Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
14 Cards in this Set
- Front
- Back
|
What are some characteristics of C-fibers? |
Unmyelinated and have small diameters. They conduct APs slowly but persistently fromthe periphery to the CNS. They relay pain information. |
|
|
What are Schwann Cells? |
They are glial cells that form the myelin coating of peripheral, myelinated neurons |
|
|
What are some characteristics of Oligodendrocytes? |
They form the myelin coating of central, myelinated neurons |
|
|
What was the correction made by Dr. Adams from lecture about what may or may not be under the myelin coating of axons? |
CORRECTION: Underneath the Myelin Coating: VCKCs are present beneath the myelin. Importantly, these channels open slowly upon depolarization; they do not open fast enough to prevent the passively-conducted depolarization from triggering an AP at the next node. However, they do eventually open and allow the plasma membrane to repolarize to the RMP (and the electrochemical equilibrium potential for K+) under the myelin. |
|
|
What happens to the K+ that is pumped out of the axon from the VGKCs found underneath the myelin coating? |
The K+ that exits the axon through these slowly-opening K+ channels is either pumped back into the axoplasm by Na/K pumps, or is absorbed into the glial cells that form the myelin coat. |
|
|
What are the Advantages of Myelination? |
1. Faster conduction (propagation) of APs 2. Reduced energy expenditure (i.e., ATP consumption) by neuron 3. Na+ enters axoplasm at Nodes of Ranvier 4. K+ exits axoplasm underneath the myelin coat - in the internodal regions of the PM. 5. Reduced pumping of Na+ and K+ by the Na+/K+ pump (ATPase) results in energy conservation. |
|
|
What is the axoplasm? |
The cytoplasm of an axon |
|
|
What Multiple Sclerosis (MS) - |
Patient's immune system erroneously thinks that myelin-forming glial cells are foreign, and it attacks them. Myelin coating is lost, and eventually the axons degenerate |
|
|
Multiple Sclerosis (MS) is described as what 2 kinds of diseases? |
Degenerative neurological disease Autoimmune disease |
|
|
Is MS rare or common? Who does MS often strike? Age range? |
Quite common Often strikes women Hits between 20 - 40 years age |
|
|
What are the symptoms of MS? |
Symptoms highly variable they may include: -sensory impairments -motor dysfunction & spasticity -bladder and intestinal problems -fatique |
|
|
What is the cause of MS? |
Myelin is destroyed by immune system |
|
|
What causes the immune system to attack myelin sheaths? |
Cause not known |
|
|
What does SCLEROSES mean? |
means "scars" (Greek for "Hardened"). Apparently the brain of an MS patient contains areas that appear to be scarred. |
