A walk through the brain - week 3 Flashcards
What is a nerve?
A nerve consists of a membrane sheath encasing bundles of axons.
Where are the nerves in the brain?
Cranial nerves
What do nerves do?
Nerves are bundles of fibers that transmit electrical impulses from the central nervous system to the body and back.
What are the 4 structures of a neuron?
Cell body (soma)
Dendrites
Axon
Terminals
What is the soma (cell body)?
The neuronal cytosol
Contains nucleus
contains cellular organelles
What do dendrites do?
Receive messages from another neuron’s terminal buttons
What do dendrites do?
Receive messages from another neuron’s terminal buttons
What is an axon ?
Slender tube - covered by a myelin sheath
Carries messages (electric charges) from the soma to terminal buttons
What are terminals or (terminal buttons)
Small knowbs end of terminals which release neurotransmitters
Where do neurons communicate with each other?
The Synapse
What is the ave. length of a neuron?
< 1.0mm
How long is the sciatic nerve on ave?
1meter
What are nodes of ranvier?
Unmyelinated gaps on the axon
In the CNS myelination is made from what cells?
Oligodendrocytes
In the PNS, myelination is made from what cells?
Schwann cells
What is myelination important for?
Sensory & motor transmission (PNS)
Neuron to neuron communication (CNS)
Afferent stimulation =
Carry messages to CNS
Alerts about environment
Efferent stimulation =
Motor neurons carry messages AWAY FROM CNS
causes muscle movement
What’s the ave. percentage of neuronal cells in the brain?
10 - 15%
What is the ave. % of glial cells in the brain?
85%
What do glia do?
Glue CNS together
Supply nutrients to soma
Insulate neurons
Destroy/remove dead neurons
GLIA = GLUE
How many types of neuroglial cells are there?
6
How many types of glia in the PNS?
2
How many types of glia in the CNS?
4
What are the 2 types of glia in the PNS?
Schwann Cells
Satellite Cells
What are the 4 types of glia cells in the CNS?
- Astrocytes
- Oligodendrocytes
- Microglia
- Ependymal cell
How many cranial nerves are there?
12
Name the 12 cranial nerves in order
I - Olfactory
II - Optic
III - Oculomotor
IV - Trochlear
V - Trigeminal
VI - Abducens
VII - Facial
VIII - Vestibulocochlear
IX - Glossopharyngeal
X - Vagus
XI - Accessory
XII - Hypoglossal
What is the BBB?
A semipermeable barrier between the blood and the brain produced by the cells in the walls of the brain’s capillaries.
Where is the BBB?
Around the brain
What does the BBB do?
he blood–brain barrier helps prevent pathogens from entering the brain, it can also prevent molecules from entering.
How does the BBB function?
The BBB regulates the composition of extracellular neuronal fluid
Protects the brain from harmful chemicals
What is an interneuron?
A neuron located entirely within the central nervous system.
What direction is anterograde?
In a direction along an axon from the cell body toward the terminal buttons.
What direction is retrograde?
In a direction along an axon from the terminal buttons toward the cell body.
What is a microtubule?
A long strand of bundles protein filaments
hollow core;
part of the cytoskeleton
transports substances within the cell.
What is an astrocyte?
A glial cell that provides sup- port for neurons of the central nervous system, provides nutrients and other substances, and regulates the chemical composition of the extracellular fluid.
ASTROCYTE = STAR CELL
What is the function of oligodentrocytes?
Provide support to axons
Produce myelin sheath
