neuroscience - chapter 2 Flashcards
Name different part of the neuron.
Dendrites, soma, axon hillock, axon, axon collaterals, axon terminal.
Description of AXON.
-Only one in each neuron!
-Sometimes branches into axon collaterals
-No rough ER, no ribosoms
-Membrane proteins different from soma membrane proteins
-Ends in an “axon terminal” (terminal bouton)
how long can an axon be?
-Can be very long
-Diameter: 1-25 μm (in humans)
Are there axon terminals at the end of axon collaterals?
Yes, its where the mitochondria is in order to make ATP.
Do microtubules extend into the axon terminal?
NO
Describe axon terminal.
-Contains many small bubbles of membrane: synaptic vesicles
-Contains may mitochondria (high need of ATP (energy currency of the cell in order to perform chemical reactions)
How many axon hillocks in one neuron?
ONE
Describe Axonal transport.
-Proteins must be transported from soma to axons
-Diffusion would be too slow (passive transport so flows until it gets there like water onshore/beach)
-Rate of transport can be as high as 1 m per day.
What is anterograde axoplasmic transport?
Direction: From the cell body (soma) to the axon terminals.
Function: This type of transport is responsible for moving proteins, organelles (like mitochondria), and synaptic vesicles containing neurotransmitters to the synaptic terminals, where they are needed for neuron function and communication.
Motor Protein: The movement is facilitated by a motor protein called kinesin. Kinesin moves along microtubules in the axon, carrying materials toward the axon terminal.
from notes:
-Material is “packed” within vesicles
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* Kinesin legs move the vesicles down microtubules (uses ATP).
* Retrograde transport to the soma uses dynein legs
-walking through the microtubules
what is retrograde axoplasmic transport?
from notes:
-Transport to the soma (retrograde transport)
* Can be used to find out what cells project to a given area
Direction: From the axon terminals back to the cell body (soma).
Function: This transport is involved in moving cellular components that need to be recycled or degraded, as well as signaling molecules that inform the cell body about the condition of the axon terminals. For example, it can carry endosomes containing growth factors or other signaling molecules.
Motor Protein: The motor protein responsible for retrograde transport is dynein. Dynein moves along the microtubules toward the cell body.
Speed: Retrograde transport is generally slower compared to the fast anterograde transport.
main difference between both?
In summary, anterograde transport delivers materials necessary for axonal function to the synapse, while retrograde transport brings back materials for recycling or signaling from the synapse to the soma.
Describe the Dendrites
-The “antennae” of the neuron
-The membrane is covered with specialized proteins: receptors
-In some neurons, the dendrites are covered with dendritic spines
How long are dendrites?
Rarely longer than 2 mm
Give the definition of a neurite.
Any projection from the cell body of a neuron. (This projection can be either an axon or a dendrite.)
Name the three different classifications of neurons based on the number of neurites and explain what it looks like.
- Unipolar (one neurite that splits into two)
- Bipolar (two branches stemming out of soma)
- Multipolar (many neurites steming out of soma)
