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BRS (PHYSIO) > CARDIOVASCULAR > Flashcards

CARDIOVASCULAR Flashcards

1
Q

Cardiac output from the eft side of the hear is the __________

A

systemic blood flow

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2
Q

Cardiac output from the right side of the hears is the ________________

A

pulmonary blood flow

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3
Q

Direction of blood flow

A
  • lungs to the left atrium via the PULMONARY VEIN
  • left atrium to the left ventricle through the MITRAL VALVE
  • left ventricle to the aorta through the AORTIC VALVE
  • from the aorta to the systemic arteries and the systemic tissues
  • from tissues to the systemic veins and vena cava
  • vena cava to the Right atrium
  • RA to the RV through TRICUSPID VALVE
  • RV to the pulmonary artery though PULMONIC VALVE
  • pulmonary artery to the lungs for oxygenation
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4
Q

Deliver oxygenated blood to the tissues

A

Arteries

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5
Q

site of highest resistance in the cardiovascular system

A

arterioles

  • arteriolar resistance is regulated by the ANS
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6
Q

________receptors are found on the arterioles of the skin, splanchnic, and renal circulations

A

alpha 1

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7
Q

____________ receptors are found on arterioles of skeletal muscle

A

B2 adrenergic

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8
Q

have te largest total cross sectional and surface area

A

Capillaries

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9
Q

Formed from merged capillaries

A

Venules

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10
Q

Under low pressure

contain the highest proporrtion of blood in the cardiovascular system

A

Veins

(the blood volume is called unstessed volume)

have alpha 1 adrenergic receptors

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11
Q

Velocity of blood flow can be expressed by this equation

A

v= Q/A

  • v = velocity (cm/sec)
  • Q = blood flow (ml/min)
  • A = cross sectional area (cm2)
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12
Q

Velocity is directly proportional to _____________

A

blood flow

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13
Q

Velocity is inversely proportion to the ______

A

cross sectional area

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14
Q

Blood flow can be expressed by the these equations _______________

A
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15
Q

The quation for blood flow (or cardiac output) is analogous to ________

A

Ohm’s law

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16
Q

____________ equation gives factors that change the resistance of blood vessels

A

Poiseuille’s

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17
Q

Resistance is directly proportional to ____________

A

viscosity of blood

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18
Q

Resistance is directly proportional to _____________

A

length of vessel.

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19
Q

Resistance is inversely proportional to the _______________

A

fourth power of the vessel

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20
Q

____________ resistance is illustrated by the systemic circulation

A

Parallel

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21
Q

When an artery is added in parallel, the total resistance ______________

A

decreases

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22
Q

___________resistance is illustrated by the arrangement if blood vessels within a given organ

A

Series

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23
Q

straight line (streamedlined) flow

A

Laminar flow

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24
Q

predicts whether blood flow will be laminar or turbulent

A

Reynauld’s number

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25
Q

When reynauld’s number is increased, there is a greater tendency for _________

A

turbulence

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26
Q

Factors affecting Reynold’s number

A

Decreased viscosity

Increased velocity

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27
Q

consequence of the fact that the adjacent layers of blood travel at different velocities within a blood vessel

A

Shear

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28
Q

velocity of blood is __a___ at the wall and ___b____ at the center of the vessel

A

a= zero

b= highest

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29
Q

Shear is highest at the ___________

A

wall

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30
Q

Decribes the distensibility of blood vessels

inversely related to elastance or stiffness

A

Capacitance

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31
Q

Capacitance is expressed by this equation

A
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32
Q

Capacitance _________ proportional to volume

A

Directly

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33
Q

Capacitance ______proportional to pressure

A

inversely

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34
Q

Capacitance is much greater for (veins or arteries) ?

A

Veins

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35
Q

capacitane of the arteries ________with age

A

Decreases

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36
Q

As blood flows through the systemic circulation, pressure _____________ progressively because of the resistance

A

Decreases

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37
Q

Pressure is highest in the ____a_____ and lowest in the _____b______.

