C&b 2 - Respiratory Mechanics And Ventilation

Front 1

Central controllers of respiration?

Back 1

Pons, medulla etc.

Front 2

Initiation of ventilation:

Role of Pneumotaxic center in pons

Back 2

first

sends signals to apneustic center

Front 3

Initiation of ventilation:

Role of apneustic center in pons

Back 3

second

controls dorsal and ventral respiratory groups in medulla

Front 4

Initiation of ventilation:

Dorsal respiratory group is ?

Back 4

inspiratory

Front 5

Initiation of ventilation:

Ventral respiratory group is ?

Back 5

inspiratory + expiratory

Front 6

Central chemoreceptors location where?

Back 6

Ventral medullae

Front 7

Central chemoreceptors respond to what?

Back 7

Hypercapnic drive

Front 8

Peripheral chemoreceptors locationS where?

Back 8

- Aortic arch

and

- carotid bodies of carotid arteries

Front 9

Peripheral chemoreceptors respond to what?

Back 9

Hypoxic drive

Front 10

What drives ventilation - hypoxia or hypercapnia?

Back 10

hypercapnic drive usually

 

hypoxic drive only if high altitude or chronic lung disease

Front 11

What is hypoxic drive?

Back 11

- incr ventilation rate response to falling PO2

- peripheral chemoreceptor mediated

- non linear response due to O2 affinity of haemoglobin

Front 12

What is hypercapnic drive?

Back 12

- incr ventilation rate response to rising PCO2

- largely central chemoreceptor mediated

- linear, immediate & significant response

Front 13

Explain the synergistic effect of hypoxia & hypercapnia

Back 13

elevated PCO2 - incr hypoxic effect on ventilation

 

reduced PO2 - incr hypercapnic effect on ventilation

Front 14

Functions of respiratory system (just the unobvious ones)

Back 14

"A-BAPI-FAPI"

- Arachdonate metabolites get synthesised

- Blood reservoir

- Acid base balance via CO2 removal

- Phonation

- Inactivation of neurotransmitters

- Filters particles

- Angiotensin 1 ---> Angiotensin 2 conversion

- Produces surfactant

- IgA secretion into bronchial mucus

Front 15

main muscles of resp.

Back 15

diaphragm

external intercostals

Front 16

accessory muscles of resp.

Back 16

scalene

pectorals

latissimus dorsi

Trapezius

abdominals (forced exhalation)

internal intercostals (forced exhalation)

Front 17

normal resp rate = ?

Back 17

15 breaths / min (10 - 18)

Front 18

How many further branching levels does the tracheobronchial tree undergo between bifurcation to the level of alveolar sacs?

Back 18

23!!!

Front 19

name the levels of tracheobronchial tree

Back 19

" Mainly loving small brothers with terminal respiratory dsa "

main bronchi

lobar bronchi

small bronchi

bronchioles

terminal bronchioles

respiratory bronchioles

alveolar ducts, sacs and alveoli

Front 20

As you go down levels of the tracheobronchial tree...

with increased branching comes:

Back 20

- Smooth muscle reduction

- Goblet and cillia cells reduction

- Seromucous glands reduction

- Cartilage reduction

- pseudostratified to squamification

- bulk flow to diffusion

- no more bronchial blood flow

Front 21

Atmospheric pressure eqn

Back 21

PB = PH2O + PO2 + PCO2 + PN2

Front 22

dry air atm pressure eqn

Back 22

PB = PCO2 / FCO2

Front 23

wet air atm presure eqn

Back 23

PB = (PCO2 / FCO2) + 47

Front 24

ideal gas eqn

Back 24

pV = nRT

Front 25

Deadspace

Back 25

lung area that is ventilated but not perfused

Front 26

Anatomical deadspace

Back 26

Air in conducting zones that don't oxygenate blood

Front 27

Physiological deadspace

Back 27

Additional volumes of lung that can't oxygenate blood 

on top of anatomical deadspace

Front 28

Anatomical deadspace should equal physiological deadspace but can change due to factors:

