Taste Buds

S: Oval bodies consisting of 3 types of cells:

Supporting, Gustatory, and Basal Cells 

F: Sensory receptor organ for taste

L: Tongue (Within Papillae), soft palate, and epiglottis 

S: Form a capsule, contains 4-20 gustatory cells

F: Insulate gustatory cells from each other

L: Taste buds

S: Contains gustatory hairs (Micro Villi),

which extends through taste pores

F: Chemoreceptors, are the primary nueron

(dendrite) of the Gustatory Pathway

L: Tongue

 
F: Produce supporting cells and then develope into gustatory cells replacing the old ones

L: Bottom of taste bud

Taste Buds / Papillae

 S: Bumpy projections (elevations) on the surface of the tongue

3 Major Types: Circumvallate, Fungiform, and Filiform

F: House taste buds

L: Tongue

S: Largest in size, dome shape, forms inverted "V" shape, and consists of 7-12 taste buds

F: Works with mucous membrane, flushes materials to ensure the taste buds can respond to changing stimuli

L: Posterior 1/3 of tongue, and side walls of the mouth

S: Mushroom shape

F: Distinguishes sweet, sour, salty, and bitter tastes

L: Covers the entire surface of the tongue,

mostly on the tip and sides of the tongue.

S: Most numerous, thin long "V" shaped cone projections, contains no taste buds in humans

F: Involved with mastication

L: Anterior 2/3 of the tongue, arranged parallel to circumvallete and transversely at the tip of the tongue

Taste Sensations (4)

Sweet (Organic substances, sugar and amino acids)

Sour (Acids, and H+ "Positive Hydrogen" ions)

Salty (Inorganic salt, and metal ions)

Bitter (Alkaloid, nicotine, and caffine)

S: Organic substances, sugar and amino acids

Transduction: Causes K+ ion channels to close

S: Acids, H+ ions

Transduction: H+ ions act as a taste cell by directly entering through a channel, opening channels that allow other cations "Positively charged ions" to enter, or by closing K+ channels

S: Inorganic salt, and metal ions

Transduction: Influx of Na+ ions through Na+ channel causes depolarization, opening voltage regulated Ca2+ gates, flooding the cell with ions, leading to the release of neurotransmitters 

S: Alkaloids, nicotine, and caffine

Transduction: Increased intracellular levels of Ca2+ 

Taste Sensations / Regions of Sensation (Tongue)

Tip - Sensative mostly to sweet and salty substances

Sides  - Sensative mostly to sour substances

Back  - Sensative mostly to bitter substances

Multiple sensations can be detected by each taste bud

Activation of Taste Receptors

The chemical substance must dissolve in saliva,

diffuse into taste pores,

stimulate the gustatory hairs (receptor),

and depolarize to produce an action potential

Facial (7), Glossopharyngeal (9), and Vagus (10)

Cranial Nerves send afferent impulses through the:

Medulla (Solitary Nuclei) and Hypothalamus

To the Primary Gustatory Area

Thermoreceptors (Hot / Cold)
Mechanoreceptors (Texture)
Nociceptors (Pain)

Temperature
Smell (Greater than or equal to 80% of taste)