A

a= aorta

b = venae cavae

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38
Q

The largst decrease in pressure occurs across the ________

A

arterioles

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39
Q

Mean pressure in the aorta

A

100 mmHg

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40
Q

Mean pressure in the arterioles

A

50 mm Hg

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41
Q

Mean pressurein the capillaries

A

20 mm Hg

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42
Q

Mean pressure in the vena cava

A

4 mm Hg

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43
Q

pulsatile pressure

not constant during cardiac cycle

A

Arterial pressure

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44
Q

Highest arterial pressure during a cardic cycle

A

systolic pressure

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45
Q

Lowest arterial pressure during a cardiac cycle

A

Diastolic pressure

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46
Q

Difference between the systolic and diastolic pressures

A

Pulse pressure

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47
Q

The most important determinant of pulse pressure is ____________

A

Stroke volume

  • as blood is ejected from the left ventricle into the arterial system, arterial pressure increases because of the relatively low capacitance of the arteries.
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48
Q

Is the average arterial pressure with respect to time

A

mean arterial pressure

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49
Q

Left atrial pressure is ________ than venous pressure

A

lower

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50
Q

Left atrial pressure is estmated by ______________

A

Pulmonary wedge pressure

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51
Q

ECG wave

A
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52
Q

Represents atrial depolarization

A

P wave

  • does not include atrial repolarization
    • buried in the QRS complex
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53
Q

interval from the beginning of the P wave to the beginning of the Q wave (initial depolarization of the ventricle)

A

PR interval

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54
Q

Depends on conduction velocity through the AV node.

A

PR interval

  • if AV nodal conduction decreases, the PR interval increases
  • decreased by stimulation of the sympathetic
  • increased by stimulation of parasympathetic
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55
Q

represent depolarization of the ventricles

A

QRS complex

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56
Q

interval from th beginning of the Q wave to the end of the T wave

Representss the entire period of depolarization and repolarization of the ventricles

A

QT interval

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57
Q

is the segment from the end of S wave to the beginning of the T wave

Isoelectric

represents the period when the ventricles are deoplarized

A

ST segment

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58
Q

Represents ventricular repolarization

A

T wave

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59
Q

the resting membrane potential [cardiac] is determined by _____

A

conductance to potassium and approaches the K equilibrium

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60
Q

Inward current brings positive charge into the cell and ______the membrane potential

A

depolarize

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61
Q

Outward current takes positive out of the cell and ________ the membrane potential

A

hyperpolarizes

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62
Q

Ventricles, atria and the purkinje system have stable resting membrane potentials of about ______mV.

A
  • 90 mV
  • This value approaches the K equilibrium potential
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63
Q

Action potentials are of long duration, especially in Purkinje fibers, where they last ____________(msec)

A

300

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64
Q

the upstoke of the action potential

  • caused by transient increase in Na conductance. this increase results in an inward Na current that depolarizes the membrane
A

Phase 0

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65
Q

is a brief period of initial repolarization

  • Initial repolarization is caused by an outward, in part because of the movement of K ions (favored by both chemical and electrical and electrical gradients) out of the cell and in part because of a decrease in sodium conductance
A

Phase 1

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66
Q

the pateau of the action potential.

  • caused by transient increase in calcium conductance, which results in an inward calcium current, and by an increase in K conductance.
  • outward and inward currents are approximately equalm so the membrane potential is stable at the plateau level
A

Phase 2

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67
Q

Repolarization

  • calcium conductance decreases
  • K conductance increases
  • large outward K current - > hyperpolarizes the membrane
A

Phase 3

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68
Q

resting membrane potential

  • period during which inward and outward currents (Ik1) are equal adn the membrane potential potential approaches the K equilibrium potential
A

Phase 4

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69
Q

Normally the pace maker of the hear

has unstable resting membrane potential

A

Sinoatrial node

  • Exhibits phase 4 depolarization or automaticiy
    • The intrinsic rate of phase 4 depolarization (nd heart rate) is fastest in the SA node and slowest n the His-purkinje system
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70
Q

[SA node]

upstroke of athe action potential

  • caused by an increase in calcium conductance
  • inward calcum current
A

Phase 0

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71
Q

[SA node]

not present in the SA node action potential

A

Phase 1 and Phase 2

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72
Q

[SA node]

repolarization

  • increase in K conductance.
  • increase in outward K current that cuases repolarization of the membrane potential
A

Phase 3

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73
Q

[SA node]

  • Slow depoalrization
  • accounts for the pacemaker activity of the SA node (automaticity)
  • inward Na current call If
A

