Flashcards in Sheet 1-NURS 314 Study Guide Exam #2 Deck (214)
Valves on left side of heart
Mitral (bicuspid) and aortic
Valves on right side of heart
Tricuspid and pulmonic
What is the direction of blood flow in the heart?
Deoxgenated blood flows from venous system and liver through the Vena cava into the Right Atrium through the Tricuspid valve into the Right Ventricle which pumps blood (systole) through the Pulmonic valve into the Pulmonic arteries to the lungs for oxygenation. From the lungs, oxygenated blood returns via the Pulmonary veins into the Left Atrium through the Mitral valve into the Left Ventricle (diastole) which pumps oxygenated blood (systole) through the Aortic valve into the Aorta for circulation through the arteries to body tissues
When do the AV valves open?
During the heart’s filling phase (diastole) to allow ventricles to fill with blood
When do the AV valves close?
During systole (pumping phase), the valves close to prevent backflow of blood into the atria
What is S1?
Closure of mitral and tricuspid valves close; beginning of systole and ventricular contraction Coincides with carotid pulse Coincides with R wave Heard over entire precordium
What is S2?
Closure of pulmonic and aortic valves; end of systole (opening of mitral and tricuspid valves during to initiate ventricular filling, diastole)
What is betweeen S2 and next S1
Diastole - blood is refilling into ventricles
Electrical conduction of the heart
1 Sinoatrial node (Pacemaker) - 80-100
2 Atrioventricular node -
3 Atrioventricular Bundle (Bundle of His)
4 Left & Right Bundle branches (which fire separately)
5 Bundle Branches
SA node: cells can depolarize on their own (i.e. automaticity; e.g. w/o having a neighboring cell do it first) (pacemaker); specialized band of tissue, highway for depolarization wave; coordinated way evenly through right and left; via internodal tracts to AV node only connection between atria and ventricles, creates a delay between contraction of atria and contraction of ventricles; important because simultaneous contraction would squeeze blood against each other, allows time for blood to move through to ventricles, to ensure blood moves in coordinated way (0.1s); then to the bundle of His down to bottom of both ventricles (right bundle and left bundle); left splits again to Perkinje fibers, electrical signal disperses to involve all the muscle cells of the myocardial cells;
What is a heart murmur?
An abnormal blowing, swooshing sound heard during S1 and S2 due to turbulent blood flow Systolic - can be normal or with heart dz Diastolic - always indicates heart dz
What causes a heart murmur?
1. velocity of blood increases (e.g. flow murmur) 2. Viscosity of blood decreases (e.g. anemia) 3. Structural defects in valves (e.g. narrowed valve, incompetent valve) or unusual openings in the chambers (e.g. dilated chamber, wall defect)
Heart murmur grading - Grade 1
Barely audible in a quiet room
Heart murmur grading - Grade 2
Clearly audible, but faint (most common)
Heart murmur grading - Grade 3
Moderately loud, easy to hear
Heart murmur grading - Grade 4
Loud; associated w/ palpable thrill
Heart murmur grading - Grade 5
Very loud, heard w/ one edge of stethoscope off chest
Heart murmur grading - Grade 6
Loudest, heard w entire stethoscope lifted off chest
What are the extra heart sounds?
S3 and S4 Midsystolic click Ejection click
What is S3?
Ventricular gallop; Sound heard during diastole from vibrations from ventricular filling. Ventricular walls are resistant to filling during early rapid filling phase (protodiastole). Occurs immediately after S2, when AV valves open and blood first enters ventricles Occurs with heart failure and volume overload
What is S4?
Atrial gallop; Occurs at the end of diastole, at pre systole, when the ventricle is resistant to filling. Atria contract and push blood into noncompliant ventricle which creates vibrations occurs with CAD
Heart sounds associated with mitral valve prolapse
occurs early in systole with the opening of the semilunar valves
Components of an ECG (electrocardiograph)
P wave PR interval QRS complex T wave
depolarization of atria
the time necessary for atrial depolarization plus time for the impulse to travel through the AV node to the ventricles) beginning of P wave to beginning of QRS complex
depolarization of ventricles
repolarization of ventricles
What is cardiac output
volume of blood in each systole (stroke volume) x beats per minute