Physiology Flashcards

1
Q

Tissues layers in Heart

A

endocardium - inner lining of chamber

epicardium - outer lining of chambers

pericardiu, - surrounds entire heart (composed of visceral and parietal layer)

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2
Q

Papillary muscules

A

attach to AV valves via chordae tendinae

  • do not help close the valves
  • help in prevevnting regurgitation into atria
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3
Q

mitral valve closes at the beginning of ______

A

isovolumetric contraction

(ventricular systole)

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4
Q

Intracellular [K+]

A

140

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5
Q

Extracellular [K+]

A

4

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6
Q

Nersnt equilibrium potential of K and Na

A

K+ = -90

Na+ = +70

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7
Q

Intracellular [Na+]

A

10

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8
Q

Extracellular [Na+]

A

140

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9
Q

Na+-K+-ATPase pump

A

maintains negative potential

3 Na out for 2 K in

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10
Q

Na+-H+ exchanger

A

regulates intracellular pH

H+ out and Na+ in

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11
Q

Cardiac Action Potential

[phase 0]

A

activation of fast Na+ channels (iNa)

  • increases membrane conductance 100x
  • generates inward current
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12
Q

Cardiac Action Potential

[phase 1]

A

inactivation of iNa and activation of transient outward K current (iTO)

  • decreases membrane potential which favors Ca2+ entry
  • influences plateau length
    • more K efflux = shorter plateau phase
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13
Q

Cardiac Action Potential

[phase 2]

A

opening of L-type Ca2+ channels (iCa-L) and Na-Ca exchanger

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14
Q

Cardiac Action Potential

[phase 3]

A

opening of delayed rectifier K (iKV)

  • increased K+ conductance
  • size of current determines plateau duration
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15
Q

Cardiac Action Potential

[phase 4]

A

“pacemaker potential”

  • small Na+ current (ib) and inward rectifier (Kir)
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16
Q

inward rectifier K+ channel (iK1)

A

maintains high K+ permeability during phase 4

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17
Q

fast Na+ voltage channel

A

accounts for phase 0

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18
Q

L-type Ca2+ channel

A

responsible for phase 2

  • enhanced by sympathetic stimulation and Beta agonists
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19
Q

Ca-ATPase

A

sequesters calcium back into SR

  • regulated by phospholamban (inhibitor)
  • catecholamines decrease inhibitor effect
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20
Q

absolute refractory period

[during which phases]

A

0, 1, 2, and 3

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21
Q

chronic heart failure

[ion channels]

A

decreased K+ (iTO) expression

  • delays repolarization, prolongs plateau, and arryhthmogenic
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22
Q

Long QT syndrome

[ion channel]

A

abnormality of delayed rectifier channel (iK)

  • prolongs plateau and results in Ca2+ overload after depolarization
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23
Q

Early After Depolarizations

A

secondary depolarizations that occur before the end of phase 3

  • increased frequency with slow heart rate
  • may lead to Torsades de pointes
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24
Q

Purkinje cells

[beats per minute]

A

15

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25
Q

AV node

[beats per minute]

A

50 - 60

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26
Q

SA node

[beats per minute]

A

70 - 80

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27
Q

Pacemaker Action Potential

[which phases are not involved?]

A

pacemaker action potentials do not include phase 1 and 2

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28
Q

chronotropy

A

increase heart rate

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29
Q

dromotropy

A

increase AV node conduction

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30
Q

inotropy

A

increased contractility

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31
Q

lusitropy

A

increased rate of myocyte relaxation

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32
Q

Phosphodiesterase Inhibitors

[effects]

A

inotropy and chronotropy

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33
Q

Phosphodiesterase Inhibitor

[examples]

A

caffeine, theophylline, milrinone, and amrinone

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34
Q

Muscarinc M1 Receptor

[location]

A

cortex and hippocampus

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35
Q

Muscarinic M2 Receptors

[location]

A

heart

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36
Q

Muscarinic M3 Receptors

A

exocrine glands and GI tract

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37
Q

Muscarinic M4 Receptor

[location]

A

neostriatum

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38
Q

Muscarinic M5 Receptor

[location]

A

substantia nigra

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39
Q

Hypocalcemia

[effects]

A

prolonged QT interval

  • possible result is EAD and torsades
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40
Q

Hypocalcemia

[possible causes]

