Exam 3 Pulmonary Physiology Flashcards
1
Q
What are the 3 functions of the respiratory neurons in the brain stem
A
- sets basic drive of ventilation
- descending neural traffic to spinal cord
- activation of muscles of respiration
2
Q
What are 3 things that activate pulmonary physiology
A
- respiratory neurons in the brain stem
- ventilation of alveoli coupled with perfusion of pulmonary capillaries
- exchange of oxygen and CO2
3
Q
What is the ventilatory cycle
A
The alveolar (avl.) pressure oscillates around atmospheric pressure (atm.)
4
Q
During inspiration what is the ventilatory cycle look like in regards to Pavl vs. Patm
A
during inspiration
Pavl. < Patm.
5
Q
During expiration what is the ventilatory cycle look like in regards to Pavl vs. Patm
A
During expiration
Pavl > Patm
6
Q
At the end of inspiration or expiration what does the ventilatory cycles equation in regards to Pavl vs Patm
A
Pavl = Patm
7
Q
Where are the respiratory centers located within the brainstem
A
- dorsal and ventral medullary group
- pneumotaxic and apneustic centers
8
Q
What do respiratory centers do
A
Affect rate and depth of ventilation
9
Q
What 3 things that respiratory centers are influenced by
A
- higher brain centers
- peripheral mechanoreceptors
- peripheral and central chemoreceptors
10
Q
What are the functions of inspiratory muscles of ventilation
A
Increase thoracic cage volumes
11
Q
What are the inspiratory muscles
A
- diaphragm, external intercostals, SCM
- Ant and Post sup. Serratus, scaleni, levator costarum
12
Q
What is the function of expiratory muscles of ventilation
A
Decreased thoracic cage volume
13
Q
What are the expiratory muscles
A
Abdominals, internal intercostals, post. Inf. Serratus, transverse thoracics, pyramidal
14
Q
What happens when muscles of inspiration are contracted
A
Increase thoracic cage volume
15
Q
What happens when muscles of expiration are contracted
A
They pull the rib cage down decreasing thoracic cage volume (forced expiration)
16
Q
What is pleural pressure
A
Negative pressure between parietal and visceral pleura that keeps lung inflated against chest wall
17
Q
What is the range of pleural pressure
A
Between -5 and -7.5 cm H2O (inspiration to expiration)
18
Q
What is alveolar pressure for inspiration and expiration
A
- sub atmospheric during inspiration
- supra-atmospheric during expiration
19
Q
What is transpulmonary pressure
A
The difference between alveolar P and pleural P
20
Q
What does transpulmonary pressure measure
A
The recoil of tendency of the lung
21
Q
What peaks at the end of inspiration
A
Transpulmonary pressure
22
Q
What is the equation for compliance of the lung
A
Change in volume divided by chang in pressure
∆V/∆P
23
Q
What is hysteresis
A
At the onset of inspiration the pleural pressure changes at a faster rate than lung volume
24
Q
What is significant between air filled lung vs. saline filled lung
A
Easier to inflate a saline filled lung than air filled because surface tension forces have been eliminated in the saline filled lung
25
What reflects back at the hilum to form visceral pleura
Parietal pleura attached firmly to the rib cage
26
Where is visceral pleura attached to
Firmly to the lungs
27
What exists between the 2 pleura
A negative pleural pressure which creates a suction such that the visceral pleura will follow the parietal pleura
28
What does expansion of the thoracic cage produce when increasing lung volume
Overrides the natural recoil tendency of the lung
29
At the end of a normal expiration, ____ are opposite but equal of ____
Chest wall forces, lung recoil forces
30
What happens in terms of volume in the lungs and functional residual capacity when all the respiratory muscles are relaxed
Volume in the lungs = FRC
31
What is the effect of thoracic cage on the lung
Reduces compliance by about 1/2 around functional residual capacity (at end of normal expiration)
32
What is greatly reduced at high or low lung volumes
Compliance
33
What is compliance (elastic) work
Accounts for most of the work normally
34
What is the viscosity of chest wall and lung
Tissue resistance work
35
How much energy is required for ventilation
3-5% of total body energy
36
What are the 4 different works of breathing
- compliance(elastic) work
- tissue resistance work
- airway resistance work
- energy required for ventilation
37
What is Eupnea
Normal breathing (12-17 b/min, 500-600 ml/b)
38
What is tidal volume
amount of air moved in/out each breath (500mL)
39
What is IRV
