Written Exam 2

Question 1

The most fundamental level of the nervous system can be divided into two sections. What are these two sections and what is involved in each?

Answer 1

• Central Nervous System
  
  • Brain
  • Spinal cord
• Peripheral Nervous System
  
  • Cranial Nerves
  • Peripheral Nerves

Question 2

What are the fundamental parts of a Neuron and their function

Answer 2

• Cell Body
• Axon
  
  • Axons convey stimuli away from the cell body
  • Each neuron has a single axon that conveys action potential or impulses away from the cell body
• Dendrite
  
  • Dendrites covey stimuli toward cell body
  • Eaxh neuron has at least one dendrite, many types you will have multiple dendrites and the many dendrites are integrated at the axon hillock
    
    • ​​A second action potential may or may not be generated at the axon hillock
• Synapse
  
  • Tiny gaps/junctions between axon terminals and either dendrites or cell bodies of the neurons
  • In some, but not all cases, axons can be myelinated
• Myelin - lipid casing
• Node of Ranvier - openings in the myelin that “jump” the signal

Question 3

What makes up white matter?

Answer 3

The neuron is insulated with these fatty substances known as myelin.

Myelin is white, which makes up the white matter in the brain.

Question 4

What makes up gray matter?

Answer 4

Cell body rich

Gray matter is gray by default, implying that it is cell rich.

Its neuronal cell area body rich area, relatively the void of myelin, although not exclusively

Question 5

Explain the act of action potentials down the axon

Answer 5

• Action potentials are conveyed down the axon
• These involve ion fluxes of sodium and potessium crossing the membrane
• However, in a myelinated axon, the ion fluxes take place ONLY in the Nodes of Ranvier
  
  • Therefore much faster velocity

Question 6

What occurs in Multiple Sclerosis

Answer 6

A Demyelinating disease

Devastating effects and it’s all about the difference between milliseconds and conduction velocities of the involved neurons.

Question 7

We categorize neurons depending on the number of processes that they have. Name and describe the types of neurons present in the body

Answer 7

First off, all neurons have an axon. But they can have multiple dendrites.

1. Multipolar
   
   1. Meaning it has multiple dendrites coming off the cell body, The amount of dendrites that come off that primary pole (cell body)
2. Bipolar
   
   1. Simply has one of each, one dendrite and one axon
3. Unipolar (aka pseudounipolar)
   
   1. Single process that bifurcates and functions sort of like a dendrite in an axon, which means it has a receptive area and axon like projection area
      
      1. Divides and functions like an axon and a dendrite
         
         1. Axon like = central process, conveys impulses to spinal cord
         2. Dendritic-like = process a peripheral process because it typically goes out to some part of the skin
   2. Common in dorsal root ganglia
      
      1. ganglia associated with the spinal nerves up and down the spinal cord
   3. These impulses are either going up into the brain or contact some intermediate relay neuron in that spinal cord which then takes impulse to the brain

Question 8

What are Glia cells and where are they located?

Answer 8

Glia cells are support cells in both the CNS and PNS.

They are named glia because scientists used to believe they were the glue of the nervous system

Question 9

Name and describe the glia cells in the central nervous system

Answer 9

• Astrocytes
  
  • Come in multiple types.
  • Found in white and gray matter
  • Form scaffolds during development that help neurons migrate to their final destination.
  • They can buffer potassium in that extracellular space and can release glutamate.
  • There are some the response to neuronal damage and responsible for forming the glial scar at the damaged area
  • Most IMPORTANT Function =has to do with calcium signaling and they orchestrate the activity across widespread groups or ensembles of neurons
• Oligodendrocytes
  
  • Produce myelin
• Microglia
  
  • Are the garbage man of the nervous system. Phagocytize
• Ependymal cells
  
  • WIthin the brain and spinal cord, we have a series of hollow cavities lined with ependymal cells. Responsible for producing cerebrospinal fluid

Question 10

Name and describe the glial cells in the Peripheral Nervous system

Answer 10

• Schwann cells
  
  • Analogous to oligodendrocytes function in the CNS, they make myelin
• Satellite cells
  
  • Supporting cells