Respiratory

Question 1

Pumonary ventilation

Answer 1

• Air flow in through inspiration and out through expiration
• Contraction of diaphargm and intercostal muscles decrease pressure within the lungs causing air to flow in. Relaxation then increases pressure and forces air out

Question 2

Ventilation

Answer 2

• External respiration- requires pressure gradient and involves exchange of oxygen and CO2 betwen the lungs and the atmosphere
• Internal respiration- Gasous exchange in capillaries between blood and tissue. o2 diffuses from blood to tissue, CO2 diffuses from tissue to blood
• Cellular respiration- as cells consume o2 CO2 is made as a waste product

Question 3

Zones of respiratory anatomy

Answer 3

• Conducting zones (trachea, bronchi, bronchioles)- this is the piping system for air to travel, carry air to site of gas exhange. They Filter, humidify and warm air
• Respiratory zones- (Respiratory bronchioles, Alveolar ducts and alveolar sacs)- exchanging O2 + CO2 with blood,

Question 4

Gaseous exchange

Answer 4

• O2 needed for conversion of glucose to ATP
• CO2 is a waste product of cellular respiration
• Exchange occurs between blood in capilary and alveolus

Question 5

Asthma

Answer 5

• In allergic asthma, mast cells release histamine, prostaglandins and leukotrienes which cause bronchoconstriction by contraction of smooth muscle, oedema and globlet cells produce mucous.
• Leukotrienes attract eosinophils that increase inflammation
• This is a reversible reaction

Question 6

Asthma triggers

Answer 6

• Pets
• Exercise
• Pollen
• Chemicals
• Cold air
• Dust
• Smoke
• Pollution
• Stress/anger

Question 7

COPD

Answer 7

• COPD is a disease state characterised by airflow limitation that is progressive and is not fully reversible
• Is characterised by a restriction of airflow both into and out of the lungs, developing over a period of time - months to years.
• COPD differs from asthma in that the restriction is permeant rather than asthma which is episodic and reversable.
• Although different pathologies, they share a set of symptoms:
  Chronic cough, expectoration, breathlessness on exertion, progressive reduction in the ability to exhale, increase susceptibility to chest infections

Question 8

COPD pathophysiology

Answer 8

• Emphysema- destruction of alveoli walls forming largers and fewer alveoli= less effective gas exchange
• Bronchiectasis- dilation of bronchioles and filling with mucus
  *

Question 9

B2 agonists

Answer 9

• Bronchodilation via agonism of B2 receptors (mainly found in airway smooth muscle)
• Salbutamol activates the enzyme adenyl cyclase (GPCR)
• Adenyl cyclase converts ATP to cyclic adenosine-3’, 5’-monophosphate (cAMP)
• Increased cAMP activates protein kinase A
• Protein kinase A inhibits the phosphorylation of myosin
• This reduces the concentration of calcium ions in the muscles, causing them to relax

Question 10

Types of B2 agonist

Answer 10

• Short acting (salbutamol/terbutaline)- Rapid onset and offset
• Long acting- Rapid onset upto 12hr duration of action (maintenance therapy)
• Super-long acting (Olodaterol)- half life ~45hrs (COPD patients)

Question 11

Antimuscarinics

Answer 11

• Acetylcholine (ACh) causes contraction of smooth muscle in the bronchi via stimulation of parasympathetic nervous system
• Antimuscarinics antagonise ACh preventing contraction
• Ipratropium (short acting), tiotropium (long acting)

Question 12

antimuscarinic side effects

Answer 12

• Dry mouth
• Constipation
• Urinary retention
• Delirium
• Arrythmias
• Systemic effects less likely from inhalers (limited systemic absorption)

Question 13

Theophylline

Answer 13

• Xanthine Theophylline is a bronchodilator. In addition it affects the function of a number of cells involved in the inflammatory processes associated with asthma and chronic obstructive airways disease. Of most importance may be enhanced suppressor T-lymphocyte activity and reduction of eosinophil and neutrophil function. These actions may contribute to an anti-inflammatory prophylactic activity in asthma and chronic obstructive airways disease.

Theophylline stimulates the myocardium and produces a diminution of venous pressure in congestive heart failure leading to marked increase in cardiac output.

Question 14

Theophylline 2

Answer 14

• Narrow therapeutic index
• Seizures
• Arrhythmias
• Hypoklaemia
• Severe vomiting

Question 15

Prednisolone

Answer 15

• After cell surface receptor attachment and entry into the cell, prednisone enters the nucleus, binds, and activates specific nuclear receptors, resulting in altered gene expression and inhibition of proinflammatory cytokine production. This agent decreases the number of circulating lymphocytes, inducing cell differentiation, and stimulates apoptosis in sensitive tumor cell populations.
• After cell receptor binding pred Inhibit T Cell activation
  Inhibit Cytokine production
  Inhibit eosinophil activation
  Inhibit mast cell migration

Question 16

Leukotriene receptor antagonist

Answer 16

Leukotrienes are released from mast cells and act on Cys LT receptors which lead to eosinophil infiltration and activation
Ashma stimuli triggers formation of leukotriene A4, which covers to B4, also C4, D4 and E4.
Leukotriene Receptor Agonists have a similar structure to these receptors and compete. As a result, they inhibit early, and late stages of bronchoconstriction induced by antigen challenge.
Used in the management of asthma

Question 17

Non-pharmacological Mx

Answer 17

Box method
Purse lip breathing
Leaning forward
Avoiding triggers