Respiratory Physiology

Question 1

Upper respiratory tract

Answer 1

Larynx and above

Question 2

Lower respiratory tract

Answer 2

Trachea and below

Question 3

What level of bronchus division for each bronchial segment?

Answer 3

Tertiary bronchi

Question 4

In which primary bronchus are aspirated foreign bodies more common and why?

Answer 4

Right. More vertical direction than left, foreign bodies more likely to enter it

Question 5

Two types of pneumocytes at alveoli and function

Answer 5

Type 1- majority of alveoli, gas exchange

Type 2- produces surfactant

Question 6

Purpose of surfactant

Answer 6

Reduces surface tension, increases lung compliance

Question 7

Lung volume

Answer 7

6000ml

Question 8

Tidal volume

Answer 8

500ml

Question 9

Expiratory reserve volume

Answer 9

1100ml

Question 10

Inspiratory reserve volume

Answer 10

3000ml

Question 11

Residual volume

Answer 11

1200ml

Question 12

Function of intrapleural fluid

Answer 12

Prevents friction, holds lungs to ribcage and diaphragm so they expand

Question 13

Muscles of inspiration

Answer 13

External intercostals and diaphragm at rest

+sternocleidomastoids and scalenes on exertion

Question 14

Muscles of expiration

Answer 14

Passive at rest

internal intercostals and abdominals on exertion

Question 15

Compliance definition and is high or low good

Answer 15

Change in volume relative to change in pressure
HIGH= good
LOW= bad

Question 16

Partial pressure of oxygen

Answer 16

100mmHg (13.3kPa)

Question 17

Partial pressure of CO2

Answer 17

40mmHg (5.3kPa)

Question 18

How does alveolar ventilation vary throughout the lung

Answer 18

Decreases with height from base to apex due to changes in compliance (highest at base, lowest at apex)

Question 19

What is value for FEV1/FVC in health?

Answer 19

around 80%

Question 20

Effect of obstructive disease on FEV1/FVC ratio

Answer 20

reduced

Question 21

Effect of restrictive disease on FEV1/FVC ratio

Answer 21

stays same, may even increase

Question 22

Where in lung is blood flow greater than ventilation and vice versa?

Answer 22

Blood flow higher at base
Ventilation higher at apex
(BLOOD FLOW AND VENTILATION BOTH HIGHER AT BASE THAN APEX, THIS IS COMPARATIVE DIFFERENCE)

Question 23

Autoregulation effects when blood flow is greater than ventilation

Answer 23

Blood vessels around poorly ventilated alveoli constrict
Diverts blood to better ventilated alveoli
Bronchioles dilate to increase ventilation

Question 24

Autoregulation effects when ventilation is greater than blood flow

Answer 24

Blood vessels dilate to increase perfusion

Bronchioles constrict to reduce ventilation

Question 25

Shunt definition

Answer 25

Passage of blood through areas of lung that are poorly ventilated

Question 26

Alveolar dead space

Answer 26

Alveoli that are ventilated but not perfused (opposite of shunt)

Question 27

Oxygen transport in blood

Answer 27

3ml dissolved per litre in plasma | 197ml bound to haemoglobin per litre

Question 28

CO2 transport in blood

Answer 28

77% transported in solution in plasma | 23% within haemoglobin

Question 29

Why does anaemia not affect PO2

Answer 29

RBCs will still be saturated as partial pressure is normal (still less RBCs)

Question 30

Types of haemoglobin

Answer 30

HbA (normal)- 92% HbA2 HbF glycosylated Hb

Question 31

Types of hypoxia

Answer 31

``` Hypoxaemic Anaemic Stagnant Histotoxic Metabolic ```

Question 32

Hypoxaemic hypoxia

Answer 32

Most common. Reduction in oxygen diffusion at lungs

Question 33

Anaemic hypoxia

Answer 33

Reduction in oxygen carrying capacity of blood due to anaemia

Question 34

Stagnant hypoxia

Answer 34

Heart disease results in inefficient pumping of blood to lungs/around body

Question 35

Histotoxic hypoxia

Answer 35

Poisoning prevents cells utilising oxygen delivered to them (e.g. carbon monoxide/cyanide)

Question 36

Metabolic hypoxia

Answer 36

Oxygen delivery to tissues doesn't meet increased demand by cells

Question 37

2 classes of chemoreceptors

Answer 37

Central and peripheral

Question 38

Central chemoreceptors location and function

Answer 38

``` In medulla Detect changes in [H+] in CSF around brain Increase ventilation (increased [H+] caused by raised PCO2) ```

Question 39

Peripheral chemoreceptors location and function

Answer 39

In carotid and aortic bodies Detect changes in arterial PO2 and [H+] Cause stimulation of ventilation in response to significant fall in arterial PO2 (not oxygen content) or increased [H+] from any origin

Question 40

Barbiturates and opioids effect on ventilatory control

Answer 40

Depress respiratory centres in brain Decreases sensitivity to pH so response to PCO2 decreases Decreases peripheral chemoreceptor response to changes in PO2

Question 41

Nitrous Oxide effects on ventilatory control

Answer 41

Blunts peripheral chemoreceptor response to decreased PaO2

Question 42

What term describes the maximum volume of air that can be voluntarily exhaled following a maximum inspiration?

Answer 42

Vital Capacity