Lecture 8 - Role of the airway in conducting clean air to the lungs Flashcards
what are the 4 different cell types within respiratory epithelium?
outlying cells - pseudostratified columnar epithelium
within epithelium - GOBLET cells.
within epithelium - BASAL cells
within epithelium - BRUSH cells
do pseudostratified cells have cilia? if so what is there function?
yes - function to move mucus towards the mouth.
what is the function of goblet cells? do they have cilia?
mucus secretion, no cilia
what is the function of basal cells, where do they attach to?
attach at base of epithelium, stem like cell that can differentiate into any other epithelial cell
what is the function of brush cells?
they are a sensory cell with thick microvilli, sense foreign material associated with trigeminal nerve
what are the two types of glands? where are they located?
glands: sit ontop of nasal septum
1. serous - watery gland secretions
2. mucus - thick, trap foreign particles
what are the 3 cell types within the olfactory mucosa?
- olfactory cells
- support cells
- basal cells
how does the olfactory cell detect and process odours to the brain?
microvilli of olfactory cell protrude into nasal cavity
–> receptors for odours –> trigger AP when odour bind –> if AP reach threshold, AP will be sent down to olfactory nerve to brain
what is the cell shape and function of basal cells within the olfactory mucosa?
cuboidal cell, function as a regenerative cell
what is the main function of the olfactory mucosa?
sense odours
what is the function of support cells?
provision of metabolic support?
describe the mylenation of the olfactory cell?
unmyelniated
what are the 5 microscopic layers of the trachea?
- epithelium (w/ basement membrane)
- laminapropria
- smooth muscle
- cartilage
- adventitia
what is the function of the laminapropria?
provide nourishment to airway wall e.g. blood vessels, lymphatics
house is the smooth muscle bound? what is its function
bound by lamina propria, contracts to make airway smaller, also engaged in immune response
what type of cartilage is the cartilage within the trachea, what is its function?
hyaline cartilage
stops trachea from collapsing under negative pressure
what is the the function of the adventitia
binds airway to the rest of the lung
where does the smooth muscle sit in the dog, ox and horse?
dog - smooth muscle sits ontop of cartilage ring
ox & horse - smooth muse sis under cartilage ring
do the bronchus (primary and secondary) and the segmental bronchi have cartilage?
interlocking and small plates of cartilage respectively.
conducting and respiratory bronchioles do not have cartilage plates, how do they stop them from collapsing?
smooth muscle control - smooth muscle tone keep little more rigid
elastic fibres - “alveolar attachment” when lung expand, stretch fibres and pull on small airways keeping them open
what are the various defence mechanisms of the respiratory system?
nasal hairs --> stop large particles cough & sneeze reflex lymphoid organs luminal epithelium mucociliary clearance specialised small airway cells - club cells alveolar macrophages
what are the defence mechanisms of the respiratory columnar epithelium?
boundary to the outside world
interact with immune cells
secrete cytokines and mediators –> support dendritic cell processes to sample the lumen
describe the action and function of the mucociliary clearance
cilia on epithelium beat in one direction –> towards mouth
epitheium secrete water solution allowing cilia to beat
stop of water secretion = mucus secreted by goblet cells
traps foreign material w/ ciliary beating moved towards mouth for swallowing or to be coughed out
what is cystic fibrosis?
mucociliary clearance doesn’t work
–> ion channels broken, no water secretion from epithelium –> mucus layer stuck and doesnt get expelled
what is the role of club cells?
smaller airways have no mucus secretions –> they would clog up
detoxify toxins by metabolising them (engulf)
secrete IgA
secrete surfactant, decreasing surface tension
what nerve innervates the sneezing reflex
trigeminal nerve - CN V
how is the trigeminal nerve innervated to initiate the sneezing reflex?
brush cell receives irritant, CN V triggered
describe anatomically what occurs during the sneezing reflex
- deep inspiration
- lung full of air
- closure of glottis
- forced contraction - internal intercostal and abd. muscle
- contraction, pushes against glottis
- forces air out through nose
what nerve innervates the coughing reflex?
glossopharyngeal nerve - CN IX
how is the glossopharyngeal nerve innervated to initiate the coughing reflex?
mechanoreceptors in trachea, larynx and bronchus detect foreign particle
describe anatomically what occurs during the coughing reflex
- deep inspiration
- brief closure of glottis
- contraction of forced inspiratory muscles - internal intercostal and abd. muscle
- abrupt force of air directed through the mouth
- cough can also be voluntary
