Chapter 19 Vocab Flashcards
Pericardium
A double-walled sac around the heart composed of: parietal layer of serous pericardium and visceral layer of serous pericardium
Endocardium
Endothelial layer of the inner myocardial surface
Epicardium
Visceral layer of the serous pericardium
Myocardium
Cardiac muscle layer forming the bulk of the heart
Intercalated discs
Link cardiac muscle cells together mechanically and electrically
Desmosomes
Protein filaments that physically connect adjacent cardiac muscle cells
Gap junctions
Protein channels that allow ions to flow between adjacent cells
Coronary vessels
Blood supply of the heart wall
Coronary arteries bring
Oxygenated blood to myocardium
Coronary veins collect
Deoxygenated blood and drain it into the coronary sinue
Systole
Contraction of a heart chamber
Diastole
Relaxation of the heart chamber
S1
First sound occurs as AV valves close
S2
Second sound occurs when semilunar valves close
Tissue perfusion
The flow of blood through arteries and capillaries delivering nutrients and oxygen to cells and removing cellular waste products
Cardiac output
Amount of blood pumped by a single ventricle in one minute
Chronotropic agents
Factors that influence heart rate
Positive chronotropic
Increase the heart rate
Negative chronotropic agents
Decrease the heart rate
Bradycardia
Persistently low resting heart rate in adults
Tachycardia
Persistently high resting heart rate
Stroke volume
Volume of blood ejected during one beat
Contractility
Force of contraction
Inotropic agents
Factors that affect contractility
Electrocardiography
Is a science of recording and interpreting the electrical activity that precedes and is a measure of the action of heart muscles
Electrocardiograph
Is a instrument for recording the changes of electrical potential occurring during the heart beat used especially in diagnosing abnormalities of heart action
Electrocardiogram
(EKG or ECG) is a graphical record (on paper or screen) of the electrical waves of the heart, as registered on the electrocardiograph
ECG (electrocardiogram)
Records the electrical activity of the heart, providing a record of cardiac electrical activity, as well as valuable information about the heart’s function and structure.
Spontaneous depolarization
Cell membranes are naturally leaky to sodium and calcium ions
SA Node
Dominant pacemaker with an intrinsic rate of 60-100 bpm
AV Node
Back-up pacemaker with an intrinsic rate of 40-60 bpm
Ventricular cells
Back-up pacemaker with an intrinsic rate of 20-45 bpm
Automaticity
Cardiac muscle tissue contracts on its own, in the absence of neural of hormonal stimulation.
Depolarization
Movement of sodium across cell membrane causing inside of the cell to become more positive resulting in contraction
Repolarization
Movement of potassium across cell membranes in which the inside of cell is restored to its negative charge
P wave
Atrial depolarization
QRS
Ventricular depolarization
T waves
Ventricular repolarization
Bradycardia
Abnormally slow heart rate below 60 per min.
Tachycardia
Abnormally fast heart rate above 100 per min.
