Nasopharynx physiology

What are the 3 functions of the nasopharynx?

Facilitates respiration, olfaction, modification of speech sounds

How does the nasopharynx help to facilitate respiration?

Air enters nasopharynx via external nares/nostrils, then made turbulent by conchae and filtered by nasal hairs to trap particles of 6um in mucous, air is warmed and moistened as it passes over mucous membrane

What structure makes air turbulent when inhaled?

Conchae - bone plate within nasopharynx

Where are impulses from olfactory receptors transmitted through?

Olfactory nerves

Where do olfactory nevres enter?

Olfactory bulb in cerebral cortex, some sent to limbic system and hypothalamus

Why do some olfactory nerves terminate in the limbic system and hypothalamus?

Responsible for emotional and memory associations of smell

Where do the impulses end from olfactory nerves?

Orbitofrontal area of the brain

What is a diagram showing the olfactory apparatus?

What moistens the surface of the olfactory plate to dissolve odourants?

Mucous

What is the threshold like for olfaction?

Very low

What are the supporting cells of mucous membranes?

Columnar epithelial cells

What is the role of columnar epithelial cells in the olfactory apparatus?

Provides physical support, nourishment and electrical insultation for the olfactory receptor cells, as well as detoxifying chemicals that come into contact with the olfactory apparatus

What type of neurons are olfactory receptor cells?

Bipolar neurons

Where does the dendrite of olfactory receptor cells end?

Olfactory hairs

Where does the axon of the olfactory receptor cells end?

Olfactory bulb

What are the basal cells?

Stem cells located in supporting cells that divide continuously to produce new olfactory receptor cells

Where are the Bowman’s glands located?

Within connective tissue and innervated by facial nerve

What does stimulation of the Bowman’s gland cause?

Production of mucous

How many sets of sinuses are present in the skull?

4

What are the names for the 4 sets of sinuses?

Frontal, sphenoidal, maxillary, ethmoid

What are the sinuses generally lined with?

Ciliated columnar epithelium, beneath is seromucinous glands

What do seromucinous glands produce?

Mucous, IgA and other immunoglobulins