Airways and Cough Flashcards
Which cell produces surfactant?
Type II pneumocytes
Type I pneumocytes are thin cells that line the exchange airways
What structures hold the lumen of the trachea open?
20 tracheal cartilages (C-shaped rings of hyaline cartilage)
trachealis muscle (gaps between cartilage rings)
What type of epithelium is found in the trachea?
pseudostratified ciliated columnar epithelium
sub-mucosa contains mixed sero-mucous glands
serous - humidify inspired air
mucous - traps particles
How is the epithelium of the tertiary bronchus different to the trachea?
tertiary bronchus - tall columnar
trachea - pseudostratified
Describe the structure of a tertiary bronchus
smooth muscle ring around lumen
less cartilage and it does not completely encircle the lumen
What is the role of Clara cells?
secrete one of the components of surfactant
What is the function of the basal cells?
form a stem cell population from which the other cell types develop
lie on the basement membrane
What is the specialised cilliated epithelium replaced with after many years of exposure to cigarette smoke?
stratified squamous epithelium - more resisitant to damage
How does the epithelium change as you move through the respiratory tract?
pseudostratified epithelium ===> cuboidal epithelium ===> squamous epithelium
What does parasympathetic stimulation of the submucosal glands cause?
secretion from the glands
afferents in these neural reflexes are stimulated by irritating stimuli or inflammation
What is the difference between the cough and expiration reflex?
in the cough reflex the subject draws air into the lungs first to reinforce a subsequent explosive effort
in the expiration reflex there is no preceding drawing in of breath
What ion controls the secretion of fluid into the lumen of the respiratory tract?
Cl-
chloride ions enter the epithelial cells from the interstitial fluid via a cotransporter, which also carries sodium and potassium ions
chloride ions enter the lumen via a regulated chloride channel
What are the neural pathways of the lung?
parasympathetic system
sympathetic system
sensory fibres
What does stimulation of parasympathetic innervation of the lung cause?
bronchoconstriction
vasodilation
mucous gland and goblet cell secretion
What are the most prevalent neurotransmitters within C-fibres in the lung?
substance P
CGRP
neurokinin A
What is the commonest cause of chronic cough?
asthma
