1
Q
What is the function of goblet cells?
A
- Secrete mucous and traps particles less than 10microm
2
Q
What forms the mucocilliary escalator?
A
- CILIA and GOBLET cells
3
Q
Do particles less than 0.5 microm pass into the mucociliary escalator?
A
- NO!!
- Macrophages remove these particles
4
Q
What are three ways that smoking leads to damage of the lungs?
A
- DESTROYS cilia lining the airways
- DAMAGES and DESTROYS walls between alveoli causing collapse
- Leads to CANCER in cells lining airways or in parenchyma (bulk of lung cells)
5
Q
What is emphysema a result of?
A
- When alveolar walls are damaged–> collapse–> larger alveoli form–> bullae
- NOt good for gas exchange–> distance for diffusion too great–> hypoxia (decreased O2)
- Leads to gas trapping
- LUNGS GET BIGGER IN VOLUME BUT TAKE IN SMALLER AMOUNTS OF AIR
- INCREASED COMPLIANCE
6
Q
What are two things that occur in bronchitis?
A
- thicker wals from inflammation
- Mucous buildup form DAMAGE to mucociliary escalators
- DECREASED FEV/FVC ratio
7
Q
What does Boyle’s law state?
A
- Thorax is a closed containeer
- If there is incresed volume in a closed system, then pressure will decrease (air moves from low area–> high pressure)
8
Q
What keeps the lungs inflated against the thoracic wall and the diaphragm?
A
- The NEGATIVE PRESSURE (atmospheric/barometric pressure)
9
Q
Is the intrapleural pressure always negative?
A
- YES
- this holds the lungs to the chest cavity
10
Q
When there is decreased INTRAPULMONARY pressure, will air move into or out of lungs? ** need to know how this changes during breathing!!
A
- INTO lungs
11
Q
What are three factors affecting pulmonary ventialtion?
A
- Radius of airway
- Compliance of chest wall (affects the volume of air that can be inhaled/exhaled)
- Surface tension of alveoli (how easily alveoli will remain open to exchange gas)
12
Q
What is TLC?
A
- total lung capacity –> can be measured with spirometer
13
Q
What is TV?
A
- Tidal volume –> volume of breath normally at rest (e.g. 0.5L)
14
Q
What is VC?
A
- Vital Capacity –> MAX amount of air you can EXHALE-INHALE
- Depends on how BIG you are and how AGE (this decreases with age)
- TOTAL volume of exchangeable air
15
Q
What is IRV?
A
- Inspiratory Reserve Volume
16
Q
What is ERV?
A
- Expiratory Reserve Volume
17
Q
What is FRC?
A
- Functional Residual capacity
18
Q
What is RV?
A
- Residual Volume
- Amount of air left in lung after FORCED EXHALATION –> Must be calculated not measured
19
Q
What is minute ventilation and how is it calculated?
A
- the amount of air breathed PER MINUTE
MV= TV (tidal volume-mL) * BREATHING RATE (breaths/minute)
20
Q
What is FEV1?
A
The forced expiratory volume in 1 second (i.e. in 1 second how much air that you breathed in can you breathe out? )
21
Q
What is FVC?
A
- Forced Vital Capacity –> max amount of air that you can breathe out
22
Q
What are examples of obstructive disorders?
A
- Asthma and COPD
- INCREASE in air flow –> DECREASED FEV1/FVC ratio (<75%)
23
Q
What occurs in a restrictive disease?
A
- Lung or chest wall can’t inflate to normal capacity (lungs or ribs become LESS compliant) –> reduced FVC but can’t make a decision–> would do a TLC test-if less than normal –> restrictive disease
24
Q
Which two factors of the spirometry graph is emphysema associated with?
A
- Increase in RV (residual volume) and increase in TLC
- Indicates gas trapping
25
Which 3 factors affect pulmonary ventilation?
1. AIRWAY RADIUS (affects rate that air can enter and leave lungs)
2. LUNG AND CHEST COMPLIANCE (How easy it is for air to get in and out of lungs affects volume of air)
3. SURFACE TENSION OF ALVEOLI (determines how easily the alveoli are open for gas exchange)
26
The volume of air into or out of the alveoli is proportional to ...
- The pressure difference between atm and alveoli
27
The volume of air flowing into or out of alveoli is INVERSELY PROPORTIONAL TO;
Resistance to flow of air in airways (highest in medium sized bronchioles) --> Poisuelles law
28
Which 4 ways is bronchomotor tone maintained?
1. Vagal efferent nerves--> Ach released to cause bronchoconstirciton
2. Sympathetic nerve supply --> NA released causes bronchodilation
3. Circulating catecholamines--> e.g. A and NA interact with B2 receptors on smooth muscle --> bronchodilation
4. Inhaled stimuli --> cigarettes, dust, cold air (reflex bronchoconstriction decreased resistance)
29
What are the two forces that determine lung compliacne?
