Physio: Review Of Reviewed Stuff

Front 1

True or False:
Action potential duration is much longer in heart than in cardiac muscle but the duration of contraction is comparable.

Back 1

True

p. 253

Front 2

[ Cardiac / Skeletal ] SR has smaller volume and more mitochondria.

Back 2

Cardiac

p. 254

Front 3

Where are T-tubules located in cardiac muscle versus skeletal muscle?

Back 3

cardiac: @ Z-line
skeletal: @ A-I bands

note: T-tubules are sparse in atria and absent in PKJ fibers

p. 254

Front 4

Junction of SR and sarcolemma differs in heart and skeletal muscle. In heart, cisterna of SR forms [ diads / triads ] with limited SR-T tubule contact.

Back 4

Diads

p. 254

Front 5

Macroscopically, cardiac fibers are [ interwoven / parallel ] whereas skeletal fibers are [ interwoven / parallel ].

Back 5

cardiac = interwoven
skeletal = parallel

p. 254

Front 6

Why does the heart's excitation-contraction coupling include a step of "Ca2+ - induced Ca2+ release" ? What does this mean?

Back 6

Small amount of calcium from I Ca is the trigger for a large release of Ca2+ from SR. SR calcium release channel is the ryanodine receptor (RyR2).

p.254

Front 7

Ca2+ - induced Ca 2+ release is graded by two factors. What are they?

Back 7

- Size of trigger (amount of Ca2+ coming in from I Ca)
- amount of Ca2+ stored in SR

p. 254

Front 8

True or False:
The primary source of Ca2+ responsible for the increase of intracellular calcium concentration is the influx of Ca2+ from I Ca.

Back 8

FALSE. The primary source of increase is from Ca2+ release from SR!!

p. 254

Front 9

When Ca2+ binds to troponin -C (TnC), tropomyosin shifts on the thin filament, unblocking myosin binding site and allowing weak binding of actin. That weak complex undergoes a cooperative conformational change, forming strong crossbridges that rapidly split ATP and generate force. These strong complexes [ decrease / increase ] the Ca2+ affinity of TnC.

Back 9

strong A-M complexes INCREASE the affinity of Ca2+ for TnC.

p. 255

Front 10

True or False:
Intracellular calcium concentration returns to near resting levels before relaxation begins; Ca2+ unbinding from TnC ends A-M ATPase activity and force production.

Back 10

True! It returns to near resting levels BEFORE relaxation begins.

p. 255

Front 11

Regarding regulation of intracellular calcium concentration, what are the sarcolemmal processes for influx (1) and efflux (2) of Ca2+?

Back 11

Influx: I Ca (L-type)
efflux: Na- Ca exchange IS THE PRIMARY MEANS OF EFFLUX)***
antiport: 3 Na+ IN , 1 Ca2+ OUT.
Another way is the sarcolemmal Ca pump which directly extrudes calcium by splitting ATP.
p. 255

Front 12

Action potential duration can influence contractile force. Why/how?

Back 12

APD is mainly dictated by the plateau created by I Ca. So decreasing APD means reduced I Ca --> smaller trigger for Ca2+ release from SR and also less amount of Ca2+ available to fill SR Ca2+ stores. p. 256

Front 13

There is no recruitment regarding cardiac muscle contractile force. What does this mean/ indicate?

Back 13

The heart is an electrical syncitium. Every fiber is activate. Each cell is electrically coupled with other cells thus every cell participates with each heartbeat. p. 257

Front 14

In cardiac muscle, there is no tetanic contraction. This is because...

Back 14

APD is slightly LONGER than the duration of contraction. Additionally, refractory period prevents stimulation at high enough rate.
p. 257

Front 15

Which part of the autonomic nervous system has a
a) positive inotropic effect?
b) negative inotropic effect?

Back 15

Inotropic effect refers to affecting the contractility (the intrinsic ability of the muscle to generate force independent of muscle length).

Positive = sympathetics (NE)
Negative = parasympathetics (Ach)
p. 258

Front 16

[ Contractility / Contractile force ] is the intrinsic ability of the muscle to generate force independent of muscle length.

Back 16

Contractility

p. 258

Front 17

True or False:
Contractility is increased by elevating heart rate either by electrical stimulation or physiologically by sympathetic stimulation.

Back 17

True

p. 258

Front 18

When HR is increased by NE, the [ duration / frequency ] of contraction decreases and rate of relaxation [ decreases / increases ], termed positive lusitropy.

Back 18

when HR is increased by NE, DURATION or contraction decreases, rate of relaxation increases.

p. 258

Front 19

The ascending staircase / positive staircase / Bowditch staircase / Treppe relates what relationship?
A. contractility : frequency
B. force of contraction : frequency
C. rest potentiation : HR

Back 19

B. force of contraction : frequency

p. 259

Front 20

After a longer thannormal interval between beats, the first beat will exhibit greater than normal contractile force. What is this phenomenon called?