A

loop diuretics

osteomalacia

hypoparathyroid

respiratory alkalosis

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41
Q

Hypercalcemia

[effects]

A

shortens QT interval

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42
Q

Hypercalcemia

[causes]

A

adrenal insufficiency

hyperparathyroid

kidney failure

malignancy

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43
Q

Hyperkalemia

[effects]

A

wide QRS and peaked T waves

  • hyperkalemia decreases equilibrium potential and closes Na+-voltage channels
    • wide QRS
  • enhanced K+ channel activity
    • peaked T-waves
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44
Q

Hyperkalemia

[causes]

A

potassium-sparing diuretics

ACE inhibitors

metabolic acidosis

MH

blood transfusions

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45
Q

Hypokalemia

[effects]

A

wide QRS with U-wave

  • reduces K+ channel activity
    • prolongs plateau and repolarization
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46
Q

Temperature’s effect on HR

A

Hyperthermia: increase 10 bpm per 1oC

Hypothermia: conduction slows and ST segment elevates; J or Osnorne wave

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47
Q

Ivabradine

A

funny channel blocker (if)

  • decreases rate of pacemaker decay
    • decreases HR
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48
Q

Adenosine

A

activates A-1 Receptors

  • slows AV conduction and slows HR
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49
Q

Bainbridge Reflex

A

increased CVP → stretch and increased HR

  • detected by baroreceptors
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50
Q

Spontaneous Ventilation effect on HR

A

Inhalation: decreases intrathoracic pressure and increases venous return (increases HR) via bainbridge reflex

Exhalation: increased pressure activates baroreceptor reflex to decrease HR

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51
Q

Beta-Blocker

[overdose treatment]

A

glucagon

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52
Q

cardiac myocytes resting membrane potential

A

about -90 mV

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53
Q

p-wave

[electrical event]

A

altrial repolarization

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54
Q

PR interval

[electrical event]

A

delay of conduction by the AV node

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55
Q

T-wave

[electrical event]

A

ventricular repolarization

phase 3

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56
Q

QT interval

[electrical event]

A

ventricle depolarization and repolarization

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57
Q

Bazett’s Formula

A

QTc = QT/sqrt(RR)

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58
Q

p-wave

[normal time]

A

0.08 - 0.12

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59
Q

PR interval

[normal time]

A

0.12 - 0.20

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60
Q

QRS complex

[normal time]

A

0.06 - 0.11

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61
Q

Horizontal plane leads

A

V1 - V6

  • view across horizontal plane
  • each lead is positive
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62
Q

Bipolar leads

A

Lead I - III

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63
Q

Unipolar leads

A

aVr, aVL, aVf

  • amplify the voltage of waves in Leads I - III
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64
Q

V1

[location]

A

right side of sternum

4th intercostal

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65
Q

V2

[location]

A

left side of sternum

4th intercostal

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66
Q

V4

[location]

A

left midclavicular line

5th intercostal

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67
Q

V5

[location]

A

left anterior axillary

5th intercostal

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68
Q

V6

[location]

A

left mid-axillary line

5th intercostal

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69
Q

which leads correspond to the high lateral wall?

A

Leads I and aVL

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70
Q

which leads correspond to the inferior wall?

A

Leads II, III and aVF

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71
Q

which leads correspond to the septal wall?

A

Leads V1 and V2

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72
Q

which leads correspond to the anterior wall?

A

Leads V3 and V4

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73
Q

which leads correspond to the lateral wall?

A

Leads V5 and V6

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74
Q

Junctional Rhythm

[heart rate]

A

40 - 60 bpm

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75
Q

Ventricular Escape Rhythm

A

20 - 40 bpm

  • esentially regular
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76
Q

(3) mechanisms associated with tachy-arrhythmias

A

enhanced automaticity

triggered automaticity

re-entry

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77
Q

QT interval

[normal time]

A

0.45 in men and 0.46 in women

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78
Q

normal heart axis

A

-30o to +90o

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79
Q

[axis of heart]

If QRS is positive in Lead I and aVF

A

normal

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80
Q

[axis of heart]

If QRS is negative in Lead I, but positive in aVF

A

right axis deviation

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81
Q

[axis of heart]

If QRS is positive in Lead I, but negative in aVF

A

LAD

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82
Q

sinus node

[location]

