Midterm Flashcards
1
Q
Anion gap
A
(Na+K) - (Cl + HCO3)
2
Q
Osmolarity
A
2(Na) + 0.055(glucose) + 0.36(BUN)
3
Q
Calculating partial pressure of gas (outside body)
A
multiply % by atmospheric pressure
4
Q
PiO2
A
(760-47) x FiO2
5
Q
PAO2
A
[FiO2 x (Pb-47)] - CO2/0.8
6
Q
Total O2 content
A
(1.37 x Hbg x sat) + PO2(0.003)
7
Q
Dissolved CO2
A
PaCO2 x 0.067
8
Q
A-a gradient
A
PAO2- PaO2
9
Q
Alveolar MV
A
(TV-DS) x RR
10
Q
Calculating Dead space
A
PaCO2-EtCO2/PaCO2 (apply % to TV) or 2 mL/kg of IBW
11
Q
Compliance
A
TV/PIP-PEEP
12
Q
Calculating CO
A
HR x SV (MAP-CVP)/SVR x 80
13
Q
SV
A
EDV-ESV
14
Q
EF
A
EDV-ESV/EDV x 100
15
Q
Which has the LEAST negative threshold- SA node, neuron, or myocyte?
A
SA node
16
Q
In the SA node, what permeability do we alter to achieve threshold?
A
potassium
17
Q
What causes the plateau phase of the action potential in the myocyte?
A
influx of calcium
18
Q
normal aortic valve area
A
2.5-3.5 cm squared
19
Q
What aortic valve area is severe aortic stenosis?
A
<1 cm squared
20
Q
Normal PCWP
A
<12 mmHg
21
Q
Normal LAP
A
4-12 mmHg
22
Q
normal LV pressure
A
100-140/3-12 mmHg
23
Q
normal aorta pressure
A
100-140/60-90 mm Hg
24
Q
normal RAP
A
0-8mmHg
25
normal RV presure
15-28/0-8 mmHg
26
normal pulmonary arterial pressure
15-30/3-12 mmHg
27
normal CO
4-6 L/min
28
normal CI
2.5-4 L/min
29
Forces that push or pull fluid OUT of vessel
capillary hydrostatic, interstitial hydrostatic, interstitial oncotic pressures
30
Pressures that push/pull fluid INTO vessel
plasma oncotic pressure
31
Net pressures at arterial vs. venous side of capillary
Higher net OUT on arterial side, higher net IN on venous side
32
Valsalva Maneuver
-forced expiration against closed glottis -mediated through baroreceptors -SNS inhibited, PNS activated - decreased HR, contractility, BP, vasodilation
33
Baroreceptor Reflex
-response to stimulation/stretch of baroreceptors -afferent signal via Hering's nerve (glossopharyngeal) or vagus nerve -signal to medulla -efferent response to decrease BP (vagus) -decreased HR and SNS outflow
34
Occulocardiac Reflex
traction of EOM, conjunctiva, or orbital structures cause reflex bradycardia -treatment- remove stimulus, antimuscarinic
35
Bainbridge/atrial reflex
increase in HR due to increase in blood volume (stretch receptors in RA) -prevents sequestration of blood in veins, atria, pulmonary circulation
36
celiac reflex
traction on mesentery/gallbladder/vagus nerve stimulation causes bradycardia, apnea, hypotension -can be elicited by pneumoperitoneum
37
Cushing reflex
physiologic response to CNS ischema from increased ICP -intense vasoconstriction to restore cerebral perfusion -Cushing's triad- HTN, irregular breathing, bradycardia -may indicate herniation -may be seen after IV norepinephrine
38
Chemoreceptor reflex
sensory receptor that transduces chemical signal into action potential -central- located on medulla, stimulated by increased H -peripheral- carotid arteries, aortic arch, stimulated by decreased O2 -results in increased MV, SNS stim, increased BP
39
Bezold Jarisch reflex
- C fibers will decrease HR to allow ventricles to fill - see this when sitting patient up during/after anesthesia
40
Phase 4 of Action potential (myocyte)
resting membrane potential -K inside cell (slow leak out) -Na and Cl are outside -remain in this stage until stimulated
41
Phase 0 of Action Potential (myocyte)
rapid depolarization (fast Na channels) -rapid influx of Na into cell (more positive membrane) -gates open between -70 and -65, go up to +20 mV
42
Phase 1 of Action Potential (myocyte)
rapid repolarization -Na gates close -K gates open, K moves out -Cl influx -slow influx of Ca
43
Phase 0 &1 of action potential make up what part of the EKG?
