Sensory

Question 1

What is the nervous system?

Answer 1

A highly specialised part of the body that coordinates action and controls body function.

Question 2

What are three characteristics of the nervous system?

Answer 2

• irritability
• conduction
• integration

Question 3

Describe irritability?

Answer 3

It responds to stimuli

Question 4

Describe conduction?

Answer 4

Transmits via action potentials over long distances

Question 5

Describe integration?

Answer 5

Can analyse and interpret information

Question 6

Describe nervous tissue?

Answer 6

Composed of neurons (nerve cells) and glial cells (supporting cells)
A single nerve is composed of thousands of nerve axons

Question 7

Describe a neuron?

Answer 7

• Composed of a cell body, including nucleus
• attached dendrites for receiving chemical signals from other neutrons
• Axon composed of nerve fibre and myelin sheath
• Axon terminal at bottom

Question 8

What are the two divisions of the nervous system?

Answer 8

The Central Nervous System

The Peripheral Nervous System

Question 9

What is the CNS?

Answer 9

The brain and spinal cord

Question 10

What is the PNS?

Answer 10

The nervous system that extends out from the brain and spinal cord to the rest of the body

Question 11

What are PNS nerves extending from the brain called?

Answer 11

Cranial Nerves

Question 12

What are PNS nerves extending from the spinal cord called?

Answer 12

Spinal nerves

Question 13

Any PNS nerve will contain two kinds of nerve axons that transmit from the PNS to the CNS, what are they?

Answer 13

Sensory or Afferent
and
Motor or Efferent

Question 14

What are PNS Sensory/Afferent Axons?

Answer 14

Axons that transmit action potentials from the periphery of the body to the CNS

Question 15

What are Motor of Efferent Axons?

Answer 15

Axons that transmit action potentials from the CNS to the body periphery

Question 16

Describe the hierarchy of a nerve, top to bottom.

Answer 16

• neuron each with their own membrane called an endonuerium
• Several neurons together form a nerve fascicle
• The fasicle has a membrane called a perineurium
• Several Fascile’s together form a nerve
• Nerve has a membrane called a epineurium
• There are blood vessels running through the nerve to supply oxygen, nutrients & metabolism

Question 17

For sensory neurones, more information is required such as?

Answer 17

Location and type of stimulus

Question 18

In order to transmit this specialised information what do some sensory nerves have?

Answer 18

Specialised nerve endings that only respond to one type of input

Question 19

Name some examples of specific sensory inputs that are analysed by the brain?

Answer 19

Sight, taste, smell, blood gas levels, limb position, blood pressure

Question 20

Discuss the layout of sensory receptors in the skin.

Answer 20

There are various types of specialised nerve ending as well as nerve endings lodged at different depths within the skin.

Question 21

Do all areas of skin have the same number of sensory receptors?

Answer 21

No, some more than others.

Question 22

What are sensory nerve receptors connected to?

Answer 22

Sensory nerve fibres

Question 23

What is the area of skin supplied by a single sensory neuron called?

Answer 23

A receptive field ( a receptive field may contains many receptors)

Question 24

Describe the two prick test in relation to receptive fields.

Answer 24

If two stimulus are detected across two receptive fields. Two distinct stimulus will be detected. If two stimulus are detected but only across one receptive field, only one single stimulus will be detected.

Question 25

What three things determine the ability to localise a stimulus?

Answer 25

• number of receptors
• sensitivity of receptors
• size and arrangement of receptive fields

Question 26

Describe sensory adaptation.

Answer 26

Some stimuli are harmless though consistent and so nerve endings quieten down and diminish the number of AP’s. Pain nerve endings do not show sensory adaptation