A

lateral edge of right atrium

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83
Q

First degree heart block

A

prolonged PR interval

(greater than 0.2 seconds)

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84
Q

Second Degree - Type I

A

progressive prolongation of the PR interval followed by a droped QRS

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85
Q

Second Degree - Type II

A

dropped QRS not preceded by PR prolongation

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86
Q

Third Degree Heart block

A

atria and ventricular rhythms are independent

  • no impulses are transmitted through the AV node
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87
Q

Right Bundle Branch Block

A

due to myocardial infarction of the Purkinje system

  • rabbit ears on V1
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88
Q

Tri-fascicular Block

A

first degree AV block

RBBB

and LAFB or LPFB

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89
Q

Atrial Fibrillation

A

loss of synchrony during excitation and resing phases

  • ventricular irregularly irregular rhythm
  • greater than 300 bpm
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90
Q

Atrial Flutter

A

re-entry circuit in the right atrium

  • 240-340 bpm
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91
Q

Wolf Parkinson White

A

accessory pathway (bundle of Kent)

  • contains delta wave and short PR interval
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92
Q

Bowditch Effect

A

increased HR causes increased contractility

  • due to increase SR calcium store
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93
Q

Extracellular

[composition]

A

3L of plasma

and

12L interstitial fluid

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94
Q

“conduit vessels”

A

arteries

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95
Q

“resistance vessels”

A

arterioles

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96
Q

“exchange vessels”

A

capillaries

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97
Q

“capacitance vessels”

A

veins

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98
Q

which electrolytes are higher interstitially?

A

Na+ and Ca2+

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99
Q

which electrolyte is higher intracellularly?

A

K+

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100
Q

Heart sounds

[S1]

A

begining of systole due to AV valve closure

  • best heart at apex
  • during isovolumetric contraction
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101
Q

Heart Sounds

{S2]

A

closing of semilunar valves beginning at diastole

  • isovolumetric relaxation after T-wave
  • inspiration will “split” sound
102
Q

Heart Sounds

[S3]

A

ventricular gallop

  • occurs after S2
  • rush of blood into ventricles during diastole
103
Q

Heart Sounds

[S4]

A

atrial gallop

  • atrial contraction and rapid filling
  • often indicates ventricular diastole stiffness
104
Q

dicrotic notch

A

closure of aortic valve

105
Q

Fick’s Equation

[in relation to Cardiac Output]

A

Q = (total O2 consumption rate) / ([arterial O2] - [venous O2])

106
Q

Ejection Fraction

[equation]

A

stroke volume / EDV

107
Q

Right coronary artery

[branches into _____ and _____)

A

posterior descending and right marginal

108
Q

left coronary artery

[branches into _____ and _____)

A

left anterior descending and circumflex

109
Q

Thebesian vein

A

empties venous blood into the oxygenated blood of the left atrium

110
Q

(3) veins that empty directly into chambers

A

arteriosinusoidal, anterioluminal, and thebesian

111
Q

Diastolic pressure

[definition/event]

A

pressure once the semilunar valves are closed and the ventricle is filling

112
Q

Contractile elements of the myocye

A

actin = thin filaments

myosin = thick

calcium binds to sites on actin, revealing a binding site that allows myosin head to attach

113
Q

Tunica adventitia

A

connective tissue of blood vessel

  • contains vaso vasorum
114
Q

tunica media

A

smooth muscle fibers and elastic lamina

115
Q

tunica interna

A

single layer of squamous epithelium

116
Q

Vaso Vasorum

A

network of small blood vessels that supply the walls of large blood vessels (aorta and vena cava)

117
Q

how much blood volume is contained within the venous system?

A

65%

118
Q
A
119
Q

aorta

[cross sectional area]

A

2.5 cm2

120
Q

largest external vein

A

great saphenous

121
Q

what vessel is responsible for draining the majority of blood from the brain?

