PBL

Question 1

Name the 4 types of bronchodilators

Answer 1

1. Beta 2 adrenergic receptor agonists
2. theophylline
3. muscarinic receptor antagonists
4. leukotriene receptor antagonists

Question 2

what are the types of beta 2 adrenergic receptor agonists? and give examples

Answer 2

1. Short-acting - salbutamol
2. longer acting - salmeterol
3. ultra-long acting

Question 3

what type of receptor is the beta 2 adrenoreceptor and what is its activation cascade?

Answer 3

G protein coupled receptors -
binding of an agonist causes the recruitment of adenylate cyclase which converts ATP to cAMP, this activates PKA.
PKAa will cause downstream protein phosphorylation causing muscle relaxation

Question 4

What are the common side effects of salbutamol?

Answer 4

tremor and tachycardia - due to the receptors in heart and skeletal muscle

Question 5

What two features characterise asthma what what does this result in?

Answer 5

characterised by:
1. inflammation in the airways
2. hyper-reactivity of the bronchioles, e.g. to irritant chemicals, cold air, stimulant drugs etc. 
Results in:
1. bronchoconstriction
2. mucus production

Question 6

Describe the development of asthma

Answer 6

IgE mediated gypersensitivity reaction. IgE made by plasma cells coat the surface of mast cells. presentation of an antigen to these mast cells causes cross linking of 2 IgE receptors leading to degranulation

Question 7

What is the mechanism of action of theophylline?

Answer 7

phosphodiesterase inhibitor. Phosphodesterase will convert cAMP to AMP. blocking this coversion will increase intracellular cAMP this in tern will activate more PKA causing downstream protein phosphorylation and therefore muscle relaxation

Question 8

what is the mechanism of action of muscarinic receptor antagonists?

Answer 8

competetive inhibition of ach receptors on smooth muscle cells. means fewer muscarininc receptors are activated, and smooth muscle stays relaxed and airways remain open

Question 9

what is the definition of potency?

Answer 9

the concentration of a drug that it takes to cause a particular effect

Question 10

what is the definition of affinity?

Answer 10

how tightly something binds

Question 11

what is the definition of efficacy?

Answer 11

the magnitude of the effect a drug can achieve at saturation

Question 12

what is psycho-somatic?

Answer 12

relating to the interaction of mind and body

Question 13

what is the brain region involved in pattern generation in breathing

Answer 13

pre-botsinger

also involved ventral and dorsal and pontine

Question 14

what are the sensory inputs that control breathing?

Answer 14

chemoreceptors
lungs and airways
chest wall

Question 15

where are the peripheral chemoreceptors located and what do they primarily sense?

Answer 15

carotid bodies and aortic arch - primarily sensitive to decreases in the partial pressure of oxygen, however also sensitive to changes in pH and CO2

Question 16

where do you find central chemoreceptors? and what is their stimulus?

Answer 16

on the surface of the medulla (and other areas of the brain stem) - stimulated by increase in PCO2 (not pH or hypoxia)

Question 17

what is the ventilation response to hypercarbia (hypercapnia)?

Answer 17

a proportional increase in ventilation rate to PCO2 until maximum is reached

Question 18

what is the ventilation response to hypoxia?

Answer 18

increasing levels of O2 will have little effects however low levels will increase levels of ventilation

Question 19

what is the mode of action of sodium cromoglicate?

Answer 19

mast cell stabiliser, prevents the release of mediators that would normally attract inflammatory cells.

Question 20

What are the criteria for diagnosis of asthma?

Answer 20

FEV1/FVC <80%
improvement with bronchodilatory administration
use of peak-flow monitoring
metacholine challenge testing - inducing an asthma type attack
skin prick test or measure of specific IgE to allergens