Lecture 30

Question 1

what occurs to the diaphragm during inspiration?

Answer 1

the diaphragm contracts, shortens and pulls flat pushing the abdominal contents downward, rib cage goes outward

shorter time than expiration

bucket handle: as ribs lift upward they swing out increasing the volume

Question 2

what occurs during expiration? what shape does the diaphragm take?

Answer 2

passive process when relaxed. diaphragm relaxes ( during tidal breathing/ normal only this muscle)

diaphragm dome shape & rib cage is lowered

Question 3

what muscles are associated with inspiration during ?

Answer 3

external intercostals, scalene, sternomatoid ( strenuous activity)

deep breathing muscles; they also contract and pull the rib cage upward and outward

Question 4

what muscles are associated with expiration?

Answer 4

internal intercostals, Rectus abdominis, obliques, transversus abdominis

internal intercostals contract and pull the rib cage downward and inward abdominal muscles also contract and help pull the rib case downward, compressing thoracic volume

Question 5

what is the difference between the internal and external intercostals?

Answer 5

the internal: compresses thoracic cage

external: lifts thoracic cage

Question 6

what is the purpose of the visceral pleural membrane?

Answer 6

it is attached to the lung surface so that the lungs cannot deflate without pulling on the pleural membrane

Question 7

what is the purpose of parietal pleura?

Answer 7

attached to the wall of the thorax and diaphragm, therefore the chest wall or diaphragm cannot move without pulling on the pleural membrane

Question 8

what does the chest wall pulling out and the elastic recoil of the lung pulling inward mean about the pressure associated with it?

Answer 8

the pleural space naturally has a negative pressure

pulling out of chest wall and pulling In go lung= intrapleural space is negative

LOOK AT PIC

Question 9

area between parietal pleural and visceral is called what?

Answer 9

intrapleural space

Question 10

what is the intrapleural pressure at rest?

Answer 10

-5cm H20

Question 11

when inspiring intrapleural pressure is what?

Answer 11

-8 cm H20

Question 12

what airway is most affected in asthma?

Answer 12

upper airway

Question 13

what is the equation for pressure ?

Answer 13

Pressure= Force/ Area

increasing surface area decreases pressure

Question 14

applying the combined gas laws what occurs to the volume when the temperature is increased?

Answer 14

it increase

P1V1/T1= P1V2/T2

Question 15

Increasing the volume in a closed system causes what in pressure?

Answer 15

pressure drops

Question 16

what is Boyles law?

Answer 16

P1V1=P2V2

Question 17

what part of the lung can relate to a closed system using Boyles law ?

Answer 17

pleural space because they aren’t open to the atmosphere

an expansion of pleural space= drop in pressure

Question 18

what part of the lung can relate to a open system using Boyles law ?

Answer 18

alveoli is related to open atmosphere. a drop in pressure would cause airflow into lungs/ pressure gradient

Question 19

what is transpulmonary pressure equation?

Answer 19

pressure inside minus pressure outside

PTp=PA-PIP

PTP= trans pulmonary pressure
PA= pressure in alveoli

PIP= pleural pressure

PIP= pleural pressure is -5

Question 20

what is alveolar pressure when not breathing?

Answer 20

0, because no pressure gradient

Question 21

what is transpulmonary pressure when thoracic cavity starts to expand?

Answer 21

0- (-8)= 8

transpulmonary pressure is positive when pleural is -

Question 22

Describe what occurs in regard to pressure change in the lung

Answer 22

look at slide 17 of the lecture

Question 23

why do we take longer to expire?

Answer 23

more airway resistance, more pressure gradients