1. Elastic forces (1/3 lung)
| 2. Surface tension of air/water surface of alveoli (2/3 lung)
30
What happens to the alveoli when there is no surfactant?
- They collapse
| - Can occur in babies when born --> can try to inject corrtisol to stimulate surfactant production
31
Which 3 things must the respiratory msucles overcome to INFLATE the lungs?
1. RESISTANCE OF CHEST WALL
2. RESISTANCE OF LUNG TISSUES
3. RESISTANCE OF AIRWAYS
32
What are some diseases where the compliance is reduced?
- IN LUNG: FIbrosis--> lung tissue stiffened by scarr tissue --> thoracic cage expands normally but tissue compliace reduced and HARDER TO INFLATE
- More fibroblasts in intersitium= thicker area
- IN CHEST WALL: Scoliosis or polio/ muscle dystrophy (respiratory muscle weakness) --> stiff chest wall--> harder to inflate
33
What does a low compliane mean for the diaphragm and inspiratory muscles?
- Must contract MORE vigorously --> generate a greater sub-atm pleural pressure to expand lungs
34
What does spirometry look at for airway radius?
-FEV1
35
What does spirometry look at for lung and chest compliacne? -
- FVC
36
What is the spirometry test done before and after administration of ?
- Bronchodilator drugs
| e. g. In asthma, after bronchdolator given (second test) it should show an INCREASE in FEV1
37
Which 3 can cause the airways to narrow?
1. thickened muscular layer (from fibrosis, edema--> decreased diffusion )
2. Increased secretion of mucous
3. Inflammatory response and edema in epithelium
38
What are the two different types of alveolar cells?
- Type I and II pneumocytes
39
What do type I alveolar cells do?
- Very thin
- Cover 95% of alveolar surface
- involved in gas exchange
40
What do type II alveolar cells do?
- Granular and cuboidal
- Ver 5% of alveolar surface
- Secrete pulmonary SURFACTANT
41
What are two factors affecting diffusion?
1. THICKNESS of membrane
| 2. AREA of membrane
42
Which two diseases/conditions increase the thickness of the alveolar membrane?
- Fibrosis and edema
43
Which two diseases/conditions REDUCE the area of the membrane available for diffusion?
- Emphysema
| - Emboli
44
How can we measure gas diffusion? -
- OXIMETER (on finger tips or ear) --> measures how much O2 binds with Hb--> we want more than 90%
- ARTERIAL BLOOD SAMPLE: Gas analysis--> normally O2= 100mmHg and Co2= 40mmHg
45
Which test is used to determine the ability of the lungs to transfer gas from air--> blood?
- TLCO (Transfer in Lung of Carbon Monoxide)
| - DCLO (Diffusion in Lung of Carbon Monoxide)
46
What is a PCO2 of 35mmHg indicating?
- The person is hyperventilating
47
What is the normla maximum transfer of oxygen trasnfer across the capillary?
- 25ml/min/mmHg
48
What does a DLCO test value of 11ml/min/mmHg indicate?
- Either a DECREASE in the SA of membrane or INCREASE in the thickness
- Possibly fibrosis
49
Which 5 factors are important for affecting the diffusion of gases?
1. Partial Pressure of gases on EITHER side of membrane
2. thickness of alveolar membrane
3. Area of lungs available for diffusion
4. Solubility of gas
5. Matching of ventilation and perfusion
50
What happens when we breathe in air?
- Goes through nose--> trachea--> PO2 decreases to 104 (PP O2 in alveolus) and PPCO2 in alveolus is 40mmHg and O2 is 104mmHg
51
What happens to the barometric pressure and pressure gradient for O2 at high altitudes?
- DECREASES AND DECREASES
52
What happens in diving underwater or sitting in hyperbaric chamber to the barometric pressure and pressure gradient for O2 respectively?
- INCREASES and INCREASES
53
Which two ways is O2 transported through blood?
- Dissolved in plasma and erythrocyte cytoplasm
| - REVERSIBLY bound to Hb
54
What does Henry's law predict about the transportation proportion of O2? -
- Amount DISSOVLED will be PROPORTIONAL to PO2 (3ml/100mL) plasma and OTHER 197mL bound to Hb for transportation
55
What is the Bohr effect?
- DECREASED pH
- INCREASED pCO2
- INCREASED temperature
- INCREASED 2,3 DPG (by-product of glycolysis)
56
In exercise what happens to pH, PCO2, Temperature, and 2,3 DPG in terms of the O2-b curve?
- They all shift to the curve to the RIGHT
57
Which 5 changes occur during exercise?
1. CO (cardiac output) increases (tissue blood flow--> top of lungs)
2. tissue blood flow INCREASES (more capillaries open up)
3. Hb saturation curve moves to the RIGHT (INCREASED O2 offloading from Hb in tissues and INCREASED CO2, H+, body temp, and RBC DPG)
4. VENTILATION INCREASES (more ventilation at APEX of lungs)
5. Perfusion of lungs INCREASES (distension of vessels and closed valves open up )
58
what percentage of O2 is offloaded from Hb during exercise? -
up to 80%
59
How much greater is the solubility of CO2 than O2?