QRS complex
44
Phase 2 of Action Potential (myocyte)
plateau phase -Na channels close (no AP at this time- absolute refractory period) -Ca influx- delays quick repolarization -K efflux
45
What does phase 2 make up on the EKG?
ST segment
46
Phase 3 of Action Potential (myocyte)
rapid repolarization -Ca channels close -K channels still open (efflux) -when Ca close, allow efflux of K to keep moving back to RMP -Na channels reset
47
What part of the EKG is phase 3 of the action potential?
T wave
48
What phase do LA's work on?
phase 4 (prevent spontaneous depolarization/Na gated channels from opening)
49
What phase do CCB's work on?
phase 2 (affect Ca channels)
50
Smooth muscle characteristics
spindle shaped, nonstriated, uninucleated, involuntary
51
Cardiac muscle characteristics
striated, branched, uninucleated, involuntary
52
Skeletal muscle characteristics
striated, tubular, multinucleated, voluntary
53
Contractile proteins of skeletal muscle
myosin, actin, tropomyosin, and troponin
54
What electrolyte disturbances cause skeletal muscle weakness?
hypocalcemia, hypermagnesemia
55
Byproducts of ACh hydrolyzation
choline and acetate (choline is repackaged)
56
NMJ Steps
1) synthesis and storage of ACh in presynaptic terminal 2) depolarization of presynaptic terminal and Ca uptake 3) Ca uptake causes ACh release into synaptic cleft 4) diffusion of ACh to postsynaptic membrane and binding of ACh to NICOTINIC receptors 5) end place potential in postsynaptic membrane 6) depolarization of adjacent muscle membrane to threshold 7) degradation of ACh
57
Intercalated Discs
Present in cardiac muscle, helps heart work in unison
58
Calcium in smooth muscle
comes from plasma/blood, not SR
59
Somatic Nervous System NT
ACh- always stimulatory
60
NT of ANS
preganglionic- ACh postganglionic- ACh (PNS) or NE (SNS)
61
SNS fiber/ganglia characteristics
-origin of fibers- thoracolumbar (T1-L2) -short pre, long post -ganglia close to spinal cord
62
PNS fiber/ganglia characteristics
-origin of fibers- craniosacral -long pre, short post -ganglia in visceral effector organs
63
Accelerator Fibers (SNS)
T1-T4
64
CN of PNS
3,5,9,10
65
Phases of LV Pressure Volume Loop
Isovolumetric Contraction Ejection Isovolumetric Relaxation Diastolic Filling
66
Aortic Regurgitation
67
Aortic stenosis
68
Mitral regurgitation
69
Mitral stenosis
70
Central Chemoreceptors
- located on medulla
- respond to changes in H or CO2 (increase stimulates ventilation)
- surrounded by brain ECF
71
Peripheral Chemoreceptors
- Located in carotid bodies (glossopharyngeal) and aortic bodies (vagus)
- sense decrease in pO2 and pH (increased pCO2) of arterial blood
- responds intensely to paO2 below 100 mmHg
- responsible for all increase in ventilation due to arterial hypoxemia (\<60mmHg)
72
Intrapleural pressure
- between parietal and visceral pleura
- normally negative (becomes more negative with inspiration)
- becomes positive with forced expiration or Valsalva
73
intrapulmonary pressure
- zero (same as atmospheric pressure) at end expiration
- becomes more negative during inspiration
74
Contributors to Stroke Volume
- proload (tension on ventricle at end of diastole)
- afterload (wall tension the myocardium needs to overcome to eject SV- pressure within LV during peak systole)
- mycoardial contractility- state of inotropy independent of preload and afterload
75
What determines coronary artery dominance?