A

internal jugular

122
Q

TCVC

A

Tunneled Central Venous Catheter

123
Q

Tunneled Central Venous Catheter

A

Hickman or Broviac

  • used for drawing blood, chemotherapy, IV fluids, blood transfusions, or IV nutrition
124
Q

Port-a-Cath

A

plastic or metal port under the skin which is connected to a central line

  • used for chemotherapy or IV treatments
125
Q

Permacath

A

hemodialysis catheter

126
Q

Greenfield Filter

A

placed in femoral vein and floated into inferior vena cava which prevents emboli from entering the heart

127
Q

(3) plasma proteins produced by the liver

A

albumin, globulin, and fibrinogen

128
Q

Diffusion coefficient for O2

A

0.0031

129
Q

diffusion coefficient for CO2

A

0.0642

130
Q

red blood cell

[life span]

A

120 days

131
Q

(6) types of anemia

A
  • hemorrhagic
  • pernicous
  • folate-deficiency
  • iron-deficiency
  • hemolytic
  • aplastic
132
Q

Osmotic Pressure

[definition]

A

across cell membranes due to ion concentrations

133
Q

Oncotic Pressure

[definition]

A

across capillary membranes due to large protein molecules

134
Q

Granulocytes

[types]

A

neutrophils, eosinophils, and basophils

135
Q

Basophils

A

essentially mast cells

(histamine)

136
Q

which leukocyte participates in fibrin degredation?

A

neutrophils

137
Q

Prothrombin Time

[test]

A

time to clot after adding thromboplastin and Ca2+

138
Q

blood product to reverse warfarin therapy

A

fresh frozen plasma

139
Q

Cholinergic Receptors

[Types]

A

nicotinic and muscarinic

140
Q

which type of choinergic receptor involves a G-protein cascade?

A

muscarinic

141
Q

parasympathetic effect on the conduction system

A

causes hyperpolarization and therefore longer to reach threshold

142
Q

murmur type

[systolic ejection]

A

aortic stenosis

143
Q

murmur type

[pan-systolic]

A

mitral regurgitation

144
Q

murmur type

[late systolic with click]

A

mitral prolapse

145
Q

murmur type

[early diastolic decrescendo]

A

aortic regurgitation

146
Q

murmur type

[mid diastolic decresendo-crescendo]

A

mitral stenosis

147
Q

murmur type

[continuous]

A

patent ductus arteriosus

148
Q

what two factors affect the size of a pressure-volume loop?

A

volume and resistance to ejection

149
Q

what (2) factors affect the shape of the pressure-volume loop

A

contractility and compliance

150
Q

mean circulatory filling pressure

[definition]

A

force exerted on blood by elastic blood vessels

  • when MCRP = right atrial pressure, venous return stops
151
Q

elderly patients generally have an _____ systolic pressure

A

over-estimated

152
Q

Central venous pressure

[normal value]

A

1 - 7 mmHg

153
Q

(2) organs where consumption is greater than distribution of cardiac output

A

heart and brain

154
Q

(2) organs where distribution of CO is greater than consumption

A

skin and kidneys

155
Q

myogenic response

A

stretch induces depolarization and opens smooth muscle Ca2+ channels

leads to vasoconstriction

156
Q

Endothelin

[effects]

A

vasoconstriction

  • released by shearing forces and Angtiotensin II
157
Q

(4) main influences on vensou return

A

sympathetic stimulation

posture

skeletal muscle pump

ventilation

158
Q

lymphatic system

[pathway]

A

lymph capillaries

collecting lymphatics

afferent lymphatics

lymph nodes

cysterna chyli

Thoracic duct

SCV

159
Q

How does the heart compensate for an increase in oxygen demand?

A

increasing blood flow

160
Q

the hepatic portal vein produces ____% of the liver’s blood

A

70%

161
Q

chemoreceptor location

A

carotid body and aortic arch

162
Q

baroreceptor location

A

carotid sinus and aorti arch

163
Q

Baroreceptor Reflex

A

baroreceptors sense an increased MAP

afferent signals to medulla

medulla inhibits SNS and promotes PNS

164
Q

which two hormones are activated by changes in blood pressure by the SNS?

A

vasopressin and aldosterone

165
Q

Cushing Reflex

A

increased contractility, bradycardia, irregular breathing, and MAP from activating SVS

due to cerebral ischemia caused by increased ICP

166
Q

aortic and carotid body chemoreceptors

[sense]

A

hypoxia, hypercarbia, and acidosis

167
Q

effets of aortic and carotid body chemoreceptors

A

increase in ventilation

vasoconstriction of splanchnic and skeletal muscle

tachycardia

168
Q

Brachiocephalic artery

[a.k.a.]

A

innominate

169
Q

which layer of a blood vessel secretes vasoactive agents?

