PHYSIO-LEC-LE-3-Feed-2022 (1) Flashcards
- The greatest blood volume
A. Arteries
B. Arterioles
C. Capillaries
D. Veins
D. Veins
- Capillaries are ideal for the exchange of substances because they have:
✔ Large cross sectional area
- Slow response action potential is present in one of these:
A. Atrial myocytes
B. Bundle of his
C. Purkinje fibers
D. SA node
D. SA node
- Conduction is more likely to be_____ due to its slow response action potential that causes response due to _____ of action potential (question unclear).
✔ Slow Amplitude
- Phase 0 of cardiac action potential is due to:
A. Ca++ influx
B. Ca++ efflux
C. K+ efflux
D. Na+ influx
A. Ca++ influx
- During phase 4 of an action potential, this occurs.
✔ Sodium enters cell through 3 sodium 1 Calcium antiporter
- Depolarization of slow response action potential is due to
✔ Lets Calcium influx through Calcium channels
- Effect of acetylcholine to myocardial
A. Decrease in Ca channels
B. Decrease in K channels
C. Increase in Ca conductance
D. Increase in Na Funny channels
A. Decrease in Ca channels
- Importance of effective refractory period
✔ Prevents cardiac muscle to produce new AP
- Conduction velocity increases when there is
✔ Increase the rate of depolarization
- Effect of more negative action potential in conduction velocity is
✔ Increase conduction due to larger amplitude of an action potential
- Ionic currents involve slow response depolarization occurs outward
✔ Calcium influx and potassium efflux, potassium currents depolarizes cell
- Heart rate decreases when there is
✔ Increase negativity in the pressure potential
- Heart rate decreases when there is
✔ Increase negativity in the pressure potential
- Mechanism for overdrive suppression is:
A. Activation of cell’s intrinsic automaticity
B. Depolarization of cardiac cell with Na+ influx
C. Hyperpolarization of cell with Na+ efflux
D. Suppression of NaKATPase
C. Hyperpolarization of cell with Na+ efflux
- Importance of conduction delay in AV node is:
✔ Allow sufficient ventricular filling.
- Significance of long refractory period of Purkinje fibers is to:
A. Prevent premature contraction of atria
B. Prevent premature contraction of ventricle
C. Promote premature contraction of atria
D. Promote premature contraction of ventricle
B. Prevent premature contraction of ventricle
- This phenomenon is responsible for the initiation of impulses through the SA node as the pacemaker
A. Absolute Refractory Period
B. Overdrive Suppression
C. Post-repolarization refractories
D. Depolarization of diastole
B. Overdrive Suppression
- The major factor responsible for contractile stage of myocardium is:
A. Free intracellular Ca++
B. K+ gradient across membrane
C. Na+ gradient across membrane
D. Sarcoplasmic Ca++ concentration
A. Free intracellular Ca++
- What occurs during myocardial contraction?
✔ Entry of calcium through calcium channels
- Cardiac glycosides increase cardiac contractile force through
✔ Increase in intracellular sodium decrease in calcium (…)
- Catecholamines have one of these effects on excitation-contraction coupling
✔ Inhibit binding of calcium by troponin C
- Increased Preload
A. Decrease BP
B. Decrease Myocardial Contraction Force
C. Increase Afterload
D. Increase Stroke Volume
D. Increase Stroke Volume
- Frank-Starling mechanism is responsible for one of this:
✔ Increased stroke volume when ventricular diastolic volume is increased
- The constant preload an increase in afterload results in
✔ Increase systolic pressure
- Positive inotropy in the heart will increase
✔ Cardiac output
- The ratio of volume ejected from LV per beat (Stroke Volume) to volume of blood in LV (EDV)
A. Blood Pressure
B. Cardiac Output
C. Ejection Fraction
D. Pulse Pressure
C. Ejection Fraction
- The cardiac valves are physiologically important because
✔ Ensure unidirectional flow of blood
- Closure of the aortic valve is best heard at the
✔ Second intercostal space right sternal boarder
- The physiologic splitting of the second heart sound is the closure of the
✔ Pulmonic valve
- R wave of the electrocardiogram coincides with one of the stages in the cardiac cycle
✔ Isovolemic contraction
- S2 is heard during what phase
A. Isovolumic contraction
B. Isovolumic relaxation
C. Rapid ejection
D. Rapid filling
D. Rapid filling
- Phase between the closing of mitral valve and opening of aortic valve
A. Isovolumic relaxation
B. Isovolumic contraction
C. Rapid filling
D. Rapid ejection
B. Isovolumic contraction
- One of these proceeds rapid phase in the cardiac cycle
✔ Opening of the aortic valve
- According to Poiseuilles Law if blood flow is increased:
✔ Radius also increases
- The most important factor that changes blood vessel diameter
✔ Smooth muscle contraction
- The 12 lead ECG is useful for the diagnosis of all of these except:
✔ Congestive heart failure