Unidirectional Flow of Neurons Quiz

neurons flow only in one direction. they start with the input layer, where the info comes in and gets integrates on the cell body, the dendrites

the output layer is a single axon, from start to end, and releases neurotransmitters to be released

• Projection neuron has a long axon which projects to a different brain area. There are gaps where we go to different regions, neurons tired, need a break to modify signals, that is where interneurons come in

• Interneurons - generally, but not always, star-shaped, they are short but only project to local area, nearby area of the brain. They modify, coordinate and synchronise when all these connections are coming in. They help with organisation. They are inhibitory but don’t block it - it’s more like “okay wait a second, okay now go” like a traffic modulator.

Glia: support cells, glue of the brain, will form a scaffold in development. Prominent role in brain dysfunction. They are a variety of different types of cells, 4 types, but either large or small.

Schwann cells and oligodendrocytes

Myelin speeds up action potential of axon or conduction. Not all animals have myelin (invertebrates)

schwann cells

oligodendrocytes

schwann, oligodendrocytes

they are a part of the blood brain barrier, they have these “feet” that wrap around to make sure no blood gets into the brain. Anything in the blood you need has to come through the astrocytes, such as oxygen or glucose. Brings in nutrition from blood flow. If you have scarring or damage in brain, it shows up in the astrocytes. They are often wrapped around neurons and synapse, additional to blood vessels. It makes sure the environment has enough sodium, not too much potassium, etc. continuously connected together, so that one astrocytic branch flows into another, making a glial network, Spreading effect.