Senses III: Taste And Smell (Not On Final) Flashcards
What is anosmia?
A partial or complete loss of the sense of smell (and with it, most of her ability to taste)
When sensory cells TRANSLATE chemical, electromagnetic and mechanical stimuli into action potentials that out nervous system can then make sense of, this is called
Transduction
Senses of touch, hearing and balance use ____ to detect sound waves and pressure on the skin and in the inner ear
Mechanoreceptors
Senses of taste/gustation and smell/olfaction are what type of senses
Chemical senses
The taste and smell functions with the help of
Chemoreceptors
Where are these chemoreceptors found
Taste buds and nasal passages in order to detect molecules of food and the air around us
The sharpest senses right at birth are
Taste and smell
What sense is powerful at activating memories, triggering emotions and alerting us to danger
Taste and smell
Cases of PTS and depression can be reminded by
Taste and smell
Function of nose hairs
To filter out the molecules we smell on the way up to the nasal cavity
Few molecules make it up all the way to the back of the nose and hit the _____
Olfactory epithelium
What is the olfactory systems main organ
The olfactory epithelium
Describe the structure of the olfactory epithelium
A small yellowish patch of tissue on the roof of the nasal cavity.
The olfactory epithelium contains millions of
Pin shaped olfactory SENSORY NEURONS
What olfactory organ contains insulating columnar supporting cells
Olfactory epithelium
Any airborne molecules that end up on the olfactory epithelium will dissolve in the
Mucus that coats the olfactory epithelium
Vision functions with the help of
Photoreceptors (cells that detect light waves)
Once in the mucus the molecules bind to the receptors on ur olfactory _____ ____ which again makes up the ______
Sensory neurons, olfactory epithelium
Assuming they hit their necessary threshold what do the sensory neurons do next
They fire/send action potentials up their long axons and through the ethmoid bone into the olfactory bulb in the brain
What is right above the ethmoid bulb
The olfactory bulb in the brain
Each olfactory neutron has receptors for just ___ kind of smell
One
The more flavours a food has the more chemicals meaning the more
Receptors will be reached for the different chemicals
Once in the brain (the olfactory bulb) the signal converges with other cells in a structure called the
Glomerulus
What is a glomerulus/ what does it do
A tangle of fibres that serves as a transfer station (nose info turns into brain info)
The olfactory axon’s signal converges with the dendrites of other nerve cells in the glomerulus called the
Mitral cell
The mitral cells function is to
Take the signal to the brain
Therefore, each mitral cell can have any number (a bunch, a little) of olfactory sensory neutron axons synapsing with it, each axon representing
A single volatile chemical
The bottoms colourful things are the different sensory neutrons the top circle is the mitral cell and if you look closer you can see the dendrites the axons synapse with
(Multiple olfactory sensory neutron cells to 1 mitral cell with multiple dendrites)
The estimated 40000 different olfactory neurons help us differentiate how many different smells
About 10,000
Where in the brain does the mitral cell send the signals it’s receiving from the sensory neurons
The olfactory tract
Olfactory tract sends signal to the
Olfactory cortex
The smell in the brain then hits two different avenues/parts of the brain which are
The frontal lobe (consciously identifies smells)
The limbic system: hypothalamus, amyglada, hippocampus… (motivational, emotional aspects of smell as well as odour associated with memory)
What does the frontal lobe/cortex do in the sense of smell?
Consciously identifies the smell
The limbic system is the
Emotional ground control (fast and quick at triggering memories from that smell and at activating ur sympathetic systems fight or flight response when the smell is associated with danger (burning).
Why is not being able to smell depressing and make you anxious?
Anxious: you can’t sense danger from smells.
Depressing:
Memories aren’t triggered anymore
Serotonin isn’t released when you smell food (normally is)
Taste is ___ smell
80%
How is taste related to smell
As one chews his/her food, air is forced up your nasal passages, so the olfactory receptor cells are registering information at the same time as the taste receptors are, so people experience both smelling and tasting simultaneously.
If you hold you nose will u taste nothing
No but you wont be able to differentiate types of sweetness (caramel and sugar), sourness (lime or lemon) ur just weakens ur taste but we are taste receptors are still there
When you take a bite all the sensory info (flavours (chemicals) in that one food are quickly sorted by the ten thousand or so
Taste buds
Taste buds cover the
Tongue
Mouth
Upper throat
All tastes register in all parts of the tongue tru or false
True, the flavours u can taste are not dependent on a specific location on the tongue.
The taste buds are actually tucked into tiny pockets hidden behind the
stratified squamous epithelial cells on the tongue
There are 50 to 100 taste receptor epithelial cells
On each taste bud which resisted and respond to different molecules in the food.
They are specialized epithelial cells not nervous tissue meaning
They go through the whole synapse sensory neutron information carrying process about the type and amount of taste back to the brain
The two types of specialized epithelial sells are
Gustatory and basal cells
In order to taste any food, those food chemicals, or tastants, must dissolve in ____ so they can diffuse through those ______ ____ and bind to receptors on those _____ cells, and then trigger an ____ potential.
Saliva
Taste pores
Gustatory
Action
Explain: each taste is sensed differently.
Salty things- full of positively charged sodium ions that cause sodium channels in gustatory cells to open which generate a graded potential and spark an action potential
Sour things are acidic and high in hydrogen ions and take a different role
Basically just understand that different tastes react action potential in different ways
So taste, like all our senses, is all about how
action potentials get triggered.
Once an action potential is activated, that taste message is relayed through neurons via the
7th, 9th and 10th cranial nerves
Those cranial nerves take the taste message to the taste area of the
Cerebral cortex
at which point does the brain makes sense of it all, and begin releasing digestive enzymes in the saliva and gastric juices in the stomach to help the breakdown of that food.
Once the taste message reaches the cerebral cortex
The gustory complex is a part of the
Sensory cortex (responsible for taste)
