Chapter 2: Myelin
What do myelinating cells make?
They make myelin sheath
Give an example of a myelinated cell
a schwann cell
Whats the difference between a normal nerve and a damage nerve?
A normal nerve has an intact myelin sheath and the message moves quickly, while a damaged nerve has a damaged or destroyed myelin sheath and the message moves slower
Gray matter is (external/internal) while white matter is (external/internal) in the brain.
A) External B)Internal
Gray matter is (external/internal) while white matter is ( external/ internal) in the spinal cord.
A) Internal B) External
Explain Saltatory Conduction and its function
A)Occurs in myelinated nerves B)The impulses jump from node to node where depolarization takes place
Both _________ and __________ have gray and white matter.
Brain and spinal cord
How many axons can one oligodendroglia contribute to?
Can contribute to many axons (CNS)
What constitutes a neuroglia cell?
Oligodendroglia or oligodendrocyte
Describe Multiple Sclerosis
Particially autoimmune Myelin Sheath of certain axons are destroyed Demyelination= immune system detects myelin and attacks Attacks the myelin in CNS
Schwann cells are found in where?
Schwann cells are found in the Peripheral
What the difference between a myelinated cell and a unmyelinated cell?
a myelinated cell has a myelin sheath and conducts impulses 10x faster. a unmyelinated cell has no myelin sheath
What is gray matter?
consists of cell bodies of neurons; where thinking and analyzation occurs
Myelin sheath help axons conduct what much faster?
helps axons conduct action potentials much quicker
What is a growth cone? What is it used for?
its where regrowth of a damage in the myelin sheath, it guides regrowth the right way. Its used for the Wallerian degeneration
What is white matter?
myelinated axons; conduction of impulses
What does "MYELEN" refer to?
refers to the spinal cord
A myelin sheath must have openings, what are those openings called?
the openings are called Nodes of Ranvier
What is the function of the myelin sheath?
to reduce leak from the axon, makes current flow faster
What is the percentage of myelin in a nerve?
50% of myelin in a nerve