May 23, 2019 Flashcards
What is meant by the term sensory adaptation?
- 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
Where is the somatosensory cortex located
-in the parietal lobe
What are spindles
- 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
Contrast proprioception from kinesthesia
Proprioception
- > includes sense of balance/position
- > cognitive
Kinesthesia
- > includes sense of movement
- > behavioural
What type of receptor allows us to sense temperature
- 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
What are the three types of nerve fibres for pain? Indicate the relative speed of their nerve transduction
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
What are pheromones? What are its functions
- 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
Describe the route that pheromones go through in animals
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
Do humans have a vomeronasal organ? Do they have an accessory olfactory bulb?
- they do have a vomeronasal organ
- > but not accessory olfactory bulb
- > as a result, we rarely rely on pheromones
What is the function of the cribriform plate
-it separates the olfactory eipthelium from the brain
What lies above the cribriform plate? Note that there is a bulb in this answer
-the olfactory bulb lies above the cribriform plate
In terms of smell, what is meant by the term glomerulus?
- 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
Describe the general idea of how an odor first activates a signal in the olfactory epithelia and then sends that signal to the brain?
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
Does smell and taste synapse onto the thalamus? What does this mean
- they do not
- >therefore, smell and taste are only ipsilateral
What does anosmia refer to
-it refers to a loss in smell
