Gustation (Taste)

By: Elizabeth, Mary, & Emma

Gustation

● The technical terminology for taste.○ Aka. the reason why we believe cookies to be amazing

● 5 Major parts of taste + 2 bonus tastes○ Sweet○ Salty○ Bitter○ Sour○ Umami

■ Water■ Metallic

What’s Umami?~ The taste of savor/ protein.

Sweet Tastes

● Common belief is that sweeter tastes come only from fructose, glucose, or lactose.

○ Other proteins and amino acids can activate the sensory cells in reaction of a “sweet taste”

■ Ex) M

https://www.ncbi.nlm.nih.gov/books/NBK279408/

Sour Tastes

● Sour tastes are caused by H+ ions splitting off by an acid dissolved in a watery solution.

○ Ex) L J O A

Salty Tastes

● Mrs. Stanton, why are you so salty? ○ Did Roddy put some extra magnesium, potassium, or sodium-chloride in

your salad dressing?

Because when your experiencing a salty taste, your receptors are often picking up not only that table salt on your french fries from lunch, but it will also be triggered from foods/ drinks with high amounts of mineral salts (potassium and magnesium) contents.

Bitter Tastes

● Brought together through evolution○ There are about 35 different proteins found within the sensory cells

responding at once to respond to a bitter taste. ○ Evolutionary, many plants developed a bitter taste or poison, this

tactic not only keeps the bugs away, but helps save the human race from eating that leaf that definitely is NOT lettuce.

Umami

● Think of a big, juicy, sizzling, steamy, buttery, fatty, steak.

○ You not only have began drooling, but also recall the taste of Umami.■ Caused by glutamic or aspartic acid, two amino acids found in a

variety of food and plants.● Ex) R T , , , .

Basic Anatomy of Taste

A. PapillaB. TongueC. Taste Receptors D. Taste BudsE. Gustatory CellsF. Taste Pores G. EpiglottisH. Water ReceptorsI. Gustatory CortexJ. Basal Epithelial

Cells

https://www.youtube.com/watch?v=8pCSVtwAZpE

K. Saliva

Papillae

● Raised bumps that contain the taste buds○ Vallate: lie on the back of the palatine section in a V-shaped; you

have a set about 7-12, back towards the throat○ Foliate: 2 groups on each side of the tongue, in front of the V of

the vallate○ Fungiform: respond to both sweet and sour tastes, scattered around

the tongue but more at the tip and sides

Tongue

● Muscular organ attached to the

floor of the mouth

● moves food while chewing and aids in swallowing

● helps to facilitate speech

● hosts papillae for taste

Taste Receptors

● Found in taste receptor cells on tongue and in upper digestive system

● Binding of neurotransmitters to the associated sensory dendrites triggers generator potentials that evoke action potentials in the fibers

● Taste receptors completely adapt in 1-5 minutes

Taste Buds

● The Sensory organs for Taste○ Location: Tongue- more specifically Fungiform Papillae, soft plate,

inner surface of cheeks, pharynx, and epiglottis.○ Number varies amongst each Papillae

■ Contains 50- 100 Epithelial Cells

Gustatory Cells

● Also known as taste receptor cells● Cells in the taste buds that activate the vagus nerve● Stimulated by the chemical makeup of solutions and

responds to the primary tastes ● When a stimulus activates a gustatory cell, an electrical

impulse will be sent to the cerebral cortex● The brain will interpret this as taste

Taste Pores/Gustatory Pores

● Located on top of taste receptor cells ● Parts of the food dissolved in the saliva come into

contact with the taste receptors via the taste pores

Epiglottis

● A flap of cartilage located at the end of the tongue by the throat and in front of the larynx

● Keeps food from entering the windpipe and lungs● Closes during swallowing to make sure that food is not

directly inhaled● Epiglottitis: when the epiglottis is swollen and causes

severe breathing difficulty

Water Receptors

● Tongues “taste” water by sensing sour taste○ Generally cause the difference in our perceptions on waters “taste”

● https://www.sciencenewsforstudents.org/article/tongues-taste-water-sensing-sour

Gustatory Cortex

● Brain structure located in the cerebral cortex responsible for the perception of taste found on the border of the anterior insula and frontal operculum

● Works with the taste buds to create the sensation

Basal Epithelial Cells

● Taste bud cells are subject to friction and are burned by hot foods

● They are replaced every 7-10 days and are the most dynamic

● Act as stem cells● Divides and differentiates into new gustatory epithelial

cells

Saliva

● Primary external fluid in taste receptor cells● Plays a role in taste sensitivity● Transport of taste substances to the taste receptor and

protection of the taste receptor● In order for food to have taste, it must first dissolve

in saliva

Pathway of TasteFirst 2/3 of the tongue:

taste receptors in taste buds →

chorda tympani of facial nerve

(CN VII) → solitary tract in

medulla → posteromedial ventral

nucleus→ thalamus → primary

gustatory cortex (taste processed)

Throat, palate, and back 1/3 of tongue:

taste receptors in taste buds →

glossopharyngeal nerve (CN IX) &

vagus nerve (CN X) → solitary

tract in medulla → posteromedial

ventral nucleus → thalamus →

primary gustatory cortex

Ageusia

Ageusia is the total lack of sense of taste.

It can be caused by:

● tissue damage to the nerves of the tongue● damage to the taste buds

○ example: long-term tobacco use

Phantogeusia

Phantogeusia is the creation of phantom tastes, or gustatory hallucinations. People with phantogeusia experience tastes (often metallic, bitter, or salty) without a stimulus.

The cause of phantogeusia is not clear, but it is thought to maybe be a result of nerve damage, damage to the ears, medication, aging, etc.

Works Cited

https://courses.lumenlearning.com/austincc-ap1/chapter/special-senses-taste-gustation/

https://www.ncbi.nlm.nih.gov/m/pubmed/14964052/

https://www.innerbody.com/image_nerv12/nerv125.html

http://www.virtualworldlets.net/Resources/Hosted/Resource.php?Name=SensoryMalfunctionTaste

https://health.howstuffworks.com/human-body/parts/tongue2.htm

http://jcda.ca/article/d86

Works Cited

https://explorable.com/neural-pathways-of-smell-taste-and-touch https://www.neuroscientificallychallenged.com/glossary/gustatory-cortex

Activity

In this activity, we ask you to blindfold yourselves and undergo a “taste test”. Essentially everyone will get a sample of each food that evokes the response of each major taste.

Additionally, you’ll be getting 2 mini cups of water from two different sources. This will help you recieve the responses from the water receptors on your tongue.

Activity

The Goal:

Identify each of the 5 tastes, and receive a better first hand experience with each individual taste.

Materials:

● 1X sample of each food● 2 X cups filled with

different waters● 1 x paper and pen● 1 X blindfold● 1 x Partner

Activity Steps: 1. Make a table consisting of the 5 main tastes, and a

blank box. Here you will write which food that belongs to.

2. 1 Partner will blindfold the other 3. The partner who is blindfolded will taste each food 1

at a time, and tell the other partner which box it belongs in.

4. Non-blindfolded partner will recall each of the detected foods.

5. Switch Roles 6. Compare Results to Actual Results depicted by

presenters

Activity

Taste: Food:

sweet Milk chocolate nugget

salty pretzels

unami Salami and cheese

sour Sour patch kids

bitter Unsweetened chocolate