Receptors

Question 1

Receptors are described as transducers. What does this mean?

Answer 1

Convert energy in stimulus into an action potential

Question 2

Name the stimulus detected by each of the following receptors
Thermoreceptor
Cone cell
Rod cell
Mechanorecptor

Answer 2

Thermoreceptor Heat/thermal –> action potential
Rod/Cone cell Light –> action potential
Mechanorecepetor Pressure –> action potential

Question 3

Name a mechanoreceptor found in the skin

Answer 3

Pacininan Corpuscle

Question 4

Describe the structure of a Pacininan Corpuscle

Answer 4

Series of membranes/lamellae
Gel between membranes
Naked axon in centre (no myelin sheath) which is attached to a sensory neurone

Question 5

How is an action potential produced in a Pacinian Corpuscle?

Answer 5

Pressure distorts the axon membrane
Stretch mediated sodium ion channels open
Sodium ions diffuse into axon
Membrane becomes depolarised
If threshold is reached an action potential is produced

Question 6

Where are the cone and rod cells found?

Answer 6

Retina of the eye

Question 7

Which type of receptor gives black and white vision

Answer 7

Rod cells

Question 8

Which type of receptor generates an action potential in high light intensities

Answer 8

Cone cell

Question 9

Which type of receptor gives high acuity

Answer 9

Cone cells

Question 10

Name the two cells shown on the diagram

Answer 10

Left = Rode cell

Right = Cone cell

Question 11

Name the photoreceptive pigment found in cone cells

Answer 11

Iodopsin

Question 12

Name the photo receptive pigment found n rod cells

Answer 12

Rhodopsin

Question 13

Describe the reaction that takes place when light shines on rhodopsin

Answer 13

Rhodopsin –> retinal + opsin

Question 14

Give the three different types of cone cell

Answer 14

Red sensitive cones
Blue sensitive cones
Green sensitive cones

Question 15

Why do cone cells have a higher acuity than rod cells?

Answer 15

Each cone cell is connected to one sensory neurone
Several rod cells are connected to one sensory neurone

Question 16

The diagram shows how rod cells are connected to the sensory neuorne.

How does this arrangement allow the rod cells to give vision in dim light?

Answer 16

Retinal convergence

More than one rod cell is connected to the sensory neurone

Small aounts of rhodopsin hydrolysis in each rod cell can be summed togehter to initiate a generator potential

Question 17

What is the function of a receptor cell?

Answer 17

To detect stimuli
Transduce energy

Question 18

In order to create an electrical impulse a receptor cell creates a …

Answer 18

Generator potential

Question 19

Why can rod cells only lead to images seen in black and white?

Answer 19

Cannot distinguish between different wavelengths of light

Question 20

Why are many rod cells connected to a single sensory neurone?

Answer 20

Allow retinal convergence
Increases chance that threshold is exceeded to generate an action potential

Question 21

Does idopsin break down in the presence of high or low light intensity?

Answer 21

High light intensity

Question 22

The lens of the eye focuses light at a central point of the retina called the …

Answer 22

Fovea

Question 23

Which type of receptor cells are found on the fovea?

Answer 23

Cone cells