Respiratory Flashcards
1
Q
The exchange of O2 and CO2 between external environment and the cells of the body is what type of respiration?
A
External
2
Q
Metabolic processes within the mitochondria using O2 and producing energy is what kind of respiration?
A
Internal respiration
3
Q
What airways make up the conducting zone?
A
Trachea
Bronchi (primary bronchus)
Bronchi (secondary bronchus)
Tertiary bronchus
4
Q
What airways make up the respiratory zone?
A
Respiratory bronchioles
Alveolar duct
Alveolar sac
5
Q
How does ANS control airways?
A
Changes the diameter of conducting airways
6
Q
SNS innervation of the airways causes ___________
A
Dilation
7
Q
PSNS innervation of the airways causes _____________
A
Constriction
8
Q
What is the structure of the alveoli?
A
Large surface area
Lined with epithelium and type II and type II pneumocytes
Closely associated with capillaries
9
Q
What must respiratory gases pass through from alveoli to capillary?
A
Surfactant -> type I pneumocytes -> basement membrane -> capillary endothelium -> RBC
0.5um - 1.5um thickness
10
Q
What is the kinetic theory of gases?
A
Pressure of a gas is the force per unit area exerted by the impact of the molecules when they collide with the walls of the container
11
Q
What is atmospheric pressure at sea level?
A
750mmHg
12
Q
Daltons Law
A
The total amount of pressure exerted by a mixture of a gases is equal to the sum of the partial pressures of the individual gases.
Ptotal = PO2 + PCO2 + PN2
13
Q
What percentage of air does oxygen occupy?
A
21%
14
Q
If atmospheric pressure is 750mmHg and air is 21% oxygen, what is the partial pressure of oxygen?
A
750mmHg x 0.21 = 159.6mmHg
15
Q
What two factors determine the amount of gas that will be dissolved in a liquid?
A
Pressure of gas at the surface
Solubility of gas
16
Q
Moisture in lungs has a partial pressure of 47mmHg.
If atmospheric pressure is 750mmHg and the composition of air is 21% oxygen, what is the partial pressure of oxygen in the lungs?
A
P02 = (Patmos - Ph2o) x Fo2
(750 - 47) x 0.21 = 149.mmHg
17
Q
Boyles Law
A
At a constant temperature, the volume of gas is inversely proportional to pressure.
P = 1/V
18
Q
Charles Law
A
The volume of a gas is directly proportional to absolute temperature
19
Q
Movement of air into the alveoli is facilitated by________________, due to expansion of the thoracic cavity
A
Negative pressure (draw air in)
20
Q
During expiration the thoracic cavity volume ________________ and the intra-alveolar pressure ___________ .
A
Decreases, increases
21
Q
Describe air flow when Palveolar = Patmospheric
A
No air movement
22
Q
Describe air flow when Palveolar is less than Patmospheric
A
Air moves into alveoli
23
Q
Describe air movement when Palveolar is greater than Patmospheric
A
Air moves out of the lungs
24
Q
What are the 4 pressures involved in a breathing cycle?
A
Atmospheric
Intra-alveolar
Intrapleural
Transmural (difference between intra-alveolar and intrapleural)
25
What prevents the outward movement of the chest wall and inward collapse of the lungs?
Intrapleural pressure
| Pressure is negative sucking the two walls together. The opposing forces prevent expansion and collapse
26
An opening into the intrapleural space will cause what?
Pneumothorax
| Negative pressure is lost. Chest cavity expands and the lung collapses
27
During inspiration will intrapleural pressure become more positive or negative? Why?
Negative.
| Chest wall expands outward, force moving outward. Less pressure within the cavity
28
What two physiological properties must the lungs have in order to breath?
High compliance - lungs can expand in inspiration
| Elasticity - lungs can recoil when force is released
29
Condition of lung stiffness
Fibrosis
30
Condition of lost recoil
Emphysema
31
The volume of gas in conducting airways is called?
Anatomical dead space
Takes no part in gas exchange
32
The volume of air that is breathed in passively is called?
