Taste and smell Flashcards
How are chemoreceptors of taste and smell stimulated?
By binding to particular chemicals
What can be influenced by the stimulation of taste and smell receptors?
The flow of digestive juice and enzymes
Where are sensory receptor cells of taste mainly located?
Packaged in taste buds
What is the average life span of taste receptor cells?
~10 days
How are taste receptor cells replaced?
By basal cells within the taste buds
What cells do taste receptor cells synapse with?
Afferent nerve fibres
What are the four types of papillae?
Filliform - most numerous
Fungiform
Vallate
Foliate
What is the only type of papillae that does not contain taste buds?
Filliform taste buds
What is a tastant?
A taste provoking chemical
What does the binding of tastants to receptor cells troduce?
A depolarising receptor potential
Where in the brain are taste signals conveyed to?
Cortical gustatory areas
What 3 cranial nerves are involved in the transmission of taste signals to the brainstem?
CN VII - chorda tympani
CN IX
CN X
What does the chorda tympani branch of CN VII innervate in relation to taste?
Anterior 2/3rds of tongue
What does CN IX innervate in relation to tase?
Posterior 1/3rd of tongue
What does CN X innervate in relation to taste?
Areas other than the tongue, such as the Epiglottis and Pharynx
What are the 5 primary tastes we can detect?
Bitter taste - alkaloids etc
Sour taste - H+
Salty taste - NaCL
Sweet taste - glucose
Umami - amino acids (glutamate)
What is ageusia?
The loss of taste function
What can cause ageusia?
Nerve damage
Local inflammation
Endocrine disorders
What is hypogeusia?
A reduced taste function
What can cause hypoguesia?
Drugs / medications
Chemotherapy
What is dysgeusia?
A distortion of taste function
What cranial nerve is responsible for the main olfactory system?
CN I
What cranial nerve is responsible for the trigeminal somatosensory system?
CN V
What cranial nerve mediates common odours?
CN I
