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BS V, Module I > Cardiac Physiology Pt. I > Flashcards

Cardiac Physiology Pt. I Flashcards

1
Q 
Why do we need to pump blood?
• Blood delivers oxygen and nutrition
• Blood removes \_\_\_\_ and waste
• Must ensure it gets to the tissues
• Cross sectional area \_\_\_\_ proportional to velocity
• Go to capillaries > CSA inversely proportional to velocity
	○ Blood goes quickly through initial vessels, and then want blood to slow down during the \_\_\_\_
A

CO2
inversely
gas exchange

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2
Q

The cardiac cycle

\_\_\_\_
Volume 
\_\_\_\_
Valves
\_\_\_\_
EKG
A

pressure
electrical triggers
heart sounds

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3
Q

Ventricular systole and diastole

• Systole: a drawing together or a ____. – Ventricular systole – squishing out blood
• Diastole: separation, ____
– Ventricular diastole – dilation, blood flows in

• Most of cardiac cycle is spent in \_\_\_\_
	○ Much \_\_\_\_and more passive
• Systole (contraction) is much \_\_\_\_
A 
contraction
expansion
diastole
slower
faster
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4
Q

Diastole filling - 80% - ____ filling

Blood flows into right ventricle
Open ____ Valve

Blood flows into left ventricle
Open ____ Valve

Closed pulmonary artery and aortic valves – ____

Pressure higher for input Input valves open
Exit valves ____

* Pressure is higher in input valves then it is in ventricular spaces; because of pressure gradient > tricuspid and mitral valves open; blood passively fills the ventricles
* Pressure is \_\_\_\_ in aorta/pulm artery > these valves are then closed
A 
passive
tricuspid
mitral
semilunar
closed

higher

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5
Q

Active filling - atrial contraction
80% - Passive filling
20% - ____ filling

Squeezing more blood into ventricle
____ Tricuspid Valve

____ Mitral Valve

____ pulmonary and aortic valve

• 80% full there is a slight squeezing in the \_\_\_\_ compartments > forces a little bit more blood in
	○ Pressure in ventricle is lower than in aorta and pulm vessels; the valves are still open
A

active
open
open
closed

atrial

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6
Q

Boyle’s Law

• Pressure inversely proportional to ____ at constant mass, ____
– As volume expands, pressure decreases
– As volume shrinks, pressure rises

A

volume

temperature

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7
Q

Isovolumic contraction - squeeze with valves closed

____ Tricuspid Valve

____ Mitrial Valve

____ Pulmonic Valve

____ Aortic Valve

Muscle contracts, same amount blood, smaller space, ____ rises

Pr pressure higher in ____ than ventricle – SL valves closed

Pr pressure higher in ____ than atrium – AV valves close

* After the contraction, the pressure in atrium is lower than in ventricle; pressure differential closes tricuspid and mitral
* Pressure in the output (exit in aorta) is still higher than in ventricles > both input and output valves are closed > the beginning of contraction of cardiac cycle
* As muscles contract > make space smaller > pressure inside ventricle increases > until it's greater than the pressure in \_\_\_\_ > ejection of systole
A

closed
closed
closed
closed

pressure
aorta
ventricle

aorta/pulm vessel

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8
Q

Systole: Ejection

____ Pulmonic Valve

____ Aortic Valve

____ pressure>aortic pressure Valves open, blood ejected

____ - Rapid ejection
____ – Reduced ejection

• Pressure is so high > valves open and blood moves
	○ 2/3 rapid; 1/3 reduced ejection
• Valves opening depends on relative pressure of the \_\_\_\_
A 
open
open
ventricular
2/3
1/3
three compartments
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9
Q

Diastole starts again

Stroke Volume=
____ – End Systole Volume

In typical resting male, =120 ml-50 ml=____ ml=____ oz (TSA compliant)

