factors affecting the tone Flashcards
What are the primary nerves that affect bronchomotor tone?
Parasympathetic nerves
They cause contraction of smooth muscle fibers.
What effect does atropine have on airways resistance?
Reduces airways resistance by about 30%
Atropine blocks the receptors of parasympathetic nerves.
Do sympathetic nerves directly supply bronchial smooth muscle?
No
Sympathetic effects in the lung are due to circulating catecholamines.
What role do circulating catecholamines play in bronchomotor tone?
They relax smooth muscle
Adrenaline (epinephrine) is a key catecholamine involved.
Why are catecholamines important in the treatment of asthma?
They relax smooth muscle
This helps alleviate bronchoconstriction.
What triggers mast cell degranulation?
Interaction of allergens with IgE antibodies
This leads to the release of mediators like histamine.
What percentage of bronchoconstriction is attributed to mast cell degranulation?
Less than 30%
This pertains to the early phase of asthma.
Fill in the blank: Atropine blocks the receptors of _______ nerves.
Parasympathetic
True or False: Sympathetic nerves directly affect bronchial smooth muscle.
False
What type of receptors are stimulated by inhalation of particles or chemicals?
Rapidly adapting pulmonary receptors
These receptors provoke contraction of airway smooth muscle via reflex action mediated by vagus nerves.
What is the effect of stimulating rapidly adapting pulmonary receptors?
Contraction of airways smooth muscle
This contraction may improve the efficiency of coughing.
What type of receptors reduce bronchomotor tone?
Slowly adapting pulmonary receptors
Their activity is linked to lung stretching.
What stimulates slowly adapting pulmonary receptors?
Stretching the lungs
An example is taking a large breath, such as a sigh.
True or False: Stimulation of rapidly adapting pulmonary receptors can lead to improved coughing efficiency.
True
The contraction of airways smooth muscle enhances the cough reflex.
