Neurons and synaptic transmission

Question 1

Neuron diagram

Answer 1

http://3.bp.blogspot.com/-7Qu2RPZuWgQ/UsXVO6gSPhI/AAAAAAAAD-g/hyOV8YwL4ZU/s1600/Neuron.gif

Question 2

Structure and function of neurons

Answer 2

Carry chemical and electrical information, allowing the brain to communicate with the nervous system
Made up of: cell body, axon and dendrites
Dendrites receive signals from other neurons
Cell body controls the neuron
Signal travels along the axon, and is passed on to other neurons at the axon terminal

Question 3

Sensory neurons

Answer 3

Carry nerve impulses from our senses to the spinal cord and brain
Can be found in the eyes, ears, skin
Long dendrites
Short axons
Function is to convert information from senses into a neural impulse

Question 4

Motor neurons

Answer 4

Located in CNS
Project axons outside of CNS to control muscles
Short dendrites
Long axons
Form synapses with muscles and control muscle contraction
Stimulation of neuron causes muscle movement
Inhibition of neuron causes relaxation

Question 5

Relay neurons

Answer 5

Neither sensory nor motor neurons
Their function is to allow sensory and motor neurons to communicate
Short dendrites
Short axons
Relay neurons are always found within brain and spinal cord

Question 6

Synaptic transmission diagram

Answer 6

https://classconnection.s3.amazonaws.com/149/flashcards/1766149/png/neural_impulse1354722028657.png

Question 7

Process of synaptic transmission

Answer 7

A nerve impulse/action potential reaches the axon terminal/ end of the neuron
Synaptic vesicles release neurotransmitters into synaptic gap/cleft
Neurotransmitters move across the synaptic gap and bind to receptors on postsynaptic neuron
Once enough neurotransmitters are bound, the signal is passed on to the receiving neuron
Enzyme is released to breakdown the neurotransmitters
Neurotransmitters returns to presynaptic neuron (re-uptake)

Question 8

Excitatory and inhibitory neurotransmitters

Answer 8

Excitatory neurotransmitters - these neurotransmitters increase the likelihood of a nerve impulse being passed on to a neuron, causing the neuron to fire (e.g. dopamine)
Inhibitory neurotransmitters - these neurotransmitters decrease the likelihood of a neuron firing (e.g. serotonin)
Summation - excitatory neurotransmitters and inhibitory neurotransmitters are summed which means which ever is highest determines whether neurons fires or not

Question 9

Why can neurons can only transmit information in one direction at a synapse

Answer 9

Receptors are only on one membrane so the neurotransmitters can’t pass both ways
Diffusion means that they only go from high to low concentration