Receptors

Question 1

Receptors

Answer 1

Detects a stimulus (change in environment)

Question 2

Relationship of receptors to a stimulus

Answer 2

Receptors are specific to one type of stimulus

Question 3

What does receptors being specific to one type of stimulus allow?

Answer 3

Humans can distinguish between different sensations eg temperature and pressure
Because different receptors in the skin can detect them

Question 4

Receptors in skin

Answer 4

Large range of different types and vary in number depending on where

Question 5

Pressure receptors

Answer 5

Can detect changes stimuli in the form of changes in pressure

Question 6

Example of pressure receptor that is required on the spec

Answer 6

Pacinian Corpuscle

Question 7

Where is the Pacinian Corpuscle found?

Answer 7

In the skin: fingers, sole of feet, tendons etc

Question 8

What describes what the Pacinian Corpuscle does overall in response to a pressure change?

Answer 8

Establishes a generator potential

Question 9

Transducer

Answer 9

Describes the Pacinian Corpuscle as it can transfer energy from one store to another

Question 10

How do Pacinian Corpuscles act as transducers?

Answer 10

Detects change in pressure via vibrations and transfers energy from mechanical energy to electric energy (can be sent as electrical impulses down sensory neuron)

Question 11

Are Pacinian Corpuscles cells?

Answer 11

No they are found at ends of sensory neuron axons

Question 12

Outline of Pacinian Corpuscle structure

Answer 12

Layers of connective tissue called lamellae surround Neuron ending
Gel in between layers contains Na+ ions
Surrounded by a capsule

Question 13

Neurons membrane contains…

Answer 13

Stretch mediated Na+ channel ion proteins

Question 14

What happens when to the neuron when Pacinian Corpuscle detects pressure?

Answer 14

The neuron membrane is stretched

Question 15

What happens when the neuron membrane is stretched?

Answer 15

Deforms stretch mediated Na+ channel ion proteins causing the channel proteins to OPEN

Question 16

Once the stretch mediated channel proteins open……

Answer 16

Na+ ions from the gel in lamellae can diffuse into the neuron

Question 17

When Na+ ions diffuse into neuron via stretch mediated channel proteins

Answer 17

This depolarises the membrane

Question 18

Depolarisation of the neuron membrane

Answer 18

Usually: pos charge in lamellae and neg charge in neuron but once Na+ ions can diffuse into the neuron: the charges are flipped

Question 19

Depolarisation of the neuron membrane means………

Answer 19

Larger generator potential

Question 20

When are impulses sent down the neuron as detected by pacinian corpuscle?

Answer 20

If the generator potential is large enough, due to large enough pressure so enough channels are opened and more Na+ ions can diffuse,
a critical voltage called threshold is reached and nerve impulses are sent along the neuron