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Terms:
Terms:
Neuron: a nerve cell that conducts nerve impulses
Neural signaling: the reception, transmission, and integration of nerve impulses by neurons, and the response to these impulses
Afferent neuron/sensory neuron: a neuron that carries impulses from sensory receptors to the central nervous system
Interneuron: a local circuit neuron of the central nervous system that relays impulses between afferent (sensory) and efferent (motor) neurons
Efferent neuron/motor neuron: da neuron that carries impulses from the central nervous system to skeletal muscles
Peripheral Nervous System: the parts of the nervous system that are outside of the brain and spinal cord. It includes all the nerves that are outside of the CNS. It connects the CNS to organs, limbs, and skin
Central Nervous System: this part of the nervous system includes the brain and spinal cord
What are Neural Pathways?
What are Neural Pathways?
Neural pathways are connections formed by axons that project from neurons to make synapses onto neurons in another location
Their purpose is to send signals from one part of the nervous system to another
They allow your certain parts of your brain to send signals/messages to specific parts of your body
Nervous system Information Processing steps
Nervous system Information Processing steps
This image shows the process/steps of how your body reacts to a stimulus that it is exposed to
Steps:
Reception - A stimulus of some kind (e.g. stepping on a nail) is felt and detected by sensory receptors in afferent neurons
Transmission - the message travels along the neuron from the afferent neurons to the interneurons
Integration - The neural messages are then sorted and interpreted
Transmission - the message travels along the neurons again and reach efferent neurons
Response - the neural messages from the efferent neurons are transmitted to the effectors. The effectors/muscles are what would make your body's reflexes kick in when stepping on a nail
In simpler words: Afferent neurons send signals to interneurons (your spinal cord/CNS that you stepped on something sharp. Your CNS/interneurons send out a message of how to respond to this. This message is carried by efferent neurons to wherever the CNS was sending the message to. In this case it would be the foot/leg; when the message reaches this area, your leg quickly moves away from the nail.
How does the Message Travel From one Neuron to the Next?
How does the Message Travel From one Neuron to the Next?
Structure of a Typical Neuron
Structure of a Typical Neuron
Receptors on the dendrites of the neuron pick up neurotransmitters/signals from other neurons
These signals cause electrical changes in the neuron that are interpreted by the Soma
The Soma takes all the info from the Dendrites and puts it in the Axon Hillock
If the signal sent by the Dendrites is strong enough, then the signal is sent to the next part of the neuron called the axon (at this point, the signal is call the 'action potential')
The action potential travels down the axon (with the myelin preventing the signal from degrading)
The action potential then reaches the axon terminals
The next step is neurotransmission
Neurotransmission
Neurotransmission
Signals are transferred from neuron to neuron through a process called neurotransmission
This process involves the release of chemical substances into the synapse (the space between the axon and dendrites)
1. The action potential travels down the axon and reaches the axon terminal
2. The action potential changes the membrane potential at the axon terminal and then opens the voltage-gated calcium channels
3. When the terminals open, calcium flows into the axon terminal (because the concentration was higher outside than inside the terminal)
4. The now increased levels of concentration of calcium inside the terminals cause to changes to proteins on the synaptic vesicle and proteins on the presynaptic membrane of the axon terminal
This interaction make them fuse together so that the inside of the synaptic vesicle is then in communication with the synaptic cleft (the area outside of the neuron)
5. By diffusion, the neurotransmitter molecules leave the axon terminal and flow into the synaptic cleft
6. The neurotransmitters then bind to receptors on the post-synaptic membrane of the target cell
7. When the action potential stops firing, the voltage-gated calcium channels close, the synaptic vesicles will stop fusing, and neurotransmitters will stop flowing into the synaptic cleft
And that is how Neurons Pass Along Signals and Neural Pathways are Formed
And that is how Neurons Pass Along Signals and Neural Pathways are Formed
by Brody Heerings
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