Lecture 2 (Neurons Basics) Flashcards
Output information is encoded in electrical impulses that a neuron provides neural input to
to Innervate the neuron
branches of neuron
arborization
information flows from the cell body of the pre-synaptic neuron to the postsynaptic neuron (info enters through input zone and out of the output zone)
Dynamic polarization
large collection of neurons
ganglia
grey matter
cell bodies and dendrites (receives and transmits information)
white matter
axons (coated in myelin sheath) transmits information
Is the basal ganglia a white or grey matter structure
grey matter (cell bodies and dendrites, receives transmits information)
Afference
information arrive at the neuron
Efferent
information moves away from the neuron
Components of the input zone:
a.) dendrites (receive information)
*dendritic spines
b.) Cell body/soma (receives synaptic input and decides whether or not to send signal)
* Nucleus
C.) Axon Hillock (integrates and gathers information from the soma)
dendritic spines
small projections on the dendrites that add extra space for synapses. They come and come (neuro-plasticity and change as is memory encoded)
Soma (roles)
Nucleus (receives synaptic inputs, and determines whether to send a signal)
synthesizes important substances
structural proteins (remodelling of cytoskeleton)
transmitters (synthesizes enzymes)
Conduction zone (components):
1.) Axon (protection that leads away from the neuron –sends the neural impulse)
- Mylein sheath –> beaded fat insulator that speeds up action potential
- nodes of ranvier –> gaps in the myelin sheath
- axoplasmic transport –> transport of vesicles of neurotransmitter (via Motor proteins)
axoplasmic transport
transport of vesicles of neurotransmitter in axon. via motor proteins (kinesin and dynein)
Kinesin
workhorse of the cell = transports proteins via walking on microtubules (two feet like structures)
wire and hose
wire: axon potential travels through axon
hose: transport flow of vesicles (axoplasmic flow)
retrograde
movement towards cell body
anterograde
movement away from the cell body
Output zone (components):
1.) Axon collaterals
2.) Axon terminals (boutons)
3.) Synapse
*synpatic cleft (lipid bilayer)
Synapse cleft is composed of a:
lipid bilayer (fat soluble, hydrophilic head, hydrophobic tail)
Steps of transmitter signal from pre to post-synaptic membrane:
1.) electrical activity causes vesicles to fuse with the presynaptic membrane
2.) vesicles rupture releasing neurotransmitter into the cleft
3.) neurotransmitter crosses the cleft and matches with the receptor
4.) alters level of excitation in post-synaptic neuron, may send a signal of its own
Three neuron shapes:
1.) Multi-polar = large neurons, long axon, dendritic arborization, several axon collaterals (MOTOR NEURONS)
2.) Bi-polar = very small, few dendritic branches, short axon (in your retina/vision)
3.) Mono-polar = dendrites are part of a single axon (Peripheral sensory neurons)
Three types of neurons:
1.) Motor neurons
2.) Sensory neurons = affected by changes in environment
3.) Interneurons = receive and send input
Four types of glial cells:
1.) Astrocytes
2.) Microglia
3.) Oligodendrocytes
4.) Schwann cells
Astrocytes
- start shaped
- close to capillaries and blood vessels = control local blood flow (allows for blood to reach active areas of the brain)
*contribute to tough membrane around brain
*secrete growth factors - can become cancerous
Microglia
*Macrophage
* scavenge at damage sites
* release pro-inflammatory substances
*break down dead cells
Glial cells that may worsen: edema – swelling after brain injury, Parkinson’s, Alzheimer’s
Microglia, and astrocytes
Oligodendrocytes
source of myelin (allows for salutatory conduction)
found in brain and spinal cord
Schwann cells
Peripheral nerves
source of myelin