Back 20

Rest potentiation.
This reflects the kinetics of SR Ca 2+ accumulation and Ca 2+ cycling in the SR.

p. 259

Front 21

Resting tension increases more rapidly with increasing muscle length in heart than in skeletal muscle. In other words,

A. a much greater preload is required to elongate cardiac muscle to max length than to elongate skeletal muscle
B. cardiac muscle is stiffer than skeletal muscle

Back 21

B. cardiac muscle is stiffer than skeletal muscle . This is due to differences in the isoform of titin.

p. 261

Front 22

Why is cardiac muscle said to only operate on the ascending limb of Force-Tension curve?

Back 22

Force produced by ventricular filling and atrial contraction is insufficient to stretch cardiac muscle beyond maximum length (and it is beyond maximum length that you'd get the descent). p. 261

Front 23

What is the maximum sarcomere length for cardiac muscle?
A. 1.9 micrometers
B. 2.0 micrometers
C. 2.2 micrometers
D. 2.5 micrometers

Back 23

C. 2.2 micrometers
is the max though working length (at end of diastole is 1.9 micrometers).

p. 261

Front 24

What are the four consequences of organs/ tissues being connected in parallel? (hint: think basic)

Back 24

1. A given volume of blood ejected from the L ventricle passes thru only one organ before entering veins.
2. Aterial blood entering each organ has the same composition.
3. Blood pressure at the entrance to each organ is the same
4. Blood flow to each organ can be controlled independently (local regulation of flow). p. 266-7

Front 25

Review of basics:

force/ area = _____

Back 25

pressure
p.267

Front 26

Review of basics:

volume / time = ____

Back 26

flow (Q)
p. 268

Front 27

Review of basics:

pressure difference / flow = ____

Back 27

resistance

blood "resists" being moved becuase friction develops between the blood and the vessel wall, in addition to the friction that develops between adjacent imaginary layers (laminae) of blood.
p. 268

Front 28

Review of basics:
Give the equation for
A) resistance in series
B) resistance in parallel

Back 28

A) series: R1 + R2 = R eff
B) parallel: 1/(R1) + 1/(R2) = 1/(Reff)
note, if the resistances are all equal in the parallel, you can also write it as R/N= R eff
p. 269

Front 29

Flow is proportional to radius (or diameter) to the ______ power.
A. 2nd
B. 3rd
C. 4th

Back 29

C. 4th power. Thus, small changes in vascular caliber can produce profond changes in blood flow thru a vascular segment. p. 272

Front 30

Which vessels are colectively known as the "resistance vessels" in the vasculature?

Back 30

Arterioles. This is where regulation of blood flow takes place. Note, capillary has the smallest radius of all blood vessels, so an individual capillary has the highest resistance to blood flow BUT the collective resistance to flow of all capillaries is less than the collective resistance to flow of all the arterioles. p. 272

Front 31

Capillary has the smallest radius of all blood vessels, so an individual capillary has the highest resistance to blood flow. So why are arterioles the ones called "resistance vessels"?

Back 31

The collective resistance to flow of all capillaries is less than the collective resistance to flow of all the arterioles. This is due to the sheer number of capillaries (much greater than arterioles). p. 272

Front 32

What is the Law of Laplace and what does it describe?

Back 32

Tension = (Transmural pressure * internal radius) / Wall Thickness

what determines the diamter of a blood vessel: take into accoun the distending force and compressing force for a thin walled object p. 273

Front 33

True or False:
Both changes in blood pressure and changes in vascular smooth muscle contractile state can produce immediate changes in vessel diameter.

Back 33

TRUE. These are what determines the diamter of a blood vessel: take into accoun the distending force and compressing force. p. 274

Front 34

True or False:
Whole blood (suspension of red cells in plasma and the viscosity of blood) depends on fluid velocity and thus is "non-Newtonian".

Back 34

True.
p. 275

Front 35

What are the four major factors that determine the viscosity of blood?

Back 35

1. Temperature ( Increase in temp = decrease in viscosity )
2. Hematocrit , the fractional volume of blood occupied by red cells. (Increase in Hct = Increase in viscosity)
3. Tube/vessel diameter ( below~300 micrometers, as diameter decreases, viscosity decreases)
4. Shear rate (relative velocity of one imaginary layer of fluid with respect to that of adjacent layers). As max shear rate increases, viscosity of blood decreases. p. 275-7

Front 36

Acute, transient increases in shear rate lead to vasodilation due to shear-induced release of vasodilator _________ from the endothelium.

