5.3 Nerve action Flashcards
What does the soma (main cell body of the neuron) contain?
The usual components of any cell e.g., nucleus, DNA, mitochondria etc)
What do the dendrons divide into?
Dendrites
What do the dendrites do?
Pick up neurotransmitters that are being sent from other cells and send that information to the soma via an electrical signal
Why are the dendrites long and complex?
Because it allows them to receive signals from many neurons at the same time
What is the function of the axon?
Carry signals away from the soma to the protrusions at the end of the neuron so that messages can be sent between the neuron and an adjacent neuron.
What is the axon coated in?
Myelin sheath
What is the myelin sheath made up of?
Schwann cells
What is in between each Schwann cell?
Tiny gaps called the nodes of Ranvier
What is the purpose of the myelin sheath?
To insulate one nerve cell from another to prevent the signal from one neuron to another being interfered with.
What is a second purpose of the myelin sheath?
Speed up the coordination of electrical signals travelling along the axon.
What is the synapse?
A gap between two neurons
What is a synaptic transmission?
The process of one neuron communicating with another neuron across the synapse
What is the first step of the process of synaptic transmission?
Chemicals called transmitters are released from the axon terminal of one neuron into the synapse
What is the second step of the process of synaptic transmission?
These chemical signals are picked up by receptors on the dendrites of the receiving neuron
What is the third step of the process of synaptic transmission?
Depending on the type of neurotransmitter, an electrical signal will be generated, which travels away from the soma
What is the fourth step of the process of synaptic transmission?
The electrical signal continues down the axon until it reaches the axon terminal
What is the fifth step of the process of synaptic transmission?
This triggers the release of neurotransmitters into the synapse at the end of this neuron, which in turn can then be picked up by the dendrites of the next neuron.
What is the structure and function of a sensory neuron?
Have an axon which is split into 2 parts and pick up incoming sensory signals from the peripheral nervous system and deliver these to the central nervous system.
What is the structure and function of the motor neurones?
Short dendrites and long axons, and send signals from the CNS to effectors in the muscles.
What is the structure an function of relay neurones?
Have short dendrites and short OR long axons, depending on their location. Communicate messages between sensory and motor neurones.