- 20x greater
60
Which 3 ways is CO2 transported throughout body as?
1. 7% dissolvedin palsma and RBC cytoplasm
2. 23% CO2 transported boudn to Hb as Carboxyhaemoglobin
3. 70% transported as bicarb ions (HCO3-) in plasma and RBC cytoplasm
61
Which enzyme converts CO2--> HCo3- in the tissue capillary?
- CA (Carboninc anhydrase)
62
What is the chloride shift in the tissues?
- BICARB moves OUT of cell and CL- moves IN
63
How is the majority of CO2 transported in the plasma?
- As bicarb (HCO3-)
64
In which two ways is ventilation controlled?
1. Neural (medulla oblongata-brain)
| 2. Chemical (chemoreceptors)
65
Which two groups does the medulla contain?
- VRG (ventral respiratory group)
| - DRG (dorsal respiratory group)
66
Which medulla group contains the 'Rhythm generator'?
- The Ventral Respiratory Group --> pacemakers sed signals to the DRG
67
Which group is the central control for inspiration?
- DRG
68
If we are exercising and actively expire, where does the signal come from?
- DIRECTLY from ventral
69
When does inspiratio shut off?
- When barometric pressure = alveolar pressure
70
What are the inputs that modulate breathing rate via the DRG?
- Stretch receptors
- Irritant receptors
- Peripheral (decreased O2, Increased CO2, Increased H+) and central (Increased CO2, Increased H+ )chemoreceptors
- Receptors in muscles and joints
71
What role do the central chemoreceptors have in the chemical control of ventilation?
- Monitor CO2 level in medulla oblongata via H+
72
What role do the peropheral chemoreceptors have in chemical control of ventilation?
- Monitor O2, CO2, H+ levels in aortic arch and carotid bodies - minor role under the normal condition
- Respond to decrease in PO2 (hypoxia), INCREASE in H+ (metabolic acidosis) and INCREASE in PCO2 (respiratory acidosis)
73
Is the peripheral chemoreceptors response to PO2 important in everyday breathing?
- NO!
| - Very important in people with respiratory disease and at HIGH ALTITUDES
74
At what level does PO2 have to drop below for peripheral chemoreceptors to take over? -
- <60mmHg
75
How do peripheral chemoreceptors travel to the medulla oblongata?
- Carotid body fibres travel (via glossopharyngeal nerve) to DRG
- These MODIFY neuronal firing of inspiratory neurons
76
What contribution do central chemoreceptors have on the response to PCO2?
- 80% response to PCO2
- Located in medulla oblongata and respond to LCOAL concentrartion of H+ in the ECF (bc. H+ can't pass through blood brain barrier)
77
What happens with an increase in PCO2 in terms of chemoreceptors?
- there will be an increase in H+ in local ECF (chemoreceptors detect this and STIMULATE ventilation from VRG and DRG _
- chemoreceptors indirectly detect the arterial PCO2 (via H+ )
78
Which condition STIMULATE the central chemoreceptors?
- COPD (PO2--> 45-50mmHg and PCO2--> 55mmHg)
- Emphysema
- Fibrosis
79
What is hypercapnia?
- Increased CO2>45mmHg
80
Why can administering oxygen to someone with COPD result in breathing stopping?
- Because levels are chronic so chemoreceptors ADAPT to the plasma CO2
81
Do alveoli at top of lung contribute more or less to tidal volume at test and exercise?
- They contriubte LESS
82
How can we measure ventilation/perfusion mathcing?
- V/Q lung scan
| - Measures circulation of air and blood within lungs
83
What are volatile acids prodcued from?
- CO2, e.g. glucose
84
What are non volatile acids produced from?
- Anything other than CO2
- e.g. aas producing sulfur
- come from ingestion of acids, incomplete carbs and fats--> lactic acid)
85
What is the reaction of CO2 dissolved in water?
- CO2 + H20--> carbonic acidd (H2CO3)
- Carbonic Anhydrase catalyses reaction! (CA)
- Then H2CO3--> H+ and HCO3-
86
What happens to CO2 levels in lung disease?
- If there is a DECREASE in respiratory rate and decrease in the removal of CO2--> BUILD UP OF CO2--> H+ ions in plasma --> decreases plasma pH so RESPIRATORY ACIDOSIS
87
What occurs in abnormal increases in ventilation and respiration?
- Decreased CO2 and decreased H+ ion concentration
- Increase in pH
- Respiratory alkalosis
88
How does the kidney maintain the normal HCO3- level of 24mmol?
- reabsorbing HCO3 and synthesis of HCO3
89
What occurs in metabolic acidosis in terms of the HCO3- concentration?
- DECREASES
| - Less buffering --> decrease in pH
90
What occurs in metabolic alkalosis in terms of HCO3- concentration?
- HCO3- increases
| - More buffering --> Increase in pH
BMS2031
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