Gustation

Gestation

Sensory perception of molecules dissolved in water that contact with organis’s sensory receptors

Begins with chemical stimulation of sensory cells clustered in 4000 taste buds

Tastings

Chemical stimuli

Lingual papillae

Visible bumps on the tongue (not taste buds)

4 types: 1 without taste buds and other 3 is beneath epithelial surface

1)Filliform

2) Foliate

3)Fungiform

4) Vallate

Filiform papillae

Small spikes without taste buds

Responsible for rough feel of tongues

Most abundant on human tongue

Congregated at the tip (most mobile part)

Aid in tongue manipulation of food by enhancing friction

Innervated and sense food texture (mouthfeel)

Sense if food has been chewed enough

Foliate papillae

Weakly developed in humans

Form parallel ridges on sides of tongue

2/3 of way back from tip, adjacent to molar and premolar teeth (most chewing occur) most flavor are

Most taste buds degenerate by 2-3 years

Fungiform papillae

Shaped like mushrooms

3 taste buds each, located on teh apex

Widely distributed, concentrated at tip and side of tongue

Respond to food texture as well

Vallate papillae

Large papillae arranged in V at rear of tongue

EAch is surrounded by deep circular trench

Glands in the root of the tongue secrete saliva into the trench and flush it out

Keeps old tastings form lingering too long around the papillae taste buds

Makes taste cells more responsive to new flavor introduced

7-12 Vallate papillae

Contain half of all taste buds (250 each on walls of papillae facing the trench

Taste buds

Shape like garlic bulb

50-100 taste cells, supporting cells, and nasal cells

Have taste hairs: tuft of apical micro ills that serve as a receptor surfaces for tastings, project into a pit (taste pore) on epithelial tongue surface

Taste cells

Epithelial cells

Synapse with sensory nerve endings at their base, where they have synaptic vesicles and release neurotransmitter

Lives 9-15 days

Basal cells

Set, cells that multiply and replace taste cells that died

Synapse with sensory nerve endings of taste buds

Plays some role in processing sensory information before signals goes to brain

Supporting cells

Curved, flattened cells

Shaped like barrel staves

Form a supportive capsule around perimeter of taste bud

Some between taste cells

No synaptic vesicles or sensory role