The nervous system and neuron

Question 1

What are the two subsystems of the nervous system?

Answer 1

• central nervous system
• Peripheral nervous system

Question 2

What does the brain do?

Answer 2

receives and processes sensory information and initiates responses,stores and memories which is vital for complex high level functions

Question 3

What does the spinal cord do ?

Answer 3

relays info between the brain and the rest of the body, some reflex processing

Question 4

What is the peripheral nervous system co-ordinated by ?

Answer 4

motor and sensory neurons

Question 5

What is the somatic nervous system?

Answer 5

• 12 pairs of cranial nerves
• 13 pairs of spinal nerves
• Controls skeletal muscles for movement
• voluntary system under conscious control

Question 6

What is the autonomic nervous system ?

Answer 6

• vital for vital bodily functions such as breathing, heart rate, digestion, stress response
• → involuntary system not under conscious control.

Question 7

What two parts do motor neurons co-ordinate ?

Answer 7

• somatic nervous system
• autonomic nervous system

Question 8

What two divisions does the autonomic nervous system have?

Answer 8

• sympathetic division
• parasympathetic division

Question 9

What is the sympathetic division?

Answer 9

releases noradrenaline involved in fight or flight
* responses urging the body into action.
* Increase heart rate / breathing rate / blood pressure

Question 10

What is the parasympathetic division?

Answer 10

releases acetylcholine works to calm the body down after SNS arousal → calms the heart
* Reduces heart rate / breathing rate / blood pressure back to resting state

Question 11

What does the sympathetic division release that is involved in flight or fight

Answer 11

noradrenaline

Question 12

What does the parasympathetic division release?

Answer 12

acetylcholine

Question 13

Nucleus

Answer 13

contains the DNA and genetic material

Question 14

Dendrites

Answer 14

receptor sites from previous neuron

Question 15

Axon

Answer 15

what the electrical charge gets fired through

Question 16

Node of ranvier

Answer 16

gap between the myelin sheath - speed up electrical charge

Question 17

myelin sheath

Answer 17

protexts the axon
increases speed of transmission

Question 18

Axon terminal

Answer 18

Seek to connect with dendrite of next neuron

Question 19

What does the sensory neuron do?

Answer 19

Carry nerve impulses from sensory receptors to CNS (brain and spinal cord)

• Sensory neurones send information to the brain → where receptors sense the information and send th info via PNS to the brain

Question 20

what does the relay neuron do?

Answer 20

they connect the sensory neurons to the motor or other relay neurons.

• Relay neurones connect with other neurones found in brain - involved in analysis of the sensation and deciding how to respond to it

Question 21

What does the motor neurons do?

Answer 21

Releasing a neurotransmitter that binds to muscle receptors triggering a response.

• Motor neurones sens messages vial axons from the brain to the muscles or effectors

Question 22

Referring to structure and function distinguish between motor and sensory neurons (4)

Answer 22

• Functionally → motor carry info away from CNS whilst sensory carry info towards
• Structurally → motor cell body one end and body in one direction
• Sensory have cell body in the middle and the axon splits in two directions
• Sensory neurons receive input from environment whilst motor connect to muscles

Question 23

Explaim why neurones can only fire in one direction?

Answer 23

• the synaptic vesicles containing the neurotransmitter are only present on / released from the presynaptic
• the receptors for the neurotransmitters are only present on the postsynaptic membrane
• diffusion of the neurotransmitters mean they can only go from high to low concentration, so can only travel from the presynaptic to the postsynaptic membrane.

Question 24

Explai the role of inhibition and excitation within synaptic transmission?

Answer 24

• If the neurotransmitter is excitatory then the post synaptic neuron is more likely to fire an impulse.
• If the neurotransmitter is inhibitory then the post synaptic neuron is less likely to fire an impulse.
• The excitatory and inhibitory influences are summed, if the net effect on the post
  synaptic neuron is inhibitory, the neuron will be less likely to ‘fire’ and if the net effect is excitatory, the neuron will be more likely to fire.

Question 25

Outline how neurones are used to transmit information

Answer 25

Sensory neurones send information to the brain → where receptors sense the information and send th info via PNS to the brain

Relay neurones connect with other neurones found in brain - involved in analysis of the sensation and deciding how to respond to it

Motor neurones sens messages vial axons from the brain to the muscles or effectors