Phase 4

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74
Q

If is turned on by _________ of the membrane potential during the preceding action potential

A

repolarization

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75
Q

upstoke of the action potential in the AV node is the result of an inward ______ current

A

Calcium

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76
Q

Reflects the time required for excitation to spread throughout cardiac tissue

A

Conduction velocity

  • depends on the size of the inward current during the upstroke of the action potential.
    • The larger the inward curent the higher the conduction velocity
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77
Q

Conduction velocity is fastest in the ___________

A

Purkinje system

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78
Q

Conduction velocity is slowest in the _________

A

AV nde

  • allows time for ventricular filling before ventriular contraction.
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79
Q

Is the ability of ardiac cells to initiate action potentials in response to inward, depolarizing current.

Reflects the recovery of channels that carry the inward currents of the upstoke of the action potential.

A

Excitability

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80
Q

Changes in excitability are described by ____________

A

refractory periods

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81
Q

begins with the upstoke of the action potential and ends after the plateau

No action potential can be initiated

A

Absolute refractory period

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82
Q

Slightly longer than ARP

period during which a conducted action potential cannot be elicited

A

Effective refractory period

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83
Q

is the period immediately after the ARP when repolarization is almost complete

Period during which an action potential can be elicited, but more than the usual inward current is required

A

Relative refractory period

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84
Q

Produces changes in heart rate

A

Chronotropic effects

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85
Q

Produces changes in conduction velocity, primarily the AV node

A

Dromotropic

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86
Q

The SA node, atria and AV node have _____________ vagal innervation

A

pasarympathetic

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87
Q

The neurotransmitter is _________ which acts on the _______receptors in the SA node, AV node, and atria

A

Acetylcholine

Muscarinic receptors

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88
Q

The mechanism of the negative chronotropic effect is __________

A

Decreased If

  • the inward Na current tht is responsible for phase 4 depolarization in the SA node
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89
Q

Autonomic effects on the heart and Blood Vessels

A
90
Q

Mechanism of action of negative dromotropic effect

A

Decreases inward calcium current and increases outward K current

  • Decreases conduction velocity through AV node
  • Increases PR interval
91
Q

_________ is the neurotransmitter acting at B1 receptors

A

Norepinephrine

92
Q

Mechanism of action of positive chronotropic effects

A

Increased If, the inward sodium current that is responsible for phase 4 depolarization in the SA node

Increases heart rate

93
Q

mechanism of action of positive dromotropic effect

A

increased inward calcium current

  • increases conduction velocity through the AV node
94
Q

Contractlie unit of the myocardial cell

A

Sarcomere

  • runs Z line to Z line
  • Similar to Skeletal muscle
95
Q

Occur at the ends of the cells

maintain cell to cell cohesion

A

Interacalated discs

96
Q

Present at the interacalted disks

low resistance paths that allow rapid electrical spread of action potential

A

gap junctions

97
Q

accont for the observation that the hear behaves as an electrical syncytium

A

Gap junctions

98
Q

Continuous with the cell membrane

invaginate the cells at the z lines and carry action potentials into the cell interior

form dyads with the sarcoplasmic reticulum

A

T tubules

99
Q

T tubules are well developed in the ____a____ but poorly developed in the ____b_____

A

a = ventricle

b= atria

100
Q

small diameter tubules in cross proximity to the contractile elements

A

Sarcoplasmic reticulum

101
Q

site of storange and release of calcium for excitation-contraction coupling

A

Sarcoplasmic reticulum

102
Q

Steps in excitation-contraction coupling

A
  1. AP spreads from cell membrane to T tubules
  2. During the plateau, Ca conductance is increase
  3. This ca entry triggers more calcium to be released (ryanodine)
  4. Intracellular calcium increases
  5. Calcium binds to troponin C and tropomyosin is moced out of the way, removin the inhibition of actin and myosin binding
  6. Actin and myosin bind
  7. relaxation occurs when calcium is reaccumulated by the SR
103
Q

Intrinsic ability of the cardiac muscle to develop force at a given muscle length

also called inotropism

A

Contactibility

  • related to the intracelleular calcium concentration
104
Q

Contractibility is estimated by the _______

A

ejection faction

normal (o.55 /55%)

105
Q

Factors that increase contractility

A

Increased heart rate

Sympathetic stmulation via B1 receptors

cardiac glycosides

106
Q

Factors that decrease contractitlity

A

Parasympathetic atimulation (ACh) via muscarinic receptos

  • decreases the force of contraction in the atria by decreasing the inward calcium current duint the plateau of the ardiac action potential
107
Q

Describes the effect of ventricular muscle cell length on the force of contraction

Analogous to the relationship in skeletal muscle

A

Length-tension relationship

108
Q

End diastolic volume

related to right atrial pressure

A

Preload

109
Q

for the left ventricle is aortic pressure.

