Unit 1 Taste and Smell Flashcards
What is taste also called and which cranial nerve is it
The gustatory system (olfactory nerve, CNI)
What do the Papillae on the tongue each contain?
several taste receptors or buds
Where can the Taste buds also be found except the tongue?
Other parts of the mouth (lips, back of the throat)
How do the Taste buds send signals to the brain?
via three distinct cranial nerves
What does each cranial nerve of the taste buds that send signals to the brain detect? (first)
One nerve detects the anterior two-thirds of the tongue
What does each cranial nerve of the taste buds that send signals to the brain detect? (second)
One nerve detects the posterior portion of the tongue
What does each cranial nerve of the taste buds that send signals to the brain detect? (third)
One nerve detects the throat area
How many tastes do Taste Buds detect?
Five tastes
What are the five tastes that the Taste buds detect?
Sweet, sour, salty, bitter, and umami
What is the umami (감칠맛) distinct taste of?
Glutamates
How do taste preferences change?
Taste preferences may change with the body’s need, which is why pregnant women may crave a variety of foods throughout their pregnancy
What is the refinement of food taste primarily dependent on?
It is primarily dependent on the sense of smell and the number of functioning taste buds
Example of Umami
MSG
What cranial nerve is used on the Posterior 1/3 of the tongue?
CNIX, Glossopharyngeal nerve
What does the posterior 1/3 of the tongue deal with?
Sensation and taste
The special sense is taste: like salt and sweet sensation is like: is the liquid hot or cold.
Where does the sensation come from in the anterior 2/3 of the tongue?
Sensation comes from the Trigeminal nerve (V)
Like what does the food feel like, what is the temperature of the food
Where does the sense of taste come from in the anterior 2/3 of the tongue?
Sense of taste will come from CNVII, Facial nerve
What is the Papillae?
The house of the taste buds
How do we also call the Papillae?
The gustatory cells
What are the gustatory cells/ what do they contain?
They contain receptive hair cells
What is the basal component of the Papillae?
they act to replace damaged cells
(ex Hot Coffee)
How many types of Papillae do we have?
Three types
What are the three types of Papillae?
Fungiform
Vallate
Foliate
What is the first function of Taste?
It will adjust based on our nutritional need
Ex: if we are really low in sodium, we’re going to crave salt
What is the second function of Taste?
It will warn on ingestion of harmful substances
Ex: Bitterness of Coffee: when we drink it for the first time, a lot of us want to spit it out because of the bitterness. This is like a signal from the body telling us that this is dangerous, so don’t consume it
What is the third function of Taste?
Taste has a reflexive component.
What does the reflexive component of the Taste do?
It prepares our body for a meal, starting salvation.
—Slaviation does not start when you put food into your mouth.
Slaviation starts by smell and thought of food.
Taste Mechanisms
Food enters the mouth and binds to specific receptors.
We are starting with calcium instead of sodium to start this neurotransmission.
Ex: A salt binds to the receptor, then calcium is going to come in and cause exocytosis of the neurotransmitter.
What do the neurotransmitters cause in taste mechanisms and where does it go to?
Neurotransmitters cause action potentials that travel to the brain for processing.
Important:
What is sweet from? (Part of Taste perception)
sugars, alcohols, amino acids
Important:
What is sour from? (Part of Taste perception)
Acids, due to the extra hydrogen ion with it which is causing the sourness
Important:
What is Salty from? (Part of Taste perception)
From metal ions
Important:
What is bitter from? (Part of Taste perception)
From alkaloids (caffeine, nicotine)
Important:
What is Umami from? (Part of Taste perception)
From glutamate and asparate
What is bitter usually telling us?
telling us that this is not safe to consume
It’s like our body’s warning of don’t consume this, this is not meant to be in the body.
Taste perception, By Mott
Let’s say we have a sour patch kids.
It’s sour at first, and sweet after.
1: So we have sour as the first thing to start.
2: Sour is from acid because of the extra hydrogen ion.
