unit 5b

Question 1

tastant molecule

Answer 1

any substance capable of stimulating the sense of taste

Question 2

papillae

Answer 2

majority of taste buds on the tongue sit on raised protrusions of the tongue surfaced called papillae
- papilla = singular form
→ papillae = plural form

there are 4 types on human tongue that differ by shape, location on tongue, & location of taste buds w/in papilla

• filiform
• fungiform
• foliate
• circumvallate

Question 3

filiform papillae

Answer 3

thin, long papillae “V”- shaped cones that dont contain taste buds but are the most numerous. Papillae are mechanical & not involved in gustation

Question 4

fungiform papillae

Answer 4

slightly mushroom- shaped if looked at in section

present mostly @ apex (tip) of tongue + on sides

Question 5

Foliate papillae

Answer 5

ridges & grooves towards the posterior part of the tongue found on lateral margins

Question 6

Circumvallate papillae

Answer 6

there are only abt 3-14 of these papillae on most ppl

• present @ back of the oral part of tongue
• arranged in circular-shaped row just in front of sulcus terminals of tongue

Question 7

Taste bud

Answer 7

structure on the tongue that contains several taste receptor cells
- young tongue contains ~ 10,000 taste buds

Question 8

taste receptor cells

Answer 8

provide taste information
- located thru-out tongue in the taste buds
- have higher sensitivity
- have very short life span (replaced freq/ w/ new taste cells)

Question 9

Microvilli

Answer 9

microscopic cellular membrane prolusioni that increase the surface are of cells & minimize any increase in volume
- involved in wide variety of functions

These microvilli extend into the mucus layer covering the olfactory epithelium, increasing the surface area for odorant molecules to bind to receptor proteins

Question 10

Taste pore

Answer 10

any of numerous spherical clusters of receptor cells found mainly in the epithelium of tongue & constituting end of organs of the sense of taste

Question 11

Supertasters

Answer 11

ppl who have genetic mutation producing extra fungiform papillae & incr. of gustatory nerve fibers per papilla
- experience greater intensity of taste than normal
- may be especially sensitive to bitter taste & texture of fat

Question 12

gustatory nerves

Answer 12

nerve fibers at each taste bud that receive info f/ taste receptor cells
- axons join 3 diff. cranial nerves to carry taste info to cortex ( which cranial nerve depends on location in tongue & pharynx/throat )

Question 13

anterior insula & front operculum

Answer 13

adjacent cortical regions involved in taste processing; considered to be PRIMARY GUSTATORY CORTEX
- plays primary role in taste identification & evaluation of taste intensity

Question 14

Orbitofrontal cortex for taste

Answer 14

ventral region of frontal lobes, located just above orbits of eyes

Contains SECONDARY GUSTATORY CORTEX (among other funcs.)
- involved in identifying taste
- determining the reward value ( pleasantness) of taste
- combining multi-sensory info to determine flavor
- signaling safety (fullness)

Question 15

Flavor

Answer 15

the perception of flavor is a multi-sensory experience
- relies on integration of cues f/ most of human senses

Process of flavor perception involves complex interaction of taste w/ smell, texture (from S1) & sight of food

Flavor perception changes over time during a meal to signal satiety - or fullness

Question 16

Gustatory map

Answer 16

cortical representation of diff taste modalities
- recent research shows gustatory map in RIGHT INSULA

Question 17

Ageusia

Answer 17

disorder of taste;
- complete loss of taste

Patients will not be able to discriminate difference among sweetness, sourness, bitterness, saltiness, & umami

Question 18

Hypogeusia

Answer 18

disorder of taste:
- partial loss of taste
→ taste sensitivity is reduced

Question 19

Dysgeusia

Answer 19

disorder of taste;
- distortion or alteration of taste
→ food tastes abnormal

Question 20

Causes of ageusia, hypogeusia, dysgeusia

Answer 20

Dysgeusia & hypogeusia: medication side effects, vitamin deficiencies, & respiratory illnesses w/ clogged nasal sinuses are common causes

Ageusia: trauma

Question 21

Geographical tongue

Answer 21

disorder of tongue
- inflammatory condition of the mucus membrane of tongue
→ in which loss of fungiform papillae produce smooth, red, painful regions that change location over time

May result form other infections or medications like antibiotics

Question 22

Fissured tongue

Answer 22

disorder of tongue;
- benign condition characterized by deep grooves (fissures) in top surface of tongue
→ assoc. w/ geographical tongue, again, environmental factors, & genetic conditions like Down’s syndrome