| Question | Answer |
| What determines stroke volume (3)? | 1. preload
2. afterload
3. contractility |
| What is the order of the valve closer that corresponds to S1 and S2? | mitral - tricuspid - aortic - pulmonary |
| 1. What is S2 splitting?
2. What is fixed splitting? | 1. aortic valve closes before pulmonic
2. splitting that does not differ upon inspiration/expiration |
| 1. What is S3?
2. What is S4? | 1. sound of rapid ventricular filling
2. ventricular filling during atrial kick |
| Which nerve innervates:
1. aortic arch baroreceptor
2. carotid sinus baroreceptors | 1. vagus
2. glossopharyngeal |
| What are the waves of the atrial pressure curve and what do they correspond to? | 1.a wave - atrial contraction
2. c wave - ventricular contraction
3. x wave - atrial relaxation
4. v wave - atrial filling
5. y wave - tricuspid open and ventricular filling |
| What do the following portions of the EKG correspond to?
1. P
2. QRS
3. T
4. PR segment | 1. atrial depolarization
2. ventricular depolarization
3. ventricular repolarization
4. how long it takes impulse to travel from SA node to ventricles |
| How do you find heart rate on an EKG? | 300/number of boxes between R waves |
| How many seconds is a large box on an EKG? | 0.2 s |
| What on the EKG is indicative of atrial enlargement? | P wave bigger than the QRS |
| What rate in normal sinus rhythm? | 60-100 bpm |
| Which chamber of the heart normally has the highest pressure? | Left ventricle |
| What does Qp/Qs signify? | Flow ratio of pulmonary blood to systemic blood flow |
| Increased blood pressure leads to increased baroreceptor firing. What does this lead to? | 1. decrease in sympathetic tone
2. increase in parasympathetic tone
3. vasodilation
4. decreased HR |
| What must happen for systemic vasoconstriction to occur without a change in systemic blood pressure | decrease in cardiac output |
| 1. What is afterload?
2. How is afterload measured?
3. How does increased arterial pressure effect afterload? | 1. measure of the pressure used by a chamber of the heart to eject blood.
2. aortic pressure
3. increases afterload because less blood is able to flow out of the ventricles |
| 1. How is EDV related to contractility?
2. How is EDV related to cardiac output? | 1. EDV directly increases the force of contraction
2. EDV directly increases cardiac output |
| What is mean systemic pressure? | pressure in systemic circulation when flow is zero |
| What is blood pressure equal to? | cardiac output x peripheral vascular resistance |
| How is venous return related to right atrial pressure? | inversely proportional
lower atrial pressure allows for a greater return |
| 1. Ejection Fraction equation
2. Can the ejection fraction of the two ventricles be different? | 1. EF = SV/EDV x 100%
2. Yes |
| 1. What is cardiac output using the Fick Principle?
2. How is O2 consumption calculated?
3. How is O2 content calculated? | 1. CO = (O2 consumption/minute)/(Arterial O2 content - venous O2 content)
2. spirometry
3. [Hb] x 1.34 x O2 sat. |
| How does increased Afterload affect the preload? | ↑afterload →↓ stroke volume →↑ preload |
| What is the best way to clinically measure contractility of the heart? | ejection fraction |
| How do positive inotropic agents effect ejection fraction? | ↑stroke volume and ↓ end diastolic volume so ↑ ejection fraction |
| 1. What do the positive inotropic agents have in common?
2. What do negative inotropic agents have in common? | 1. ↑ intracellular calcium
2. ↓ intracellular calcium |
| What is the formula for pulse pressure? | PP = systolic pressure - diastolic pressure |
| What is the greatest influence on blood viscosity? | hematocrit |
| Which receptors in the systemic vasculature cause vasodilation? Constriction? | 1. B2 → Gαs→ vasodilation
2. α1→ Gαq→ vasoconstriction |
| S4 occurs in what physiological states... | decreased ventricular compliance or increased ventricular stiffness |
| What two ways does Atrial Natriuretic Peptide act to decrease BP? | 1. decrease aldosterone and renin (decreased Na reabsorption)
2. vasodilation of renal arterioles |
| What 2 ways does AVP act to increase blood pressure? | 1. vasoconstricts renal arterioles
2. increases water reabsorption from collecting duct and distal convoluted tubule |
| 1. Vasodilation in coronary vasculature is mediated by what?
2. When is this substance released? | 1. increased adenosine
2. ↑ metabolic activity of heart, ↓ blood flow to heart, ↓ myocardial PO2 |
| 1. Cardiac cells are permeable to which ion during resting phase (phase 4)?
2. Which channel do these ions flow through? | 1. K+
2. inwardly rectifying current |
| What pumps and exchangers are active during resting phase? | 1. Na/K ATPase - 3 Na out, 2 K in
2. Calcium/Na exchanger - 1Ca out, 2 Na in
3. Calcium ATPase - 2Ca out |
| Which direction do the concentration and electrical membrane forces influence K flow? | 1. concentration influences K flow out of cell
2. electrical potential favors flow into cell |
| How does an increased permeability to K affect the resting membrane potential? | more K exits the cell creating a more negative RMP |
| How does acetylcholine affect RMP? | - increases membrane permability to K so more exits cell
- cells become hyperpolarized |
| Acetylcholine acts mainly where in the heart? | parasympathetic NS acts mainly on nodal cells and small amount on atrial myocytes |
| In slow fibers:
T-type calcium channels are open during phase__.
