Olfaction and taste

Question 1

Layers of the olfactory/smell system

Answer 1

Cribriform plate
olfactory epithelium
Olfactory sensory neurones

Question 2

Why do you loose your sense of smell with covid?

Answer 2

damage to the cells that support and assist the olfactory neurons

Question 3

Stages of the olfactory system

Answer 3

Olfactory bulb-PC(3 layered)-Thalamus- Associational cx

Question 4

What feature does olfactory pathway have that other sensory pathways have?

Answer 4

No mandatory thalamic relay-

Question 5

How many olfactory receptor neurone do we have compared to other mammals

Answer 5

Humans have a low amount around 12 million

Question 6

odour dimensionality

Answer 6

This is when you smell something certain parts of the olfactory system is triggered
Humans can distinguish around 10^27 odours

Question 7

Experiment with olfaction

Answer 7

Man and dog asked to track scent over loud periods of time
Overtime both dog and human got better
Dog was significantly quicker and more efficient

Question 8

What does sensitivity to odours depend on

Answer 8

Concentration

Question 9

hyposmia

Answer 9

Lack of olfactory sensitivity also presented in Parkinson’s disease

Question 10

Anosmia

Answer 10

Lack of smell and taste also presented in Parkinson’s disease

Question 11

Pheromones

Answer 11

Animals have a system of smell to report evolutionary fitness

Question 12

ORNs(olfactory receptor neurones)

Answer 12

Bipolar neurones with connections to colliery and mucus layer
They are supported by basal cells

Question 13

ORN issues

Answer 13

They are placed in a risky position and can easily be damaged but are slowly replaced

Question 14

Where can you measure receptor potential in ORNs

Answer 14

Cilia of receptor neurone

Question 15

Olfactory G protein

Answer 15

G protein binds to terminus C causing the release of cAMP which activates cyclic nucleotide gated channel allowing passage of na+ and ca2+

Question 16

Ordarant receptor proteins

Answer 16

Genes associated with smell are TM1-TM7

Question 17

Mechanism of odourant transduction?

Answer 17

odourant molecule binds to receptor-Active G protein- GTP activates cAMP-opens sodium and calcium channels-Chloride channel opens and diffuses out

Question 18

olfactory glomerulus

Answer 18

axons of many olfactory receptor cells converge on an individual glomerulus in the olfactory bulb, where they make contacts with the distal dendrites of mitral and tufted cells.
Only 1 or 2 are activated by an odour

Question 19

Mitral cells

Answer 19

Projection neurones

Question 20

3 reasons for tase

Answer 20

Is it edible
Is it dangerous
Preparation for digestion

Question 21

Taste system

Answer 21

T

Question 22

Taste system

Answer 22

Taste buds send signal through cranial nerve to solitary tract to the thalamus

Question 23

Different types of taste

Answer 23

Sour
Bitter
Salty
Sweet

Question 24

Types of taste receptor cells

Answer 24

Type I- detects salty things In mouth releases potassium ions and re-uptake of glutamate
Type II- detects sweet and bitter cause release of ATP and release serotonin
Type III-Activate the presynaptic cell and promotes transmitter release

Question 25

sensory transduction in taste cell stages

Answer 25

Odourant binds to villi
Secondary messengers cause membrane depolarisation
release of multiple transmitters
Action potential is received from postsynaptic neurone
Signal is sen to cortex

Question 26

What type of molecule opens up GPCR?

Answer 26

sugary molecules open up GPCR(heteromeric complexes/2 subunits) and activate TRMPM5

Question 27

Taste experiment

Answer 27

Different genes were deleted in order to test if they are responsible for certain taste
Gene responsible for sweet taste is T1R2