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Question 1

The costal cartilage of which rib articulates with the sternum at this level?

Answer 1

2nd rib

Question 2

In which way do the intercostal muscles run?

Answer 2

fibres run downwards and forwards (anteriorly) to the rib below
muscle contraction causes elevation of the ribs and an increase in the lateral and anterograde-posterior diameters of the chest

Question 3

a 24y/o woman with DVT of the Femoral vein develops sudden, onset sharp chest pain over the left lower chest. the pain is worse on breathing and coughing. a pulmonary embolism causing a pulmonary infarction is suspected. what feature of the intercostal nerve best explains this pain?

Answer 3

they supply the parietal pleura and the skin overlying each intercostal space

• breathing and coughing causes movement of the parietal pleura, aggravating the pain
• intercostal nerve sensory to the strip of parietal pleura lining the intercostal space (ICS) and the strip of skin overlying the ICS.

Question 4

what supplies the diaphragm?

Answer 4

Phrenic nerve- C3,4,5 nerve roots

Question 5

in which intercostal space is a student most likely to find the upper limit of dullness when percussing the right side of the chest?

Answer 5

5th intercostal space
L: 5th intercostal space in the MCL
R: 5th rib (not ICS)

Question 6

what is a characteristic of the L lung?

Answer 6

absence of the horizontal fissure

- only has the oblique fissure which divides it into an upper and lower lobe

Question 7

what is the best Place on the chest wall to listen for clinical signs of R lower lobe pneumonia?

Answer 7

R lower chest posteriorly

• oblique fissure extends from spinous process of T2 vertebra post - 6th costal cartilage anteriorly
• follows medial border of the scapula when the arm is abducted

Question 8

does the trachea have complete or incomplete cartilage rings?

Answer 8

incomplete C shaped cartilages

Question 9

at what level does the bifurcation of the trachea lie?

Answer 9

sternal angle

Question 10

what does elevation of the ribs do?

Answer 10

increases the AP diameter in a ‘pump handle’ type movement

- therefore both lateral and AP diameters are increased

Question 11

what does the azygous vein drain into?

Answer 11

SVC
R side of the thoracic vertebrae
The azygos vein transports deoxygenated blood from the posterior walls of the thorax and abdomen into the SVC.

Question 12

what supplies the parietal pleura and the visceral pleura?

Answer 12

parietal pleura: intercostal arteries

visceral pleura: bronchial arteries

Question 13

at which vertebral level does the opening in the diaphragm lie for the oesophagus?

Answer 13

T10

Question 14

which muscle is responsible for majority of chest expansion in quiet inspiration?

Answer 14

diaphragm

Question 15

which combination of muscles are most likely being used for forced inspiration?

Answer 15

in addition to the diaphragm and external intercostal muscles the SCM, an accessory muscle, is also being used

Question 16

which mechanism is responsible for quiet expiration?

Answer 16

the elastic recoil of the lungs

Question 17

patient has reduced chest expansion on both sides but no barrel chest. GP suspects reduced lung compliance. which mechanism is most likely for this finding?

Answer 17

increased amount of collagen in alveolar interstitium

- reduced lung compliance as the lungs are most stiff

Question 18

which muscles are most likely to bring about an increase in the transverse diameter of the chest in inspiration?

Answer 18

external intercostal muscles

- elevate the ribs to increase the transverse and anterograde-posterior diameter of the chest

Question 19

which condition is characterised by increased lung compliance?

Answer 19

emphysema

- breakdown of elastin fibres and alveolar walls make the lungs more stretchable

Question 20

T/F: in a forced expiration the diaphragm is driven into the thorax by contraction of the intercostal muscles

Answer 20

false

• contraction of anterior abdo wall muscles increase the IAP
• drives the diaphragm upwards into the thorax

Question 21

T/F: the pressure in the pleural space at the end of quiet expiration is slightly higher than atmospheric pressure

Answer 21

false

• at the end of quiet respiration the outward recoil of the chest wall is counterbalanced by the inward elastic recoil of the lung
• equal and opposing forces pulling on the pleural fluid film results in the pleural pressure being sub atmospheric

Question 22

T/F: the physiological dead space will be increased by a pulmonary embolism

Answer 22

true

Question 23

T/F: diffuse lung fibrosis decreases lung compliance

Answer 23

true

• collagen fibres harder to stretch than elastic fibres
• increased collagen deposition in interstitial space will make the lungs stiffer and less compliant