Inspiratory reserve volume
| - max volume one can inspire above normal inspiration (3000mL)
40
What is ERV
Expiratory reserve volume
| - max volume one can expire below normal expiration (1100mL)
41
What is RV
Residual volume
| - volume of air left in lungs after max expiratory effort (1200mL)
42
What is FRC
Functional residual capacity
- RV+ ERV
- volume of air left in lungs after normal expiration
- balance point of lung recoil and chest wall forces
43
What is inspiratory capacity
- TV+IRV
| - max volume on can inspire during inspiration effort
44
What is vital capacity
- IRV + TV + ERV
| - max volume one can exchange in respiratory cycle
45
What is total lung capacity
- IRV + TV + ERV + RV
| - the air in lungs at full inflation
46
What is the helium dilution method
FRC = ([He]i/[He]f-l)Vi
- [He]i = initial concentration of helium
- Hef is final concentration
- Vi is initial volume of air in jar
47
What is determined from basic spirometry
ERV and VC
48
What decreases with restrictive lung conditions
VC, IRV, IC
49
What is minute respiratory volume
Resting rate x tidal volume
50
What is the breakdown of airways in the lung
Trachea, bronchi, bronchioles, respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli
51
What is the amount of anatomical dead space
150mL
52
What is physiological dead space
Anatomical + non functional alveoli
53
What is alveolar volume
Alveolar volume (2150mL) = FRC (2300mL) - dead space (150mL)
54
What is the turnover of alveoli
6-7 breaths
55
What is the equation of rate of alveolar ventilation
Va= RR(Vt-Vd)
56
What are NANC nerves
Non adrenergic, non cholinergic
- inhibitory release of VIP and NO = bronchodilation
- stimulatory = constriction
57
What part of autonomic control contains neuropeptides
C fibers = selectively stimulated by capsaicin
58
What histamines and prostaglandins are associated with dilation
Prostaglandin E and histamine binding to H2 receptors
59
What histamines and prostaglandins are associated with constriction
Prostaglandin F and histamine binding to H1 receptors
60
What will metabolic acidosis or alkalosis do
- Acidosis (HCO3 <24) = stimulate ventilation
| - alkalosis (HCO3 >24) will inhibit ventilation
61
What is the normal level of CO2 and how does it affect ventilation
- acidosis (CO2>40) stimulates ventilation
| - alkalosis(CO2<40) inhibits ventilaiton
62
What will low alveolar O2 cause
Release of local vasoconstrictor that automatically redistributes blood to better ventilated areas
63
What happens with SNS stimulation on pulmonary vascular smooth muscle
SNS stimulation= mild vasoconstriction mediated by alpha receptors. No more at 30Hz then vasodilation mediated by Beta receptors takes over
64
What is the major constrictor effect on pulmonary vascular smooth muscle
Low alveolar O2
65
From apex to base what happens to capillary pressur
Capillary pressure increases
66
What happens in zone one hydrostatic pressure
- no. Flow
- alveolar P > capillary P
- normally does not exist
67
What happens in zone 2 of hydrostatic P
- intermittent flow (to apex)
- systole = capillary P>alveolar P
- diastole=alveolar P>capillaryP
68
Effect of hydrostatic pressure of zone 3
- continuous flow (toward base)
| - capillaryP>alveolarP
69
What happens during exercise for hydrostatic pressure zones
Always zone 3
70
What is boyle’s law
At constant T, V of gas is inversely proportional to P it exerts
71
What is avogrado’s law
V of gas at same T/P contain same # of molecules
72
What is charles law
At constant P the V of gas is proportional to absolute T
73
What is the gas law sum
PV=nRT
74
What is grahams law
Rate of diffusion of gas is inversely proportional to square root of molecular weight
75
What is henry’s law
Quantity of gas that can dissolve in fluid is = to partial P of gas x the solubility coefficient
76
What is daltons law of partial pressures
The P exerted by mixture of gases is = the sum of individual (partial) P exerted by each gas
77
At body temp vapor P of H2O is what
47 mmHg
78
What are the alveolar gas concentrations of O2 and CO2
O2 = 104 mmHg, CO2= 40mmHg
79
What diffuses at least 20x more readily than oxygen
CO2
80
The first 100mL of expired air is from where
Dead space
81
The last 250mL of expired air is from where
Alveolar air
82
What happens to ventilation if ventilation perfusion ratio decreases or increases
Decrease = decrease ventilation, increase = decreased perfusion of lungs
83
A decreased V/P ratio as ventilation goes to 0 results in what?
