Respiratory Physiology Intro Flashcards
(121 cards)
1
Q
What are the four purposes of pulmonary system?
A
supply O2/remove CO2
maintain acid/base
phonation
pulmonary defence
2
Q
Partial pressure of gases at 1 atmosphere
A
O2: 160 mmHg
N2: 600 mmHg
CO2: 0.3 mmHg
H2O: 3 mmHg
3
Q
What does anaerobic metabolism yield?
A
2 ATP, pyruvate, and lactic acid
4
Q
Where does anaerobic metabolism occur?
A
glycolysis occurs in the cytoplasm
5
Q
Where does aerobic metabolism occur?
A
The mitochondria
6
Q
What does aerobic metabolism yield?
A
38 ATP, CO2, water, heat
7
Q
What innervates the cricothyroid muscle?
A
SEM (SLN external motor)
8
Q
What innervates the majority of the larynx motor?
A
RLN
9
Q
What innervates the sensory (VC and above)
A
SLN (internal)
10
Q
What innervates the sensory (VC and below)
A
RLN
11
Q
Abduction of vocal cords
A
Posterior CricoArytenoid (please come apart)
12
Q
Adduction of vocal cords
A
Lateral CricoArytenoid (let’s close airway)
13
Q
Relaxation vocal cords
A
ThyroaRytenoid (they relax)
14
Q
Tension of vocal cords
A
CricoThyroid (cords tense)
15
Q
What is the degree of angle for right bronchus?
A
25
16
Q
What is the degree of angle for the left bronchus?
A
45
17
Q
What % of TLC is the right lung?
A
55% and it is 3 lobes
18
Q
What % of TLC is the left lung?
A
45% and it is 2 lobes
19
Q
How many generations do the lungs have?
A
20-25 generations (bifurcations) with 10 bronchopulmonary segments
20
Q
What is the conducting zone?
A
Generation 0 - 16
Trachea –> Bronchi –> Bronchioles –> Terminal Bronchiol
NO GAS EXCHANGE
Goblet cells here
21
Q
What is the respiratory/transitional zones?
A
Respiratory bronchioles –> Ducts –> Sacs
22
Q
Phrenic nerve innervation
A
C3, C4, C5 nerve roots bilaterally
23
Q
Muscles for inspiration
A
Diaphragm, external IC (forced)
24
Q
Muscles for expiration
A
passive
forced: internal IC, abdominal muscles
25
What are the three types of pneumocytes?
Type I: structural
Type II: surfactant producing
Type III: Macrophages (alveolar) monocyte that moved into tissue conducting airways
26
How many alveoli do humans have? What is their surface area?
300 million; 60 - 80 m^2
27
What is the distance from the front incisors to the carina?
26 cm (13 from teeth to larynx; 13 from larynx to carina)
28
What are the type of cells in the conducting zone?
Pseudostratified ciliated epithelium --> ciliated columnar epithelium --> cuboidal epithelium
*mucus-secreting goblet cells are also present
29
What is the blood supply in the conducting zone?
thyroid, bronchial, internal thoracic arteries (systemic circulation)
30
What is the size of the terminal bronchioles? What do they lack?
1 mm
| Lack cartilaginous plates
31
What makes up anatomic dead space?
The conducting zone!!
32
How do you measure anatomic dead space?
150 mL
1/3 the Vt
1 mL/lb or 2 mL/lb (IBW)
33
What are the cells of the respiratory zone?
cuboidal --> squamous
34
What is the blood supply to the respiratory zone?
Pulmonary.. duh
35
What is the size of the respiratory bronchioles?
0.5 mm; flow moves by diffusion at this point
36
Name the accessory muscles for inspiration
sternocleidomastoid & scalene
37
Name the accessory muscles for expiration
rectus, internal/external obliques, transverse abdominus
38
Transpulmonary pressure
the difference between the intrapleural and intra alveolar pressures; it determines the size of the lungs. a higher transpulmonary pressure corresponds to a large lung
39
What are the components of WOB?
Elastive
| Resistive
40
Discuss the medulla's control over breathing
DRG: pacemaker for breathing; stimulates inspiration
VRG: stimulates inspiration/expiration (forced)
41
Discuss the pon's control over breathing
Modifies the medulla output.
- Pneumotaxic: decreases Vt for fine control (located high in the pons)
- Apneustic: increases Vt for long, deep breathing (located lower in the pons)
* output limited by baroreflex, pneumotaxic*
42
How do central chemoreceptors work?
respond to H+ ions
43
How do peripheral chemoreceptors work?
respond to CO2, pH, and hypoxemia
44
What carries the aortic arch and lung stretch signals?