Ejection fraction = ____/ End Diastole Volume
=70ml/120 ml x100= ____

SV = EDV – ESV 
EF = SV / EDV
• Now begin the \_\_\_\_ filling of diastole
• SV
	○ \_\_\_\_ of blood that gets pumped out (when start to squeeze, and how much you have when you squeeze it out)
• EF
	○ What \_\_\_\_ of blood can you pump w each contraction
	○ Increase efficiency can increase your health; problems if decreased too much
A

end diastole volume
70
1.7

stroke volume
58%

passive
amount
portion

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10
Q

The cardiac cycle

* Changes in \_\_\_\_ and volume > largely what you're looking at for cardiac cycle
* \_\_\_\_ pressure > most important (red)
A

pressure

ventricular

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11
Q

Start of diastole, ventricular blood volume ____

Ventricular volume ____ ml at lowest.
Blood flowing into atrium and ventricles, passive flow

* Diastole > passive filling of blood
* \_\_\_\_ valve opening > volume increases and ventricular pressure drops
A

lowest
50
AV

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12
Q

Pressure-volume curves for diastole

• Increase is due to squeezing and contraction of \_\_\_\_ > atrial kick
	○ \_\_\_\_ extra volume that comes from squeezing of contraction from atrial muscles
A

atria

30%

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13
Q

____: atrial contraction – squeezing an extra 20%

A

p-wave

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14
Q

Pressure volume curves for diastole

• At this point pressure in ventricle is greater than inside atrium > valves \_\_\_\_ > isovolumetric contraction > big increase in \_\_\_\_, no change in volume > both valves are closed > contraction with no change in volume

• At a certain point here (B)
◦ we see that the pressure inside the ventricle is greater than the aortic pressure
‣ that is when these valves open

A

close

pressure

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15
Q

____
– ventricular contraction

• QRS event > electrical event in ventricles
	○ Relates to mechanism of increased contraction of muscles in the ventricles
A

QRS wave

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16
Q

Ventricular contraction, ejection

Ventricular pressure rises, shuts ____ valve, pressure increases rapidly

____ rise as valves closed, no blood moves

Aortic valve ____, blood squeezed out, volume falls
____ -wave ventricular contraction

Aortic valve closes

* Rapid decrease in volume > slows down > most blood exits ventricle
* Pressure rises at first > volume goes down > pressure drops > when less than aortic pressure > the valves close
* Isometric relaxation > both valves closed > muscle is relaxing > decrease in pressure from within the \_\_\_\_
* All changes in volume are due to physical changes in contraction due to \_\_\_\_ and differential pressure is due to \_\_\_\_ of the valves
A

AV
isovolumetric pressure
opens
QRS

ventricles
electrical signals
opening/closing

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17
Q

Pressure, valves & ventricular volume

Isovolumetric contraction

Pressure rises enough to open ____ valves, blood flows out

Ventricle relaxes, pressure falls, ____ valve opens

* Opening/closing of valves > important in allowing \_\_\_\_ to go up; ventricular relaxation > \_\_\_\_ valve opens and allows filling to begin again
* Valves, pressure and volume are intimately related
A

SL
AV
pressures
AV

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18
Q

Pressure & Aortic Flow

Aortic valve only opens when ____ pressure higher than aortic pressure – pushes valve open

• Pressure at which aortic valves open > blood pressure value
	○ \_\_\_\_ > ventricles have to be greater then to push the valve open
A

ventricular

120/80

19
Q

CARDIAC CYCLE SUMMARY

KNOW ME!

• Ejection portion
	○ Mitral is \_\_\_\_, aortic valve is \_\_\_\_ > pressure of LV/aortic pressure > continues to increase then decreases > continues to increase as the contraction goes through > as the volume decreases >  you begin to see in both the ventricle and aortic pressure as the bolus is passed through > the pressure goes \_\_\_\_
• Filling portion
	○ Initial diastole portion
	○ Mitral valve is \_\_\_\_ > mitral is open, aortic is \_\_\_\_ > LV is increasing, AP is decreasing (slowly going down), volume of LV is increasing (filling period)
A

closed
open
down

open
closed

20
Q

Heart Valves: TPMA

Aortic ____ valve
Pulmonary ____ valve
____ valve
____ valve (mitral

A

semilunar
semilunar
tricuspid
bicuspid

21
Q

Cardiac valves

Mitral – 2 Tricuspid – 3 Pulmonary – 3 Aortic - 3 Why 2 cusps in Mitral? Developmental twisting?

