Neurons and synaptic transmission

What are the three type of neurons?

• sensory

• relay

• motor

Where do sensory receptors reside ?

eyes, ears, tongue and skin

where does the sensory neuron carry impulses?

spinal cord and brain

When the impulses from the sensory neuron reaches the Brian , what do they turn into ?

sensations such as vision , hearing , taste and touch

why might some sensory neurons stop at the spinal cord ?

allows for quick reflex actions

what is the structure of a sensory neuron ?

Where are relay neurons found in terms of neurons ?

between the sensory input and motor output

where are relay neurons found in the body ?how does this aid their function ?

brain and spinal cord - PNS - in clusters known as ganglia

to allow sensory and motor neurons to communicate

where are motor neurons found ?

in the CNS

what do motor neurons control?

muscle movement

what happens when motor neurons are stimulated ?

they release neurotransmitters that bind to the receptors on muscles to trigger a response which leads to movement

what is the structure of motor neurons ?

what Is the structure of relay neurons?

How is the dendrite similar in all three neurons ?

• dendrites receive signals from other neurons or receptor cells

• they are usually connected to the cell body - control centre as it contains the nucleus

how is the axon similar in all three neurons?

• long slender fibre , carries nerve impulses in the form of electrical signals known as an action potential away from the cell body towards the axons terminals , were the neuron ends

what surrounds the axon in most neurons except for which ? how does this assist the axon?

Myelin sheath - except for relay

to insulate the axon so electrical impulses travel faster along axon

what connects neurons to eachother? and what is the process called?

axon terminals

synaptic transmission

what is released from axon terminals?

neurotransmitters aka terminal buttons

What are the axon terminals also responsible for ?

re uptake of excess neurotransmitters that didn’t get passed along in synaptic transmission

why does the myelin sheath ensure that only one nerve cell is insulated ?

so the impulse from one neuron doesn’t interfere with another neurons impulse

what manufactures the myelin sheath ?

Schwann cells

What segments the myelin sheaths?

Nodes of Ranvier

What does the nodes of Ranvier allow?

speeds up the transmission of the impulse - forcing it to jump along the gaps of the axon

what connects the terminal boutons ?

dendrites across the synapse

how is info passed down the axon of the neuron?

as an electrical impulse -

what is electrical impulses also known as ?

action potential

the action potential must be transferred form the pre synaptic neuron to the post synaptic neuron , what is this gap called?

synaptic gap

what is at the end of the Neuron , in the axon terminals ?

synaptic vesicles

what does the synaptic vesicles contain ?

neurotransmitters

what happens when the electrical impulses reach the synaptic vesicles what happens ?

they release their contents of neurotransmitters

how are signals transmitted WITHIN the neuron ?

electrically

how are signals transmitted BETWEEN the neurons?

chemically

what are the two types of neurotransmitters ?

• excitatory or inhibitory

how do excitatory neurotransmitters affect the post synaptic cell?

makes it more likely to fire