L-type calcium channels are open during phase __. | phase 4
phase 0 |
| What happens at each stage in fast fibers
0.
1.
2.
3.
4. | 0. Na channel open and enter cell
1. transient outward K+ open and exit cell
2. L-type Ca2+ open - enter to balance K+ exit
3. Delayed K+ channels open net K+ influx
4. inward rectifier K+ open - K+ in |
| 1. What is effective refractory period?
2. What is the relative refractory period? | 1. when an action potential cannot be elicited
2. when an AP can be elicited if there is a greater than normal stimulus |
| How do the areas that are sympathetically and parasympathetically stimulated differ in the heart | 1. sympathetic - effects both atrial and ventricles
2. para - effects atrial only |
| What are the relative conduction speeds for: atria, AV node, purkinje fibers and ventricles? | purkinje fibers > atria > ventricles > Av node |
| Stroke volume is affected by: | 1. Contractility
2. Afterload
3. Preload |
| Myocardial O2 demand is increased by | anything that ↑ tension or rate
1. ↑ afterload (↑ EDV)
2. ↑ heart rate
3. ↑ heart size (↑ wall tension) |
| 1. How do venodilators affect preload?
2. How do vasodilators affect afterload? | 1. ↓ preload
2. ↓ afterload |
| Which phase of the cardiac cycle is the period of highest O2 consumption? | isovolumetric contraction |
| What is the bowditch staircase and why is it seen? | increase heart rate leads to increased force of contraction in a stepwise fashion by slowing increasing levels of intracellular calcium |
| What are the positive inotropic agents? | 1. increased HR
2. sympathetic stimulation
3. cardiac glycosides |
| How do cardiac glycosides affect inotropy? | 1. inhibit the Na/K ATPase so more Na accumulates in cell
2. high intracellular Na prevents the Na/Ca exchanger from removing Ca from the cell
3. leads to increased intracellular Ca |
| 1. What is the law of la place in relation to the heart?
2. How does increased end diastolic volume affect wall tension?
3. How does the heart compensate for this | 1. T = (P x r)/wall thickness
2. ventricular dilation increases radius of ventricle so increases Tension
3. hypertrophies and increases wall thickness |
| 1. How do positive inotropic agents affect preload?
2. How does an increase venous resistance affect preload? | 1. decrease preload
2. increases preload |
| Normal: CO = 4 L/min, O2 consumption = 0.25 L/min, pulmonary ventilation = 5 L/min
During Exercise: CO = 20 L/min, O2 consumption = 3 L/min, pulmonary ventilation = ? L/min | Pventilation during exercise/Pventilation at rest = O2 consum. during exercise/O2 consum. at rest
Pventilation during exercise = 60 L/min |
| How does in increase in contractility change the end systolic volume? | decreases the end systolic volume |
| What are the 3 cellular causes for the Starling Mechanism (increased contracility from increase EDV)? | 1. altered sensitivity of tropnin-C for calcium
2. optimum association between actin and myosin
3. more calcium "channels" or stretch calcium channels |
| Strength of cardiac muscle contraction is a function of: | number of actin-myosin crossbridge formed
amount of Ca2+ entering muscle fibers from extracellular fluid
activity of the Na+/K+ ATPase pump |
| Which part of the cardiac myosin contains ATPase activity? | head |
| Describe the steps of the cross-bridge cycle in the sarcomere: | 1. ATP bound to myosin is hydrolyzed to ADP and Pi
2. ADP spontanteously released and active comple shifts the thin filament
3. ATP binds myosin again and the complex dissociates |
| What is the resting compliance and resting length tension of the heart compared to skeletal muscle? | cardiac muscle has low compliance and higher testing length tension |
| How does contractility differ from Frank-Starling Mechanism? | contractility changes cardiac performance independent of fiber length (preload) or afterload |
| During stage 2 of the cardiac cycle Ca2+ enters the cell through __-type Ca2+ channels, also known as ____. | L-type
dihydropyridine |
| Do cardiac glycosides affect preload or afterload? How? | decrease preload because they prolong the plateau phase of cardiac depolarization thus slowing ventricular contraction |
| 1. most likely cause of a systolic ejection murmur in children?
2. in adults? | 1. pulmonary stenosis
2. aortic stenosis |
| Which ventricle performs more work? Why? | Left Ventricle; performs at a higher Pressure and
W = PV |
| 1. What is the external work of the heart?
2. What is the internal work of the heart? | 1. that which expels blood from the LV
2. the strength and lengthening of myocardial elements |
| How do positive inotropic agents affect EDV? | decrease EDV of subsequent beats by leaving less in the ventricle after contraction (less ESV) |
| How does increased filling pressure affect cardiac output? | lowers |
| 1. What is the major energy source for cardiac myocytes?