For the right ventricle, pulmonary artery pressure

A

Afterload

  • Increases in aortic pressure cause an increase in afterload on the left ventricle
  • increase in pulmonary artery pressure cause an increase in afterload on the right ventrile
110
Q

Frank starling relationship and the effect of positive and inotropic agents

A
111
Q

Determines the maximum number of cross bridges that can form between actin and myosin

A

Sarcomere lenght

  • dtermines the maximum tension or force of contraction
112
Q

Velocity of contraction ata fixd muscle length is maximal when_____

A

afterload is zero

113
Q

Describes the increases in SV and cardiac output that occur in response to an increase in venous return or EDV

A

Frank starling relationship

114
Q

Increases in EDV cause an _______ in ventricular fier length, which produces an increase in developed tension

A

Increase

115
Q

Is the mechanism that matches cardiac output to venous return

A

Frank staling relationship

  • The greater the venos return, the greater the cardiac output
116
Q

Increase in contractily cause an _____ in cardiac output for any level of RA pressure or EDV

A

Increase

117
Q

Constrcuted by combining systolic and diastolic pressure curves

A

Ventricular pressure-volume loops

  • A single left ventricular cycle of contraction, ejection relaxation, and refililig can e visualized by combining the two curves into a pressure-volume loop
118
Q

Steps in the ventricular-pressure loops

A
  • isovolumetric contraction
  • ventricular ejection
  • isovolumetric relaxation
  • ventricular filling
119
Q

Isovolumetric contraction

A
  • Point 1-2
  • Cycle begins at the end of diastole at point 1
  • The left ventrile is filled with blood from LA (140ml)
    • End diastolic volume
  • Ventricular pressure is low becausse the ventricular muscle is relaxed
  • on excitation, the ventricle contracts and pressure increases.
  • the mitral valve closes when the LV pressure is greater than the LA pressure
    • no blood can be ejected from the ventricle
120
Q

Ventricular ejection

A
  • point 2-3
  • Aortic valve open at point 2 whenpressure in the LV exceed pressure in the aorta
  • Blood is ejected to the aorta
    • ventricular volume decreases
    • The volume that is ejected = stroke volume
      • ​width of he pressure volume loop
  • the volume remaining in theleft ventricle at point 3 is End systolic volume
121
Q

Isovolumetric relaxation

A
  • point 3-4
  • at point 3, the ventricle relaxes
  • When ventricular pressure decreases to less than aortic pressure = aortic valve closes
    • ventricular volume is constant
      • isovolumetric
122
Q

Ventricular filling

A
  • Point 4-1
  • once LV pressure decreases to less than aortic pressure
    • mitral valve opens = filling of the ventricle begins
  • ventricular volume increases to about 140 ml (EDV)
123
Q

Changes in ventricular pressure volume loop

A
124
Q

simultaneous plots of cardiac output and venous return as a function of right atrial pressure or end diastolic volume

A

Cardiac and vascular function curves

125
Q

Depicts the Frank starling relationship for the ventricle

Shows the cardiac output is a function of EDV

A

The cardiac function (cardiac output) curve

126
Q

Depicts the relationship between the blood flow through the vascular system (or venous return) and right atrial pressure

A

Vascular function (venous return) curve

127
Q

the point at which the vascular function curve intersects the x axis

equals right atrial pressure when there is “no flow” in the cardiovascular system

A

Mean systemic pressure

128
Q

Mean systemic pressure is inreaased by an _______ in boodv volume

A

Increase

129
Q

mean systemic pressure is increased by ________ in venous capacitance

A

decrease

130
Q

Slope of the venous return curve is determined by ______________

A

resistance of the arterioles

131
Q

A clockwise rotation of the venous return curve indicates a ____________ in total peripheral resistance

