(10)

Question 1

(Estimation of Afterload)

1. difficult to measure aortic impedance
2. clinically estimate using what? not valid if what?

(increased afterload causes….)

3. need for what?
4. increase in afterload can reduce what?

Answer 1

2. arterial P; outflow obstruction is present
3. increased ventricular pressure generation and need for increase pressure generation thorughout ejection and therefore increased ventricular wall stress
4. stroke volume

Question 2

(Force of Contraction - 2 main determinants)

1. What two are they?

(Frank-Starling mechanism)

2. balances what?
3. what does it do?

(contractile state of myocardial fibers)

4. intrinsic property of fibers - independent of what? influenced by what?
5. an increase in Ca will do what?
6. what will increase Ca availability?
7. what will decrease Ca availabilty?

Answer 2

1. Frank Starling mechanism and contractile state of the myocardial fibers
2. LV and RV output
3. increased preload –> increases output
4. load; free Ca and contractile proteins
5. increase contractility
6. catecholamines, thyroid hormone, drugs
7. beta blocker and Ca entry blocker drugs

Question 3

(Contractilty)

(“Ionotrpopic state” - contractile state)

1. increased contractility = ?
2. incrased contractility –> ?

(…)

3. increased contractilty almost always means what?

(…)

4. contractile state is an important determinant of use of what?

(…)

5-7. What are the three determinants of contractility at the celluar level are what?

Answer 3

1. increased velocity of contraction and increased peak tension development
2. greater SV and smaller ESV (end systolic volume)
3. increased systolic rate of rise and increased peak cytosolic [Ca]
4. myocardial O2
5. cytosolic [Ca]
6. the contractile proteins (function, structure, etc)
7. senstivity to Ca ions present

Question 4

(Contractility)

(decreases when…)

1. what is depelted?
2. beta-recepotr blockade does what?
3. what kind of damage?
4. control of what is abnormal?

Answer 4

1. energy (by anoxia or ischemia)
2. decrease cytosolic Ca
3. myocardial damage or fibrosis occurs
4. cytosolic Ca fluxes (eg chronic heart farilure)

Question 5

(Contractilty)

(measurement of intrinsic contractilty)

1. is problematic
2. what methods are best?
3. no clinical index is totally independent of what?

Answer 5

2. invasive
3. both preload and afterload

Question 6

(Idealized concept of contractilty)

1. defined as what?
2. also called what?

Answer 6

1. max veloicty (Vmax) of contration when there is no load on muscle
2. V0 (max velocity at zero load)

guy on left is Pzero

Question 7

(Force-Velocity Relationship)

1. when initial muscle length (preload) is held constant, there is an inverse relationship between what?
2. force velocity relationhsip varies with changes in what?
3. positive iontropic agents increase what two things?

Answer 7

1. velocity and tension (initial velocity plotted against load)
2. contractility (inotropic state)
3. increase velocity of shortening for any given load and increase maximum force at Pzero

Question 8

enalapril - angiotensin converting enzyme inhibitor - allows vasorelaxation

why did blood pressure fall? vasodilation, more blood in at less pressure

effect on LV afterload? decreased - easier for ventricle to pump blood out because arteiral pressure went down

decreased afterload –> ?

Answer 8

increased CO

Question 9

(The heart as a pump)

(depends on a number of interrelationships)

1. synchronous activation of what?
2. potential of the ventricular wall to do what?
3. total load imposed on what?
4. what dimensions?
5. appropriate filling between what?

Answer 9

1. different chambers
2. perform muscular work (contractility)
3. myocardial fibers (preload and afterload)
4. ventricular dimensions
5. systoles

Question 10

this diagram allows us to look at interrelationships of pressures between different chambers, electrical activation vs mechanical, place in series of events the heartsounds

if you can recreate this without looking you will much better and understanding once you get to clinics…

1. what’s the first thing that starts the cycle?

she talked a long time about this figure - would probably be a good idea to watch - at ~40min 4/17 9Am lecture

Answer 10

1. electrical activation

Question 11

(Cardiac Output)

1. CO = ?
2. stroke volume depends on what two things?
3. in heart failure, ventricular residual volume becomes greater or less? SV?
4. CO is often related to body surface area (related to animal size - cardiac index - this is a small point)

Answer 11

1. HR X SV
2. contractility and loading conditions (normally is 65% of total end diastolic volume)
3. greater; relatively smaller

Question 12

(Fick Principle)

1. the amount of a substance taken up (or released) by and organ per unit time = ?

Answer 12

1. difference between [arterial] and [venous] of the substance X blood flow thorugh that organ

Question 13

FICK!