Tidal volume (10-20ml/kg)
33
The volume air in conducting airways and alveolar volume that is not taking place in gas exchange is called?
Physiological dead space
Anatomical + alveolar dead space
34
In a restrictive lung disease what happens to the volumes of the lung? Why?
Decreased volume.
Decreased compliance causes a decreased expansion
35
What is an example of an obstructive lung disease? What effect will this have on respiration?
Asthma (narrowed airways), or chronic bronchitis (mucus plugs/ inflammatory swelling)
And increased resistance to movement of air
Respiration is more difficult
Not necessarily a change in volume
36
What is functional residual capacity of a lung?
The total volume of air left in the lungs after a tidal expiration.
37
If elastic forces increase and compliance decreases what is happening to the lungs?
Lungs are getting stiffer (fibrosis)
38
If elastic forces decrease and compliance increases what is happening to the lungs
Lungs are getting more elastic
39
Hookes Law
Force exerted by a spring is proportional to its extension
40
Law of Laplace
P=2T/r
Pressure is related to surface tension and radius
Radius effect- pressure is greater in smaller alveoli
Consequence - air will flow from smaller alveoli into larger alveoli
41
What produces surfactant?
Type II pneumocytes
42
What does surfactant do?
Phospholipid that breaks up bonding between water molecules in alveoli.
Decrease surface tension.
In smaller alveoli the effective concentration of surfactant is larger decreasing surface tension even more -> due to law of LaPlace no pressure difference between large and small alveoli
43
What occurs when surfactant is deficient?
Lungs become less compliant (stiff) and areas of alveolar collapse
44
Two effects of surfactant on lungs
Increased pulmonary compliance
| Decreased tendency to recoil
45
What is the purpose of Type I pneumocytes
Gas exchange
46
What do type II pneumocytes produce
Surfactant *
47
Chronic obstructive pulmonary disease (COPD) and oedema increase ____________ of airway
Resistance
48
What factors impact airflow?
Change in pressure (mouth - alveolar gradient)
| Resistance of airway (RAW)
49
In laminar airflow, what equation applies to airflow?
Poseuilles equation
R= 8(viscosity)(length) / (pi)(r^4)
50
How is resistance of airways changed under normal conditions?
ANS acts on smooth muscle to dilate or contract smooth muscle
51
Bronchomotor tone is controlle primarily by the PSNS or the SNS?
PSNS
52
What is released in PSNS action on smooth muscle of the airways? What receptor does it activate?
Neurons release Acetylcholine (ACh) which activate muscarinic receptors causing bronchoconstriction
53
During SNS innervation on airway, what is released? What receptor does it act on?
Neuron releases adrenaline which acts on B2 receptors causing bronchodilation
54
What holds open the airway of trachea and alveolar ducts
```
Cartilagenous rings (trachea)
radial traction (alveolar)
```
55
In forced expiration, what could happen to the airway?
High force on lung (coughing) causes rise in intrapleural pressure and collapse of lung
56
In ventilation, which region of the lung is able to have more ventilation
Bottom
At top of lung, it is more expanded/ distended. Lower lung has more ability to expand and fill during inspiration
57
Does the top or bottom of the lung have a greater intrapleural pressure?
Bottom P= -2.5 (more squished)
Top P= -8
58
What is ventilation rate?
Volume of air / time
59
What is respiratory minute volume?
Total rate of air movement in and out of lungs in a minute
Tidal volume (ml/breath) x respiratory rate (breath/min)
60
If dead space increases, will a increased respiratory rate or increased depth of breathing be more effective?
Depth of breathing.
Increase amount of air taking place in gas exchange
61
Alveolar ventilation
Air that takes place in gas exchange
Tidal volume - dead space x respiratory rate
62
What is atelectasis?
Lung collapse
63
If disease changes the thickness of alveolar membrane, what happens to gas diffusion
Slower / decreases
Ficks law. Diffusion in inversely related to membrane thickness
64
Is oxygen exchange diffusion or perfusion limited?
