Question 1

What are the 2 cell types present in the alveoli and what do they do?

Accepted Answer

type 1 pneumocyte - gas exchange surface type 2 pneumocyte - surfactant

Question 2

What does surfactant do?

Accepted Answer

stops surface tension and reduces lung stiffness and transudation

Question 3

Why towards end of breath does force not increase the flow of air?

Accepted Answer

Effort independent. Pressure midway between alveolar and mouth decreased below intrapleural pressure and airway collapses - eventually it will reopen and this produces brassy sound of forced exhalation

Question 4

whats the diffusing capacity? and how is it calculated?

Accepted Answer

Permeability and area of the lungs. Co uptake = DLCO x (alveolar PCO - capillary PCO(=0 because Co strongly binds to haemoglobin)) so DL=Co uptake from lungs/alveolar PCO

Question 5

name a perfusion and diffusion limited gas?

Accepted Answer

``` perfusion = 02 diffusion = CO ```

Question 6

whats the resting 02 consumption and at exercise?

Accepted Answer

250ml/min and 4L/min

Question 7

What is the haldane effect?

Accepted Answer

co2 content of oxygenated blood is less than that of deoxygenated blood. As deoxygenated Hb is a better proton acceptor. H2Co3 goes to H+ and HCO3-

Question 8

Symptoms of hyperventilating?

Accepted Answer

light headiness, muscle cramps (respiratory alkalosis can affect Calcium balance), cerebral vasoconstriction.

Question 9

Where are the central chemoreceptors located? what do they measure? and what contribution do they have to the ventilation response?

Accepted Answer

Ventrolateral surface of medulla and medullary raphe, responds to blood CO2 indirectly through H+. and 80% of response to Co2. BBB not permeable to H+ so not responsive to blood pH.

Question 10

Where are the peripheral chemoreceptors and what do they measure? what 2 cell types do they have?

Accepted Answer

Carotid and aortic bodies and changes in co2, H+ and o2. Glomus and sheath cells

Question 11

Name 3 lung receptors and their effects? and innervation?

Accepted Answer

Stretch receptors - Hering breurer inspiratory reflex. Juxtapulmonary receptors - alveolar and bronchial walls - stimulated by fluid and oedema and cause rapid shallow breathing and decreased HR and BP. Irritant receptors - in trachea cause cough and in lower airways shallow breathing. All vagus nerve

Question 12

Does V/Q mismatch affect CO2 to the same extent as O2?

Accepted Answer

No Overventilated areas can lose extra co2 and partly compensate unlike 02

Question 13

Where is the pneumotaxic area located?

Accepted Answer

In rostral pons in parabrachialis area midway between the midbrain and the pons

Question 14

apneustic area location? and DRG location?

Accepted Answer

caudal pons , bilaterally in NTS

Question 15

structures that make up the VRG and their functions?

Accepted Answer

Top - Botzinger complex - expiratory Pre-Botzinger complex (generates rhythmic bursts) and nucleus ambiguus - inspiratory Nucleus retroambigualis - expiratory

Question 16

Where are carotid body chemoreceptors and where are carotid baroreceptors?

Accepted Answer

``` chemo = birfurcation baro = carotid sinus just above bifurc ```

Question 17

does carotid body respond to h+ pco2 and po2 individually?

Accepted Answer

yes

Question 18

How does sns increased breathing? One way

Accepted Answer

Carotid body have rich fenestrated capillary supply which is innervated by ANS. When sns increase vessels constrict and fool receptor into thinking low o2 increasing breathing

Question 19

Out of pco2, po2 and h+ which gives the greatest ventilatory response?

Accepted Answer

pco2

Question 20

describe the dangers of hypercapnia in pulmonary disease?

Accepted Answer

PCo2 increases and remains elevated. pH of CSF slowly recovers due to HCO3- influx. Now higher Co2 required to stimulate ventilatory reponse. o2 drive is now dominate. give o2 supress o2 drive co2 levels rise to over 100 has depressing effect on ventilation -death

Question 21

If left venticle has loss of definition what does that imply?

Accepted Answer

Disease in lingula lobe

Question 22

What does displacement or loss of the aortic knuckle indicate?

Accepted Answer

aortic aneurysm

Question 23

Why does smoking decrease the effectiveness of steroids?

Accepted Answer

Decreases histone deacetylase and so stops steroids being able to switch off inflammatory gene. The increased expression of inflammatory genes is regulated by acetylation of core histones around which DNA is wound, and conversely these activated genes are switched off by deacetylation of these histones. HDAC-2 is required by corticosteroids to switch off activated inflammatory genes, so that is why you get steroid resistance.

Question 24

What is the FET?

Accepted Answer

Forced expiratory time - amount of time the patient exhales during the FVC maneuver.

Question 25

What is FRC?

Accepted Answer

Volume of air in lungs following a tidal volume exhalation =ERV +RV

Question 26

Whats VC?

Accepted Answer

vital capacity - max vol of air that can be exhaled after max inhalation.

Question 27

TLC ?

Accepted Answer

total vol of air in lungs at full inhalation - IC + FRC

Question 28

Whats IC?

Accepted Answer

Inspiratory capacity - max volume of air that can be inhaled from tidal vol end expiratory level = Vt + IRV

Question 29

how is RV measured?

Accepted Answer

Breath analysis with He Gas

Question 30

how long does fvc maneuver have to go on for? how many times does it need repeating?

Accepted Answer

6s and 3. You should have three readings of which the best two are within 100ml, or 5%, of each other. For some COPD patients with severe COPD may take them 15seconds to blow out. So encourage them to blow out for as long as possible.

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2.02 Breathless: Asthma, Anaemia, Acute Respiratory failure, Bronchiectasis, COPD, Cor pulmonale, Heart failure Flashcards

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