Neuro: Neuroscience Flashcards
The basilar membrane sits above a fluid-filled compartment of the cochlear and movement of the fluid transmits to movement of the basilar membrane.
What cells attached to the basilar membrane and tectorial membrane above translate this movement into a nerve impulse?
Hair cells
Hair cells on basilar membrane are moved by sound waves passing into fluid in the cochlear.
What does this movement cause on the hair cell membrane that helps generate a nerve impulse?
Mechanically gated K+ ion channels open.
In the central auditory pathway, what are the key steps of the route nerve impulses take from the cochlear?
“E.COLI”
Eighth cranial nerve (vestibulocochlear)
Cochlear nucleus
Olivary complex
Lateral lemniscus
Inferior colliculus
What is the first structure in the central auditory pathway where the auditory nerve (vestibulocochlear CN VIII) enters the brain stem?
Cochlear nucleus
(Remember: “E.COLI”
Eighth cranial nerve
Cochlear nucleus
Olivary complex
Lateral lemniscus
Inferior colliculus)
In neurons, where do action potentials propagate from?
Axon hillock
What are the two types of neuron synapses?
Chemical (neurotransmitters)
Electrical (ions)
Electrical neuron synapses are less abundant than chemical synapses.
Where might you find electrical synapses?
Brainstem, hypothalamus, etc.
What triggers neurotransmitter release in neuron chemical synaptic transmission?
Influx of calcium ions (which is triggered by the axon potential depolarising synaptic terminal membrane).
What is a connexon?
A protein structure that forms a gap junction in a neuron electrical synapse.
What part of the neuron structure might change as part of neural plasticity?
Dendritic spines (can change number, size, or composition).
What are glia?
Non-neuron cells in the brain, e.g. oligodendrocytes.
Give two important functions of oligodendrocytes.
- Myelinating neurons (one oligodendrocyte can myelinate multiple neurons)
- Provide metabolic support for axons.
Myelin is composed of lipids and proteins.
What is the percentage composition of myelin?
70% lipid, 30% protein.
What are three key functions of microglia?
- immune surveillance
- phagocytosis
- synaptic plasticity (spine pruning)
What is the difference between M1 and M2 microglia?
M1 cause inflammation
M2 help resolve damage/repair
What happens to microglia when they are activated?
Retract their processes and become unramified/amoeboid and motile.
What are the resident immune cells of the CNS?
Microglia.
What are the most numerous glial cells in the CNS?
Astrocytes
Are all astrocytes stellate (star-shaped)?
No, astrocytes are highly heterogeneous.
How do astrocytes help form the blood-brain barrier?
In capillaries, astrocyte end feet cover the basement membrane and maintain the tight junctions in between capillary endothelial cells.
Glutamate is one of the most abundant neurotransmitters, and is a precursor for GABA.
How are astrocytes in tripartite synapses involved in the glutamate-glutamine shuttle?
Astrocyte processes envelope synapses and take up excess glutamate in the synaptic cleft then convert it into glutamine.
What is neurovascular coupling?
The process by which neuronal activity increases blood flow to active areas of the brain.
Give four important features of the blood brain barrier.
- More tight junctions between capillary endothelial cells.
- Fewer fenestrations in basement membrane.
- Astrocyte end feet cover basement membrane.
- Pericytes embedded in basement membrane.
What ciliated glial cells line the brain’s ventricles and the spinal cord’s central canal?
Ependymal cells