Crux (where coronary and posterior interventricular sulcus meet)
majority of population is RCA dominant
76
L main coronary artery
- emerges from behind pulmonary trunk
- divides into LAD, L CFX, diagonal branch
77
L anterior descending coronary artery
multiple branches -anterior 2/3 of interventricular septum, R and L bundle branches, papillary muscles of mitral valve and anterior lateral and apical walls of LV
78
Left circumflex artery
- travels posteriorly around L heart
- multiple branches, may include sinus node artery
- supplies LA wall, posterior lateral LV, anterolateral papillary muscle, AV node, SA node
79
Right coronary artery
- supplies SA and AV nodes, RA and RV, posterior 1/3 of interventricular septum, posterior L bundle, interatrial septum
- in 90% of pop, it travels from R coronary sinus to right AV groove, to crux and onto posterior AV groove
- multiple branches- sinus node artery, AV node artery, proximal bundle branches, posterior descending artery, LA/LV terminal branches
80
Coronary Sinus
- located in posterior AV groove near crux
- collects 85% of blood from LV, drains into LA
- cath for LV studies
- may be cannulated during bypass to delivery cardioplegia
81
Anterior cardiac veins
- 2-4 veins drain anterior RV wall
- drain into RV directly or into coronary sinus
82
Thebesian veins
- transverse myocardium and drain into RA, RV, LV
- may carry 40% of blood returned to RA
83
Nicotinic Receptors
- MUSCLES, all ganglionic neurons
- effect of ACh is always STIMULATORY
84
Muscarinic Receptors
- found in PNS target organs
- ACh is either inhibitory (cardiac) or excitatory
85
Beta 1 Receptors
- heart, kidneys
- NE binding increases HR/strength, stimulates renin release
86
Beta 2 receptors
- lungs, other sympathetic target organs
- NE binding is inhibitory- dilates BV and bronchioles, relaxes smooth muscle
87
Alpha 1 receptors
- found in blood vessels, sympathetic target organs
- NE binding constricts vessels, sphincters, pupil dilation
88
Alpha 2 receptors
- found on membrane of adrenergic axon terminals, pancreas, platelets
- NE binding inhibits NE release- inhibits insulin secretion, promotes blood clotting
89
Increased plasma osmolarity triggers?
thirst mechanism
90
Osmosis
- movement of WATER across SPM (solutes do not move)
- H2O moves from low solute concentration to high solute concentration
91
What are the sensors of the respiratory control system?
chemoreceptors, baroreceptors, lung stretch receptors
92
What is the central controller of the respiratory control system?
brain (pons, medulla)
93
What are the effectors of the respiratory control system?
muscles of respiration
94
Major output of central control (respiratory control system) occurs through what nerve?
phrenic (C3-5)
95
What are the affector nerves for the respiratory control system?
vagus, glossopharyngeal
96
Pneumotaxic Center
- located in pons
- fine tunes breathing (controls volume and rate)
- inhibits inspiration
97
Apneustic Center
- located in pons
- prolonged inspiratory gasps (brain injury)
- excitatory effect on inspiration
98
Dorsal Respiratory Group (DRG)
- located in medulla
- intrinsic periodic firing
- basic rhythm of ventilation
- can be overriden by pneumotaxic center
99
Ventral respiratory group (VRG)
- located in medulla
- usually not active during normal breathing
- more active with forceful breathing
100
Surfactant
- made by alveolar type II cells
- decreases surface tension
101
Law of Laplace
P= 2T/R (for sphere)
102
P50
partial pressure where 50% of Hgb is saturated (usually around 27 mmHg)
103
Shifting of Oxyhemoglobin Dissociation Curve
Right- O2 affinity for Hgb reduced (O2 unloads easier)
* caused by increased H, PCO2, temp, 2-3 DPG
Left- increased affinity for Hgb (less unloading)
* caused by decreased temp, H, PCO2, 2-3 DPG
104
What PO2 is required to achieve a sat of 90% normally?
60 mmHg
105
Bohr effect
- change in PCO2 affects O2 dissociation curve
- curve shifts to the left into lungs (facilitate O2 loading)
106
Haldane Effect
- change in PaO2 affects CO2 dissociation curve
- at tissue, O2 diffuses into tissues so CO2 affinity increases for loading
- at lungs, O2 diffuses from alveoli into blood- CO2 curve shifts to R to facilitate unloading
107
Hypertonic volume expansion (3% admin)
108
Hypotonic volume expansion (SIADH)
109
Isotonic volume loss (diarrhea)
110
Isotonic volume expansion (0.9 admin)
111
Static Volumes (Lungs)
TV, RV, ERV, IRV, CV
112
Dynamic Lung Volumes
FEV1, FVC, FEV1/FVC
113
Tidal volume
- normal volume of breathing
- 6 mL/kg of IBW
114
Residual Volume
air left after maximal expiration (1200 mL)
115
Expiratory Reserve Volume
maximum air from end of normal inspiration to maximal expiration (1100 ml)
116
Inspiratory Reserve Volume
maximum inspired air from rest (3000 mL)
117
Closing Volume
volume at which alveoli close at end expiration (normally above residual volume)- absolute voluem of gas in lungs when small airways close
-increases with age, may exceed FRC in supine position
118
FEV1
forced expiratory volume in one second
-normal 4L
119
FVC- forced vital capacity
volume of gas that can be exhaled forcefully
-normal 5 L
120
FEV1/FVC
ratio of parameters that allows distinction of obstructive vs. restrictive lung disease
- normal is 0.8
- restrictive lung disease may have normal ratio (both parameters decreased)
121
Zone 1 of Lung
- top
- minimal blood flow
- ventilated but not perfused (alveolar dead space)
- PA\>Pa\>Pv
122
Zone 2 of Lung
- waterfall zone
- blood flow determined by difference between arterial and alveolar pressures
- Pa\>PA\>Pv
123
Zone 3 of lung
- blood flow determined by arterial-venous gradient
- continuous blood flow
- where tip of PA cath should be
- Pa\>Pv\>PA
- greatest compliance
124
Zone 4 of lung
- PATHOLOGICAL
- present with pulmonary edema
- low lung volumes, reduced blood flow
- Pa\>Pi\>Pv\>PA
- Pi is interstitium pressure
125
What is on the x and y axis of the flow volume loop?