• Developmental twisting in \_\_\_\_ > mitral valve with \_\_\_\_ cusps
A

embryonic development

2

22
Q

Increased pressure closes valves, prevents backflow

• Valves open only in ____ direction after blood pushed through – prevent backwash
• Example:
– Left Atrial Pressure > Ventricle Pressure
Mitral Valve is ____
– Left Atrial Pressure < Ventricle Pressure
Mitral Valve is ____

Papillary muscles contract and ____
tighten, prevent inversion into atria

• Not just pressure, but also \_\_\_\_ contracting > chordae tendon maintain the shape of the valves
A 
one
open
closed
chordae tendinae
muscles
23
Q

Cardiac cycle & heart sounds

* Heart sounds > reflection of closing of the \_\_\_\_ > useful diagnostic tool > allow auditory input into how valves are functioning
* Heart sound 1 > closing of \_\_\_\_ valve
* Heart sound 2 > closing of \_\_\_\_ valve
A

valves
mitral
aortic

24
Q

Heart sound S 1 (LUB)
long and loud

  • Closure of ____ valves
  • Onset of ____
  • ____
  • Longest (____sec)
  • Mitral v : ____ mid- clavicular
  • Tricuspid v : ____ of sternum
A 
closure
systole
loudest
0.14
5th ICS
5th ICS left
25
Q

Heart sound S 2 (DUB) higher

  • Closure of ____ valves
  • Onset of ____
  • Higher ____ – because SL valves more taut
  • Lower ____
  • Listen at the ____
  • Aortic v : ____ right of sternum
  • Pulmonary v : ____ left of sternum• Higher pitch > structure of the valves ____ to one another
A 
semilunar
diastole
frequency
intensity
base
2nd ICS
2nd ICS
relative
26
Q

Heart sound S3 and S4

  • “____ Gallop” •
  • Middle 1/3 of ____ •
  • Rapid ____ filling
  • Dull&lowpitched
  • Normal in ____
  • May indicate ____ or cardiomyopathy in adults

____ “gallop”
Corresponds to ____ contraction
Rarely a normal finding
Associated with “stiff”, ____ ventricle

* Normally not heard
* Can be indicative of benign changes, or can indicate pathology
* S4 occurs just before S1; S2 right before S3
A

ventricular
diastole
children
congestive heart failure (CHF)

atrial
atrial
hypertrophied

27
Q

Balancing the electrical and chemical gradients across the membrane

• both the chemical and electrical gradient drive ____ in
◦ both the chemical and electrical gradient for ____ drive it into the cell
◦ the cell is very ____
◦ but the ____ gradient for potassium drive it in
‣ because potassium is positively charged and the cell is negatively charged
‣ but there is a lot of potassium inside the cell and not very much outside
• this forces/will push potassium ____ of the cell

A 
sodium
calcium
negative
electrical
out
28
Q

Because PK>PNa, PCl, Vm close to ____

The greater the ____, the more influence an
ion has on the membrane potential!

A

Ek

permeability

29
Q

Goldman-Hodgkin-Katz equation

Time-dependent
changes in the permeability to ____ and ____ underlie the neuronal action potential

• AP dictated by a \_\_\_\_ change…
A

Na+
K+
time-dependent

30
Q

Heart beat coordinated through impulses

  • Pacemaker cells in ____
  • Pass through cells to right atrial muscle and left atrial muscle
  • ____, bundle of His, Purkinje Fibers• Efficiency of pumping blood is dependent on having one contraction of all muscle; do not want different parts contracting at different times/out of order
    • SA node
    ○ Primary pacemaker of the cardiac signal > pass to contraction of atrial muscle > and then slowly to the AV node > leads to ____ of the right and left signals > AP passed to the ____ > into the left and right bundles > purkinje fibers > contraction of ventricular muscle
A

