Respiratory Physiology 2.1-Anatomy of Pleural cavity

Question 1

What is the pleural cavity?

Answer 1

a cavity within the thoracic cavity

Question 2

What is average total volume of lungs?

Answer 2

6L

Question 3

How full are lungs when breathing normally?

Answer 3

about half full

Question 4

What is the tidal volume?

Answer 4

how much air you breathe in and out each time

Question 5

What is functional residual capacity?

Answer 5

amount of air that we normally have left in our lungs at the end of our relaxed expiration

Question 6

What is inspiratory reserve volume?

Answer 6

extra air that we can breathe in when making big effort to fill up lungs.
Around 3L

Question 7

What is expiratory reserve volume?

Answer 7

Extra air that we can expire with a bit more effort.
About 1L

Question 8

What is vital capacity?

Answer 8

maximum amount of air that we can voluntarily expire after a maximum inspiration.
Inspiratory reserve volume plus tidal volume plus expiratory reserve vol.

Question 9

Diff between capacities and volumes?

Answer 9

capacities- no. different volumes added together
volumes- one volume

Question 10

How much air is left in lungs after a maximum expiratory effort and what is the name for it ?

Answer 10

Residual volume - 1-1.2 L

Question 10

Why is residual volume important?

Answer 10

stops the alveoli collapsing
-when the elastic fibres recoil, those elastic fibres don’t cause complete collapse of the alveoli as retain air in them.
If no air, would involve a much greater effort to inflate that alveoli again in inspiration.
Less energy required to inflate the alveoli in the next breath.

provides a volume of air that can allow gas exchange to take place between breaths
-oxygen and carbon dioxide don’t only exchange when we breathe in

Question 11

Why is expiration passive?

Answer 11

we don’t invest any energy in expiration

Question 12

When do we invest energy?

Answer 12

in expanding chest wall
invest energy in recruiting muscles to expand the chest wall in inspiration and in doing so stretch elastic fibres

Question 13

Give characteristics of dead space?

Answer 13

dead space volume is 150 ml
air sitting in those airways unable to participate in gas exchange

Question 14

What is the hilum of the lungs?

Answer 14

the point at which the lungs connect with the major airways

Question 15

Describe the pleural cavity?

Answer 15

thin cavity around the lungs
incredibly important in lung function
fluid filled cavity, around 3mls in each cavity
containing pleural fluid

Question 16

What aspects does the pleural cavity have?

Answer 16

visceral and parietal aspect
a.k.a parietal pleural membrane and visceral pleural membrane

Question 17

Where is the parietal pleural membrane?

Answer 17

part of pleural membrane that is closest to the ribs and superior surface of diaphragm

Question 18

Where is the visceral pleural membrane?

Answer 18

attached to the outer surface of the lungs

Question 19

What does the pleural fluid sitting in the pleural space mean?

Answer 19

the cohesive forces of that fluid ensure that the parietal pleural membrane and the visceral pleural membrane remain in contact with each other.
And allows them to glide across each other but not separate.

Question 20

Why is the fact the pleural membranes can glide across each other important?

Answer 20

Cohesive force ensures that the lungs are effectively stuck to the ribcage and the diaphragm. because everytime you breathe in your lungs have to glide across the surface of the ribs and the diaphragm.
Your rib cage moves and the lungs have to glide across the rib cage as those two movements occur.
Creates a friction free movement of the lungs.
Make sure the lungs are always stuck to the rib cage so if the rib cage expands, the lungs expand.
Id diaphragm contracts then the lungs follow the diaphragm as well.

Question 21

What is pleurisy?

Answer 21

inflammation of the pleural membranes stops that smooth gliding of the two pleural membranes across each other

Question 22

What happens to chest wall during inspiration?

Answer 22

expansion of lungs

Question 23

What happens to chest wall during expiration?

Answer 23

recoil of chest wall

Question 24

What stops the lungs wanting to recoil further and the chest wall wanting to expand further?

Answer 24

cohesive force of the pleural fluid that is holding the lungs against the chest wall

Question 25

What is pneumothorax?

Answer 25

lung recoils away from chest wall and collapses to unstretched size as pleural cavity is opened for e.g. by penetrating wounds.