biopsychology- neurones and synaptic transmission

Question 1

what are the types of neurons?

Answer 1

sensory neurone, relay neurone and motor neurone.

Question 2

how to remember what each neurone looks like

Answer 2

sensory neurone - cell body in between myeline sheath
relay- loads of axons, spikey
motor- loads of axons, spiky but with loads of myein sheath

Question 3

what are the functions of the following; dendrites, axon, myelin sheath, nodes of ravnier and terminal buttons

Answer 3

dendrites- protrude from cell body, carry nerve impulses from neighbouring neurones towards the cell body
axon- carries impulses away from the cell body down the length of the neurone
myelin sheath- fatty layer which protects the axon and speeds up electrical transmission of the impulse.
nodes of ravnier- speed up the transmission of the impulse by forcing it to jump across the gaps along the axon
terminal buttons- at the end of the axon and communicate with the next neurone in the chain across a gap known as the synapse

Question 4

what are the functions of the different neurones ?

Answer 4

sensory- carry messages from the PNS to the CNS. have long dendrites and short axons
relay- these connect the sensory to he motor, or other relay neurones. they have short dendrites and short axons
motor- these connect the CN to effectors such as muscles and glands. short dendrites long axons

Question 5

what is the location of neurones?

Answer 5

cell bodies of the motor neurones may be in the cns but they have long axons which form part of the pns. sensory neurones are located outside the cns, in the pns known as ganglia. relay neurones make up 97% of all neurones and most are found within the brain and visual system.

Question 6

explain electrical transmission- the firing of a neuron

Answer 6

when a neurone is in resting state the inside of the cell is negatively charged compared to the outside. when a neurone is activated by stimulus, the inside of the cell becomes positively charged for a split second causing action potential to occur. this creates an electrical impulse that travels down the axon towards the end of the neuron.

Question 7

what is synaptic transmission?

Answer 7

when neighbouring neurones communicate with each other by sending chemical messages across the synapse that seperates them

Question 8

whats a neurotransmitter

Answer 8

brain chemicals released from synaptic vesicles that relay signals across the synapse from one neurone to another. neurotransmitters can be excitory or inhibitory

Question 9

whats excitation ?

Answer 9

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

Question 10

whats inhibition?

Answer 10

when a neurotransmitter such a serotonin
increases the negative charge of the postsynaptic neuron. this decreases the liklihood that the post synaptic neuron will pass on the electrical imulse.

Question 11

explain the process of synaptic transmission

Answer 11

• an impulse arrives at the end of the presynaptic neuron
  -vesicles move towards and fuse with the presynaptic membrane. this releases neurotransmitters into the synaptic cleft
  -the neurotransmitters diffuse across the synaptic cleft (down a concentration gradient)
• neurotrasmitters attach to receptors on the post synaptic membarne
• this triggers and impulse which travels along the postsynaptic neuron
• the neurotransmitter are recycled or destroyed once an impulse is sent