Vagus (X) carries it to the DRG
45
What carries the carotid body signals?
Glossopharyngeal (IX) carries it to the DRG
46
Parasympathetic control over the airway
```
From vagus (X)
Causes: mucous secretion, increased vascular permeability, vasodilation, bronchospasm, bronchoconstriction (greatest in upper airway)
```
47
Sympathetic control over the airway
intrinsically, small effect --> inhibit mediator release from mast cells, increase mucociliary clearance
48
What is the Vt of a patient?
usually 6-8 ml/kg IBW
49
Inspiratory capacity
IRV + Vt
50
VC
IRV + Vt + ERV
51
FRC
ERV + residiual volume; 2L
52
What does a normal tidal breath bring into the respiratory zone?
350 mL inspiration (21% O2)
| 350 mL expiration (5-6% CO2)
53
Per minute, how much oxygen & co2 diffuse at alveolar/capillary membrane
250 mL of O2, 200 mL of CO2
| respiratory quotient
54
What are some reasons for decreased static compliance? (7)
fibrosis, obesity, edema, vascular engorgement, ARDS, external compression, atelectasis
55
How do you calculate static compliance?
= Vt/ (Pplat - PEEP)
| normal = 60 - 100 ml / cmH2O
56
How do you calculate dynamic compliance?
= Vt/ (PIP - PEEP)
| normal = 50 - 100 mL / cm H2O
57
Reasons for decreased dynamic compliance
bronchospasm, tube kinking, mucous plugs, increased RR
58
Laminar flow
small airways ( < 2000)
59
Turbulent flow
large airways (greatest resistance in medium sized bronchi) (> 4000)
60
Reynold's Number
```
Re = pvd/n
p= density
v = velocity
d = diameter
n= viscosity
```
61
Poiseuille's Law
R = 8nl/r^4
62
Zone 1
alveolar > arterial > venous
v/q > 1
no blood flow
63
Zone 2
arterial > alveolar > venous
v/q = 1
intermittent blood flow
64
Zone 3
arterial > venous > alveolar
v/q = 0.8 yay
alveolar compliance and perfusion are the greatest
i am where blood pools
65
Zone 4
arterial > IS > venous > alveolar
v/q < 1 (disease)
66
Alveolar concentrations of gas
```
O2 = 100
CO2 = 40
H2O = 47
N2 = 575
```
67
Expired concentrations of gas
```
O2 = 116
CO2 = 32
H2O = 47
N2 = 565
```
68
Arterial concentrations of gas
```
O2 = 95
CO2 = 40
H2O = 47
N2 = 575
```
69
Capillaries concentrations of gas
```
O2 = 40
CO2 = 46
H2O = 47
N2 = 575
```
70
Venous concentrations of gas
```
O2 = 40
CO2 = 46
H2O = 47
N2 = 575
```
71
What is closing volume
the volume above residual volume where small airways close
72
What is closing capacity
the absolute volume of gas when small airways close (CV + RV)
increases from 30% (age 20) of TLC to 55% of TLC (age 55)
increased by: supine, obesity, pregnancy, copd, chf, aging
73
what does hemoglobin consist of?
4 protein subunits (2 alpha, 2 beta)
4 heme subunits
Iron
each gram of hgb binds to 1.34 mL of oxygen
74
left shift of oxyhemoglobin curve
loves - higher affinity
| -low temp, low CO2, high pH, low DPG
75
right shift of oxyhemoglobin curve
releases - lower affinity
| -high temp, high CO2, low pH, high DPG
76
haldane effect
oxygenation of blood displaces CO2 from hgb; curve shifts up and left when PO2 decreases
*occurs at A/C membrane*
77
bohr effect
hgb affinity for O2 is inversely r/t CO2 levels
*occurs at tissue level*
78
what is the p50
PaO2 at which 50% of hgb is saturated
| 26 - 28 mmHg
79
70% saO2
40 mm Hg PAO2
80
90% saO2
60 mm Hg PAO2
81
DLCO
tests the lungs diffusing capacity for carbon monoxide
normal > 75%
mild: 60%
moderate: 40 - 60%
severe < 40%
82
How is CO2 transported in the blood?