Question 24

T/F: lack of surfactant reduces lung compliance

Answer 24

true

• absence of surfactant the surface tension of the thin film of fluid lining the alveolus is high
• harder to expand the alveoli during inspiration

Question 25

T/F: the resistance to air flow through the bronchioles is greater in expiration than in inspiration

Answer 25

true - in inspiration as the alveoli expand, the radial traction on the bronchioles is greater - during expiration the radial traction will be less and therefore the lumen of the bronchioles will be smaller - this would increase the resistance to air flow in expiration

Question 26

atmospheric pressure = 71kPa atmospheric air O2= 21% saturation vapour pressure of water at 37 degrees= 6kPa what is the partial pressure of O2 in the moist inspired air in his trachea?

Answer 26

13.6kPa (71-6) x 21%

Question 27

on examination he has reduced chest expansion and fine crackles in both lungs. diffuse lung fibrosis is suspected. what set of abnormalities are most likely to be seen from an arterial blood gas analysis?

Answer 27

pO2 low pCO2 normal - alveolar capillary membrane thickened due to deposition of fibrous tissue in the interstitium, which causes a diffusion defect - CO2 diffusion less affected than O2 diffusion as it has high solubility

Question 28

people residing at high altitudes have an increased conc of 2,3-DPG in their red cells. what beneficial effect does this have?

Answer 28

shifts oxygen dissociation curve to the R

Question 29

44y/o has severe pneumonia. temp is 39 degrees and O2 sat is 92%. what change is most likely to have occurred in his oxygen dissociation curve?

Answer 29

curve shift to the R - rise in temp shifts curve to the R - means O2 is given up more readily

Question 30

athlete is sweating and experiencing muscle aches due to build up of lactic acid. what factor has the greatest effect in increasing oxygen delivery to his muscles?

Answer 30

large drop in pO2 in the tissues

Question 31

in what form is the majority of CO2 transported in the blood from tissues to the lungs?

Answer 31

as bicarbonate (HCO3-) ions in the plasma

Question 32

what set of arterial blood gas changes is most likely to be seen in a hyperventilating patient?

Answer 32

pO2 increased pCO2 decreased pH increased (alkalosis due to the low CO2)

Question 33

what is the most important stimulus in the minute to minute control of ventilation in a healthy person?

Answer 33

the effect of a change in arterial PCO2 on central chemoreceptors - very sensitive to small changes in arterial pCO2 - increase in pCO2 causes CSF pCO2 to rise which drops CSF pH - impulses sent to the resp centre causing increase in rate and depth of respiration which restores the arterial pCO2 and CSF pH to normal.

Question 34

man goes to high altitudes and his resp rate increases. stimulation of receptors in which location are most likely to have brought about a change in his resp rate?

Answer 34

carotid bodies - low atmospheric pO2 will lead to a low alveolar pO2 and low arterial pO2 - only peripheral chemoreceptors are sensitive to hypoxaemia - peripheral chemoreceptors are located in the carotid and aortic bodies.

Question 35

patient has long standing hypoxia and hypercapnia. what is the reason the central chemoreceptors are no longer responsive to the raised arterial pCO2?

Answer 35

choroid plexus has imported more HCO3- into the CSF | - increased HCO3- to restore CSF HCO3- to CO2 ratio to restore CSF pH

Question 36

breathlessness for 6 months. ex smoker. FVC: 2.8, FEV1: 2.2. what is the most likely pathology causing these results?

Answer 36

pulmonary fibrosis FEV1:FVC = 0.79 but both FEV1 and FVC are reduced this is a restrictive pattern

Question 37

69y/o breathless and a chronic cough productive of small amounts of white sputum for the last 2 years. ex smoker. prebronchodilator: FVC: 3.58, FEV1: 1.9 postbronchodilator: FVC: 3.6, FEV1: 2.0 what is the most likely diagnosis?

Answer 37

COPD shows obstructive defect as <70% no significant improvement on bronchodilators so no significant reversibility of the airway obstruction

Question 38

70y/o presents with 6 month history of progressive breathlessness and dry cough. ex smoker. FVC: 1.6, FEV1: 1.3 what is the most likely diagnosis?

Answer 38

lung fibrosis FEV1:FVC ratio = 0.81 restrictive pattern

Question 39

all the lung volumes can be measured by spirometry except:

Answer 39

residual volume - this volume cannot be exhaled - measured using the Helium dilution method