sinoatrial node
AV node
unification
bundle of His

31
Q

The cardiac conduction system

  • Time (in sec) after SA node signal
  • ____ right to left atrium
  • Built in delay top to bottom so atria empties before ____ contract
  • L&R ventricle ____
  • SA node drives because it has ____ discharge rate – overrides pacemaking of AV node, Purkinje fibers• Bundle of His > the contraction of L/R ventricles occur simultaneously > driving from bottom to top to squeeze blood through aorta
    • SA node > drives contraction because it is the fasted; AV node pacemaking activity and in PF
    ○ ____ period; AP originating at SA node and through AV node through heart > dominates and drives the contraction; very important you only have one contraction
A

delay
ventricles
faster

AP/refractory

32
Q

Pacemaker potential Depolarized and leaking

  • Pacemaker resting potential ____V, then “leakiness” of ____. Then ____ brings potential to threshold without additional input
  • Slower to peak than myocytes, but myocytes with ____• PP > change in membrane potential > without additional input > AP oscillations
    • Have to have an AP generating without any other input > contribution of different ion channels
    ○ The membrane potential is ____ depolarized > -55mV
    ○ A lot of leakiness > in pacemaker cells, Na+ goes through (leaks) channels > depolarizes the membrane > achieve threshold > AP
    § PM depolarization is slower to peak than in the myocytes (these are all-or-none)
    § PM AP > ____ Ca+ open first, then the ____ Ca+ > AP, the ____ channels open > hyperpolarize the MP > brings it back down > leaking Na+ channels that allows us to have a continuous depolarization
A

-55m
Na+
Ca++
plateau

more
T type
L type
K+

33
Q

Cardiac myocyte AP/contraction longer than nerve or skeletal muscle

Don’t want a ____ twitch

Influx - ____ Na+, ____ Ca2+, then ____K+ efflux

• Peak potential of \_\_\_\_ and myocyte is same; but depolarization of the myocyte achieves a long plateau > want a long contraction because you need to have a steady control to squeeze that blood out
	○ \_\_\_\_ situation; all fibrils have to contract and it has to be coordinated
• -90 mV resting > Na+ enters depolarizes > entry of Ca+ maintains the plateau > with a delay > K+ increases and repolarization
	○ Delayed opening of K+
	○ Presence of Ca++ to allow \_\_\_\_ contraction
A

quick
fast
slow
delated

nerve
all-or-none
long

34
Q

Ionic conductance changes
ventricular AP

____ Ca2+ conductance
and ____ K+ conductance allow for prolonged contractions

• Na+ driven > big \_\_\_\_ in Na+ permeability; then an increase in Ca+ and decrease in K+ > allows for the plateau
A

increased
decreased
increase

35
Q

Refractory periods maintain ventricular AP - can be modified to change heart rate

Effective RP vs Relative RP modify rate

• ERP > initial part
	○ \_\_\_\_ period in contract muscle
• RRP
	○ Can use \_\_\_\_ to modify (faster or slower)
• Change HR by changing the amount of time the myocyte AP takes to \_\_\_\_
A

fastest
drugs
recover

36
Q

Cardiac muscle a syncytium

  • ____ connect the end of cell so action potential spreads to all cells. Coordinated contraction: all at once.
  • Atrial vs. ventricular syncytium; separated by ____ fibers• Gap junctions at end of fibers > allow cardiac muscles to act as syncytium > enhance cardiac efficiency when it’s time to beat
    ◦ by coupling the muscle fibers electrically through these gaps junctions
    ‣ you make sure that these action potentials signals pass rapidly from one cell to another
    • ____ coupling allows for much faster spreading in a coordinated conduction• Atria/ventricle chambers > depends on there being different contraction times > having non-conductive fibers that separated atria from ventricles > electrical signal going through AV and bundle of His passing through the NCF
A

gap junctions
non-conductive
gap junction

37
Q

Excitation contraction in cardiac muscle – influx of Ca2+ key

  • The same Ca2+ influx through ____ VDCC that underlies plateau also triggers release of calcium-dependent calcium release through ____ channels on sarcoplasmic reticulum
  • More Ca2+ maintained in ____ than for skeletal muscle, bound to ____• Influx of Ca+ is critical to the cardiac muscle
    • Larger T tubules > more Ca++ is bound within
    ○ ____ bind Ca++ so there is enough Ca++ to enter the cardiac muscle > AP comes along > transmitted into T tubule > opens Ca channel > Ca enters (electrochemical gradient mandates that it open) > Ca++ dependent Ca release cahnnels on SR (ryanodine channels) > secondary release of Ca (much more here) > contraction
    § Two sources > ____ signal and ____ controls the signal; ensure a solid and firm contraction, and to control the time
    ○ Entry of ____ is critical for contraction and actin-myosin cross bridge sitation
A

