Respiratory Physiology

Question 1

What does gas flow equal?

Answer 1

Pressure gradient divided by resistance

Question 2

How thick is the respiratory membrane?

Answer 2

0.5- 1 micrometres thick- efficient gaseous exchange

Question 3

What does pneumonia do to membrane?

Answer 3

Increases thickness

Question 4

What does carbonic anhydrase catalyses?

Answer 4

The reaction between carbon dioxide and water to form carbonic acid

Question 5

What does the chloride shift do?

Answer 5

HC03 moves out of the red blood cellars Cl- ions move in, to balance the ion exchange

Question 6

What regions of the brain regulates breathing?

Answer 6

reticular formation: medulla and pons

Question 7

What are the key physiological features of chronic obstructive pulmonary diseases?

Answer 7

Irreversible decrease in ability of lungs to force out air

80% sufferers have a history of smoking

Dispnea- difficult or laboured breathing (air hunger) that gets progressively worse

Coughing and frequent pulmonary infections

Development of respiratory failure manifesting as hypoventilation, respiratory acidosis and hypoxemia

Question 8

What is COPD linked to?

Answer 8

Emphysema
Chronic bronchitis
Asthma

Question 9

What does emphysema cause?

Answer 9

Permanent enlargement of the alveoli

Destruction of the alveolar walls

Question 10

What must be enlisted to breathe due to emphysema?

Answer 10

Accessory muscles leading to fatigue

Question 11

How much of total energy is required for breathing if a individual has emphysema as oppose to being healthy?

Answer 11

15-20% total energy as oppose to 5% in healthy individuals

Question 12

What happens to the bronchioles during breathing with emphysema?

Answer 12

They open during inspiration but collapse during expiration, trapping air in the alveoli

Question 13

What causes the left ventricle of the heart to enlarge in emphysema?

Answer 13

Damage to pulmonary capillaries as alveolar walls disintegrate

Question 14

What causes chronic bronchitis?

Answer 14

Inhaled irritants lead to chronic production of excessive mucus.
Mucosae of the lower respiratory passageway becomes inflamed and fibrosed.

Obstructs airway

Increases pulmonary infections.

Question 15

What are the two types oaf patients who have COPD?

Answer 15

1. ‘Pink Puffer’- loose weight due to increased effort in maintaining adequate ventilation
2. ‘Blue Boaters’- stocky build, becoming hypoxicconstriction of pulmonary blood vessels leading to pulmonary hypertension and right sided heart failure

Question 16

What are treatments of COPD?

Answer 16

Bronchodilators

Corticosteroids

Surgery- removal of enlarged part of lung to allow greater expansion of remaining lung tissue

Oxygen- (use with caution) dilates pulmonary arteries and drives more CO2 form Hb into alveoli from where it cannot be removed

Question 17

What is asthma characterised by?

Answer 17

Coughing, dyspnea, wheezing and chest tightness.

Sense of panic for acute attacks

Question 18

What is the cause of asthma?

Answer 18

Immune response associated inflammation of the lungs

Question 19

What is the treatments of asthma?

Answer 19

bronchodilators and inhaled corticosteroids

Question 20

What is Tuberculosis caused by?

Answer 20

Infectious disease caused by the bacterium Mycobacterium tuberculosis

Question 21

What is TB spread by?

Answer 21

Coughing and spread by inhaled air

Question 22

When are symptoms of TB apparent?

Answer 22

When immunity is reduced

Question 23

What are symptoms of TB?

Answer 23

Fever, night sweats, weight loss, racking cough, coughing up blood

Question 24

What causes lung cancer?

Answer 24

90% cases from smoking

Question 25

When do sufferers usually die from diagnosis?

Answer 25

Within one year of diagnosis

Question 26

What are the three common types of lung cancer?

Answer 26

Adenocarcinoma Squamous cell carcinoma Small cell carcinoma

Question 27

Where does Adenocarcinoma develop?

Answer 27

develops from bronchial glands and alveolar cells

Question 28

Where does Squamous cell carcinoma develop?

Answer 28

develops from epithelium of the bronchi

Question 29

Where does small cell carcinoma develop?

Answer 29

develop from the main bronchi and grow aggressively

Question 30

What are the specific causes of asthma?

