Heart Flashcards
What structures are considered to be part of the cardiac conduction system?
SA node, AV node, Purkinje fibers
What layer lines the inner chamber of the heart?
Endocardium
The blunt inferior point tip of the heart is known as what?
Apex
What are the three layers of the heart wall, from deep to superficial?
Endocardium, myocardium, epicardium
What is the volume of blood ejected by each ventricle in one minute called?
Cardiac output
What is the volume of blood ejected by a ventricle in one contraction of the heart?
stroke volume
What are the components of the cardiovascular system?
heart, blood vessels
What is a recording of all nodal and myocardial action potentials in the heart?
ECG
Which side of the heart supplies blood to the pulmonary circuit?
Right
What is the relationship between pressure and volume?
they are inversely proportional
Starting with the superior and inferior venae cavae, list the chambers of the heart in the order which the blood would flow
1: Right atrium
2: Right ventricle
3: Left atrium
4: Left ventricle
The inferior chambers of the heart that pump blood to the arteries are called what?
ventricles
What is the study of the heart and its disorders called?
cardiology
what circuit carries blood from the right ventricle to the lungs for gas exchange and returns it to the left atrium of the heart?
pulmonary
Starting with the return of blood to the heart, place the major phases of the cardiac cycle in order
1: Ventricular filling
2: Isovolumetric contraction
3: Ventricular ejection
4: Isovolumetric Relaxation
What is the normal heart rate set by the SA node referred to as?
sinus rhythm
the heartbeat is coordinated by what?
cardiac conduction system
What chemicals can cause increased heart rate?
caffeine, nicotine, thyroid hormone
What term refers to the relaxation of the heart?
diastole
What carries action potentials throughout the ventricular myocardium to excite the ventricles?
purkinje fibers
Which part of the cardiac conduction system acts as the pacemaker?
sinoatrial (SA) node
List the events of an action potential in a ventricular cardiocyte in order
1: Voltage-gated Na+ channels open
2: Influx of Na+ causes more Na+ channels to open; depolarization
3: Na+ channels close as membrane potential peaks at +30mV
4: Ca2+ enters through slow calcium channels; creates plateau
5: Ca2+ channels close, K+ channels open; repolarization
What are short, thick, branched muscle cells of the heart?
cardiocytes
What term refers to the contraction of the heart?
systole