L-type
ryanodine
T tubule
mucopolysaccharides

mucopolysaccharides
magnifies
temporally
Ca++

38
Q

Ca++ channel blockers demonstrate the importance of Ca++ influx for contraction

  • Show that cardiac muscle relies on extracellular calcium
  • Force generation can be modulated by calcium ____ of the cell
  • ____®
  • Verapamil®
  • ____®
    • Increase cxn of drug > plateau phase of muscle is ____ > cardiac muscle depends on extracellular calcium coming in
    • Forces in mN over time > the ____ is also decreased by the blocker
A 
outside
diltiazem
nifedipine
reduced
force
39
Q

When plateau ends, cytoplasmic Ca2+ levels return to normal – end contraction

  • ____ Ca2+ channels close, no more influx
  • Na/Ca & Na/K transporters actively transport ____ to outside (remember primary and secondary active transport?)
  • Ca2+ actively transported back into SR by ____

• We talked about how important this is to have important temporal control over the contraction
◦ this applies to not just the beginning of the contraction but also the end
• Removing calcium is how we limit the contraction
◦ this is done in a couple of ways:
• SERCA ATPase > uses energy of ____ to actively pump Ca++ out of the cytoplasm into the SR to refill the stores again
○ Energy dependent aspect of muscle contraction*
• Na/Ca exchangers > pump Ca++ outside (from cyto to EC space and loaded into ____)
• Primary > ____:
◦ ATP binds here (Na/K channel) so that we have a driving force to bring that sodium back in
‣ that driving force bringing Na in across the myofibril is what allows us to pump ____ out

• The closing of those calcium channels and the time has come for them to close is critical to
reduce this as well
◦ the uptake into the SERCA depends on ____
◦ the Ca/Na exchanger (secondary active transport pushing calcium outside the cell based ultimately on the ____ pump) and have the channels closed so no more calcium comes in

A

L-type
Ca++
SERCA-ATPase

ATP
T tubule
NaK ATPase
Ca+

ATP
ATP

40
Q

Electrocardiogram

P = \_\_\_\_ depolarization
QRS = \_\_\_\_ depolarization 
T = ventricular \_\_\_\_

ECG=EKG Elektrokardiographie German / American

A

atrial
ventricular
repolarization

41
Q

EKG and cardiac cycle

• ____ – atrial depolarization/ contraction
• ____ ventricular depolarization/ contraction
• ____ – ventricular
repolarization

• P wave depolarization > leads to additional \_\_\_\_
A

p wave
QRS
T-wave

42
Q

Polarity of EKG vs. cells

• ____ different from cell membrane potential – it’s complicated

• Phase I > corresponds to \_\_\_\_  The T wave ◦ corresponds to the repolarization ( \_\_\_\_)

• They are both ____ waves on the EKG

◦ One represents a depolarization (QRS) and one represents a ____ (T wave)

A 
tissue potential
QRS
phase III
positive
hyperpolarization
43
Q

EKG - intervals and segments

  • P-Q(R) interval: ____ contraction, ____ sec
  • Q-T interval: contraction of ____, ____ sec
  • S-T segment: ____ depolarized, ____ sec
  • ____Interval = heart rate, 1/0.9 sec =1.11 bps x60 = 66 BMP• the R is the largest ____ that you are going to see on the EKG
    • RR > interval of ____
    • QT > ____contraction
    ○ Delay the plateau > increase the ____
    • PQR > time in between ____ and ventricular contraction
    • ST > ____ phase
A 
atrial to ventricular
0.16
ventricle
0.35
ventricular myocytes
0.1
1/RR
depolarization
HR
plateau
interval
atrial
contraction

BS V, Module I (15 decks)

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