Ch. 2 Key Terms Flashcards
Action potential
Change in electrical potential of the heart muscle when it’s stimulated
Aorta
Largest artery in the body
Transports oxygenated blood from the left ventricle to the entire body
Aortic semilunar valve
Located in the aorta and prevents backflow of blood into the left ventricle
Atrioventricular (AV) node
Delays the electrical impulse to allow the atria to complete their contraction (atrial kick)
Atrium (plural: atria)
Top two chambers of the heart
Automaticity
Ability of the heart to initiate an electrical impulse without being stimulated by an independent source
AV bundle
The Bundle of His
Bachmann’s bundle
Structure that relays the electrical impulse from the SA node to the left atrium in a normal heart
Bundle branches
Left and right Bundle Branches of the Bundle of His that conduct impulses down either side of the interventricular septum to the left and right ventricles
Bundle of His (AV bundle)
Next to AV node
Provides transfer of the electrical impulse from the atria to the ventricles
Cardiac cycle
Contraction and relaxation of the heart
Chordae tendineae
Structures that connect the atrioventricular (tricuspid and mitral) valves to the papillary muscles and prevent them from opening in the wrong direction
Complexes
Atrial or ventricular depolarizations as they appear on the ECG
Complete ECG waveforms
Conductivity
Ability of the heart cells to receive and transmit and electrical impulse
Contractility
The ability of the heart muscle cells to shorten in response to an electrical stimulus
Coronary circulation
Circulation of blood to and from the heart muscle
Deoxygenated blood
Blood that has little or minimum oxygen (oxygen-poor blood)
Depolarization
Electrical activation of the cells of the heart that initiates contraction of the heart muscle
Diastole
Phase of the cardiac cycle when the heart is expanding and refilling
Aka the relaxation phase
Excitability
Ability of the heart muscle cells to respond to an impulse or stimulus
Aka irritability
Interval
Period of time between two activities of the heart
Interventricular septum
Partition or wall (septum) that divides the right and left ventricles
Ischemia
Sudden loss/reduction of blood supply (oxygen) to a region of the heart tissue
Occurs due to the presence of atherosclerotic plaque, blood clot, emboli, or vascular spasms (Prinzmetal’s angina)
Isoelectric
Period when the electrical tracing of the ECG is at zero or a straight line, no positive or negative deflections are seen
Left atrium
Left upper chamber of the heart that receives oxygenated blood from the lungs
Left ventricle
Left lower chamber of the heart, which pumps oxygenated blood throughout the body
Biggest and strongest chamber (workhorse of the heart) bc of this role
Mitral (bicuspid) valve
Valve with two cusps or leaflets located between the left atrium and left ventricle
Prevents backflow of blood into the atrium
Myocardial
Pertaining to the heart (cardia) muscle (myo)
Oxygenated blood
Blood having oxygen (oxygen-rich blood)
Papillary muscles
Muscles in the ventricle that anchor the chordae tendineae and atrioventricular valves
Parasympathetic
Branch of the autonomic nervous system that helps slow the heart rate
Pericardium
Two-layered sac of tissue enclosing the heart
Polarization
State of cellular rest in which the inside is negatively charged, and the outside is positively charged
Pulmonary artery
Large artery that transports deoxygenated blood from the right ventricle to the lungs
Only artery in the body that carries deoxygenated blood
Pulmonary circulation
Transportation of blood to and from the lungs
Blood is oxygenated in the lungs during this
Pulmonary semilunar valve
Valve found in pulmonary artery that prevents backflow of blood into the right ventricle during pulmonary circulation
Pulmonary veins
Transport oxygenated blood back into the left atrium of the heart
Only veins in the body that carry oxygenated blood
Purkinje fibers
Fibers within the heart that distribute electrical impulses from cell to cell throughout the ventricles
Purkinje network
Spreads the electrical impulses throughout the ventricle by means of the Purkinje fibers
Repolarization
Return of heart muscle cells to their resting electrical state, causing the heart muscle to relax
Right atrium
Right upper chamber of the heart
Receives deoxygenated blood from the body
Right ventricle
Right lower chamber of the heart
Pumps deoxygenated blood into the lungs
Segment
Portion/part of the electrical tracing produced by the heart
Semilunar valve
Valve with half-moon-shaped cusps that open and close, allowing blood to travel only one way
Located in pulmonary artery and aorta
Sinoatrial (SA) node
In the area of specialized cells in the upper right atrium that initiate the heartbeat
Sympathetic
Branch of the autonomic nervous system that causes an increase in the heart rate
Systemic circulation
Pathways for pumping blood throughout the body and back to the heart
Tricuspid valve
Valve located between the right atrium and right ventricle
Prevents backflow of blood into the right atrium
Vena cava (plural: venae cavae)
Largest vein in the body, which provides a pathway for deoxygenated blood to travel from the body to the right atrium
Upper portion: superior vena cava; Blood comes from head arms, and upper body
Lower portion: inferior vena cava; Blood comes from the lower body and legs
