Neurons and Glial Cells (Week 1)

Brain Tissue

Very densely packed together, making it hard to prove it is made of cells.

Black Reaction

A staining technique discovered by Camillo Golgi.

Stained Cells

Some brain cells (neurons) were stained.

Electron Microscope

Tool that allowed viewing of synapses and proved the neuron doctrine.

Neuron Doctrine

Current understanding attributed to Ramon Y Cajal.

Dendrites

Branch-like structures that receive chemical messages and conduct post-synaptic potentials.

Dendritic Spines

Small protrusions on dendrites that receive input from a single axon and show plasticity.

Axons

Long structures that conduct electrical signals called action potentials.

Myelin Sheath

Fatty insulation provided by glial cells that insulates axons and speeds up signal transmission.

Nodes of Ranvier

Gaps in myelination that allow saltatory conduction of action potentials.

Axon Diameter

Larger diameter axons have less resistance and transmit signals faster.

Local Circuit

Short axons that communicate with nearby neurons.

Projection Neurons

Long axons that communicate with distant neurons.

Axon Terminal

Contains mitochondria and synaptic vesicles that release neurotransmitters.

Cell Body (Soma)

Contains cytoplasm, nucleus, and integrates signals from various inputs.

Neurocytoskeleton

Composed of microtubules, neurofilaments, and microfilaments that support and transport within neurons.

Neural Membrane

Phospholipid bilayer that defines intracellular and extracellular boundaries and is selectively permeable.

Bipolar Neurons

Have two processes separated by a cell body, often sensory.

Pseudounipolar Neurons

Single elongated process with a cell body off to the side, primarily sensory.

Multipolar Neurons

Many dendrites and a single axon, most common type.

Sensory Neurons

Carry signals to the brain and spinal cord (afferent).

Motor Neurons

Carry signals from the brain and spinal cord to muscles and organs (efferent).

Interneurons

Connect one neuron to another within the brain or spinal cord.

Astrocytes

Most common glial cells that provide structural support and contribute to the blood-brain barrier.

Oligodendrocytes

Myelinate multiple axons in the central nervous system.

Schwann Cells

Myelinate a single axon segment in the peripheral nervous system.

Ependymal Cells

Line ventricles and secrete cerebrospinal fluid (CSF).

Radial Glia

Stem cells that guide young brain cells during neurodevelopment.

Microglia

Immune cells in the CNS that respond to cellular damage and inflammation.

ALS

Condition where motor neurons stop sending signals, leading to muscle weakness and paralysis.

Protein Aggregation in ALS

Misfolded proteins build up in the cytoplasm, causing toxicity.

Mitochondrial Damage

Can lead to oxidative stress and impaired DNA repair.

Vesicle Release

If vesicles cannot be released, neurons cannot send signals.

Glial Cells in ALS

Oligodendrocytes do not function properly, while astrocytes and microglia are associated with damaging factors.