Anatomy of chest wall and mechanics of breathing

Question 1

which nerve innervates the diaphragm

Answer 1

phrenic nerve

Question 2

which muscles are involved in inspiration?

Answer 2

external intercostal muscles and the diaphragm (Normal breathing)

If hyperventilating - also sternocleidomastoid muscles- lift up rib 1 and 2 and scalene muscles) but the diaphragm is most important
ACTIVE PROCESS

Question 3

which muscles are involved in expiration?

Answer 3

internal intercostal and abdominal muscles PASSIVE AT REST

Question 4

describe what a pneumothorax is.

Answer 4

It’s when air gets into the lungs (piercing of lung etc) causing the lung to collapse to unstretched size. Relationship between lung and chest cavity is lost so the chest wall becomes separated from the lung and the lung becomes completely useless.

Question 5

pressure inside the pleural cavity (intra-pleural) is always ____ ?

Answer 5

negative

Question 6

pressure inside the thoracic cavity, (essentially pressure inside the lungs) can be?

Answer 6

negative or positive compared to atmospheric pressure.

Question 7

Visceral pleural membrane covers what?

Answer 7

outer surface of the lung. N.B ‘Vicera’ means organ.

Question 8

Parietal pleural membrane covers what?

Answer 8

the inner surface of the ribs

Question 9

what is pleurisy?

Answer 9

inflammation of the pleura