the central nervous system

Question 1

what is the central nervous system?

Answer 1

the body’s system for decision-making and coordination

Question 2

what does the CNS consists of?

Answer 2

the brain and the spinal cord. it connects nerves that serve the body

Question 3

what do motor neurones do?

Answer 3

carry information about movement out from the brain; these are motor neurones

Question 4

what dos sensory neurones do?

Answer 4

move information inward to the CNS on the spinal cord

Question 5

what do neurones do and where are they found?

Answer 5

found in the brain. pass information around inside the brain. it then communicates with the rest of the body through the nerve cells in the nervous system, telling different parts of the body what to do.

Question 6

how do neurones communicate with one another? and why is this important?

Answer 6

though synapses. this allows the brain to process thoughts and memories

Question 7

what is a synapse and what happens?

Answer 7

a synapse is a gap/ junction between neurones where neurotransmitters are released and passed from one neurone to the dendrite of the receiving neurone. this process converts the chemical signal back into an electrical nerve impulse

Question 8

what is an axon?

Answer 8

part of the neuron that takes information away from the cell body> axon terminals

Question 9

Axon terminals

Answer 9

hair like ends on axons which passes information on to another neuron

Question 10

dendrites

Answer 10

extensions that receive messages from other neurones to take to the cell body in order to trigger an action potential

Question 11

define action potential

Answer 11

The neurones threshold much be reached before a change from resting potential to action potential occurs. The message by which a nerve impulse travels down an axon and the polarity changes across the membrane. once the threshold potential is reached, the neuron completely depolarises. when this happens the cell resets its membrane voltage back to original resting potential.

Question 12

what is the speed of conduction influenced by?

Answer 12

By the diameter of the axon and the axon’s resistance to current leak

Question 13

what does Myelin act as?

Answer 13

acts as an insulator that prevents current from leaving the axon, increasing speed of action potential conduction.

Question 14

what is the node of Ranvier?

Answer 14

a natural gap in myelin sheath along the axon. Flow of irons though these channels regenerates the action potential over and over again on along the axon. action potential jumps from one node to the next, without this, Action Potential would occur slowly

Question 15

synaptic transmission

what is reuptake?

Answer 15

when action potential causes info to be transmitted from the axon to the first neuron (presynaptic) to the dendrites or cell body of the second neuron (postsynaptic) by the secretion of neurotransmitters.

when molecules of the neurotransmitter do not bind to receptors in the post- synaptic, reuptake will occur when the molecules are taken up by presynaptic neuron

Question 16

what do drugs do?

Answer 16

they imitate neurotransmitters, to bind with receptors so that the message is sent in the drug to pass the message on and function in the way it would normally.
alternatively, the drug could block the natural neurotransmitter as the receptor is not accessible.

Question 17

what does caffeine do?

Answer 17

blocks chemical signals in your brain, by blocking the reuptake of dopamine stopping you from feeling sleepy. it is good in moderate doses and can improve mental ability