Answer 30

Immune dysfunction, allergen crosslinks with IgE bound mast cell membrane receptors and causes mast cell degranulation

Question 31

What are advantages of drugs delivered to the lungs by inhalation?

Answer 31

Direct delivery to the lungs Smaller doses- reduce side effects Rapid onset of action

Question 32

What is the optimum particle size for drug delivery to the lungs?

Answer 32

2-5 micrometers

Question 33

What happens to particles smaller than 1 micrometer?

Answer 33

Will not reach lower respiratory tract

Question 34

What happens to particles larger than 10 micrometers?

Answer 34

Will be swallowed

Question 35

What are pressurised metered dose inhalers and what is used as the propellant?

Answer 35

Most common for delivery of bronchodilators and anti-inflammatory drugs Uses hydrofluoroalkane as a propellant

Question 36

What is the spacer on the pressurised metered dose inhaler for?

Answer 36

A plastic reservoir acts as a chamber Removes need to co-ordinate inhalation

Question 37

What are the features of breath actuated metered dose inhaler?

Answer 37

Activated by inspiration Needs flow rate of 30L/min to discharge Can deliver an aerosol or dry powder

Question 38

How does dry powder inhalers work?

Answer 38

Inspiration generated turbulence resulting in dispersion of the drug

Question 39

What does nebulisers do?

Answer 39

Delivers drug from a reservoir solution 10 times as much drug is required to produced the effect of a metered dose device

Question 40

What are examples of short,long, and ultra long acting beta 2 adrenoceptor agonist?

Answer 40

Short acting: sabutamol, terbutaline Long acting: formoterol, salmeterol Ultra long acting: indacaterol

Question 41

What is the mechanism of action of beta 2 adrenoceptor agonists?

Answer 41

Beta2 adrenoceptors are expressed highly in the bronchial smooth muscle Stimulation stabilises receptor in its active form Causes an increase in cAMP and thus PKA leading to regulation of muscle tone Bronchodilation is due to reduced Ca2+ release from intracellular stores

Question 42

What are examples of antimuscarinic agents?

Answer 42

Ipratropium, tiotropium

Question 43

What is the mechanism of action of antimuscarinic agents?

Answer 43

Cells of respiratory system have nicotinic and muscarinic surface receptors. M3 receptors mediate bronchoconstriction and enhance mucociliary clearance; via a PKC and IP3 pathway M2 receptors inhibit ciliary activity as well as bronchodilation by inhibiting adenylyl cyclase

Question 44

What are examples of methylxanthines?

Answer 44

aminophylline, theophylline

Question 45

What is the mechanism of action of methylxanthines?

Answer 45

Found in coffee, tea, chocolate Vasodilatory, anti-inflammatory, immunomodulatory actions Inhibit enzyme phosphodiesterase (PDE).

Question 46

What are examples of corticosteroids?

Answer 46

beclometasone dipropionate, budesonide, fluticasone

Question 47

What is the mechanism of action of corticosteroids?

Answer 47

Supress inflammation and the immune response

Question 48

What is a cough for?

Answer 48

Protective mechanism that removes excessive mucus | Triggered by receptors located in the epithelial surface of the airway mucosa

Question 49

Where are receptors located in response to a cough reflex?

Answer 49

Pharynx, trachea, bronchi and bronchioles

Question 50

What are the afferents nerves involved in a cough reflex?

Answer 50

Vague and glossopharyngeal nerves

Question 51

What is the cough centre?

Answer 51

medulla

Question 52

What are the efferents nerves in a cough reflex?

Answer 52

Vague, phoenix and spinal motor nerves

Question 53

What are the effector muscles in a cough reflex?

Answer 53

Glottis, external intercostal, diaphragm

Question 54

What are the treatments for a cough?

Answer 54

``` Antitussive: Centrally acting (opioid) ``` And Peripherally acting

Question 55

What do centrally acting opioid do?

Answer 55

Increase threshold for stimulation

Question 56

What are peripherally acting antitussives and what do they do?

Answer 56

``` Local anaesthetics (lidocain) Antihistamines to reduce post-nasal drip from allergic rhinitis, which can stimulate cough ```