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Flashcards in Physiology of Resp Deck (105)
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1

what is ventilation/ external resp

the mechanical process of exchange of air in atmosphere and of alveoli in lungs

2

internal resp

biochemical reactions

3

describe inspiration

active process
contraction of respiratory muscles

4

describe expiration

passive process
relaxation of respiratory muscles

5

forces keeping alveoli open

surfactant
transmural pressure gradient
Alveolar interdependence

6

forces keeping alveoli closed

Elastic recoil of lungs and chest wall
Alveolar surface tension

7

what is transmural pressure?
describe the three pressures

sub-atmospheric pressure gradient in pleura- keeps alveoli open

atmospheric and intra-alveolar pressures are equal
intrapleural pressure is sub-atmospheric

8

major inspiratory muscles

Diaphragm and external intercostal muscles

9

accessory muscles of respiration

sternocleomastoid
scalenus
pectoral

10

muscles of active expiration

Abdominal muscles
internal intercostal muscle

11

What is a pneumothorax?
2 methods of how this can occur

A build up of air in the intra-pleural space, abolishing the TPG, causing the lung to collapse
Puncture to chest wall or hole in lung

12

Symptoms and Signs of pneumothorax

SOB, pleuritic chest pain
hyper-resonance, reduced chest expansion and chest sounds
small PX can be asymptomatic

13

Boyle's Law

as the volume of a gas increases, the pressure exerted by that gas decreases

14

What happens during inspiration

Active process
Contraction of diaphragm- phrenic nerve C3,4,5 (increases volume vertically) and external intercostal muscles (increased volume A, P, L)
volume of thorax increases therefore intra-alveolar pressure decreases and air moves in

15

what happens during expiration

passive process
relaxation of diaphragm (dome- vertical volume decreases) and external intercostal muscles (A, P, L)
Elastic recoil of chest and lungs so decreased volume- increased pressure- air moves out

16

What causes alveolar surface tension

H2o molecules lining the alveoli interface

17

-Cells that produce surfactant
-Contents of surfactant
-Function

Type II pneumocytes
lipids and proteins
Reduces alveolar surface tension, preventing collapse

18

Equation for alveolar pressure

P=2T/R

19

RDS in new born and its treatment

Premature baby, born without adequate surfactant, high surface tension, lung collapse
Steroids to mum before birth, synthetic surfactant

20

Alveolar interdependence

one alveoli starts to collapse, neighbouring alveoli stretch and recoil, exerting an expanding force to open the alveoli.

21

what lung volumes/capacities cannot be measured by spirometry

residual volume, functional residual capacity and TLC

22

tidal volume

volume of air entering or leaving lungs during a single breath 0.5L

23

IRV

Extra Volume of air that can be maximally inspired above TV 3.0L

24

ERV

Extra Volume of air that can be maximally expired by maximal contraction after normal TV 1.0L

25

RV

Minimum volume of air remaining in lungs after maximal expiration 1.2L

26

inspiratory capacity (+equation)

IC= IRV+TV 3.5L
Maximum volume of air that can be inspired after normal quiet expiration

27

FRC

FRC=RV+ERV 2.2L
volume of air that remains in lungs after passive expiration

28

VC

VC= IRV+TV+ERV 4.5L
Maximum volume of air that can be expired in a single breath after maximal inspiration

29

TLC

TLC= RV+VC
5.7L
Total volume of air that the lungs can hold

30

when would RV increase

loss of lung elasticity eg emphysema