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pt momints > Heart as a pump > Flashcards

Heart as a pump Flashcards

1
Q

which valves are open in late diastole

A

mitral and R AV

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2
Q

explain what happens in late diastole

A

blood will flow from SVC to R atrium to R ventricle
blood from pulmonary veins into L atrium to L ventricle

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3
Q

phase of atria nd ventricle filling

A

late diastole

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4
Q

explain the percentages of blood nd how it travels from atria to venticles

A

70% - passively bc of low psi in ventri
30% - atrial systole

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5
Q

why is the remaining 30% need to be pumped in atrial systole

A

bc ventricles are 70% filled - not low psi anymore - needs force

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6
Q

why is there regurgitation during atrial systole

A

as atria contracts - strong - no valves present in great veins - most to ventricle some to veins - normal

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7
Q

when does AV valve close

A

during ventricular systole; towards close pa lng sa late dias and atrial sys to prople remaining 30%

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8
Q

explain why isovolume ventricular contraction is needed

A

ventricle has low psi compared to pulmo artery nd aorta - need to be high psi to overcome pulmo and aortic valves

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9
Q

explain the ventricular systole

A

1st part - isovlome contract - ventr contracts but no ejection - only to build up psi

2nd part - ventri ejection - aortic nd pulmo valces open - rapid ejection slows as systole progress

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10
Q

if psi declines in vent sys why does blood continue to flow in late systole

A

bc of momentum built up is ivc

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11
Q

how do AV valves close in vent sys

A

strentch of ventricles pull down AV valves

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12
Q

explain the volumes of blood in vent during dias and sys

A

dias 130 ml - sys 50 ml tira - 65% ejection fraction (should be pumped) - not all is pumped - 80 ml pumped

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13
Q

significance of ejection frac

A

if <65% ok for operation bc heart is strong

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14
Q

what valves close in early dias

A

aortic nd pulmonic

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15
Q

why does aortic nd pumonic close in early dias

A

psi in vent drops - high psi aorta nd pulmo art - closes to avoid backflow

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16
Q

explain the sig of IVR

A

dec in vent psi - prep for opening of mitral nd AV valves - for vent filling - dapat lower than atrial psi end when it is

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17
Q

signifies close of AV valve

A

C prime

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18
Q

what is the signifcance of the pericardium

A

Separates it from thoracic viscera

  • Pericardial sac has 5 - 30 ml clear fluid
  • Lubricates the heart
  • Permits it to contract with minimal friction
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19
Q

which atrial systole happens first

A

right before left - bc of SA node on R atrium

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20
Q

which ventric contraction happens first

A

LV before RV - L has thiccker muscle - more force to overcome in IVC so need to contract first

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21
Q

which ventric eject begins first

A

RV before LV - 10 mmHg on RV - 80 mmHG on LV

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22
Q

explain the timing of closing of pulmo nd aortic valves in respiration

A

expire - simultaneous
inspurt - aortic muna

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23
Q

why aortic valve closes slightly before pulmonic valve in inspire

A
  • psi in thorax creates suction effect that causes backflow in aorta kaya need to close first
24
Q

co of both vent are

A

=

25
Q

what is arterial pulse

A

waves of blood along arteries; what we palpate

26
Q

speeds of arterial pulse in diff arteries

A

4 m/s in aorta; 8 m/s in large arteries; 16 m/s in small arteries of young adults

27
Q

when is radial pulse felt

A

0.1 sec after peak of systolic ejection in aorta

28
Q

why hsould hr nd pr be =

A

not equal - TAO - masks out pulse

29
Q

why is pr faster in older pt

A

Aging produces rigid vessels thus makes waves travel faster

30
Q

give causes of pounding heart

A

palpitations - aortic insufficiency - allergic reax

31
Q

what is dicrotic notch

A

Small oscillation on the falling pulse wave cause by aortic valves snaps shut

32
Q

pulse is thready in

A

shock - hemmorhage

33
Q

explain rising atrial pressure

A

Atrial systole - atria has to pump the remaining blood to the heart

Isovolumetric contraction o AV valves bulge into the atria; because the pressure is building up in the ventricles

  • Blood flows in the atria until AV valves open
  • Seen in atrial systole, isovolumetric ventricular contraction and before AV valves are open
34
Q

what is A wave

A

Due to atrial systole; Blood regurgitation o Venous inflow stops = rise in venous pressure

35
Q

C wave

A

Rise in atrial pressure due to bulging of the AV valves during isovolumetric contraction

36
Q

V wave

A

Rise in atrial pressure before AV valves open in diastole.

37
Q

s1 vs s2

A

s1 - close AV
s2 - close aortic nd pulmo valves

38
Q

what are the patholig cheart sounds

A

s3 - 1/3 dias; rapid filling of vent
s4- before s1; in stiff vent - psi of atria to high - vent hypertophy

39
Q

stenosis vs insufficiency

A

stenosed - valve not open maayos - narrow
insuff - valve does not close properly - backflow

40
Q

timing of murmurs of aortic/pulmo valves

A

sten - sys
induff - dias

41
Q

timing of murmurs of mitral/tricusp

A

sten - dia
insuff - sys

42
Q

explain ficks principle

A

o Amount of substance taken up by an organ per unit time is equal to the arterial level of the substance minus the venous level (A-V difference) times the blood flow o Substance is oxygen

43
Q

normal CO

A

5L/min

44
Q

cardiac index

A

an organ recieves 3.2 L of blood

45
Q

factors that control CO

A

hr, myocardial contractility, preload, afterload

46
Q

CO in diff situations

A

no change - sleep, moderate temp change
inc - anxiety - excite - 700% - hogh temp - pregy - epi
dec - sitting to stand rapid - arrythmias - heart disease

47
Q

what is + chronotrpic effect

A

inc co - ne and e

48
Q

what is + inotropic action

A

inc co - in qual of contract - ne and e

49
Q

relate frank starlings law to CO

A

Extent of the preload o More venous return, the better the stroke volume would be and multiply that with the heart rate, cardiac output will also increase

  • Is proportionate to the end-diastolic volume

Preload, venous return, contractility of the heart will affect myocardial fiber shortening according to FrankStarling Law

  • If Frank-Starling Law is good, then the stroke volume will also be good
  • Stroke volume x heart rate = cardiac output
50
Q

factors affecting end dia vol

A
  • Increase
    o Stronger atrial contractions o Increased total blood volume o Increased venous tone o Increased pumping action of skeletal muscles o Increased negative intrathoracic pressure
  • Decrease
    o Standing o Increased intrapericardial pressure o Decreased ventricular compliance
51
Q

exp sympathetic stim in myocardial contractility

A

Sympathetic stimulation
Shift upward & to the left of the curve
Positive chronotropic and inotropic effect

52
Q

exp force-frequenct in myocardial contractility

A

Ventricular extrasystoles condition the myocardium that the next contraction is stronger
Postextrasystolic potentiation ▪ Increased Ca++ availability

53
Q

oxygen consumptions

A

2 ml/100g/min –heart stoppage

  • 9 ml/100g/min – beating heart at rest
54
Q

what determines o2 consumption

A

Intramyocardial tension
Contractile state of the myocardium
Heart rate

55
Q

why does o2 consumtion inc when SV inc

A

25% increase in SV without a change in arterial pressure produces the same increase in O2 consumption & vice versa.

If there is 25% increase in stroke volume, then that 25% correlates to 7x the work of left ventricle than that of right ventricle * Pressure work produces > O2 consumption

pt momints (10 decks)

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