Perfusion limited
65
Explain the PO2 gradient change from airway to tissue.
| Why is it important for PO2 to remain high?
Airway 150mmHg
Alveolus 100mHg
Tissue 50mmHg
Mitochondria 1mmHg
As blood moves throughout body oxygen is lost to various processes/ tissues. A high PO2 is required to make sure enough O2 gets to mitochondria to generate energy.
66
What is the anatomical R-L shunt?
Bronchial circulation goes to airways and lung tissue and returns to left heart creating a venous admixture (oxy = deoxy)
Via Thebesian veins
67
What is a physiological shunt?
Perfusion is normal but the alveolus is not ventilated
| Creates a venous admixture
68
What is the A-a gradient
The difference between PAO2 and PaO2
Aveolar partial pressure of oxygen and arterial partial pressure of oxygen. Due to R-L anatomical shunt
69
How is blood flow in lungs increased?
Recruitment of previously closed vessels
Open in response to increased CO2
70
Why do you not want a high capillary pressure within the lungs?
Oedema
| Capillary rupture and clotting
71
What effect will hypoxia have on pulmonary vascular resistance?
Vasoconstriction to increase flow
Hypoxia pulmonary vasoconstriction
72
Why is it a good idea to shut down blood flow to hypoxia regions of the lungs?
Increase flow to where oxygenation in good
73
Why is it a bad idea to shutdown blood flow to hypoxic regions at high altitudes?
At high altitudes, all the lung is receiving a lower PO2. All lung is hypoxic
74
In optimal gas exchange V/P =?
V/P= 1
There is no ventilation -perfusion mismatch
75
What is a ventilation - perfusion mismatch?
When either flow is greater than ventilation or ventilation is greater than flow
76
If ventilation is normal and Flow (Q) is decreased, what is occurring?
Physiological dead space
V/Q = 1/0 = infinity
77
If ventilation is not occurring and flow (Q) is normal, what is occurring?
Physiological shunt
Perfusion occurs but no ventilation
78
What is a normal A-a difference caused by?
R-L anatomical shunt
Under normal conditions about 2% of cardiac output
79
What is occurring in a physiological shunt
Perfusion is occurring but the alveoli is not ventilated
| Creates a venous admixture
80
The condition of low blood O2 is called?
Hypoxia
81
If cardiac output is halved, what would V/Q be?
Ventilation is normal (1)
Cardiac output is 1/2
1/ (1/2) = 2
82
___________________ is the volume of air left in the lungs after a forced expiration
Residual volume
83
After a tidal volume expiration, the amount of air that can be forcible pushed out of the lungs is ____________________
Expiratory reserve volume
84
The amount of air that can be inhaled after a tidal volume inspiration is _________________
Inspiratory reserve volume
85
Within the blood, oxygen can be bound or dissolved. What contributes to the partial pressure of oxygen
Free dissolved oxygen
86
How is most of the oxygen transported around the body?
Bound by hemoglobin in RBC
87
What is P50?
The partial pressure of oxygen at which 50% of the binding sites on hemoglobin are filled. (50% saturated)
88
The oxygen dissociation curve is sigmoidal, what does the steepness of the curve demonstrate about hemoglobin binding to oxygen
There is cooperative binding of hemoglobin and oxygen. The binding of one oxygen to hemoglobin makes it easier for other oxygen to bind. (Affinity for oxygen increases)
In reverse, the dissociation of oxygen from hemoglobin will cause hemoglobin to give up its oxygen (affinity decreases)
89
At high PO2 in the pulmonary capillaries hemoglobin will _____________ oxygen, and _____________ in tissues where PO2 is low
Bind, unload
90
If the oxygen dissociation curve is shifted to the right, does hemoglobin have a higher or lower affinity for oxygen.
Lower affinity
At the same PO2, a right-shifted curve will have a lower percent of oxygen bound than a normal curve.
91
What are some causes of a right-shifted curve?
Acidosis
Increased CO2
Increased temperature
92
Does a left-shifted curve, demonstrate hemoglobin with increased or decreased affinity for oxygen?