A

intima

170
Q

systemic resistance

[mmHg/mL/min]

A

0.02

171
Q

pulmonary resistance

[mmJg/mL/min]

A

0.003

172
Q

CVP waveform

[a wave]

A

atrial systole

173
Q

CVP waveform

[c wave]

A

bulging of tricuspid valve

174
Q

CVP waveform

[v wave]

A

passive filling of the atria

175
Q

CVP waveform

[x descent]

A

atrial relaxation

176
Q

CVP waveform

[y descent]

A

AV valve opens

177
Q

What is the effect of hyperkalemia on the resting membrane potential

A

will decrease concentration gradient

closer to threshold

178
Q

KATP channels

A

open during ischemia

shortens plateau phase causing less contraciton to decrease the work of the heart and decrease O2 consumption

179
Q

Digitalis

[negative effects]

A

inhibits Na-K pump causing a buildup of Na intracellularly

  • causes Ca to accumulate inside the cell
  • higher resting membrane potential
  • slower rise of phase 0
  • shorter refractory period
180
Q

where in the conduction pathway is the fastest transmission?

A

purkinje fibers

181
Q

what is more tonically active in the heart, SNS or PNS?

A

PNS

182
Q

describe the cascade following activation of PNS M2 receptor

A

Gi activated which inihibits adenylene cyclase

hyperpolarizes cell membrane by opening KAch

183
Q

which electrolyte imbalance will cause peaked T-waves

A

hyperkalemia

184
Q

which electrolyte abnormality will cause U-waves to appear

A

hypokalemia

185
Q

how much time does each square represent on an EKG?

A

0.2 seconds for each large square

(0.5 mV on y-axis)

186
Q

what may cause a left axis deviation?

A

laying down, deep exhalation, and diaphragm displacement

187
Q

(6) factors that increase Preload

A
  • ventricular failure
  • decreased heart rate
  • increased afterload
  • decreased inflow resistance
  • increaed CVP
  • increased ventricular compliance
  • increased atrial contractility
188
Q

Glycocalyx

A

thin layer of negatively charged albumin molecules that determine overall permeability

189
Q

What are the endothelium channels responsible for the increase in intracellular Ca2+

A

receptor operated channels (ROC)

store operated channels (SOC)

KCa channels

190
Q

KCa channels

A

potassium channels activated by Ca2+ to hyperpolarize the membrane and allowing more calcium to enter

191
Q

how does nitric oxide cause vasodilation

A

activates cGMP through guanylyl cyclase

high [NO] directly activates BKCa channels of vascular myocyte causing hyperpolarization

192
Q

main difference between capillary and cell membranes

A

cell membrane is not permeable to electrolytes

193
Q

normal body osmolarity

A

280

194
Q

D5W osmolarity

A

252

195
Q

LR osmolarity

A

273

(closes to normal body osmolarity)

196
Q

hetastarch osmolarity

A

310

197
Q

normal saline osmolarity

A

308

198
Q

albumin osmolarity

A

330

199
Q

hyperosmolar will draw fluid _____ intracellular space

A

out

200
Q

Albumin

[risks]

A

anaphylactoid reaction

HIV and hepatitis

Creutzfeldt-Jakob

201
Q

cardiac cell refractory period is determined by the reactivation of which ion channel

A

Sodium

202
Q

Calcium conductance is highest during which phase of the cardiac action potential in ventricular muscle?

A

phase 2

203
Q

Stimulation of the adrenergic receptors on the pacemaker cells of the heart increases in the membrane conductance to:

A

calcium

204
Q

Conduction velocity is the slowest in the heart through the _____

A

AV node

205
Q

stimulation of the vagus nerve causes _____

A

an increased resting potential

(hyperpolarizes)

206
Q

the precordial leads are _____

A

leads V1 - V6

207
Q

T-wave on an EKG represents

A

ventricular repolarization

208
Q

Effects of hypokalemia on EKG

A

U-wave

reduces K permeability

flattening of T-wave

209
Q

how is the QRS affected in a bundle branch block

A

prolonged

210
Q

A decrease in contractility will shift the Starling’s curve to the _____

A

right

211
Q

Y-axis variables on the Starling curve

A

contractile force

ventricular systolic pressure

stroke volume

stroke work

212
Q

_____ begins when the mitral valve opens

A

rapid ventricular filling

213
Q

____ ends with the highest left atrial pressure

[cardiac cycle event]

A

isovolumetric relaxation

214
Q

the R wave of the ECG coincides with the beginning of _____

A

isovolumetric contraction

215
Q

the period with the greatest rise in left ventricular pressure

A

isovolumetric contraction

216
Q

the fourth heart sound occurs in this period

A

atrial systole

217
Q

arterial compliance _____ with age

A

decreases

218
Q

In an individual with constant CO and total peripheral resistance, an increase in arterial compliance will _____ pulse pressure

A

decrease

219
Q

A B2 adrenoceptor antagonist would block which of the following events mediated by norepinephrine?