A

decrease

132
Q

A counterclockwise rotation of the venous return indicates an ______________ in TPR

A

increase

133
Q

Effect of a positive inotropic agent on the cardiac function curve, cardiac outpu, and RA pressure

A
134
Q

Inceases in blood volume or decrease in venous capacitance _________ the Mean systemic pressure

A

Increase

135
Q

Decrease in blood volume or increase in venous capaciance _________ mean systemic pressure

A

Decrease

136
Q

Increasing TRP causes a ______ in both cardiac output and venous return

A

decrease

137
Q

Decreasing TPR causes an _________ in both cardiac output and venous return

A

Increase

138
Q

The volume ejected from the ventricle on each beat

A

Stroke volume

SV = EDV -ESV

139
Q

Formula for cardiac output

A

SV x HR

140
Q

the fraction of the end diastolic volume ejected in each stroke volume

Relate to contractility

A

Ejection fraction

EF = SV/EDV

141
Q

is the work the heart performs on each eat

equal to pressure x volume

A

Stroke work

(aortic pressure x stroke volume)

142
Q

the primary energy source for stroke work

A

Fatty acids

143
Q

Directly related to the amount of tension developed by the ventriles

A

Cardiac oxygen consumption

144
Q

Fick Principle fir measuring cardiac output

A
145
Q

Preceded by the P wave

Contributes to, but is not essential for ventricular filling

A

Atrial systole

146
Q

The increase in atrial pressure (venous pressure) caused by the atrial systole is the ______ wave on venous pulse wave

A

a wave

147
Q

In ventricular hypertrophy, filling of the ventricle by atrial systole causes the _______

A

4th heart sound

148
Q

begins during the QRS complex

A

Isocolumetric ventricular contraction

149
Q

ventricular pressure reaches its maximum value during __________

A

Rapid ventricular ejection

150
Q

________ wave on venous pulse curve occurs because because of the bulging of tricuspid valve into the RA during right ventricular contraction

A

C wave

151
Q

The onset of T wave, which represent repolarization of the ventricles, marks the end of both ventricular contraction and reapid ventricular ejection

A

Rapid ventricular ejection

152
Q

Ejection of blood from the ventricles continues, but slower

Venricular pressure begins to decrease

Aortic pressure also decreases because of the runoff of blood from large arteries into smaller arteries

A

Reuced Ventricular ejection

153
Q

Cardiac cycle

A
154
Q

_____wave on venous pulse curve represents blood flow into the RA (rising phase of wave) and from RA into RV

A

V wave

155
Q

Repolarization of the ventricles (end of T wave)

The AV valves remain closed during most of this phase

A

Isoviumetric ventricular relaxation

156
Q

The blip in the aortic pressure tracing occurs after closure of the aortic valve and is called the_______

A

dicrotic notch or incisura

157
Q

When ventricular pressure, becomes less than atrial pressure, the mital valcve opens

A

Rapid ventricular filling

158
Q

Rapid flow of blood from the atria into the ventricles causes the _________

A

third heart sounds

159
Q

The longest phase of the cardiac cycle

ventricular filling continues, but at a slower rate

The time required for diastasis and ventricular filling depends on heart rate

A

Reduced ventricular filling (diastasis)

160
Q

The most important mechanisms for regulating arterial pressure a fast, neurally mediated _______a_____ and a slower, hormonally regulated __________b_______mechanism

A

a = baroreceptor

b = renin-angiotensin aldosterone mechanism

161
Q

Includes fast, neural mechanisms

negative feedback system that is responsible for the minute to minute regulation of arterial blood pressure

A

baroreceptor reflex

162
Q

______are stretch receptors located within the walls of the carotid sines near the bifurcation of the common carotid arteries

A

baroreceptors

163
Q

Steps in the baroreceptor reflex

A
  1. A decrease in arterial pressure decreases stretch on the walls of the carotid sinus
  2. Decreased stretch decreases the firing rate of the carotid sinus nerve. [Herring’s nerve, cranial nerve], which carries information to the vasomotor center in the brain stem
  3. The set point for mean arterial pressure is the vasomotor center is about 100 mmHg.
  4. The responses of the vasomotor center to a decrease in mean arterial bp are coordinated to increase the arterial pressure back
    • Decreased parasympathetic (vagal) outflow to the heart
    • Increased sympathetic outflow
164
Q

