PS1090 - Understanding Neuroscience Flashcards
What happens when neurons connect to other neurons?
- Can stimulate other neurons (excitatory synapses/ neurons)
- Can inhibit other neurons (inhibitory synapses/neurons)
- Can receive input from many neurons
- Can send output to many neurons
What are dendrites?
Dendrites are protrusions where neurons collect information from other neurons, it integrates that information and makes a ‘decision’ about whether to pass information through the axon, it conducts signals through the axon.
What happens at axon terminals?
At the axon terminals, the neuron connects to other neurons, it can stimulate other neurons and either excite them and make them likely to fire a signal or inhibit them from sending a signal. Each neuron can receive information from many other neurons and also send output to other neurons.
What are glia or glial cells?
Glia or glial cells are non-neuronal cells in the central nervous system – brain & spinal cord
How can the shape of neurons indicate function?
if they have a very widespread dendritic tree, it could mean that they receive input from lots of neurons. If they have a widespread axon terminal ending, it could mean it connects with many other neurons.
What do neurons do?
They receive, process and transmit information.
What’s a simple reflex arc?
A receptor (neuron that detects the stretch of a muscle) connects to a motor neuron (neuron that controls muscles in the spinal cord) and that neuron then causes the muscle to contract.
How do neurons connect to make networks?
In the brain, there are complex patterns of convergence and divergence. There are neurons in one area passing on information to other areas. They spread out their information to multiple neurons (divergence) Each neuron will receive input from multiple neurons (convergence).
What does the function of a neural circuit depend on?
- How the neurons are connected
- How strong are the connections (synapses)? They can be very strong and pass signals easily or be weak and only pass a signal if there’s a lot of stimulation.
- Whether the connections (synapses) are excitatory (EPSP) or inhibitory (IPSP)
How can the function of a neural circuit change?
The function of a neural circuit can change through changes in synaptic strength – for example, memory!
What are the functions/characteristics of glial cells?
Supportive function
Protective function
Metabolic function - help clean up metabolites
Unlike neurons they divide throughout life
What are glial cells?
Glia, also called glial cells or neuroglia, are non-neuronal cells in the central nervous system and the peripheral nervous system that do not produce electrical impulses.
What are the most abundant type of cell in the central nervous system?
Glial cells are the most abundant cell types in the central nervous system.
What are the 4 types of glia?
• Astrocytes: star shaped (most common)
• Oligodendrocytes: few extensions, have a very specific function (only found in the CNS)
• Schwann cells (PNS – peripheral NS: found outside the brain)
Very similar to Oligodendrocytes but they’re outside the central nervous system.
• Microglia: smaller than the rest
How do astrocytes provide a scaffold by connecting neurons to blood vessels?
- They attach to blood and neurons
- Provide physical support
- Help control blood flow
How do astrocytes help to control blood flow?
How is this the basis of neuroimaging techniques?
They react to active neurones by controlling blood flow. They cause the capillaries (that they are attached to) to dilate when neurons around them are active. Bringing oxygen and nutrients to the neurones.
When neurons are active, blood flow increases and that’s caused by the astrocytes – this is the basis of neuroimaging techniques.
Apart from being a physical support and controlling blood flow, what are the other functions of astrocytes?
- Separate synapses (astrocytes maintain the gap between synapses which is important for neuronal communication.)
- Clean up debris that is generated by neuronal signalling (when one neuron communicates with another, it does so by excreting transmitter substances – small molecules that have to be cleaned up after each firing session)
Briefly bullet point the 5 functions of astrocytes.
- Attach to blood and neurons
- Provide physical support
- Help control blood flow
- Separate synapses
- Clean up debris that is generated by neuronal signalling
Where are oligodendrocytes found?
In the central nervous system
What are oligodendrocytes called in the peripheral nervous system (PNS)?
Schwann cells
Briefly bullet point the function of oligodendrocytes.
- Support axons
* Insulate axons and speed up information transmission
How do oligodendrocytes speed up information transmission.
They have a round shape and extend these sheath-like growths around the axon and surround each axon with a layer of fatty substance known as myelin which insulates them.
They provide electrical insulation which underlies the ability of neurons to send signals from one place to another really fast.
Explain what happens to the immune system of Multiple Sclerosis patients.
• It’s a demyelinating disease
• Induces numerous scars (multiple scleroses) in the brain
• Immune system attacks the myelin produced by oligodendrocytes
• Inflammation of CNS nerves
• Affects insulating layer of axons
• As the insulation becomes degraded, neurons can’t communicate as fast with one another. This causes problems for M.S. patients. • • First, they get problems with movement and motor control and then starts affecting cognition.
This is a very debilitating disease but fortunately the treatment for it is getting better.
What are microglia?
• Aren’t really glia • Precursors of blood cells • Part of the brain’s immune system • Related to macrophages Eat up debris and hostile bits