Increased.
At the same PO2, a left shifted curve will have a higher percent of oxygen bound than a normal or right shifted curve
93
What causes a left-shifted curve
Alkalosis
Decreased CO2
Decreased temperature
94
Highly active tissues produce what byproduct of glycolysis that will alter hemoglobin binding of oxygen?
2,3-DPG
95
Production of 2,3-DPG causes the oxygen dissociation curve to shift what direction? Why?
Right
| Binds to hemoglobin, takes up binding sites so oxygen cannot bind therefore hemoglobin has a lower affinity to oxygen.
96
Who is the best at physiology?
YOU ARE! :)
97
Does hemoglobin or myoglobin give up oxygen more readily?
Hemoglobin
Myoglobin has a higher oxygen affinity. Takes up oxygen from blood and stores it in muscle until tissue oxygenation is super duper low.
98
Does fetal hemoglobin or adult hemoglobin have a higher affinity for oxygen?
Fetal hemoglobin
Because fetus is a little parasite that must steal oxygen away from mother ... so their hemoglobin is more greedy and stronger and pulls oxygen off of momma hemoglobin
99
In what three forms is CO2 transported around the body?
Dissolved
Reversible bound to hemoglobin
Bicarbonate
100
What do you call a hemoglobin with a carbon dioxide attached?
Carboxihemoglobin
101
How is it that a RBC can constantly produce bicarbonate and never reach equilibrium?
Chloride shift- chloride moves into cell and bicarbonate moves out
Any H+ ions produces are bound by hemoglobin
102
What is the Haldane effect?
For any given PCO2, the CO2 content of deoxygenated blood is higher than oxygenated blood.
Seems reasonable right?
Why does this happen? Let me tell you. When oxygen dumps hemoglobin, hemoglobin is sad and goes to the bar and finds a rebound molecule H+, H+ and hemoglobin leave the bar. The bouncer then lets in more CO2 (sober people), which then turn into drunk people and dissociate from their friends becoming H+. Which then again go home with random hemoglobin and more CO2 is taken up ...
103
Decreased CO2 is called _________
Respiratory alkalosis
104
Increased CO2 is called _____________
Respiratory acidosis
105
How is PCO2 related to ventilation
PCO2 is inversely related to alveolar ventilation
PCO2 = 1/ (alveolar ventilation)
106
Hypoventilation leads to_____________, which results in peripheral ________________.
Hypercapnia, vasodilation
107
Hyperventilation leads to ___________________, causing cerebral ___________________
Hypocapnia, vasoconstriction
108
What 3 factors are monitored by chemoreceptors?
Decreased arterial PO2
Increased arterial PCO2
Increase concentration of H+
109
Where are peripheral chemoreceptors located and what signals them?
Carotid and aortic bodies
Low PO2
High PCO2
Low pH
110
Peripheral chemoreceptors respond to hypoxia by _______________
Increasing ventilation
Ventilation will also increase in response to increase in PCO2
111
Where are central chemoreceptors located?
Medulla
112
Central chemoreceptors respond to what stimulus?
High PCO2
| Acidosis (low pH)
113
Central chemoreceptors causes what action?
Increased ventilation
114
What does it mean to be normoxic?
The central chemoreceptors are driven by changes in PCO2.
If PCO2 remains constant a change in PO2 will not produce a ventilation change until about 60mmHg (out of norm)
115
What effect will a V-Q mismatch have on gases and what will the respiratory system do to compensate?
A V-Q mismatch causes partial pressure of O to decrease and partial pressure of CO2 to increase. The increase in CO2 causes stimulation of ventilation which will restore gas partial pressures.
116
What receptors response to lung over inflation
Pulmonary stretch receptors
117
Which receptors respond to a inhaled irritant?
Irritant receptors
118
Lung receptor signals all travel to the respiratory center and travel back to the lungs on the ____________ nerve
Vagus
119
Which receptors respond to oedema or substances released due to lung damage / allergy?
Juxtapulmonary 'J' receptors