y- flow (L/sec)
x- volume
126
Normal flow volume loop
127
Fixed upper airway (kinked ETT)
128
Obstructive lung disease
129
Restrictive Lung Disease
130
Semilunar valves
aortic and pulmonic (each have 3 cusps)
131
AV valves
tricuspid (R side, 3 leaflets)
mitral (L side, 2 leadflets)
132
Inferior EKG leads
II, III, aVF
RCA
133
Anteroapical EKG leads
V3 and V4
distal LAD
134
Anteroseptal EKG Leads
V1, V2
LAD
135
Anterolateral EKG Leads
I, aVL, V5, V6
Circumflex artery
136
Extensive Anterior EKG Leads
I, aVL, V2-V6
proximal LCA
137
True Posterior EKG leads
Tall R in V1
RCA
138
Average Total Blood Volume
5 L
139
What % of blood volume is RBCs?
40% or 2 L
140
What % of blood volume is water?
60% or 3 L
141
Variations in age with water content
babies- more water
elderly- less water (less muscle mass)
142
Norepinephrine synthesis
143
How is NE removed from the synpase?
reuptake or metabolized by MAO and COMT
144
NE metabolites
DOMA, NMN, MOPEG, VMA
145
Where is NE synthesized?
nerve terminal
146
Which has a longer effect, NE or ACh?
NE- takes longer to metabolize
reuptake is how its action is stopped
147
Limb placements for Einthoven's triangle
RA (-/-)
LA (+/-)
LL (+/+)
148
Lead Directions
149
Which lead follows the electrical direction of the heart?
Lead II
150
Layers of Pericardium
visceral- covers outer surface of heart
parietal- outer layer
normally 10-25 mL of serous fluid of between
151
Layers of Cardiac Musculature
epicardium- outermost layer
myocardium- middle/muscle layer- pumping action
endocardium- thin, innermost layer
152
Simple Diffusion
- passive transport
- nonpolar lipid soluble substances diffuse directly through phospholipid bilayer (gradient)
153
Facilitated Diffusion
- passive process
- certain lipophobic molecules (glucose, amino acids, ions) use carrier proteins or channel proteins
- proteins are selective, saturable, and can be regulated in terms of activity/quantity
154
Is coronary blood flow continuous or noncontinuous?
Non-continuous
155
Functional Residual Capacity (FRC)
air left after normal expiration
RV+ERV
2300 mL
reservoir for O2
156
Vital Capacity
maximal inspiration followed by maximal expiration
(IRV+TV+ERV)
4500 mL
157
Inspiratory Capacity
IRV+TV
3500 mL
158
Total Lung Capacity (TLC)
volume in lungs after maximal inspiration
IRV+TV+ERV+RV
5800 mL
159
Hypoxic Pulmonary Vasocontriction
determined by ALVEOLAR PO2
inhibition of nitric oxide pathway
shunts blood away from hypoxic areas
160
Nitric Oxide effects on pulmonary vasculature
- relaxing factor
- increases cGMP- smooth muscle relaxation
- disruption can lead to pulmonary HTN
161
Prostacyclin effects on pulmonary vasculature
- vasodilator
- activates adenyl cyclase
- inhibits platelet aggregation
162
Pulmonary vasoconstrictors
- endothelin 1
- thromboxane 2
