Physiology Flashcards
What range of frequency can humans hear?
20Hz - 20,000Hz
What opens the Eustachian tube?
tensor veli palatini & levator palatine muscles.
What can dysfunction of the eustachian tube lead to?
Middle ear negative pressure
Describe the cochlea?
Curved spiral lamina
2 1/2 turns around central modiolus
Where is the endolymph of the cochlea?
In between the scala tympani and scala vestibuli (perilymph)
What are the otolith organs?
Utricle and saccule
What are the vestibular end organs?
maculae of utricle and saccule
Ampullae of lateral, posterior and superior semicircular canals
What are otoconia?
Calcium carbonate crystals
Where does the capula sit?
In the ampulla of the SCC
How is deflection caused?
Movement of perilymph
What causes the sterocilia to deflect?
bending
What is vestibular schwannoma?
Tumour of VIII nerve sheath (Schwann) cells
How does vestibular schwannoma cause imbalance?
Slowly progressive loss of function
What kind of receptors are responsible for taste and smell?
Chemoreceptors
What do taste buds consist of?
sensory receptor cells and support cells. Arranged like orange slices
How long do taste receptor cells live for?
~10 days
Where are taste receptor cells replaced from?
Basal cells
Where are taste buds present?
Tongue
Palate
Epiglottis
Pharynx
What are the four kinds of tongue papillae?
Filliform - no taste buds
Fungiform
Vallate
Foliate
What is the taste provoking chemical?
Tastant
Where are the signals conveyed from?
Cranial nerves via brainstem and thalamus to corticol gustatory areas
What nerve does the anterior 2/3rds of the tongue?
VIIth cranial nerve
chroda tympani branch of facial nerve
What does the posterior 1/3rd of the tongue?
Glossopharyngeal nerve IX
What does the epiglottis and the pharynx?
Vagus X
What are the 5 primary tastes?
Salty Sour Sweet Bitter Umami
What is the name for loss of taste function?
Ageusia
What is the name for reduced taste function?
Hypogeusia
What is the name for distortion of taste function?
Dysgeusia
Where is the olfactory mucosa?
Dorsal roof of nasal cavity
What cell types are present in the olfactory mucosa?
Olfactory receptor cells
Supporting cells
Basal cells (secrete mucus)
What does each neurone have? (olfactory)
a thick, short dendrite and an expanded end called an olfactory rod
What is the life span of an olfactory receptor?
~2 months
What do basal cells act as?
Precursors for new olfactory receptor cells
Where do the afferent fibres of the olfactory nerve go?
They pierce through the cribiform plate of the ethmoid bone and enter the olfactory bulbs in the inferior surface of the brain
What must a substance be in order to be smelled?
Sufficiently volatile and sufficiently water soluble.
What is the inability to smell called?
Anosmia
What is reduced ability to smell?
Hyposmia
What can hyposmia be an early sign of?
Parkinsons disease
What is an altered sense of smell?
Dysosmia
