May 23, 2019

Question 1

What is meant by the term sensory adaptation?

Answer 1

• it is the change over time of a receptor to a constant stimulus
• > down regulation of a sensory receptor in the body
• note if cells are overexcited
• > they can die
• with sensory adaptation
• > information does not get sent to the brain if there is no change in stimuli

Question 2

Where is the somatosensory cortex located

Answer 2

-in the parietal lobe

Question 3

What are spindles

Answer 3

• they are tiny little receptors/sensors
• > located in our muscles
• > send signals that go up to spinal cord and brain

-note spindle has a protein that is sensitive to stretching

Question 4

Contrast proprioception from kinesthesia

Answer 4

Proprioception

• > includes sense of balance/position
• > cognitive

Kinesthesia

• > includes sense of movement
• > behavioural

Question 5

What type of receptor allows us to sense temperature

Answer 5

• TrypV1 receptors
• > the receptor is also sensitive to pain
• heat causes a conformation change in the protein
• > pain also allows for a conformation change in the protein
• > allowing the receptor to be activated and sending signals to the brain

Question 6

What are the three types of nerve fibres for pain? Indicate the relative speed of their nerve transduction

Answer 6

1) A-beta fibers
- >thick and covered in myelin

2) A-delta fibers
- >smaller diameter than A-beta and less myelin

3) C fibers
- >small diameter and unmyelinated

Question 7

What are pheromones? What are its functions

Answer 7

• it is a chemical signal released by 1 member of the species
• > and sensed by another species to trigger an innate response

-it can be linked to: mating, fighting and communication

Question 8

Describe the route that pheromones go through in animals

Answer 8

1) Pheromones go to the accessory olfactory epithelium
- >in here, you have a vomeronasal system
- >in this system, you have basal and apical cells

2)Molecules will activate either basal or apical cells

3) If basal cells are activated
- >the cell sends a signal through the accesory olfactory bulb to the glomerulus
- >then the mitral or tufted cells which eventually goes to the amygdala

4) Amygdala is involved in the emotion, aggression, mating, etc
5) Signal transduction then occurs, where the signal binds to a GPCR and then the signal goes to the brain

Question 9

Do humans have a vomeronasal organ? Do they have an accessory olfactory bulb?

Answer 9

• they do have a vomeronasal organ
• > but not accessory olfactory bulb
• > as a result, we rarely rely on pheromones

Question 10

What is the function of the cribriform plate

Answer 10

-it separates the olfactory eipthelium from the brain

Question 11

What lies above the cribriform plate? Note that there is a bulb in this answer

Answer 11

-the olfactory bulb lies above the cribriform plate

Question 12

In terms of smell, what is meant by the term glomerulus?

Answer 12

• glomerulus are referred to as an olfactory bulb
• > they are a receptor type
• > eg; there is a benzene glomerulus
• note at the glomerulus
• > each receptor then synapses on another cell known as a mitral or tufted cell
• > this cell then projects to the brain

Question 13

Describe the general idea of how an odor first activates a signal in the olfactory epithelia and then sends that signal to the brain?

Answer 13

1) molecule binds to GPCR receptor on olfactory epithelia
2) Triggers AP and then this signal is sent to the cribriform plate
3) Then this signal goes to the glomerulus
4) Activates the mitral/tufted cells
5) Finally, there is a synapse of signals onto the brain

Question 14

Does smell and taste synapse onto the thalamus? What does this mean

Answer 14

• they do not

- >therefore, smell and taste are only ipsilateral

Question 15

What does anosmia refer to

Answer 15

-it refers to a loss in smell

Question 16

Where do the signals of taste/smell go after they synapse onto the olfactory bulb

Answer 16

• they then go to the amygdala and the piriform cortex

- >from there, the signal is then transferred to the orbitofrontal cortex

Question 17

What are the 5 main tastes that we have

Answer 17

1) bitter
2) salty
3) sweet
4) sour
5) umami

Question 18

Where are taste buds located?

Answer 18

-they are located in structures called papillae

Question 19

What mechanisms do sweet, umami and bitter depend on

Answer 19

-they depend on GPCR receptors

Question 20

What mechanisms do sour and salty depend on

Answer 20

-they depend on ion channels