Pharmacology of Respiratory system Flashcards
describe the end of terminal bronchioles
do not take part in airway respiration, they don’t have air sacs at there terminal points
describe what the parasympathetic system does to the airways
- Bronchoconstriction
- Acetylcholine causes this by binding to M3 (muscarinic 3) receptor
- It innervates smooth muscle in bronchi
what does the parasympathetic system innervate in the airways
- It innervates smooth muscle in bronchi
describe what the sympathetic system innervate
- There is not good evidence that sympathetic nerves innervate the airways
- It can innervate the adrenal medulla that leads to the release of adrenaline, and this can lead to release of mediators that have an effect on the airway smooth muscle cells therefore it innervates them indirectly
- Targets for the sympathetic system – submucosal gland
- Can cause hypersecretion of the submucosal glands
what does the sympathetic system do in the airways
- THEY REGULATE BRONCHILA BLOOD FLOW AND MUCUS SECRETION
what is the receptor for the sympathetic system in the airways
beta 2 (Major drug target for drugs used to treat elements of the respiratory tract)
where are the cell bodies of the preganglionic fibres of the parasympathetic system located
located in the brainstem
where are the cell bodies of the postganglionic fibres of the parasympathetic system located
- Cell bodies of the postganglionic fibres are embedded in the walls of the bronchi and bronchioles
how does the parasympathetic system cause bronchodilation
bronchial smooth muscle contraction caused by M3 muscarinic ACh receptors on ASM cells, and increased mucus secretion mediated by M3 muscarinic ACh receptors on gland cells
how does bronchoconstriction happen
- Acetylcholine binds to G protein via G coupled muscarinic M3 receptors
- this increases phospholipase C and therefore IP3 (as it splits into IP3 and DAG)
- IP3 binds to ligand gated IP3 receptors on the endoplasmic reticulum
- This causes calcium to be released from the endoplasmic reticulum into the cytoplasm
- The calcium then binds to calmodulin and causes myosin light chain kinase MLCK to become active forming the calcium MLCK complex
- This phosphorylated the light chain of myosin
- This causes actin myosin cross linking and smooth muscle contraction
How does bronchodilator happen
- Bronchodilator nerves in human airways are non-adrenergic non cholinergic NANC
- Neurotransmitter is NO(nitric oxide)
- NOS expressed in epithelial and nerve cells
what are Two major respiratory conditions
Asthma and COPD
what is asthma and COPD caused by
- This is driven by inflammatory cells and mediators
- In the airways if there is chronic inflammation it leads to airway remodelling such as bronchoconstriction and mucus hypersecretion
what are the types of bronchodilators
SAMA and LAMA
SABA and LABA
What do SAMA and LAMA do
- Short or long acting muscarinic antagonists (SAMA and LAMA) block the binding of acetylcholine to M3 muscarinic receptors= inhibits smooth muscle contraction