Cardio4

Question 1

Stroke Volume is affected by?

Answer 1

Contractility
Afterload
Preload

“SV CAP”

Question 2

Contractility (and SV) INcrease with: (4)

Answer 2

• Catecholimines
• INcreased Ca+ pump in Sarcoplasmic Ret.)
• INcreased INtracellular Ca++
• DEcreased EXtracellular Na+
• DEcreased Na+/Ca+ exchanger
• Digitalis

Question 3

What is the MOA of Digitalis?

Answer 3

• Blocks Na+/K+ pump
  
  • INcreased INtracellular Na+
    
    • DEcreased Na+/Ca++ exchanger
      
      • INcreased INtracellular Ca++

Question 4

Contractility (and SV) DEcrease with: (5)

Answer 4

• beta1-Blockade (DEcreased cAMP)
• Heart failure (systolic dysfunction)
• Acidosis
• Hypoxia/Hypercapnea
  
  • DEcreased PO2/INcreased PCO2
• Non-dihyrdophyridine Ca++ channel blockers

Question 5

What happens to SV in anxiety, exercise, and pregnancy?

Answer 5

INcreases

Question 6

Myocardial O2 demand is INcreased by:

Answer 6

INcreased:

• Afterload (proportional to arterial pressure)
• Contractility
• Heart rate
• Heart size (INcreased wall tension)

Question 7

Preload =

Answer 7

Ventricular EDV

Question 8

Afterload =

Answer 8

Mean Arterial Pressure

*Proportional to Peripheral Resistance

Question 9

What effect do Vasodilators have on Afterload?

Answer 9

DEcrease afterload

“vAsodilators (e.g., hydrAlAzine) decrease Afterload (Arterial)”

Question 10

Nitroglycerin is a _____________. What does it do to Preload?

Answer 10

VEnodilator – DEcreases Preload

“vEnodilators - decrease prEload”

Question 11

Preload INcreases with:

Answer 11

• Exercise (slightly)
• INcreased blood Volume (ie., overtransfusion)
• Excitement (INcreased SYmpathetics)

Question 12

Force of contraction is proportional to ___________ of cardiac muscle fiber (preload).

Answer 12

End-Diastolic Length

Question 13

Ejection fraction equation.

Answer 13

EF = SV/EDV = (EDV - ESV) / EDV

Question 14

EF is an index of what?

Answer 14

Ventricular contractility

Question 15

EF is normall ___%.

Answer 15

> /= 55%

Question 16

T/F - Ejection Fraction DEcreases in systolic heart failure.

Answer 16

True

Question 17

change in Pressure =

Answer 17

P = flow (Q) x resistance (R)

*similar to Ohm’s law: V = IR

Question 18

Resistance (R) =

Answer 18

R = driving pressure (P) / flow (Q)

= (8(viscosity) x length) / pi x r^4

Question 19

Blood viscosity depends mostly on what?

Answer 19

Hematocrit

Question 20

Viscosity INcreases in:

Answer 20

• Polycythemia
• Hyperproteinemic states
  (ie. , multiple myeloma)
• Hereditary Spherocytosis

Question 21

Viscosity DEcreases in:

Answer 21

Anemia

Question 22

Resistance is DIRECTLY proportional to:

Answer 22

Viscosity & Vessel Length

Question 23

Resistance is INVERSELY proportional to:

Answer 23

Radius to the 4th power

Question 24

What accounts for most of the total peripheral resistance?

Answer 24

Arterioles –> regulate capillary flow