ‘spent’ blood to the right atrium
- drain into the coronary sinus on the posterior aspect the right atrium
What is the path of blood flow in the heart
- sup/inf vena cava
- right atrium
- tricuspid valve
- right ventricle
- pulmonary valve
- pulmonary artery
- lungs
- pulmonary veins
- left atrium
- mitral valve
- left ventricle
- aortic valve
- aorta
- tissues of the body
What does the right side of the heart handle
deoxygenated blood returning from the body tissues (systemic circuit)
What does the left side of the heart handle
oxygenated blood returning from the lungs (pulmonary circuit)
What do the four valves of the heart ensure
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)
How the thicknesses of the left and right ventricles differ
left ventricle - thick, cylindrical shaped chamber
right ventricle - thin, crescent shaped chamber
What does the left ventricle do
pumps blood under high pressure to all body systems (systemic circuit)
What does the right ventricle do
pumps blood under low pressure to lungs (pulmonary circuit)
What are the ventricles separated by
interventricular septum (wall)
What is the function of the fibrous skeleton
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
What causes the opening and closing of heart valves
changes in pressure on each side of the valve
What are the AV (atrioventricular) valves made of
valve leaflets attached to subvalvular apparatus (chordae tendinae & papillary muscles)
What does the subvalvular apparatus do
prevent AV valve eversion (prolapse) during ventricular systole
What can lead to AV valve insufficieny (regurgitation)
damage to papillary muscle (eg. heart attack)
How do the subvalvular apparatus function during diastole
valve cusps open
- chordae tendineae = slack
- papillary muscles = relaxed
How do the subvalvular apparatus function during systole
valve cusps close
- chordae tendineae = taut
- papillary muscles = contract
What do the semilunar valves do
prevent backflow of blood from the great vessels (aorta & pulmonary trunk) back into the ventricles
When and why is there backflow of blood in the heart
during atrial systole
because no valves guarding the venous entry points into the left and right atrium
How does the heart prevent backflow during atrial systole
atrial muscles contract –> compresses/collapses the weak walls of the venous entry points to minimize backflow
What is auscultation
listening to heart sounds
How are heart sounds created
turbulent blood flow and the closure of heart valves
What are the four heart sounds
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
Which heart sounds can you hear - what causes them
Where is the best spot to hear
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
