Lec 2: Neurophysiology Part 1: Cells and Connections Flashcards
What is a nerve cell (neuron)?
Fundamental component of the nervous system
In general, what is a glial cell?
support system for neurons
What functions do glial cells do for neurons?
- Set neurons and connections to stay in place
- Removes, Repairs, & migrates damaged neurons
- Middle-man between blood and brain, therefore…
- Help energize neurons to provide nutrients and oxygen from blood to brain
- Forms Myelin around axons/neurons
What are the (3) Types of Neurons?
Motor Neurons “Efferent Neurons”
Sensory Neurons “Afferent Neurons”
Interneurons
How do Motor Neurons “Efferent Neurons” function?
Motor Neurons receive input by other neurons, but send output to muscles.
Between the two types of Motor Neurons, which one sends output directly from the Central Nervous System to muscles to create movement?
Alpha Motor Neuron
Between the two types of Motor Neurons, what do Gamma Motor Neurons do?
Test and activate sensory receptors, muscle spindles, in the muscle to tell the nervous system how the muscle is behaving
How do Sensory Neurons “Afferent Neurons” function?
Receive info my sensory receptors, then send output to other neurons involving direction of flow from periphery back to the brain
What are Interneurons, and how do they function?
Neuron that receives input from another neuron, forming connection with other neurons.
Function: Process information in the brain to create action
Where does a neuron receive its input? Output?
Input = Dendrites Output = Axon Terminal
Describe the process of how a neuron functions?
1) Dendrites receive impulses from other neurons and flows to the soma (cell body)
2) Soma gains action potential
3. ) Potential travels through the axon to other neurons by exiting through the Axon Terminal
What is the Soma?
Neuron Cell Body between dendrites and axon
What happens in the Soma? What is the significance of the “Summation Principle”?
In the soma, a variety of impulses are collected /summed from multiple dendrites
.
What is the “All or None Principle”?
Depending on the neuron’s threshold, if the summation of impulses do not surpass and are not generated. It will not fire action potential through the axon.
Surpasses threshold? Action potential will fire through the axon.
What is EPSP (Excitatory post-synaptic Potential))?
When impulse is coming into a dendrite, the neuron that is receiving the input will decrease,taking time to reach cell membrane potential.
Why do Post Synaptic Potentials last for 15 milliseconds?
Opportunity for action potential to gather in the soma and cross threshold completely.
This will allow time for the soma to gather more impulses to reach potential consistently. If a 2nd input comes quick enough to the waiting 1st input, a better chance to cross threshold and fire will result.
Summation = combination ( or balance) of ____ + ____
EPSP + IPSP ( Inhibitory Post-Synaptic Potential)
combination ( or balance) of (decrease + increase)
What are (2) types of Summation?
Temporal & Spatial Summation
What is Temporal Summation?
If the 1st input is quickly accompanied by a faster 2nd input within the 15 milliseconds, a larger action potential will occur and likely pass the threshold faster
What is Spatial Summation?
When multiple synapse sites are directly effecting the dendrites, sending inputs all at once into the soma. This will allow potential to cross the threshold very very quickly.