An increase in “physiologic shunt blood” = blood that is not oxygenated as it passes the lung
84
Increased V/P ratio due to what
Decreased perfusion of lungs from RV
85
What happens in transport of O2
- 5mL/dl carried from lungs-tissue
- dissolved = 3%
- bound to hemoglobin = 97%
86
What happens in transport of CO2
- 4ml/dl carried from tissue - lungs
- dissolved = 7%
- bound to hemoglobin = 23%
- bicarbinate ion = 70%
87
What is the pH of arterial blood
7.41
88
What is the blood pH of venous blood
7.37, buffered by blood buffers
89
Exercise venous blood pH can drop to what
6.9
90
What happens in oxy-hemoglobin dissociation if shifts to the right
Increase temp, increase CO2(decrease pH), increase 2,3 DPG
91
What are the physiological roles of CO
- signal for NS
- vasodilator
- immunne, resp, GI, kidney, liver
92
The nervous system adjusts the level of ventilation to match what
Perfusion of the lungs
93
By matching ventilation with pulmonary blood flow we also match what
Ventilation with overall metabolic demand
94
What provides neural control of ventilation
Dorsal respiratory group located primarily in nucleus tractus solitarius in medulla
95
Where is the pneumotaxic center located and what does it do
Dorsally in n. Parabrachialis of upper pons, inhibits duration of inspiration by turning of DRG ramp signal after inspiration starts
96
Where is the ventral respiratory group of neurons and what does it do
Located bilaterally in ventral aspect of medulla can stimulate inspiratory/expiratory muscles during increased ventilatory drive
97
Where is the apneuistic center and what does it doe
Lower pons and funx to prevent inhibition of DRG under some circumstances
98
What stimulates sneezing and coughing
Irritant receptors among airway epithelium
99
What stimulates when pulmonary caps are engorged or pulmonary edema
J receptors
100
What creates a feeling of dyspnea
When j receptors stimulated by pulmonary caps engorged/edema
101
What is responsive to hypoxia
Peripheral chemoreceptors
102
What are some consequences of hyperventilation
Blood flow decreased all around, muscle spasm/tetany, oxyhemoglobin affinity increased, repolarization of heart is impaired
103
What is the effect of edema on the brain
Depression/inactivation of respiratory centers tx is use o iv hypertonic solution
104
What is the effect of anesthesia/narcotics on ventilation
Most prevalent cause of respiratory depression
- sodium pentobarbital
- morphine
105
How much stored O2 dos the body contain
About 2 L used for aerobic metabolism mostly combined with hemoglobin
106
What happens to stored O2 in exercise
Used within 2 minutes, O2 debt can reach 11.5 L
107
How long is o2 debt in alactacid and lactic acid
Alactacid (3.5L) = first couple minutes, lactic acid (8L) over 40 minutes post exercise
108
How much cm H2O of negative plueral P is necessary to open alveoli on first breath
40-60 cm H2O
109
What closures happen at birth
Foramen ovale, ductus arteriosus, ductus venosus
110
What happens in acute mountain sickness
Onset is hours to 2 days,
- cerebral edem = hypoxia, stimulation of local vasodilation
- pulmonary edema = hypoxia stimulation of local vasoconstriction
111
What happens in chronic mountain sickness
Increase in red cell mass, pulmonary BP, RV enlargement, decreased TPR, congestive Heart failure, person dies if not moved to lower altitude
112
What happens in acclimitization
Increase in RBC, diffusion capacity, vascularity, use of O2, synthesis of 2,3DPG (shifts dissociation to the right)
113
What is hyperbarism
To keep lungs from collapsing in air must be supplied at high pressures exposing pulmonary capillary blood to extremely high alveolar gas pressures, can be lethal
114
What is the effect of high partial pressures of high PN2
Causes narcosis = state of stupor, drowsiness, unconsciousness similar to alcohol intoxication
115
What effect does high partial pressure have from high PO2
Oxygen toxicity = seizures, coma, cannot exceed established max depth of given breathing gas to prevent
116
What is the effect of high partial pressure of CO2
Usually not a problem as depth does not increase alveolar PCO2, can occur in certain diving gear occurring when alveolar PCO2>80mmHg
117
What is decompression
When person breaths air under high pressure the amount of N2 in body fluids increases, N2 not metabolized, potential problem if person submerged at deep level for hours
118
Decompression sickness
Aka the “Bends” = nitrogen bubbles out of fluids after sudden decompression
119
Where does the lung rank as an organ of metabolism
Second to liver, advantage though because all blood passes through lung
120
What are examples of lung as organ of metabolism
Angiotensin, prostaglandins
121
What is the average inhalation amount of air/day
10,000L
122
What protects the upper respiratory tracts
Nasal passages have vibrassae (long hairs) and nares filtering out larger particles
123
What are nasal turbinates
Highly vascularized, act as radiators to warm air
124
What nerve stimulates cough
CN X
125
What is associated with sneeze reflex
Nasal passages, irritation signals CN V to medulla different than cough because uses uvula
126
What clears the smaller airways
Mucociliary elevator moves mucous from bronchioles up to pharynx
127
What are dust cells
Alveolar macrophages
128
What is the complement system
Small proteins found in blood synthesized in liver for antibodies and phagocytosis
129
What antibodies are associated with the mucosa
IgG=lower resp. Tract, IgA=upper resp, IgE = a mucosal antibody
130
How do dust cells work
Present pieces of organism to effector cells through interactions involving cytokines promoting more vigorous/widespread response
131
What is the humoral immune system
Antibodies, accessory processes using Th2 activation and other stuff
