L11 Lung Volumes

Question 1

Lung primary function

Answer 1

• External respiration- Gas exchange

Question 2

what is the trachealis

Answer 2

smooth muscle enables adjust air flow

Question 3

what are the plueru

Answer 3

visceral= lungs
parietal= chest

Question 4

function of plural fluid

Answer 4

• Reduction of friction- during recoil
• Creation of pressure gradient- negative
• Compartmentalization- prevents infection spreading quickly

Question 5

2 lung zone + functions

Answer 5

• Conducting Zone:
  1. To warm and humidify air
  2. To distribute the gas
  3. To serve as part of the body’s defense system

• Respiratory Zone:
1. Site of Gas Exchange

Question 6

what nerve innervates lungs

Answer 6

phrenic

Question 7

describe inflation of lung mechanism

Answer 7

infaltion= contraction of diaphragm (skeletal muscle) – thoracic cavity expands and lungs are inflated
• Contraction of diphragm pushed abdominal organs down (increases space vertically) and pushes ribcage out (increases space horizontally)

Question 8

why is normal expiration passive

Answer 8

elastic properties of lungs and thoracic cavity

Question 9

atmospheric pressure number

Answer 9

760MMHG

Question 10

daltons law

Answer 10

Pb= Pn + O2 + H20 + Pco2

Question 11

boyls law

Answer 11

p + volume

Question 12

charles

Answer 12

t + volume

Question 13

henrys law

Answer 13

the solubility of a gas in a solvent is directly proportional to the partial pressure of the gas in contact with the solution S/P=k.

Question 14

explain intraplural pressure

Answer 14

• press= neg (due to elasticity)
• stretched lungs= potential to recoil inwards, + chest wall = potential to recoil outwards. opposing forces = pleural P to decrease below atm P.

Question 15

average changes in Ppl

Answer 15

more neg during inspiration

only pos during forced ex

Question 16

explain pneumothorax

Answer 16

presence of air in pleural space - lungs collapse due to elastic recoil, and chest wall simultaneously recoils outwards. Ppl = atm P, and PL is zero

Question 17

alveolar, airway, plural pressure abbreviations

Answer 17

PA (alveolar)
Pta (airway)
Ppl (plural)

Question 18

what is transmural (trans airway pressure)

Answer 18

Ptm
pressure difference across the airways
- prevents collapsing during forced ex

Question 19

what is transpulmon (trans airway pressure

Answer 19

PL = PA – Ppl = pressure difference across the lung wall

Question 20

explain pressures at end of expiration

Answer 20

muscles are relaxed and there is no airflow. Pa = 0, Ppl=-5, so PL = +5

Question 21

why is PL always pos during normal breathing

Answer 21

keeps the lungs inflated).

Question 22

explain pressures during inspiration

Answer 22

thoracic cavity expands – Ppl becomes more –ve (-8) – PL increases and the lungs inflate Alveolar diameter increases – Pa becomes –ve – air moves into lungs

Question 23

why does airflow stop (pressure)

Answer 23

Pa = atm P.

Question 24

explain pressures during expiration

Answer 24

, rib cage drops Ppl becomes less –ve, PL decreases and the stretched lungs recoil and deflate. As alveolar diameter decreases, Pa becomes +ve ie greater than atmospheric P and air is pushed out of the lungs until Pa = atm P.

Question 25

typical respir volumes

• TV
• IRV
• ERV

Answer 25

TV- 500ml
IRV- 3L
ERV- 1.3L

Question 26

Typical respir capacities
- TLC
VC
IC
FRC

Answer 26

= TLC= 6L
VC = 4.7L
IC = 3.5L
FRC = 2.5L

Question 27

Determinatns of lung volume

Answer 27

height wight altitude disease gender

Question 28

what is pulmonary ventilation

Answer 28

Ve= total volume ventilated/min

= VT x F

Question 29

average pulmonary vent

Answer 29

500ml x 12

= 6L

Question 30

what is anatomical dead space

Answer 30

not all air does not participate in gas exchange.

• Anatomical DS = air in conducting airways = usually 150ml

Question 31

what is alveolar ventilation

Answer 31

VA= total volume of air in gas exchange

= (VT-150ml) x Bf

Question 32

typical VA

Answer 32

4.2l