neurons and synapses

Question 1

what is the function of sensory neurons?

Answer 1

transmit sensory info towards brain and spinal cord

Question 2

what is the function of relay neurons ?

Answer 2

allow sensory and motor neurons to communicate

Question 3

what is the function of motor neurons?

Answer 3

controls muscle movements

Question 4

where are sensory neurons found?

Answer 4

in the peripheral nervous system

Question 5

where are relay neurons found?

Answer 5

in the CNS - only in the brain and spinal cord

Question 6

where are motor neurons found?

Answer 6

in the nervous system but their axons reach out into the peripheral nervous system

Question 7

where do sensory neurons direct info to and from?

Answer 7

from sensory receptors towards the brain and spinal cord

Question 8

where do relay neurons direct info to and from?

Answer 8

from one neuron to another

Question 9

where do motor neurons direct info to and from?

Answer 9

from the brain towards effectors ( an organ or cell that acts in response to a stimulus)

Question 10

what are the differences in structure between relay motor and sensory neurons?

Answer 10

cell body of sensory neurons is in the middle. and they have a myelin sheath

relay neuron do not have myelin sheath and cell body is at the top of neuron

motor neuron has myelin sheath and cell body is at the top

Question 11

what is the function of an axon?

Answer 11

carries impulses away from the cell body down the length of the neuron.
the electrical impulse is the action potential

Question 12

what is the function of dendrites?

Answer 12

pick up nerve impulses from other neurons and carry them towards the cell body

Question 13

what is the function of the cell body ?

Answer 13

contains everything the nerve needs to survive and contains the nulceus

Question 14

what is the function of the myelin sheath?

Answer 14

protects the axon and speeds up the electrical transmission of the impulse

Question 15

what is the function of the nodes of ranvier?

Answer 15

speed up transmission of the action potential by forcing it to jump across synapses

Question 16

what is the function of axon terminals?

Answer 16

the action potential has to travel to the dendrites of another neuron through synaptic transmission

Question 17

what is an action potential?

Answer 17

electrical signal passed from neurons along their axons

Question 18

true or false ?sensory neurons recieve information from the outside world.

Answer 18

true

Question 19

true or false? motor neurons directly or indirectly control muscles

Answer 19

true

Question 19

what is the reflex arc?

Answer 19

sensory receptors in the sensory neuron detect stimulus. e.g hot temperature

it transmits sensory info towards the relay neuron

the relay neuron allows sensory and motor neurons to communicate

relay neuron takes the information from sensory neuron to the motor neuron

the motor neuron controls muscle movements

the info gets to the brain and towards effectors in muscle that acts in response of stimulus

which results in action e.g moving hand away from a hot item

Question 20

what is the process of synaptic transmission?

Answer 20

electrical impulses (action potentials) reach the presynaptic terminal

electrical impulses (action potentials) trigger release of neurotransmitters (or named example)

neurotransmitters cross the synapse from vesicles

neurotransmitters combine with receptors on the postsynaptic membrane

stimulation of postsynaptic receptors by neurotransmitters result in either excitation (depolarisation) or inhibition (hyperpolarisation) of the postsynaptic membrane

Question 21

what are the 2 types of neurotransmitters?

Answer 21

excitatory and inhibitory

Question 22

what are excitatory neurotransmitters

Answer 22

these excite the nervous system increasing the likelihood that a neuron will fire an action potential

they do this because they are positively charged. they depolarise post synaptic cell and enough of them can generate an action potential

generate excitatory post synaptic potential

Question 23

what are inhibitory neurotransmitters?

Answer 23

inhibit the nervous system decreasing the likelihood that a neuron will fire an action potential

they do this because they ate negatively charged. they hyperpolarise the post synpatic cell and enough of them can inhibit an action potential

they generate inhibitory post synaptic potential

Question 24

what are reuptake sites ?

Answer 24

where left over neurotransmitters can be collected by vesicles ready to be used again in the future

Question 25

why can neurons only transmit information in one direction at a synapse?

Answer 25

the synaptic vesicles containing the neurotransmitter are only present on/released from the presynaptic membrane

the receptors for the neurotransmitters are only present on the postsynaptic membrane

it is the binding of the neurotransmitter to the receptor which enables the signal/information to be passed/transmitted on (to the next neuron).

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.