PS267 Lecture Notes - Lecture 4: Schwann Cell, Pseudounipolar Neuron, Astrocyte
Microstructures of the Brain (what can be seen with a microscope)
Neural activity aka How Neurons Work
Development of the Nervous System
● Neurons are highly specialized type of cell - need support cells like glia - can’t take care
of themselves
● Still same as other cells, mitochondria etc etc - remarkable feature is that they have
electrical properties (most cells do not)
● Morphology is odd - multiple shapes of neurons but has cell body (always), and usually
dendrites and axons
● Dendrites are way of collecting electrical/chemical info and send signal down axon to
communicate to next neuron
● Types of neurons based on shape
○ Multipolar - more than one dendrite coming from cell body, tend to be most
common in brain
○ Bipolar - only 2 ends, involved in sensory systems (retinal neuron, olfactory)
○ Unipolar, pseudounipolar - pseudo (one pole but two parts coming out), unipolar
is one process coming out (dendrite), rare but common in somatosensory
system, receives information only (doesn’t send)
○ Anaxonic - found throughout CNS, function known as interneuron (connects 2
others), cell body covered with dendrites, no axon
Neuronal Connectivity
● Divergence
○ Single neuron can talk to up to 1000s of other neurons
● Convergence
○ In theory 1000 neurons can all target one
The Talent Must be Managed
● Neurons would not survive without glia
● Even oxygen is slightly toxic to neurons
● Glial system are our support cells, various types
● CNS: astrocyte, oligodendrocyte, microglial
● PNS: schwann cell
● Schwann cell and oli.. Provide myelin for neurons
● Astrocytes basic role is to feed the neurons, interface with the vascular system and
transport oxygen and glucose to the neurons, send back carbon dioxide
● Microglial cells responsible for phagocytosis, clean things up
Neural Activity
The Synapse
● Heart of communication between neurons
● Couldn’t view synapse till 1970s
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Document Summary
Microstructures of the brain (what can be seen with a microscope) Neurons are highly specialized type of cell - need support cells like glia - can"t take care of themselves. Still same as other cells, mitochondria etc etc - remarkable feature is that they have electrical properties (most cells do not) Morphology is odd - multiple shapes of neurons but has cell body (always), and usually dendrites and axons. Dendrites are way of collecting electrical/chemical info and send signal down axon to communicate to next neuron. Multipolar - more than one dendrite coming from cell body, tend to be most common in brain. Bipolar - only 2 ends, involved in sensory systems (retinal neuron, olfactory) Unipolar, pseudounipolar - pseudo (one pole but two parts coming out), unipolar is one process coming out (dendrite), rare but common in somatosensory system, receives information only (doesn"t send)
