Upper Respiratory Passageways - Comparative Anatomy and Structural/Functional Considerations

M.9,W.1,L.2

describe respiratory epithelium

Pseudostratified columnar ciliated epithelium with goblet cells

how does the respiratory nasal passageway modify and regulate the volume of inspired air?

• rich blood supply warms the air

• Glandular secretions/mucus moisten the air

• mucus and cilia cleanse the air

• blood vessel congestion or constriction regulates airflow

what does the olfactory nasal pathway do?

runs alongside resp. pathway

responsible for detecting smells

which respiratory passages are NOT lined by respiratory epithelium?

• ethmoidal and middle conchae

• Vomeronasal gland

describe a mucus sheet (what produces it and functions)

• produced by goblet cells and submucosal glands

• moistens air

• traps particulate matter

describe the cilia in respiratory epithelium

• motile; beats at same time

• wafts mucus and trapped particulate towards pharynx where it is swallowed or expectorated

describe the submucosa of respiratory epithelium

• highly vascular

• warms incoming air

• erectile tissue like

  • congestion - disrupts airflow

  • vasoconstriction - allows increased airflow during exercise

what passages have an olfactory epithelium?

• ethmoidal conchae (and middle concha)

• vomeronasal organ

list the contents that make up the olfactory epithelium

• Olfactory receptor cells

• Bowmans glands

• Supporting cells

• Basal cells

describe olfactory receptor cells and how they work

bipolar neurons - apical pole carries non-motile cilia with specific odorant binding receptors

unite to form an olfactory nerve which passes through the cribriform plate to terminate in olfactory bulb

what do Bowmans glands do?

secretion solubilizes incoming odorants and washes away excess

what do the supporting cells of olfactory epithelium do?

provide metabolic and physical support to olfactory cells

what do the basal cells of olfactory epithelium do?

stem cells - can differentiate and replace olfactory receptor cells

how many olfactory receptors in the nose: dogs vs humans?

300 million - dogs

600 million - humans

list the bony boundaries of the adult bovine skull?

what are the palpable landmarks of an adult bovine skull?

• facial tuberosity

• Naso-incisive notch

• Infra-orbital foramen