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Question 1

what is the central nervous system (CNS)

Answer 1

• brain and spinal cord
• receives and interprets messages and then initiates response

Question 2

what is the peripheral nervous system (PNS)?

Answer 2

• sensory neurons carry messages from the body to the brain
• motor neurons carry messages from the brain to muscles

Question 3

what is the myelin sheath?

Answer 3

it is a protective layer of fatty cells around the axon

Question 4

describe the components of a motor neuron

Answer 4

• nucleus
• cell body/soma
• dendrites
• axon
• axon terminals

Question 5

what additional components do myelinated neurons have?

Answer 5

• Schwann cells which make the myelin sheath
• nodes of Ranvier

Question 6

what are neurons?

Answer 6

specialized cells to transmit electrical impulses

Question 7

what happens when there is a nerve impulse?

Answer 7

• the dendrite receives the nerve impulse
• the nerve impulse travles along the axon
• the nerve imulse is passed to another nerve or to another muscle at the terminal end of the axon

Question 8

how are potentials created?

Answer 8

the potential is created by making the charges on one side of the membrane opposite to the other side

Question 9

how do nerve cells create potentials?

Answer 9

By pumping Na+ out of the cell and K+ into the cell using the sodium-potassium pump.

Question 10

what is inside the nerve cell?

Answer 10

the inside of the nerve cell is full of negatively charged proteins and Cl-

Question 11

what is the sodium-potassium pump

Answer 11

is an active pump that pumps 3Na+ out and 2K+ into the cell

Question 12

what is resting potential?

Answer 12

when a neuron is not currently sending an impulse

Question 13

what are the charges of a neuron at resting potential?

Answer 13

-the inside is negative and the outside is positive.
-the sodium is on the outside and the potassium is on the inside

Question 14

what is an action potential?

Answer 14

selt propagating wave of ion movements in and out of the neuron membrane
- the action potential is the movement of sodium ions

Question 15

what is depolaristion?

Answer 15

sending an impulse

Question 16

what are the steps of depolarization?

Answer 16

1. a physical stimulus causes an action potential to begin
2. the impulse causes the sodium ion channels to open
3. sodium ions rush into the cell via facilitated diffusion
4. this sudden change to a positive charge on the inside causes the next sodium ion channel to open this continues down the axon

Question 17

what is repolarization?

Answer 17

return to resting potential

Question 18

what are the steps of repolarization?

Answer 18

1. during the action potential the inside of the cell becomes positive causing the potassium ion channels to open
2. potassium diffuses out of the cell
3. the cell is then + on the inside and - on the outside
4. the sodium and potassium are on the wrong side
5. after repolarization the Na and K pump moves the ions back to the correct side to re-establish the resting potential

Question 19

Which way does polarization/ depolarization occur?

Answer 19

down the axon, this is an impulse

Question 20

what is the myelin sheath composed of?

Answer 20

a series of Schwann cells

Question 21

what are the gaps between the myelin sheath?

Answer 21

the nodes of Ranvier

Question 22

what is saltatory conduction?

Answer 22

when action potential on myelinated axons skips from one node or Ranvier to the next

Question 23

what is the benefit of salatatory conduction?

Answer 23

faster and uses less energy (the Na/K pump has to act fewer times)

Question 24

what is the synapse?

Answer 24

the place where the terminal axon of one neuron meets the dendrite of another

Question 25

what is the presynaptic neuron?

Answer 25

the neuron where the impulse is coming from

Question 26

what is the postsynaptic neuron?

Answer 26

the neuron receiving the impulse

Question 27

how is the impulse passed across the synapse?

Answer 27

using a chemical called a neurotransmitter which is stored at the end of the presynaptic neuron

Question 28

what is the neurotransmitter involved in the movement of muscles?

Answer 28

Acetylcholine

Question 29

when is acetylcholine used?

Answer 29

when an action potential reaches the end of a moto neuron acetylcholine binds to the receptors on muscles cells causing them to contract.

Question 30

what are neonicotinoids?

Answer 30

they are a type of insecticide

Question 31

what do neonicotinoids do?

Answer 31

they permanently bind to receptors on the muscle blocking the neurotransmitter from binding

Question 32

what is the effect of the neonicotinoids?

Answer 32

the muscles can’t contract and results in permanent paralysis of all muscles (death)