3: It locks up on to the taste buds.
4: When we lock on to the taste buds in the front, we are using the CN VII (facial). If we lock on to the taste buds at the back, then it is CN IX (Glossopharyngeal)
5: So we lock on, calcium rushes in, which leads to exocytosis of neurotransmitter.
6: Then it travels up to the midbrain and there is no crossing, it just stays on the same side up to the thalamus
7: And finishes at the insula
Where is the insula?
It is deep in the temporal lobe.
What is so special about Taste Perception when it comes to crossing?
It does not cross, it stays on the same side of the body.
Right side of the tongue will go the right side of the brain
Where will the taste perception from the left tongue go?
left side of the tongue will go to the left side of the brain
Where will the taste perception from the right tongue go?
right side of the tongue will go to the right side of the brain
What can Taste be impacted by? (clinical implications)
By upper respiratory infection and middle ear infection
Taste relies quite a bit on smell
Eating relies quite a bit on smell because we start to initiate salavation with smell.
Where is the large impact found in relation to loss of taste perception? (Clinical implications)
found in radiation of malignancies, especially with head and neck cancers.
We see the loss of taste for them.
What is the Taste loss a side effect of?
Side effect of ACE inhibitors and Calcium Channel blockers.
It makes a lot of sense because we are using calcium for the exocytosis of the neurotransmiiters.
What is decreased taste associated with?
decreased taste is associated with decreased appetite (식욕) and decreased food intake.
Where does the sense of smell arises from?
Arises from the receptors located in the olfactory region of the nasal cavity
When we sniff, I smell perfume or regardless of what you are inhaling, what are you inhaling?
You are inhaling a particle of whatever you smell into your nose.
Taste and what is closely related?
Taste and smell are closely related
What does pleasant food odors stimulate?
Digestive enzymes
What is smell also closely linked to?
Memory
By mott: When we are smelling something
When we are smelling something
1: We sniff, we pull particles up to the roof of our nose
2: We have the olfactory bulb sitting at the top, the nerves are hanging down
3: The particle latches onto the nerve, goes up the olfactory bulb
4: Then travels back to the brain for conscious perception.
Where is Olfactory Epithelium located?
Located in the roof of nasal cavity (It’s at the top of nose)
What does the Olfactory sensory neuron located in the olfactory epithelium undergo every 30-60 days?
Undergo turnover (Olfactory nerves are constantly regenerating).
What do the olfactory sensory neurons contain?
Olfactory cilia, so we can pick up particles that are coming by
Where does olfactory Sensory Neuron terminate in? 끝나다, 종료되다; 끝내다, 종료하다
In olfactory bulb
Olfactory pathway (Sense of smell)
1: Olfactory Sensory Neuron (sense of smell) is stimulated; we are taking deep breaths in, and yup that is a particle that is foreign, we pull the particle up into our nose
2: Then the first relay is going to be the olfactory bulb
3: There are two potential pathways
–Frontal lobe: perception of smell (yup, I know what that smell is)
–Limbic system: activate emotional response with our smell
How smell travels to 2 different places
1: We take our sniff, travels up
2: We activate our olfactory nerves, which go directly up to our Olfactory tract
3: We are going through the cribriform plate/going right through the nose
4: Up to the olfactory bulb
5: We have 2 routes:
–Frontal Lobe: Conscious perception
–Limbic system: Emotional response with the smell
Clinical significance of what’s happening to our nose:
When we are smelling, what are we coupling with?
When we are smelling,
we are coupling with taste and memory
What is Olfactory decline common in?
It is common in aging.
When we age, we don’t have the acute perception of smell anymore.
What is Anosmia?
Loss of smell
What is Anosmia a early sign of?
Neurodegeneration
Ex: Loss of Smell could be a risk factor for Parkinson’s disease, Alzheimer’s disease
What is smell linked together with?
Smell with taste
What is hearing linked together?
Hearing and Vision
(especially with the vestibular system)
