Sensory Receptors Flashcards Preview

A Level Biology - Unit5 > Sensory Receptors > Flashcards

Flashcards in Sensory Receptors Deck (16):
1

Where are sensory receptors located?

In the sensory organs like ears and eyes

2

What do sensory receptors do?

Convert the stimulus into a nerve impulse

3

What are the 4 types of sensory receptors?

Mechanoreceptor
Chemoreceptor
Thermoreceptor
Photoreceptor

4

Give an example of a mechanoreceptor

Pacinian corpuscle

5

Give an example of a chemoreceptor

Olfactory receptor

6

Give an example of a thermoreceptor

End bulbs of Krause

7

Give an example of a Photoreceptor

Cone cell

8

What is multiple sclerosis?

An autoimmune disease that affects nerves in the brain and spinal cord. When the myelinated sheath thins and breaks down.

9

What are myelinated neurones?

Neurones with axons covered in myelin sheath (many layers of plasma membranes)

10

How are the layers of myelin created?

Schwann cells grow around e axon many times and add layers of phospholipids each time.

11

What is the role of the myelin sheath?

Insulate the axon
Helps conduct electrical impulses at a faster speed

12

What are the two main features of sensory receptors?

They are specific to a certain type of stimulus.
They act as a transducer by converting stimuli into impulses

13

Explain step by step briefly how your body detects your finger has touched a pin?

1) Resting state- sodium ion channels are too narrow for sodium ions to pass through.
2) pressure applied changes the shape of the corpuscle, this causes the membrane surrounding the neurone to stretch and deform.
3) membrane stretches, sodium ion channels widen, sodium ions diffuse into the neurone.
4) influx of sodium ions changes the potential of the membrane.
5) The generator potential creates an action potential that passes along the axon of the sensory neurone

14

How are sensory receptors like transducers?

They convert stimuli into nervous impulses, called a generator potential.

15

What is the refractory period?

The period of time after an action potential when the axon cannot be excited again. The voltage gated sodium ion channels remain closed.

16

Why is a refractory period important?

It makes sure action potentials are unidirectional.
It ensures action potentials do not overlap and occur as discrete impulses.