Sensory Practical Flashcards
Which areas have the most touch receptors
Why
Lipids / fingers
Greater density as more needed in these areas
Name the 4 touch receptors
Merkels disc
Meissner corpuscles
Krause end bulbs
Root hair plexus
What are the 2 pressure sensors
Pacinian corpuscles
Ruffin endings
Where do primary receptors have more overlapping receptor fields
Calf
How many signals are sent when receptor field is activated
1
In cold water what’s activated
Pain receptors
What causes numbness in cold water
Touch receptors not working well
When put back into room temperature water,
why do cold hands feel warmer
Why do warm hands feel colder
Both have adapted to the first temperature via free nerve endings
Acuity meaning
Determining the location of the stimuli
Why is sensing temperature at high acuity not easy
Thermoreceptors are spaces out in the skin
Not a high acuity
What does sensing temperature over a larger area enable
Helps with thermoregulation
Why don’t thermoreceptors fire at body temperature
They’re inactivate at 37*
Stops spontaneous activation
Define the field of vision
Entire area seen by the eye when fixed in one position
Why can determining he visual fields be useful?
Help in determining blindness
Help in localising brain lesions
What sees white light
Rods
What sees red/blue/green
Cones
Where are rods found? What does this allow
All over retina
Enables to see more
Where are cones found
Middle retina
More focused vision
Which field had the largest influence
White —> blue —> red/green
Why is our visual field not circular
Shape of face prevents total full circular view
Brain block signals for nose / cheek bone
Why does the afterimage of red cyan
Bleaching the various cones leads to overstimulation of the cone
Come doesn’t respond
Only other receptors can be used
Ishihara tests what
If someone is colour blind
What colour blindness is most common
Red-green most common
What happens with red-green colour blindness
Lack of red cone
Green stimulates
Perceived red as being green