A

bronchiole relaxation

220
Q

end organs innervated by post-ganglionic parasympathetic fibers have _____ receptors

A

M

221
Q

resistance vessels have more _____ than similar sized capacitance vessels

A

smooth muscle

222
Q

In fast response cardiac action potentials, iK1 turns off during _____ and is reactivated during ____

A

phase 0

reactivated during phase 3

223
Q

post-repolarization refractoriness is due to slow recovery of _____

A

calcium channels

causes a protective effect in a-fib

224
Q

a drug which decreases heart rate could do so by decreasing _____

A

iF

225
Q

cardiac contractility is increased by inhibiting the _____

A

Na-K pump

226
Q

In which phase of the cardiac cycle is both the mitral valve open and ventricular pressure falling

A

rapid ventricular filling

227
Q

Aortic Stenosis

[triad of symptoms]

A

syncope, angina, and dyspnea

228
Q

aortic stenosis

[physical findings]

A

pulsus parvus et tardus

systolic ejection murmur

paradoxically split S2

229
Q

Split S2

[causes]

A

severe aortic stenosis

LBBB

hypertrophic cardiomyopathy

230
Q

TAVR

A

Transcatheter Aortic Valve Replacement

231
Q

Dihydropyridines

A

vascular smooth muscle selective

decrease SVR by vasodilation

amlodipine, nicardipine, nifedipine

232
Q

Phenylalkylamines

A

selective for myocardium

decrease oxygen demand and HR

Verapamil

233
Q

Hierarchy of Vascular Control

A

1st: (lowest) myogenic response
2nd: intrinsic regulatory chemicals
3rd: extrinsic regulation

234
Q

all nitrates provide venous dilation, which one also provides arterial dilation?

A

sodium nitroprusside

235
Q

what blocks your endothelin Eta receptor, preventing vasoconstriction?

A

bosentan

236
Q

Traube-Hering Waves

A

changes in MAP due to oscillations in sympathetic drive

BP decreases on inhalation

237
Q

Mayer Waves

A

driven by resonance in baroreceptor reflex

BP oscillates at 6 per minute

238
Q

Triple response of Lewis

A

cutaneous reaction

red - flare - wheal

239
Q

what recieves afferent information from sensory receptors?

A

nucleus tractus saltarious

240
Q

Metabolic Syndrome

A

risk factors that together increase risk for IHD or stroke

  • abdominal obesity
  • TG > 150
  • HDL < 40
  • fasting glucose > 100
  • hypertension > 130
241
Q

gold standard for diagnosing CAD

A

cardiac catheter

242
Q

what adenosine receptor causes coronary vasodilaton?

A

A2A

243
Q

What are some drugs used in a pharmacological stress test?

A

Adenosine

Dobutamine

Dipyrdamole

Regadenosine

244
Q

Enzymes for diagnosing MI

A

CK-MB > 5% peaks within 24 hours

Troponin persists for 7 days

245
Q

when doing a PCI, what should your door to balloon time be?

A

90 minutes

246
Q

Takotosubo

“broken heart syndrome”

A

apical ballooning cardiomyopathy

due to stress

247
Q

Phase I of valsalva maneuver

A

increased intrathoracic pressure

increased aortic pressure

baroreflex mediated and decrease HR

248
Q

Phase II of valsalva maneuver

A

increased intrathoracic pressure

decreases venous return and preload

decreased CO and MAP

baroreflex increased HR and SVR

249
Q

Phase III of valsalva maneuver

A

valsalva ends, normal breathing

decreased intrathoracic pressure

baroreflex increase HR

250
Q

Phase IV of valsalva maneuver

A

results in increased MAP and decreased HR

251
Q

3 drugs to avoid in aortic stenosis

A

nitrates

over diuresis

vasodilators

252
Q
A