2. Parasympathetic NS innervates which area of the heart? | 1. fatty acids
2. SA/AV nodes and atrial myocytes |
| 1. What is the metabolism pattern (with respect to glucose and fatty acid metabolism) in normal heart?
2. How is metabolism in heart affected under ischemic condition? | 1. normally 10-40% of acetyl-CoA comes from glucose and lactate, 60-90% of acetyl-CoA comes from beta-oxidation of fatty acids.
2. during fatty acid beta-oxidation ↓ and there is an ↑ in use of glucose and lactate. |
| NEW NOTECARDS START HERE****** | |
| Which coronary artery supplies the SA and AV nodes? | Right coronary artery |
| Which heart chamber:
1. most posterior and can compress the esophagus
2. most anterior | 1. left atrium
2. right ventricle |
| How is the total resistance calculated for blood vessels within an organ? | connected in series:
R1 + R2 + R3... |
| How is total resistance calculated for blood vessels within the systemic circulation? | connected in parallel:
1/R1 + 1R2 + 1/R3... |
| What accounds for most of the total peripheral resistance in the circulation? | arterioles |
| If the radius of an arteriole doubles, how does resistance change? | Resistance is inversely proportional to the inverse of radius to the 4th power. Doubling radius will decrease resistance by a factor of 16. |
| How does S2 splitting change with inspiration? | splitting should increase during inspiration because increased venous return to right heart → longer pulmonary valve closure |
| Which heart defect presents with fixed splitting (does not change with inspiration)? | atrial septal defect |
| Which heart defects present with paradoxical splitting (Pulmonic valve closes before aortic)? | 1. aortic stenosis
2. left bundle branch block |
| How does squatting or hand grip exercise change mitral or trispid regurgitation? | ↑ TPR enhances mitral regurgitation, not tricuspid |
| Which ion channels does the autonomic nervous system act upon to change:
1. heart rate
2. conduction velocity | 1. If channels
2. inward Ca2+ current |
| Ventricles are not innervated by which ANS component? | parasympathetic nervous system |
| In which part of the cardiac conduction circuit is the velocity the slowest? | AV node - allows time for ventricular filling |
| What effect does atrial natriuretic peptide have on the kidney's to reduce blood volume? | cases constriction of the efferent renal arteriole and dilation of the afferent arteriole promoting diuresis |
| Chemoreceptors respond to PO2, PCO2, and pH.
1. Which do peripheral chemoreceptors respond to?
2. Which do central receptors respond to? | 1. all of the above
2. only PCO2, and pH |
| What is the Cushing reaction? | 1. ↑ intracranial pressure compresses arterioles → ischemia
2. sympathetic discharge → ↑ HR, hypertension
3. baroreceptors sense ↑BP and ↑ parasympathetic outflow → bradycardia |
| How are lung arterioles affected by hypoxia differently than systemic arterioles? | 1. lung arterioles constrict
2. systemic arterioles dilate |
| Why does systolic blood pressure decrease during cardiac tamponade? | 1. RV cannot adequately contract bc of ↑ volume in pericardiac sac
2. instead, it pushes against the intraventricular septum reducing the blood volume that can enter the LV |
| How do the following murmurs change with squatting:
1. Hypertrophic cardiomyopathy
2. VSD
3. aortic stenosis | 1. decrease
2. increase
3. increase |
| A person's EKG has no P wave, but has normal QRS complexes and normal T waves. where is the pacemaker located? | AV node |
| Two causes of turbulent blood flow leading to bruits | 1. decreased blood viscosity
2. increased blood velocity |
| How does the valsalva maneuver effect cardiac output? | decreases venous return to the heart and decreases CO |
| Which murmurs increase with the valsalva? | hypertrophic cardiomyopathy, mitral valve prolapse |
| 1. What is the max pressure in the atria
2. What is the max pressure of the right ventricle? | 1. 10mmHg
2. 25mmHg |
| Which arrhythmia presents with absent P waves on EKG and a fast HR? | Atrial fibrillation |
| 1. Which nerve innervates the aortic body
2. Which nerve innervates the carotic body | 1. vagus
2. glossopharyngeal |
| What effect does hypertension have on baroreceptor firing? | increase in blood pressure will increase baroreceptor firing |
| Role of Ryanodiine receptor | calcium stimulates ryanodine receptor, which allows release of larger pool of calcium from within the sarcomplasmic reticulum |
| Renin levels during congestive heart failure? | increased because of poor perfusion of kidneys; leads to edema |
| Which ion is the ventricular myocyte most permeable to during phase 4 | potassium (funny channels in pacemaker cells) |
| At which site is systolic BP the highest:
1. aorta
2. central vein
3. pulmonary artery
4. renal artery
5. renal vein | renal artery |
| Which coronary artery supplies the diaphragmatic surface of the heart? | posterior descending artery, a branch of the right coronary artery |
