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Flashcards in respiratory physiology Deck (35)
1

what is intrapleural pressure relative to intrapulmonary pressure (pressure within the alveoli)

-4 drops to -6 on inspiration which decreases intrapulmonary pressure by -1. this increases the volume by 500mls

2

describe how the pressure changes

 

decreases on inspiration and increases on expiration

3

what is the equation linking airflow to airway resistance

flow = change in pressure / resistance

4

what is work of breathing

energy required to

contract muscle

stretch elastic components

overcome airway resistance

overcome friction and inertia

5

where is the greatest resistance to airflow found

segmental bronchi

 

low cross sectional area and high airflow and turbulence

6

what is compliance

the ease of distensibility of the lung tissue when an external force is applied

the change in volume of the chest for a given change in pressure

 

determined by elastic components and alveolar surface tension

healthy = 1L per kPa

7

how can you change compliance?

decrease: pulmonary fibrosis

blocking smaller resp passages

increases surface tension

decreasing flexibility of the thoracic cage

 

increase: emphysema by reducing surface tension. also poor deflation leading to trapped air and barrel chest

 

 

lung compliance also changes with lung volume which explains differences between the base and apex. the base volume is less so more compliant

8

what produces surfactant

type 2 alveolar cells

made of phospholipids

prevents alveolar collapse and increases compliance

9

what are the 4 lung volumes

expiratory reserve volume

inspiratory reserve volume

tidal volume

residual volume

10

what are the 4 lung capacities

vital capacity

total lung capacity

inspiratory capacity

functional residual capacity

 

11

what is dead space

anatomical: parts of airways not involved in gas exchange

 

functional: anatomical plus alveolar where gas exchange is suboptimal

12

describe a vitalograph reading for a restrictive lung disease

FEV1 is reduced

FEV1 divided by FVC is normal

13

describe a vitalograph from an obstructive airway disease

FEV1 is reduced

14

where are the respiratory centres located

 

medulla and pons

15

what are the two pontine centres

pneumotaxic

apneustic

16

what are the two medullary centres

inspiratory- upper part of medulla aka DRG

 

 expiratory in the anterolateral part aka VRG

17

pneumotaxic centre function and location

upper pons

controls medullary resp centres esp DRG

18

location of the apneustic centre and function

lower pons

increases the depth of inspiration by acting on the DRG

19

what afferent nerves are involved in respiration

vagus and glossopharyngeal

20

what information does the resp centre receive

 

chemoreceptor and info about movement of the thorax

21

what higher centres can influence the respiratory centres

cerebral cortex, limbic, hypothalamus

22

what is the Hering breur reflex

when the lung inflates neurones send impulses to the DRG which prevents over inflation

23

what a J receptors aka pulmonary C fibres

juxtacapillary receptos present in the walls of the alveoli

stimulated in oedema, congestion, pneumonia and histamine

induces apnea and rapid shallow breathing

24

what do irritant receptors do

situated on the walls of bronchi and bronchioles

stimulated by harmful chemicals

induces rapid shallow breathing and long deep breaths to reverse slow lung collapse

25

what do proprioceptors do

found in chest wall, joints, tendons, muscle spindles

 

stablises ventilation

26

what do thermoreceptors do

stimulates hyperventilation to the cerebral cortex

27

what do pain receptors do`

signal to resp centre, signals hyperventilation

28

what does the cough reflex do

stimulates vagus nerve

forced expiration against closed glottis due to irritants

29

what is the sneezing reflex

irritation of nasal mucous membranes

forceful expiration with open glottis

30

what is the deglutition reflex

swallowing apneoa

31

what do chemoreceptors detect

hypoxia

hypercapnia

ph

32

where are central chemoreceptors found

medulla oblongata close to DRG

sensitive to increase in H+

H+ cannot cross BBB but CO2 can which forms H+

sensitive due to low buffering in CSF

33

where are peripheral chemoreceptors found

carotid sinus and aortic arch

carotid bodies more important in respiration

detects O2, CO2, pH, blood flow and temp

34

describe some diseases affecting ventilation

CNS trauma

stroke

poliomyelitis

diptheria

botulism

Duchennes muscular distrophy

35