neurons

Question 1

neurons : nucleus

Answer 1

contains genetic material

Question 2

neurons: cell body

Answer 2

contains the nucleus

Question 3

neurons: dendrites

Answer 3

carry nerve impulses from neighbouring neurons towards the cell body

Question 4

neurons: axon

Answer 4

carries the impulses away from the cell body down the length of the neuron

Question 5

neurons: myelin sheath

Answer 5

protects the axon and speeds up electrical transmission of the impulses

a fatty layer

Question 6

neurons: nodes of ranvier

Answer 6

gaps in the myelin sheath

speed up the transmission of the impulse by forcing it to jump across the gaps along the axon

Question 7

neurons: terminal buttons

Answer 7

communicate with the next neuron in the chain across the synapse

Question 8

neurons in action: knee jerk reflex

Answer 8

1. a hammer hits knee (stimulus) - this is detected by receptor cells in the PNS which carries message along sensory neuron
2. reaches CNS where it connects with interconnecting neuron
3. transferred to a motor neuron which carries message to the (effector) muscle which causes knee to jerk (response)

Question 9

3 types of neuron

Answer 9

sensory neuron
relay neuron
motor neuron

Question 10

sensory neuron function

Answer 10

carries message from PNS to brain and spinal cord CNS

convert info from senses into neural impulses

when impulse reach the brain = translated into sensations

unipolar - only transmits info

located in PNS in clusters called ganglias

Question 11

sensory neuron structure

Answer 11

long dendrites
short axon

Question 12

relay neuron function

Answer 12

carry messages form one part of CNS to another

connect motor and sensory neurons so they can communicate

found only in brain, spinal cord and vision

multipolar - send and receive messages from many sources

Question 13

relay neuron structure

Answer 13

short dendrites and long axon

Question 14

motor neuron function

Answer 14

carry signals from CNS to help organs and muscles function

form synapses with muscles

when stimulated they release neurotransmitters that bind to receptors on the muscle and trigger a response

multipolar - send and receive messages from many sources

Question 15

motor neuron structure

Answer 15

short dendrites and long axons

Question 16

electrical transmission

Answer 16

when a neuron is in rtsing rate the inside of the cell is negatively charged compared to the outside

when a neuron is activated the inside becomes positively charged for a split second causing an actual potential to occur

this creates an electrical impulse that travels down the axon towards the end of the neuron