Airway Tone

Question 1

What is responsible for bronchoconstriction

Answer 1

Parasympathetic

Controlled by Vagus

Question 2

Describe parasympathetic control of bronchoconstriction

Answer 2

Short post-synaptic fibres reach the muscle and release Ach which acts on muscarinic receptors on the M3 subtype of muscle cells

Stimulates airway smooth muscle contraction and reduces diameter

Question 3

What is responsible for bronchodilation

Answer 3

Sympathetic innervation

Question 4

Describe sympathetic control of bronchodilation

Answer 4

Relaxation of bronchial smooth muscle via beta-2 receptors

Cause increase in airway diameter

Useful in exercise

Question 5

Describe muscarinic receptors

Answer 5

Ach receptors

G-protein coupled receptors found in CNS and within post-ganglionic parasympathetic neurones

Sites located at the junction between postganglionic parasympathetic neurones and the target organ

Smooth muscle

Question 6

Describe nicotinic receptors

Answer 6

Ach receptors

Found within NMJ, within CNS and the sympathetic and parasympathetic nervous system

Stimulates receptors on muscles and sympathetic and parasympathetic postganglionic receptors

Skeletal muscle

Question 7

What is the parasympathetic effect on the lungs vs cardio

Answer 7

Bronchoconstriction

Vasodilation

Question 8

What is the sympathetic effect on the lungs vs cardio

Answer 8

Bronchodilation

Vasoconstriction