Respiratory-physiology

Question 1

FEV1

Answer 1

FEV1=max volume of air exhaled in 1 second.reduced with obstruction and restriction

Question 2

FVC

Answer 2

total volume exhaled after full inhalation.Reduced w/ restriction

Question 3

Peak flow

Answer 3

measured with a peak flow meter, simple test of OBSTRUCTION =used to test asthma control

Question 4

resistance

Answer 4

ease which gas flows through conducting airways

Question 5

compliance

Answer 5

expandability of lungs and chest wall

Question 6

Obstructive disease

Answer 6

Dx: FEV1:FVC ratio<75%
Asthma:obstruction=narrowed airways due to bronchoconstriction
COPD:chronic airway and lung damage

Question 7

how do you tell the difference between COPD and asthma?

Answer 7

-test for reversibility, give bronchodilator(salbutamol) obstruction reversed in asthma but not COPD

Question 8

restrictive disease

Answer 8

FEV1 and FVC equally reduced
FEV1:FVC ratio is the same 
causes:
interstitial lung disease
neurological eg motor neurone disease
scoliosis or chest deformity 
obesity

Question 9

mixed obstructive/restrictive disease

Answer 9

• inspiration limited by restrictive disease
• expiration limited by airway obstruction
• very uncommon clinically

Question 10

severe COPD

Answer 10

• hyperinflation limits inspiration

- airway closure limits expiration

Question 11

asthma(juvenile)

Answer 11

-volumes and capacities unchanged, but flow rate to achieve them is reduced

Question 12

lung volume averages

Answer 12

tidal volume-500mL
inspiratory reserve vol -2.5L
expiratory reserve volume-1.5L
residual vol -1.5L
total lung capacity-6L

Question 13

surfactant

Answer 13

• lipoprotein
• secreted by type ii alveolar cells
• production increases markedly after 34 weeks
• increases compliance

Question 14

several hormones stimulate surfactant production…

Answer 14

• cortisol(most important)
• thyroxine
• prolactin

Question 15

surfactant clinical importance

Answer 15

infant respiratory distress syndrome=>premature birth<32 weeks give corticosteroids

Question 16

type I pneumocyte

Answer 16

gas exchange, squamous cells, site of gas exchange

Question 17

type II pneumocyte

Answer 17

secrete surfactant into alveoli -changes surface tension in alveoli preventing collapse of the alveoli hence increasing compliance

Question 18

dust cells

Answer 18

(macrophages in the lungs) immune response

Question 19

cartilage

Answer 19

keep airways open in normal respiration

Question 20

V/Q matching

Answer 20

• greater perfusion and ventilation at bottom of the lungs

- maximises gas exchange across the alveoli

Question 21

pulmonary shunt

Answer 21

ventilation is cut off in the lung so blood gets no oxygen so V/Q ration=0

Question 22

dead space

Answer 22

blood supply to alveoli are cut off so V/Q ration is high

Question 23

Type 1 hypersense

Answer 23

-exogenous
-IgE
-eosinophils
allergic asthma, hay fever

Question 24

type II hypersensitivity

Answer 24

-exogenous
-IgG,IgM
-antibody and complement
haemolytic d, graves disease, myasthenia gravis

Question 25

type III hypersensitivity

Answer 25

-cell surface -IgG,IgM -complement and neutrophils systemic lupus, erythematous

Question 26

type IV hypersensitivity

Answer 26

-cell mediated -monocytes and lymphocytes -T cell mediated multiple sclerosis,type 1 diabetes,IBS,psoariasis

Question 27

Down's syndrome

Answer 27

``` non-disjunction trisomy 21 single palmar crease low IQ alzheimers cardiac problems ```

Question 28

Edward's syndrome

Answer 28

``` non-disjunction trisomy 18 small head low ears heart problems low birth weight ```

Question 29

Patau's syndrome

Answer 29

``` non-disjunction trisomy 13 cleft lip/palate small eyes or absence of eyes abdominal problems ```

Question 30

Emanuel syndrome

Answer 30

translocation of 22/11 chromosome decreased muscle tone low IQ

Question 31

Wolf-hirschonn syndrome

Answer 31

``` deletions in chromosome 4 broad flat nasal bridge high forehead protruding eyes poorly formed ears small philtrum ```

Question 32

DiGeorge syndrome

Answer 32

``` deletion of chromosome 22 small head, low nasal bridge flat mid face thin upper lip short nose smooth philtrum ```

Question 33

cri-du-chat syndrome

Answer 33

``` deletions in chromosome 5 high pitched cry downward slanting eyes delayed growth webbing fingers low birth weight ```

Question 34

Turner syndrome

Answer 34

``` missing X chromosome female only webbed neck short stature infertility heart problems ```

Question 35

where does stridor result from

Answer 35

the larynx and trachea

Question 36

which antibody class binds to the Fc receptors on basophils to mediate type 1 hypersensitivity

Answer 36

IgE

Question 37

how does the secretion of surfactant by type II pneumocystis help to make the work of breathing easier ?

Answer 37

increases compliance

Question 38

you're on a ward and a really educated patient comes in and tells you that he has an alpha 1 anti trypsin deficiency .what does this mean ?

Answer 38

-he is suffering from hyperinflation of the lungs Alpha 1 antitrypsin usually stops elastin in the lungs being broken down by proteases.Therefore a deficiency means elastin is broken down and so lungs can't inflate and come down.