Receptors Flashcards
Receptor to detect change in pressure
Pacinian corpuscle
Channel proteins in Pacinian corpuscle
Stretch-mediated sodium ion channel proteins
Describe how stimulation of a Pacinian corpuscle produces a generator potential (3 marks).
- Increased pressure deforms membrane/lamella(e)
- This opens the stretch-mediated sodium ion channels (in the membrane);
OR (Increased pressure) deforms/changes sodium ion channels;
- Sodium ion channels open;
- Sodium ions diffuse in;
- Depolarisation (leading to generator potential);
TRUE or FALSE:
The generator potential must exceed the threshold stimulus to trigger an action potential in the sensory neuron
TRUE
[1] pressure leads to more stretch-mediated sodium [2] channels opening. This leads to [3] and makes it more likely the generator potential produced exceeds the [4] stimulus for an action potential.
This is an example of the [5] principle.
[1] Increased
[2] ion
[3] depolarisation
[4] threshold
[5] all or nothing
TRUE or FALSE:
A new generator potential in the axon of the Pacinian corpuscle can be produced during the refractory period.
FALSE
The resting potential inside the axon must be re-established
Example of photoreceptors
Rods & cones
Photoreceptors location
Macula
(middle of retina)
Cone location
Fovea
(the centre of the macula)
Rod location
Edges of the macula
(not present in the fovea)
Rods and cones convert [1] energy into electrical energy in the form of [2].
Rods and cones convert [1] energy into electrical energy in the form of [2].
Sensivity of rods
High sensivity to low light intensity
In rods, light breaks down the pigment [1] and this leads to the release of [2]. This leads to a [3] potential in the [4] neurone.
[1] rhodopsin
[2] neurotransmitter
[3] generator
[4] bipolar
Retinal convergence
Several rod cells connected to a single bipolar neurone
Spatial summation
Release of neurotransmitter from one rod cell leads to generator potential below threshold stimulus in the bipolar neurone
Neurotransmitter released from several/additional rods cells connected to same bipolar neurone helps exceed the threhold and trigger an action potential
Photoreceptor with low visual acuity
Photoreceptor with low visual acuity
Acuity
How clear / detailed the image is
photoreceptor with high visual acuity
cones
Types of cone cells
3 cone cells specific to different wavelengths of light: red, blue & green.
Sensivity of cones
Sensivity of cones
in cones, high intensity light breaks down the pigment [1] and this leads to the release of [2]. This leads to a [3] potential in the [4] neurone.
[1] iodopsin
[2] neurotransmitter
[3] generator
[4] bipolar
Each [1] cell is connected to a single [2] neurone. This sends [3] impulses to the visual cortex via the optic nerve.
[1] cone
[2] bipolar
[3] separate
the fovea of the eye of an eagle has a high density of cones. An eagle focuses the image of its prey onto the fovea.
Explain how the fovea enables an eagle to see its prey in detail.
Do not refer to colour vision in your answer (3 marks).
- Each cone cell is connected to a single bipolar neurone
OR no retinal convergence;
- Cones send separate (sets of) impulses to brain / optic nerve;
- Produces high visual acuity;
The retina of an owl has a high density of rod cells.
Explain how this enables an owl to hunt its prey at night.
Do not refer to rhodopsin in your answer (3 marks).
- High sensitivity to low light intensity
- Retinal converage OR several rods connected to a single bipolar neurone;
- Enough neurotransmitter released to reach/overcome threshold
OR spatial summation to reach/overcome threshold;
