neurons and synaptic transmission

Question 1

what is a neuron

Answer 1

the basic building blocks of the nervous system, neurons are nerve cells that process and transmit messages through electrical and chemical signals

Question 2

sensory neurones

Answer 2

these carry messages from the PNS to the CNS. They have long dendrites and short axons

Question 3

relay neurons

Answer 3

these connect the sensory neurons to the motor or other relay neurons. They have short dendrites and short axons

Question 4

motor neurons

Answer 4

these connect the CNS to effectors such as muscles and glands. They have short dendrites and long axons

Question 5

exitation

Answer 5

when a neurotransmitter, such as adrenaline increases the positive charge of the postsynaptic neuron. This increases the likelihood that the postsynaptic neuron will pass on the electrical impulse.

Question 6

inhibition

Answer 6

when a neurotransmitter, such as serotonin, increases the negative charge of the postsynaptic neuron. This decreases the likelihood that the postsynaptic neuron will pass on the electrical impulse.

Question 7

electrical transmission

Answer 7

• When resting - negatively charged compared to outside
  
  • When activated by stimulus - inside the cell becomes positively charged for a split second causing an action potential to occur - creates an electrical impulse that travels down the axon towards the end of the neuron

Question 8

chemical transmission

Answer 8

• Neural networks - neurons communicate with eachother within groups
  
  • Signals between neurons are transmitted chemically across the synapse
  • Electrical impulse reaches the end of the neuron (presynaptic terminal) - triggers the release of neurotransmitter from synaptic vesicles

Question 9

neurotransmitters

Answer 9

• Chemicals that diffuse across the synapse to the next neuron in the chain
  
  • Taken up by postsynaptic receptor site on dendrites
  • Several dozen types of neurotransmitter have been identified
  • Acetylcholine found at each point where a motor neuron meets a muscle

Question 10

summation

Answer 10

process that decides whether a postsynaptic neuron fires
- Excitatory and inhibitory influences are summed - if net effect on the postsynaptic neuron is inhibitory then the postsynaptic neuron is less likely to fire