Neurons and Action Potentials

Neuron

electrically excitable nerve cell and fiber of the nervous system

what is a neuron composed of?

cell body (soma), nucelus, dendrites, main axon branch (with possible axon collaterals), and terminal boutons

cell body

stores the genetic codes of the organism

dentrites

• tree-like processes that attach to the cell body

• recieves messages from the terminal boutons of a presynaptic neuron

axon hillock

the region where the cell body and axon attach

axon

fiber emerging from the axon hillock and extendoing to the terminal boutons

myelin

composed of lipids and proteins; acts as an insulating substance of the axon

nodes of ranvier

spaces between the myeline where nerve signals jump from one node to the next

Multiple sclerosis (MS)

involves random demyelination of the CNS that disrupts communication between neurons, leading to various neurological symptoms.

Amyotrophic lateral sclerosis

severe degenerative neurological disorder affecting motor function; causes muscle weakness and atrophy due to motor neuron degeneration.

Myasthenia Gravis

chronic autoimmune disorder that affects the neruomuscular junction of voluntary muscles; characterized by production of acetylcholine receptor antibodies that block or destroy receptors, leading to muscle weakness and fatigue.

axon collaterals

transmit nerve signals to several parts of the nervous system

terminal boutons (synaptic boutons)

emerge from the end branches of the axon and contain neurotransmitter-filled vesicles that release chemicals into the synapse, facilitating communication between neurons.

synaptic cleft

space between a presynaptoc neurons terminal boutons and a postynaptic meurons dentrites

neurotransmitter

chemcial stored in the terminal boutons

presynaptic neuron

first order neuron that releases its neurotransmitter into the synaptic cleft

postynaptic neuron

second order neuron; recieves the presynaptic neuron's neurotransmitter and generates a response.

what are the neurotransmitter activity termination ways?

diffusion, enzymatic degradation, and re-uptake process

diffusion

neurotransmitter detaches the postynaptoc receptor, drifts out of the synaptic cleft, and absorbed by the glial cells