Four effects that increase the arterial pressure back to normal

A
  • Increase heart rate
    • decreased parasympathetic tone
    • increased sympathetic tone
  • Increase contractility and stroke volume
    • increased sympathetic tone to the heart
  • Increase vasoconstriction of arterioles
    • increased sympathetic outflow
  • Increase vasoconstriction of veins
    • increased sympathetic outflow
165
Q

Renin angiotensin aldosterone system

A
166
Q

enzyme that catalyze the conversion of the angiotensinogen to angiotensin I in plasma

A

Renin

167
Q

catalyzes the conversion of angiotensin I to angiotensin II, primarily in the lungs

A

Angiotensin converting enzyme

168
Q

Four effects of angiotensin II

A
  • Stimulates the synthesis and secretion of aldosterone by the adrenal cortex
  • Increases Na-H exchange
  • It increases thirst and therefore water intake
  • causes vasoconstriction of the arterioles, thereby increasing TPR and arterial pressure
169
Q

When the brain is ischemic, the partial pressure of ___________ in brain tissue increases

A

carbon dioxide

170
Q

Chemoreceptors in the vasomotor center and respond by __________ sympathetic outflow to the heart and blood vessels

A

Increasing

171
Q

example of the response to cerebral ischemia.

Increases in intracranial pressure cause compression of the cerebral blood vessels, leading to cerebral ischemia and increased cerebral PCO2

A

Cushing reaction

172
Q

Are located near the bifurcation of the common carotid arteries and along the aortic arch.

have very high rates of Oxygen consumption and are very sensitive to decrease in the partial pressure of oxygen

A

Chemoreceptors in the carotid and aortic bodies

173
Q

_____in PO2 activate vasomotor centers that produce vasoconstriciton, an increase in TPR and an increase in arterial pressure

A

Decrease

174
Q

involved in the regulation of blood pressure in response to hemorrhage, but not in minute to minute regulation of normal blood pressure

A

Vasopressin (ADH)

175
Q

Vasopressin is a potent vasoconstrictior that increases TPR by activating ___________ on the arterioles

A

V1 receptors

176
Q

Vasopressin increases water reabsorption by the renal distal tubule and collecting ducts by activating _____________receptors

A

V2

177
Q

released from the atria in response to an increase in blood volume and atrial pressure

causes relaxation of vascular smooth muscle

causes increased excretion of sodium and water by the kidney which reduces blood volume and attemps to bring arterial pressure down to normal

A

Atrial natriuretic peptide (ANP)

178
Q

Atrial natriuretic peptide inhibits _________ secretin

A

renin

179
Q

At the junction of the arterioles and capillaries is asmooth muscle band called the __________

A

Precapillary sphincter

180
Q

true capillaries do not have smooth muscle; they consist of a single layer of _______________ surrounded by a basement membrane

A

Enothelial cells

181
Q

In the liver and intestine, theclefts are exceptionally wide and allow passage of protein. These capilalries called

A

sinusoids

182
Q

large water soluble substances can cross by ___________

A

pinocytosis

183
Q

The starling equation

A
184
Q

Fluid flow

A

when Jv is positive, there is net fluid movement out of the capillary (filtration)

when Jv is negative, there is net fluid movement into the capilalry (absorption)

185
Q

_______is the filtration coefficient

the hydraulic conductance (water permeability) of the capillary wall

A

Kf

186
Q

determined by arterial and venous pressures and resistances

A

capillary hydrostatic pressure

  • an increase in Pc favors filtration out of the capillary
  • an increase in either arterial or venous pressure produces an increase in Pc; increases in venous pressure have a greater effect on Pc
  • Higher at the arteriolar end of the capilalry than at the venous end (except in glomerular capilalries, where it is nearly constant)
187
Q

Interstitial fluid hydrostatic pressure

A

opposes filtration

normally close to 0 mm Hg

188
Q

Factors that increase filtration

A
  • Increase in capilalry hydrostatic pressure
    • caused byincreased arterial pressure, increased venous pressure, arteriolar dilation and venous constriction
  • decrease interstitial hydrostatic pressure
  • increase capillary oncotic pressure
    • caused by decreased protein concentration in the blood
  • increase in interstitial oncotic pressure
    • inadequate lymphatic function
189
Q