1. physical solution (5-10% dissolved)
2. chemically combined w/aa or proteins (5-10% hgb)
3. bicarbonate ions (80-90%)
83
hamburger shift
hco2 leaves the RBCs; chloride enters to maintain electrical neutrality aka chloride shift
84
hypoxic hypoxia
generally an issue w/lungs
low fiO2
hypoventilation
v/q mismatch
r - l shunt
*supplemental O2 does help*
85
clinical examples of hypoxic hypoxia (8)
```
high altitudes
O2 equipment error
drug OD
COPD
pulmonary fibrosis
PE
atelectasis
CHD
```
86
circulatory hypoxia
reduced CO
ex: HF, dehydrated, sepsis, SIRS
supplemental O2 does not help
87
hemic hypoxia
reduced hgb content/function
examples: anemia, CO, methemoglobinemia (NTG, prilocaine)
supplemental O2 does not help
88
histotoxic hypoxia
increased O2 consumption or inability to use O2
examples: fever, sz, cyanide
supplemental O2 does help
89
what is HPV affected by?
PAo2, ph, pco2, temp
eliminated by elevated fio2, VA > 1 MAC
90
MOA of HPV
alterations in leukotrienes and PG synthesis, inhibits NO
91
deadspace V/Q mismatch
causes: PE, hypovolemia, cardiac arrest, shock
| * anything that causes a decrease in pulmonary blood flow*
92
shunt
causes: mucous, mainstem, atelectasis, PNA, PE
| * anything that causes the alveoli to collapse*
93
anatomical dead space
air that is present in the airway that never reaches the alveoli, therefore, never participates in gas exchange
94
alveolar dead space
air found within alveoli that are unable to function, such as those affected by disease or abnormal blood flow
95
physiologic dead space
anatomical + alveolar
*all of the air in the respiratory system that is not being used for gas exchange*
96
Vd (deadspace equation (bohr))
Vt x (PaCO2 - PeCO2)/PaCo2
97
what is PeCO2
is normally 2-5 mmHg less than PaCO2 d/t mixing with anatomic deadspace during exhalation
*increases w V/Q mismatch*
98
venous admixture (3)
result of mixing of non-oxygenated blood w/oxygenated blood distal to the alveoli
1. communicating between bronchial & pulmonary circulation*
2. thebesian veins
3. low V/Q areas
99
what does PVO2 represent?
the overall balance between VO2 and DO2
100
what decreases PVO2 (3)
decreased CO, increased O2 consumption, decreased Hgb
101
absolute shunt
v/q = 0
| -hypoxia unresponsive to supplemental oxygenation
102
shunt-like alveoli
v/q < 1
| -low PO2 and high PCO2
103
deadspace-like alveoli
high v/q > 1
| -high PO2 and low PCO2
104
fick's law
V = D * A* deltaP/T
105
alveolar oxygen tension (PAO2)
PAO2 = (PB - H2O) x FiO2 - (PaCO2/0.8)
106
alveolar arterial oxygen tension gradient
```
P(A-a)O2= PAO2 - PaO2
normal = 5 - 15
```
107
A-a gradient increases with?
age, obesity, supine, heavy exercise
108
A/a ratio
PAO2/paO2
good indicator of overall gas exchange
normal > 75%
109
oxygen content
CaO2 = (hgb x 1.34 x saO2) + (PaO2 x 0.003)
110
DO2
CO x CaO2
CO = 5L/m
CaO2 around 200
111
VO2
Fick Equation
CO x (CaO2 - CvO2)
usually around 250 mL/m
112
P/F Ratio
PaO2/FiO2
normal = 400 - 500
tells you if there is a problem, just not the etiology
113
< 300 P/F Ratio
mild ARDS
114
< 200 P/F
moderate ARDS
115
< 100 P/F
severe ARDS
| *takes 100% O2 to yield a normal PaO2*
116
How is CO2 produced?
acetyl coA (2)
ETC (6)
kreb's cycle (4)
117
What does ETC do?
oxidizes NADH/FADH2, consumption of O2
118
What does proton gradient do?
produces phosphorylation of ADP to ATP
119
Normal PO2 & CO2
```
V/Q = 0.8
PAO2 = 100
PACO2 = 40
PaO2 = 100
PaCO2 =40
```
120
TOTAL Airway obstruction PO2 & CO2
```
*shunt*
V/Q < 1
PAO2 = 0
PACO2 = 0
PaO2 = 40
PaCO2 =46
```
121
PULMONARY EMBOLUS PO2 & CO2
```
V/Q > 1
PAO2 = 150
PACO2 = 0
PaO2 =
PaCO2 =
```
