Static Respiration Lecture 9

Question 1

eupnea defintion

Answer 1

normal quiet breathing; using only the diaphragm

Question 2

hyperpnea definition

Answer 2

an increase in the expansion of the chest to enhance breathing; e.g. during exercise

Question 3

muscles involved in forced inspiration (1) and expiration (1)

Answer 3

inspiration = exterior intercostals
expiration = internal intercostals

Question 4

sub-atmospheric pressure in the pleural cavity is caused by what two forces?

Answer 4

elastic recoil of the lungs and spring tension of the chest cavity

Question 5

pleural pressure definition and abbreviation; how does it change during INSPIRATION

Answer 5

the pressure in the pleural fluid between the layers of pleura. Ppl is abbr. Ppl goes down during inspiration

Question 6

alveolar pressure definition and abbreviation; how does it change during INSPIRATION

Answer 6

pleural pressure plus the pressure caused by the elastic nature of the lungs themselves; abbr. = PA, does down during inspiration

Question 7

transpulmonary pressure definition and abbreviation

Answer 7

P-TP or PL; difference in pressure from the PA to the Ppl (inside-outside)

Question 8

transmural pressure definition

Answer 8

a pressure that tends to have the effect of keeping open a vessel or system (pressure inside pushing out)

Question 9

pneumothorax; synopsis of condition

Answer 9

chest wall/lung punctured -> lung collapse, chest wall expansion; Ppl = Pb

Question 10

lung compliance definition; is this distensibility or elasticity?

Answer 10

volume change per unit pressure; as in, how much does the lung inflate given a pressure differential of 10 cmH2O; this is distensibility; elasticity is how much it will spring back into shape once stretched

Question 11

situations of high and low compliance

Answer 11

high compliance is when you have an obstructive disease; low compliance during restrictive diseases

Question 12

hysteresis definition

Answer 12

the fact that the compliance curve for inspiration and expiration have different shapes

Question 13

ratio of work done during inspiration that goes to overcoming surface tension

Answer 13

2/3rds

Question 14

Laplace’s law

Answer 14

P (collapsing pressure) = (T (tension, surface tension)/r (radius of alveoli)) x 2

Question 15

atelectasis

Answer 15

alveoli collapse (generally) - can be caused by no surfactant to protect small alveoli from surface tension

Question 16

detergents and surface tension

Answer 16

detergents like to displace water at the air/water interface because they are hydrophobic and the interruption in the water chain lowers surface tension

Question 17

effects of surfactant

Answer 17

increased compliance, decreases atelectasis and decreases transudation

Question 18

what produces surfactant and what is it made of?

Answer 18

type II alveolar cells and DPPC (dipalmitoyl phosphatidylcholine)