Pharmacology - Asthma

Question 1

Where are the postganglionic fibres in parasympathetic division embedded in regards to airways?

Answer 1

In the bronchi and bronchioles. Slide 3

Question 2

What happens when the postganglionic cholinergic fibres are stimulated?

Answer 2

Bronchial smooth muscle contraction by M3 receptor and increased mucus secretion by M3 receptors on gland cells. Slide 3

Question 3

What happens when the postganglionic noncholinergic fibres are stimulated?

Answer 3

Bronchial smooth muscle relaxation by NO and VIP. Slide 3

Question 4

Where are the postganglionic fibres in sympathetic division embedded in regards to airways?

Answer 4

In the submucosal glands and the smooth muscle of blood vessels. Slide 4

Question 5

What happens when the postganglionic fibres are stimulated?

Answer 5

Bronchial smooth muscle relaxation by B2 receptors activated by adrenaline.
Decreased mucus secretion.
Increased mucociliary clearance by B2 receptors on epithelial cells.
Vascular constriction by A1 receptors. Slide 4

Question 6

What does Ca bind to to activate the inactive form of MLCK?

Answer 6

Calmodulin. Slide 6

Question 7

What causes the contraction of smooth muscle?

Answer 7

When myosin light chain (MLC) is phosphorylated due to the presence of elevated intracellular Ca. Slide 7

Question 8

What causes the relaxation of smooth muscle?

Answer 8

Dephosphorylation of MLC by myosin phosphatase. Slide 7

Question 9

What are the causes of asthma attacks?

Answer 9

Allergens (in atopic individuals), exercise, respiratory infections and environmental pollutants (dust). Slide 9

Question 10

What is chronic asthma?

Answer 10

When there are pathological changes to the bronchioles that result from long standing inflammation. Slide 10

Question 11

What are the pathological changes that causes asthma?

Answer 11

Increased mass of smooth muscle.
Accumulation of interstitial fluid.
Increased mucus secretion.
Epithelial damage (exposed nerve endings).
Sub-epithelial fibrosis. Slide 10

Question 12

What is bronchial Hyper - responsiveness in asthma?

Answer 12

When there is epithelial damage and nerve endings are exposed (C-fibres) which contribute to increased sensitivity of the airways to bronchocontrrict. Slide 11

Question 13

What are the 2 things when testing for asthma does a test indicate?

Answer 13

Hyper-reactivity and hypersensitivity. Slide 11

Question 14

What are the two phases of an asthma attack and what type of sensitivity is it?

Answer 14

Early phase which is type I hypersensitivity, and the late phase which is type IV hypersensitivity. Slide 12

Question 15

What the differences between how a nonatopic and an atopic individual deal differently with an allergen?

Answer 15

Nonatopic: Low level of TH1 response and cell mediated immune response involving IgG.
Atopic: Strong TH2 response and an antibody mediated response involving IgE. Slide 13

Question 16

What is the induction phase of developing allergic asthma?

Answer 16

Antigen presentation where TH2 cells activate B cells and produce IL-4 so B cells secrete IgE. Slide 14

Question 17

What is the effector phase when developing allergic asthma?

Answer 17

The TH2 cells release IL-5 and activate eosinophils and IL- 4/13 cause mast cells to express the IgE receptors. Slide 15

Question 18

What happens when a mast cell is activated during development of allergic asthma?

Answer 18

Due to the activation, Ca is released from intracellular stores and causes secretory granules and substances which promote airway smooth muscle contraction and attract inflammatory cells. Slide 16

Question 19

What stimulates the late phase of asthma?

Answer 19

The chemotaxins and chemokines produced from the immediate phase which cause infiltration of cytokines. These release TH2 cells which activate inflammatory cells. Slide 17