Special Senses: Taste
CREATED BY:
BEN JUDY
TEMI OLAFUNMILOYE
TOMI JEGEDE
PD. 4B
What is Taste?
 Taste can be categorized as a gustatory
perception.

That is a sensation that is the result of the taste buds giving off
information about the chemical properties of food and liquid
substances.
 Humans perceive taste through sensory organs on
the tongue called taste buds.


Taste buds act as specific receptors in the oral cavity.
They are widely scattered throughout the tongue, soft palate,
and inner surface of cheeks.
The Tongue
 The dorsal tongue surface is
covered with papillae,
which are small peglike
projections.
 Taste buds are found on
the sides of the big,
rounded circumvallate
papillae and the
fungiform papillae.
 Cells that respond to
chemicals dissolved in the
saliva are called gustatory
cells.
 They are epithelial cells
with gustatory hairs that
project from the taste
pores.
The Gustatory Cells
 The gustatory cells are composed of microvilli, long
gustatory hairs, that protrudes through the taste
buds.
 When stimulated, the microvilli depolarize, which
sends impulses to the brain.
 Three cranial nerves carry taste impulses.

The facial nerve (VII), the glossopharyngeal nerve (IX),
and the vagus nerve (X).
 Gustatory cells are subject to a lot of friction, so they
are replaced every few days with basal cells.
Anatomy of the Taste Buds
 There are 5 five basic taste sensations
Basic Taste
Sensations
that correspond with the 5 main types
of taste buds.
 Sweet receptors sense sugars,
saccharine, some amino acids, and
some lead salts
 Sour receptors recognize hydrogen
ions.
 Bitter receptors respond to
alkaloids.
 Salty receptors sense metal ions in
solutions.
 Umami receptors respond to the
amino acid glutamate (savory “beef
taste”).
Sensory Pathway
 There are 3 different pathways for
taste impulses. They travel from the
taste buds to the gustatory cortex.



The facial nerve conducts electrical
signals from the anterior sides of the
tongue.
The glossopharyngeal nerve
conveys signals from the posterior on
the tongue.
The vagus nerve sends taste signals
from the mouth and the larynx.
 The 3 pathways join the brain stem in
the nucleus of the solitary tract (NST).
 They go to the thalamus before
heading to 2 frontal regions: the
insula and the frontal operculum
cortex.
 BMS is a very painful condition that feels
Burning
Mouth
Syndrome
(BMS)
as if your tongue, gums, and mouth are
on fire.

A person with this syndrome often feels a
scalding sensation throughout his or her
entire mouth.
 The symptoms are a dry and sore mouth,
numbness of your lips and mouth, loss of
taste, or only a bitter sense of taste.
 BMS is referred to as a neuropathic
condition, for most BMS victims’ nerves
are not sending or processing
information correctly.


This is due to short circuiting of taste and
sensory nerves of both the central and
peripheral nervous systems.
This short circuit causes the brain to not be
able to turn off the pain receptors, which
result in the chronic pain.
Bell's Palsy
 Bell Palsy's is a disorder of
the cranial facial nerve (VII).
 Symptoms include loss of
the sense of taste, partial
impairment of taste, facial
pain, difficulty eating,
running of a fever, and onesided facial paralysis or twosided facial paralysis
 It temporarily paralyzes the
facial nerves, and disrupts
sensory receptors in the face,
causing extreme numbness.