Back 36

nitric oxide

remember, shear rate is the relative velocity of one imaginary layer of fluid with respect to that of adjacent layers
p. 279

Front 37

In low flow states (circulatory shock, for ex), [ high / low ] shear rates lead to [ decreased / increased ] viscosity that tend to reinforce the low flow creating a positive feedback that results in a vicious cycle.

Back 37

in low flow states, LOW shear rates lead to INCREASED viscosity that tend to reinforce low flow!! p. 279

Front 38

As the maximum shear rate increases, the viscosity of blood decreases. This is due to...

Back 38

the breakup of aggregates of RBC (forms aggregates at low flows b/c they have a natural tendency to stick together). p. 278

Front 39

True or False:
Reynold's number helps distinguish between laminar and turbulent flow.

Back 39

True. For values above 2,000 flow becomes turbulent. p. 280

Front 40

Increase in shear rate [ decreases / increases ] viscosity. Why?

Back 40

Increase in shear rate decreases viscosity. RBCs tend to stick together, thus increasing shear rate (relative velocity between RBCs) decreases aggregating tendencies and thus decreases viscosity. p. 279

Front 41

S1 "lub" heart sound is due to [AV / semilunar ] valves snapping shut.

Back 41

AV valves snapping shut

Front 42

S2 "dub" heart sound is due to [AV / semilunar ] valves snapping shut.

Back 42

semilunar valves snapping shut (note the aortic valve shuts slightly before the pulmonary valve).

Front 43

True or False:
Systole, active contraction of the heart, is about 1/3 of the cardiac cycle.

Back 43

True
p. 281

Front 44

Stroke volume is...

Back 44

amount of blood ejected during systole (ml/beat). calculated by:
Stroke Volume = End Systolic Volume - End Diastolic Volume
p. 281

Front 45

_________ is the volume of blood in the ventricle at completion of _______ as marked by closure of the aortic and pulmonic valves

Back 45

ESV (end systolic volume) ; completion of systole p. 281

Front 46

The ejection fraction for the normal heart is always greater than or equal to:
A. 0.45
B. 0.50
C. 0.55
D. 0.60

Back 46

C. 0.55
p. 281

Front 47

Cardiac output is typically ___ L / min. Can be calculated by the equation...

Back 47

5 L/ min ; can be calculated by the equation CO = HR* SV
p. 281

Front 48

What is this?

Back 48

Cardiac Function Curve!
Relates Right Atrial Pressure to CO.
p. 282

Front 49

True or False:
The Law of LaPlace relates tension and pressure relationship.

Back 49

True. For thin-walled sphere, P=(2HT)/r where H is wall thickness, T is tension, r is radius, P is pressure
p. 282

Front 50

According to the Law of LaPlace, what is the relationship (proportional, inversely proportional) between
A. Tension and Pressure
B. Tension and Radius
C. Tension and Wall Thickness

Back 50

A. Tension is proportional to Pressure
B. Tension is proportional to Radius
C. Tension is inversely proportional to Wall Thickness
p. 282

Front 51

Regarding EDV (end diastolic volume), ______ is "preload" and ______ is "afterload".

Back 51

For EDV,
right atrial pressure = preload
aortic pressure = afterload

p. 283

Front 52

Back 52

Front 53

What does this relate?
A. Increased afterload
B. Increased preload
C. Increased contractility

Back 53

B. Increased preload
p. 284

Front 54

What does this relate?
A. Increased afterload
B. Increased preload
C. Increased contractility

Back 54

A. Increased afterload
p. 284

Front 55

True or False:
Regarding Frank-Starling Compensation, the basis for compensation is a shift of blood volume between arterial and venous circulation, thereby altering preload and SV.

Back 55

True.
p. 285

Front 56

True or False:
Regarding Frank-Starling Compensation, compensation operates over several beats and is NOT complete.

Back 56

True
p. 285

Front 57

With cardiac function curves, which of the following is NOT held constant to isolate effects of right atrial pressure on cardiac output?
A. afterload
B. contractility
C. TPR
D. HR

Back 57

A. afterload

Afterload (aortic pressure) is allowed to vary as a function of flow (CO). p. 286

Front 58

The steepest part of the cardiac function curve is between RAP values of...

Back 58

0 - 4 mmHg

(note: @ RAP greater than or equal to 7 mmHg, CO reaches a plateau)

p. 287

Front 59

What accounts for the plateau in the cardiac function curve?

Back 59

1. increased afterload offsets increased preload.
2. Pericardium is rather inelastic and limits EDV.

Front 60

If a positive inotropic effect occurs, what happens to the cardiac function curve? Specifically, what happens to SV and CO, respectively?

Back 60

+ inotropic effect means increase in contractility. That means increase in SV and increase in CO!

Cardiac function curve will shift to Left and become slightly steeper. p. 288

Front 61

If a negative inotropic effect occurs, what happens to the cardiac function curve? Specifically, what happens to SV and CO, respectively?

