neurons

Question 1

What is the nervous system made from ?

Answer 1

made of specialised cells called neurons . They send electrical and chemical signs through brain and body .

Question 2

What are the parts of a neuron

Answer 2

1. Soma : houses the nucleus
2. Dedrites : receive signals from other neurons
3. Axon : conducts messages away from the soma

Question 3

What is the nerve and glacial cell

Answer 3

1. A nerve is an enclosed bundle of axons
2. Glacial cells support and nourish neurons
3. Myelin is a fatty layer which surrounds many axons .

Question 4

What is the gray matter and the white matter ?

Answer 4

Soma and dendrites form grey matter
Axons form white matter

Question 5

What sensory neurons receive ?

Answer 5

signals from sense organs

Question 6

What motor neurone send ?

Answer 6

it send signals to muscle cells

Question 7

What interneurons connect

Answer 7

connect neurons to other neurons

Question 8

Describe resting potential

Answer 8

1. Outside has more Na+ and Cl- ions
2. Inside has more K+ and protein anions
3. Sodium -potassium pump transports K+ into the cell and the Na+ out of the cell.
4. The resting potential is about -70 millivolts (mV)

Question 9

Describe action potential

Answer 9

1. Electrical stimulation can cause sodium channels to open
2. Na+ ions flow into the cell
3. The voltage shifts form -70mV to + 40 mV in about 1 millisecond

Question 10

Describe resting potential restarted

Answer 10

1. Sodium channels close
2. Potassium channels open
3. K+ ions flow out of the cell
4. The K + channels close and the sodium - potassium pump restores the resting potential .

Question 11

what are the key points about action potentials

Answer 11

1. Action potential are all or none
2. must threshold to trigger an action potential
3. graded potential can combine to trigger an action potential

Question 12

Explain action potential process

Answer 12

nearby Na+ channels open , the signal flows along the axon .
While K+ ions flows out , membrane is not excitable
SO
flow is unidirectional
and the firing rate limited to 200-300 per second

Question 13

What is myelination

Answer 13

1. Myelin insulates axons
2. The signals jump from node to node , this allows faster transmission
3. Loss of myelin can cause health problems

Question 14

What is a synaptic transmission ( define 5 steps )

Answer 14

Neurotransmitters are chemicals which carry signals across synaptic cleft

Five steps
1. synthesis
2.storage
3.release

Question 15

Explain the process of binding neurotransmitters

Answer 15

Each neurotransmitter binds to specific receptors

Excitatory neurotransmitters cause Na channels to open

Inhibitory neurotransmitters cause K= to flake out or Cl- to flow in

Question 16

Explain the process of deactivation

Answer 16

the neurotransmitter is broken down in synaptic cleft

The re-uptake happens in the pre-synaptic cell

Question 17

explain the process of contraction with acetylcholine

Answer 17

1. Binding trigger flow of of sodium ions into muscle cells

Question 18

explain the process of paralysis with acetylcholine

Answer 18

Botulinum toxin blocks synaptic release

Question 19

What is the process convulsions with acetylcholine ?

Answer 19

Black window venom triggers massive release .

Question 20

In which part of the body is ach important ?

Answer 20

for memory and it underproduced in Alzheimer disease