Receptors Flashcards
What do receptors do?
Respond to changes in mechanical pressure on the skin.
Receptors are specific, what does that mean?
They will only respond to certain stimuli
What stimulus do pacinian corpuscles respond to?
Changes in pressure
When Pacinian corpuscles detect a change in pressure, what is generated?
A generator potential
Inside finger tips, where would Pacinian corpuscles be found?
Deep under the skin
Which type of neurone and part of it is the Pacinian corpuscle made from?
The end of the sensory neurone
The Pacinian corpuscle is surrounded by gel. What is contained in this gel?
Na+ ions
Na+ ion channels in the sensory neurone membrane will open when what happens?
When pressure is applied, Na+ channels open
Explain how a generator potential is created in Pacinian corpuscles.
What happens to the sensory neurone membrane?
Opening of Na+ ion channels causes a movement of ions in, causing the charge inside the cell to increase and charge outside the cell decreases. Membrane depolarises.
What are the sodium channels in Pacinian corpuscles called?
Stretch mediated
What do rod and cone cells do as transducers?
Convert light energy from the retina to electrical energy.
Why are images produced by rod cells in black and white?
They cannot distinguish between different wavelengths of light.
What are rod cells connected to in the eye?
Sensory neurones in the optic nerve
Do rod cells detect high or low light intensity?
Low
Why is there a higher chance of threshold being exceeded in rod cells?
Because rod cells are connected to a single bipolar cell
Name the pigment in rod cells.
Rhodopsin
How is the pigment broken down in rod cells?
Rhodopsin pigment is broken down which is powered by energy from low intensity light
Several rod cells link to how many bipolar cells?
1
Why is only a single impulse generated even when several rod cells are stimulated?
These several rod cells will only be connected to one neuron.
Where are rod cells absent in the eye?
Fovea
Where are rod cells found in abundance in the eye?
At the periphery of the retina.
What does ‘low visual acuity’ of rod cells mean?
You cannot distinguish between 2 separate sources of light.
What colour will light detected by cone cells be?
Any colour
How are specific colours detected by cone cells?
All wavelengths of light for different colours will be absorbed. The wavelength reflected will be the colour that we see.
How many cone cells we be attached to one bipolar neurone?
1
Explain why cone cells have high visual acuity.
Because cone cells are connected to their own bipolar cell, this means that 2 separate wavelengths of light can be distinguished against.
Are cone cells used to detect high or low intensity light?
High
Which type of summation do cone cells rely on?
Temporal
What is temporal summation?
Where one pre synaptic neurone releases neurotransmitter to try and trigger the next neurone to fire.
Where in the eye are cone cells found in high concentration?
Fovea
Where in the eye are cone cells found in low concentration?
Periphery of retina
Name the pigment found in cone cells.
Iodopsin
Why do cone cells produce higher resolution?
Because the cone cells are connected to their own individual bipolar cell. This means the brain will receive a separate impulse for each wavelength.
