Cardio vascular coupling

Question 1

Preload defines_____

Answer 1

the maximal force ventricle can produce. The volume in the ventricles at the end of diastole. this is a passive filling of the ventricles and atria. governed by starling law=gets the sarcomeres to the best position for contraction

Question 2

Describe the heart cycle

Answer 2

1. Late diastole
   
   1. bothe atria and ventricles fill passibely
2. atrial systole
   
   1. atrium contracts pusching 20-30% of blood into ventricles
3. isovolumic ventricular contraction
   
   1. ventricles contract pushing closed the AV valves. Not enough pressure to open the semilunar valves
4. ventricular ejection
   
   1. pressure equal and then is above atreies, semilunar valves open and blood is ejected
5. isovolumic ventricular relaxation
   
   1. ventricles relax, pressure falls velow that of arteries and semilunar valves close

Question 3

Explain the pressure-colume loop

Answer 3

1. ventricles fill, passivly, generating higher ventricular pressure
   
   1. junction between 1 and 2 = pressure difference to close the AV valves
      
      1. this volume is PRELOAD
         
         1. ​max force ventricle can produce
         2. theoretical 250mm
2. ventricle contracts isometrically until the ventricular pressure matches the aortic pressure
   
   1. junctions between 2 and 3
      
      1. aortic valve opens this pressure is called AFTERLOAD
3. blood ejected, pressure continues to rise as it contracts
   
   1. once the volume of the blood is ejected, the pressure drops
   2. ventricular pressure now drops below aortic pressure and closes aortic valve 3 AND 4
4. ventricular relaxation

Question 4

define stroke volume, ejection fraction and cardiac output.

perform the calculations for a following chart

Answer 4

1. stroke volume
   
   1. volume ejected by each heart beat
   2. when mitral valve closes (end diastolic volume)** and when the aortic valve closes **( end diastolic volume)
      
      1. resting for 70kg male= 70ml
2. ejection fraction
   
   1. proportion of stroke volume at the end of diastole
   2. stroke volume /diastolic volume
3. cardiac output
   
   1. volume of blood ejected over time
   2. amount of blood ejected / time
      
      1. ​stroke volume(ml) x heart rate(bpm)

Question 5

in accordance with frank starlings law, what is the outcome of more venous inflow?

what are the two intrinsic controls of cardiac output?

Answer 5

higher cardiac output in accordance with Frank-Starling law.

1. stretching right atrium increases HR
   
   1. Bainbridge reflex
2. stretching SA node directly increases HR
   
   1. due to an increase in tropinin-Ca affinity

Question 6

1. diagram and explain the following changes in the P-V loop. Describe what changes with the stroke volume, ejection volume, pressure, diastolic volume and end systolic
   
   1. increased preload
   2. increase afterload
   3. increased contractility

Answer 6

1. increased preload
   
   1. leads to greater stroke volume
   2. atrial pressure is higher and mitral valves closes later and ventricular volume is higher
   3. example
      
      1. moved leg or stood up and the volume of blood in the veins increases and/or the veins constrict
2. increasing afterload
   
   1. leads to reduced stroke volume
      
      1. occurs with hypertension
   2. heart cannot generate the additional pressure to eject the excess volume of blood remaining
   3. increase in after load and decrease in stoke volume
3. increased contractility
   
   1. leads to greater stroke volume.
      
      1. ventricles can generate a higher force and thus eject more blood
   2. increased stroke volume, decrease in end systolic, increase in pressure

Question 7

Where des the FS extend in the cardiomyocytes.

Answer 7

FS for individuals cardiomyocytes can be extended to whole heart

Question 8

Draw the wriggers diagram and stated important parts

Question 9

What is Qh, Qr, Pa, Pv, Ca, Cv, Ct, Rf? And what are the major contorllers? determine the calculation of Rf with the folowing values

Answer 9

Qh= Cardiac output (flow out of the heart)

Qr = flow in vasculature

Pa=pressure in arteries

Pv = pressure in veins

Ca=arterial compliance

Cv= venous compliance, C=change in volume/change in pressure

Ct=total vascular compliance,

Rf=resistance in arterioles

major controllers

1. cardiac factors
   
   1. heart rate
   2. myocardial contractility
2. coupling factors
   
   1. preload
   2. afterload

Qh=Qr, in steady state

Rf=(Pa-Pv)/Q

Rf=(102-2)/5=20

Question 10

What is Qh is dependent on 4 things. explain

Answer 10

1. Heart Rate
2. contractily
3. preload
4. afterload

Question 11

What is your venous pressure proportional to?

Answer 11

p=1/Qh

Question 12

What is Pmc proportional to?

Answer 12

blood volume

Question 13

Slop of Pv-Qh with Rf

compare the following

1. vasodilation
2. normal resistance
3. vasoconstriction

Answer 13

Pmc does not change with R(resistance)

• however, there is a shift in blood to the arteries relative to veins with increasing resistance

Question 14

What defines the steady state condition of the heart function?

Answer 14

FS and Pv-Qh

Question 15

Cardiac function curves are manipulated by (4)

Answer 15

1. compliance
2. Heart Rate
3. resistance
4. blood volume

Question 16

what is the reason for the Pa to fall to a much greater extent than Pv?

Answer 16

Compliance

C=change in volume/Change in pressure

Question 17

What happens during the 1st part of the PV loop?

Answer 17

mitral valve opens(due to pressure difference of atria and ventricles), and the ventricles passivly fill passivly, mitral vlave closes from 1-2

Question 18

which of the flollowing would lead to increase and decrease cardiac output?

Answer 18

1. increase
   
   1. increase preload
   2. increase contractility
2. decrease
   
   1. increased afterload

Question 19

what happens during EKG

Answer 19

Pwave = atrial depolarization

PR=atrial contraction

QRS = ventricle polarization

QT=systole, ventricular contraction

Question 20

describe the change in curve for venous pressureXCO when blood volume increases and decreases

Answer 20

Question 21

diagram the chang in peripheral resistance

Answer 21

Pmc does not change with R.

shiftt in blood to the arteries relative to veins with increasing resistance.

Question 22

incresaig the stroke volume (contractility or preload) diagram the chanig in compliance based on cardiac output

Answer 22

Question 23

Answer 23

Question 24

describe the change in blood volume and R

Answer 24

• change in VOLUME only!- no change in cardiac output, onlt
• change in resistance
  
  • cardiac output shifts down with dilation(decreased resistance)
  • caridac outtput shift

Question 25

diagram the heart rate and stroke volume. what does Heart rate affect

Answer 25

preload, afterload and contractility.

increase= sympathetic chronotropic : decreasing diastolic time