Excess filtered fluid is returned to the circulation via the ___________

A

lymph

190
Q

__________permits interstitial fluid to enter, but notleave, the lymph vessels.

flow through larger lymphatic vessels is also unidirectional

A

one-way flap valves

191
Q

oCcurs when the volume of interstital fluid exceeds the capacity of the lymphathics to return it to the circulation

can be caused by excess filtration or bloccked lymphatics

A

Edema

192
Q

causes both arteriolar dilation and venous constriction, which together produces a large increase in Pc and local edema

A

Histamine

193
Q

produced in the endothelial cells

causes local relaxation of vascular smooth muscle

A

Nitric oxide

194
Q

Causes and examples of edema

A
195
Q

The mechanism of action

A

activation of guanylate cyclase and production of cyclic guanosine monophosphate (cGMP)

196
Q

Blood flow to an organ remains constant over a wide range of perfusion pressures

A

Autoregulation

  • Organs that exhibit autoregulation are the
    • heart
    • brain
    • kidney
  • if perfusion pressure to the heart is suddenly decreased, compensatory vasodilation of the arterioles will occur to maintain a cconstant flow
197
Q

Summary of control of special circulations

A
198
Q

is an increase in blood flow to an organ that occurs after a period of occlusion of flow.

the longer the period of occlusion is, the greater the increase in blood flow is above the peocclusion levels

A

Reactive hyperemia

199
Q

Mechanism tat explain local control of blood flow

A

Myogenic hypotheis

Metabolic hypothesis

200
Q

Explains autoregulation but not active or reactive hyepremia

based on the observaton that vascular smooth muscle contracts when it is stretched

A

Myogenic hypotheis

201
Q

based on the observation that te tissue supply of oxygen is matched to the tissue demand of oxygen.

vasodilator metabolites are produced as a result of metabolic activity in tissue.

A

metabolic hypothesis

  • Vasodilators”
    • CO2
    • H
    • K
    • lactate
    • adenosine
202
Q

Increae in sympathetic tone cause__________

A

vasoconstriction

203
Q

causes arteeriolar dilaion and venous constriction

produces increaed filtraion out of the capilalries and causes local edema

A

Bradykinin

204
Q

causes arteriolar constriction and is released in response to blood vessel damae to help prevent blood loss

implicaed in the vascular spasms of migraine headaches

A

Serotonin

205
Q

E series prostaglandings are ___________

A

vasodialtors

206
Q

F series prostaglandins are ________

A

vasoconstrictors

207
Q

Thromboxane A2 is a ________

A

vasoconstrictor

208
Q

Coronary circulation is controlled almost entirely by____________

A

local metabolic factors

  • exhibits autoregulation
    • exhibits active and reactive hyperemia
209
Q

The most important metabolic factors are ___________________

A

hypoxia and adenosine

210
Q

Cerebral circultion is almost entirely controlled by ___________

A

local metabolic factors

  • Exhibits autoregulation
    • exhibits active and reactive hyperemia
211
Q

The most important local vasodialtor for the cerebral circualtion is ________

A

CO2

212
Q

Primary regulato of blood flow to the skeletal muscle at rest

A

Sympathetic innervation

213
Q

Stimulation of alpha 1 receptors cause_______

A

vasoconstriction

214
Q

stimulation of B2 receptors causes ____________

A

vasodialtion

215
Q

During exercise, when demand is high these _______________are dominant

A

local metabolic mechanisms

216
Q

is the principal fucntion of cutaneous sympathetic nerves.

A

Temperature regulation

217
Q

Changes occur when an individual moves from a supine to a standing position

A
  • significant volume of blood pools in the lower extremities because of high compliance of the veins
  • Increased local venous pressure. - > edema
  • venous return decreases - > SV and cardiac output decreases
  • Arterial pressure decreases
  • Compensatory mechanis will attempt to increase BP
    • carotid sinus baroreceptors - > decrease the firing rate of the carotid sinus nerves
218
Q

Summary of responses to standing

A
219
Q

Summary of Effects of exercise

A
220
Q

Cardiovascular response to exercise

A
221
Q

Summary of compensatory response to Hemorrhage

A
222
Q

cardiovascular response to hemorrhage

A

BRS (PHYSIO) (14 decks)

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