Back 61

- inotropic effect means decrease in contractility. That means decrease in SV and decrease in CO!

Cardiac function curve will shift to Right and become slightly less steep. p. 288

Front 62

If TPR increases, what happens to the cardiac function curve? Specifically, what happens to SV and CO, respectively?

Back 62

If TPR increases, aortic pressure (afterload) increases, SV decreases, and CO decreases. The cardiac function curve will shift slightly to the R and be slightly less steep. p. 288

Front 63

If TPR decreases, what happens to the cardiac function curve? Specifically, what happens to SV and CO, respectively?

Back 63

If TPR decreases, aortic pressure (afterload) decreases, SV increases, and CO increases. The cardiac function curve will shift slightly to the Left and be slightly steeper. p. 288

Front 64

At a constant SV, an increase in HR must increase CO. At HR > _____ bpm, diastole is too brief for complete filling and EDV is reduced but it is not until ~ _____ bpm that CO peaks (under conditions used to obtain the cardiac function curve).

Back 64

100bpm; 125 bpm

p.288

Front 65

True or False:
At resting HR, atrial contraction has only a minor effect on EDV (5%).

Back 65

True.
p. 288

Front 66

True or False:
The time for diastolic filling of ventricle is inversely proportional to HR.

Back 66

True. At HR less than or equal to 100 bpm, filling is complete. At HR > 100 bpm, filling is incomplete. At HR > 125, CO starts to fall.
p. 289

Front 67

True or False:
When a normal heart is in circulation, it is primarily the properties of the vascular system which determine the cardiac output. In contrast, during heart failure, both the heart and vascular system determine cardiac output.

Back 67

True
p. 292

Front 68

When a normal heart is in circulation, it is primarily the properties of the vascular system which determine the cardiac output. When would both the heart and vascular system determine cardiac output?

Back 68

with heart failure
p.292

Front 69

True or False:
The "knee" of the vascular function curve is a consequence of the negative pressures in the thoracic cavity.

Back 69

TRUE. p. 296

Front 70

True or False:
The "knee" of the vascular function curve is a consequence of the negative pressures in the thoracic cavity.

Back 70

TRUE. p. 296

Front 71

What would change the slope of the vascular function curves?
A. changes in contractility
B. changes in HR
C. changes in TPR

Back 71

C. changes in TPR!

remember the equation:
Venous return = -[(Cv/Ca)+1] / TPR * (Pv-Pms) p. 295-6

Front 72

What are two ways to increase stressed blood volume?

Back 72

1) Increase in total blood volume (transfusion) --> increase in stressed blood volume --> increase Pms.
2) Increasing venoconstriction. The other way to change stressed volume is to change the amount of blood subjected to stress! This too leads to an increase in Pms.
p.298

Front 73

What would increase Pms (mean systems pressure)?
A. decrease in blood volume
B. increase in blood volume
C. venoconstriction
D. venodilation

Back 73

B. increase in blood volume
C. venoconstriction

p. 298

Front 74

What would decrease Pms (mean systems pressure)? (2)
A. decrease in blood volume
B. increase in blood volume
C. venoconstriction
D. venodilation

Back 74

A. decrease in blood volume
D. venodilation

p. 298

Front 75

True or False:
Positive changes in the cardiac function curve under resting circumstances produce little change but negative changes in the cardiac function curve create substantially profound effect of increased right atrial pressure.

Back 75

True.
p. 306-7

Front 76

Positive changes in the cardiac function curve under resting circumstances produce [ little / substantial ] change and negative changes in the cardiac function curve create [little / substantial ] change of increased _______ .

Back 76

+ CFC change --> little change in RAP
- CFC change --> SUBSTANTIAL change in RAP
p. 307

Front 77

True or False:
Elevated right atrial pressure are strong clinical indicators of heart failure.

Back 77

True. Because this means the heart is less able to transfer blood from the veins to the arteries and hence the higher right atrial pressure and lower vascular flow rate. p. 307

Front 78

Inotropic changes shift the [ Cardiac Function Curve / Vascular Function Curve ] thus affecting the [ CO / RAP ] whereas changes in blood volume shift the [ Cardiac Function Curve / Vascular Function Curve ] thus affecting the [ CO / RAP ].

Back 78

Inotropic changes --> change in CFC --> change in RAP.

Blood volume changes --> change in vascular function curve --> change in CO. p. 308

Front 79

Quickly sitting/standing up and feeling faint due to gravity's force on venous return is a condition referred to as...

Back 79

orthostatic hypotension
p. 310

Front 80

Inspiration [ decreases / increases ] venous return to the right heart and [ decreases / increases ] right heart output.

Back 80

both increase! why? During inspiration, the pressure within the thorax and around the heart decreases, thus increasing transmural pressure and thus flow of blood into ventricles. p. 311