Module 5 - Chapter 13

Question 1

Why is coordination important in the nervous system?

Answer 1

To maintain a constant internal environment

Question 2

How is the nervous system coordinated?

Answer 2

Cell signalling coordinates cellular activities

Question 3

What is the function of neurones?

Answer 3

To conduct and process information: thought perception, and control of movement

Question 4

What type of signal do neurones send in the nervous system send?

Answer 4

Electrical (action potential)

Question 5

What type of signal is in the blood in the endocrine system?

Answer 5

Chemical (hormones)

Question 6

What is the speed of signals in the nervous system compared to in the endocrine system)?

Answer 6

Faster in the nervous system

Question 7

What is the type of action/response in the nervous system?

Answer 7

It can be voluntary or involuntary

Question 8

What is the type of action/response in the endocrine system?

Answer 8

It’s always involuntary

Question 9

What is the target of the signal in the nervous system?

Answer 9

Localised (the cells connected to the neurone)

Question 10

What is the target of the signal in the endocrine system?

Answer 10

The target is often distant (many cells are effected)

Question 11

What are the key features of neurones?

Answer 11

cell body, dendrons, axons

Question 12

Describe the cell body in neurones

Answer 12

• contain DNA located in a nucleus
• contain rough endoplasmic reticulum and mitochondria

•these are in abundance for neurotransmitter production by ribosomes

Question 13

Describe the dendrons in neurones

Answer 13

They input synapses by receiving signals from axons and carry impulses towards the cell body

Question 14

Describe the axons in neurones

Answer 14

Signals are taken away from the cell body (a for axon = away)

Axons can be very long - for example the sciatic nerve from the toes to the spine

However they are only 1 micrometre in diameter

Question 15

List the structures in a typical neurone

Answer 15

Dendrites, nucleus, cell body, axon, myelin sheath, Schwann’s cells, Nodes of Ranvier, axon terminals

Question 16

What are Nodes of Ranvier?

Answer 16

The gaps between the Schwann cells on the axon/dendron

Not a structure (a gap) so don’t label as a structure if asked to so specifically

Question 17

Describe the myelin sheath in neurones

Answer 17

• made of many layers of cell membranes of Schwann cells - a double layer of phospholipid bilayer is established each time
• there are 20 layers of membranes
• myelin is a lipid

Question 18

What happens if the myelin sheath breaks down?

Answer 18

It degenerates so the impulses are slower and there is a lack of insulation

Myelinated neurones have an impulse speed of 100m/s but unmyelinated = 1 m/s