Chapter Two Flashcards
Myelin:
fatty substance deposits that surround an axon of some cells (mostly motor)
blocks the Na/K exchange allowing the signal to jump to the Nodes of Ranvier
Destruction of myelin is found in a number of pathologies, most notably…
multiple sclerosis
Briefly summarize how inhibitory (GABA) neurons function:
makes the inside more negative than normal and harder to depolarize
etc: chloride channels
What are the differences between these two groups:
- serotonin, dopamine, acetylcholine
- GABA and glutamate
modulatory which can have bodily effects; their cell bodies are localized but their axonal projections spread diffusely
GABA and glutamate have their cell bodies distributed throughout the brain
Explain the process of AP:
- Passive currents collectively carry the strength to reach a threshold and Na+ channels begin to open
- Na+ enters the cell and the negative potential inside is reduced (depolarization)
- Cell membrane is completely permeable and momentarily reverses.
- Negative potential of the cell is restored via the outward flow of K+. Na+ closes.
- Hyperpolarization occurs, preventing AP from traveling backward.
How does myelin allow an AP to propagate faster?
This blocks the Na/K transfer and the AP jumps via passive conduction
What are some biological functions that can have a high spiking rate? Low?
High: speech
Low: vision
The function of a brain region is determined by its…
Neurons responding to similar types of information tend to…
neuronal inputs and outputs
be grouped together
Gray matter consists of […].
White matter consists of […].
neuronal cell bodies; axons and support/glia cells
Association tracts: []
Commissures: []
Projection tracts: []
WM tracts project between different cortical regions of the same hemisphere
WM tracts project between different cortical regions in different hemispheres
WM tracts project between cortical and subcortical structures
Ventricles:
hollow chambers filled with CSF carries waste, transfers messenger signals, protective cushion
Raised folds of the cortex [].
Buried grooves of the cortex [].
Gyri
Sulci
What are the three types of densities?
- neocortex
- mesocortex
- allocortex
What structural component divides the frontal and temporal lobes?
Sylvian fissure
What is the island cortex of the brain? Where is it located?
insula; located buried underneath the temporal lobe