Back 28

Obesity

pulmonary embolism

emphysema

Front 29

VA - Alveolar ventilation -

Back 29

flow of air that oxygenates blood

70% of tidal volume usually

Front 30

Minute ventilation - 

Back 30

Airflow into lungs per minute

Front 31

Vital capacity

Back 31

Volume of air moved by max inspiration and expiration

Front 32

Tidal Volume (VT)

Back 32

Volume of air moved by regular inspiration and expiration

Front 33

Inspiratory reserve volume

Back 33

Max vol. inspirable on top of tidal volume

Front 34

Expiratory reserve volume

Back 34

Max vol. expirable on top of resting expiratory level

Front 35

total lung capacity

Back 35

vol. in lungs after max inspiration

Front 36

Residual volume

Back 36

Air remaining even after maximal expiration

Front 37

Inspiratory capacity

Back 37

Max vol inspirable from resting expiratory level

Front 38

Functional residual capacity

Back 38

Max vol expirable from resting expiratory level

Front 39

resting expiratory level

Back 39

normal breathing, after air has been expired regularly

Front 40

Effects on PaCO2?

Hyperventilation -

Hypoventilation - 

Back 40

Hyperventilation - reduces PaCO2

Hypoventilation - increased PaCO2

Front 41

How to measure airway resistance

Back 41

Measure:

1) PEFR

2) FEV1 / FVC

Front 42

% of airway resistance from upper airways?

Back 42

50%

Front 43

Factors affecting airway resistance:

Back 43

- Lung volume (collapsed/narrowed airways)

- Bronchial smooth muscle contraction

Front 44

What drugs can relax bronchial muscle and dilate airways?

Back 44

β-2 agonists and anticholinergics

Front 45

Diaphragm's innervation?

Back 45

Phrenic nerve from C3 - C5

Front 46

External intercostals innervation?

Back 46

Intercostal nerves

Front 47

Whats Transpulmonary / transmural pressure 

Back 47

Difference between Alveolar pressure (PA) and Intrapleural pressure (Ppl)

PA - Ppl

Front 48

Why is transpulmonary pressure always +ive?

Back 48

cause intrapleural pressure always is -ive

Front 49

What happens when transpulmonary pressure = 0 such as in a pneumothorax?

Back 49

elastic recoil causes lungs to collapse

Front 50

Effect of asthma on lungs

Back 50

1) Bronchial tube muscles tighten

2) airways inflame and mucus builds up

3) narrowed airways ---> dynamic hyperinflation

4) work done to move air larger

Front 51

Effect of COPD or emphysema on lungs

Back 51

loss of elasticity in airways ---> dynamic hyper inflation

Front 52

Dynamic hyperinflation is...

Back 52

tendency for airways to collapse during expiration thus trapping air in alveoli

Front 53

Compliance is...

Back 53

how compliant it is to change in volume with given pressure change

Front 54

compliance eqn, C = ?

Back 54

C = change in V / Change in transpulmonary p

Front 55

How to obtain compliance curve?

Back 55

Plot transpulmonary pressure against lung volume

Front 56

Gradient of compliance curve means...?

Back 56

compliance

Front 57

Disease states:

Fibrosis

Back 57

Fibrosis - reduced compliance

because lung parenchyma replaced with collagen

Front 58

Disease states:

Emphysema

Back 58

Emphysema - increased compliance

because elastin destroyed and alveolar septae destroyed

 

may cause dynamic hyperinflation

also loss of surface area for gas exchange

Front 59

What is Respiratory distress syndrome

Back 59

Premature babies:

- Insufficient surfactant

- lungs unable to expand

Front 60

Surfactants are secreted by:

Back 60

Type 2 alveolar cells

Front 61

Surfactants help to ...

Back 61

reduce surface tension so alveoli don't recoil inwards and collapse

Front 62

Law of Laplace eqn :

Back 62

P = 2T / r

 

Pressure needed to balance out collapsing force from surface tension over a certain alveolar radius

Front 63

Laminar flow

Turbulent flow

Back 63

smooth

rough

Front 64

W - Work done in breathing eqn:

Back 64

W = P * change in V

P - pressure

V - volume

Front 65

Resistive load?

Back 65

e.g. in COPD

stuff resisting/blocking

Front 66

Elastic load?

Back 66

e.g. pulmonary fibrosis

more force to breathe