Exam 5 Tips 11-13

Question 1

What are the two major parts of the nervous system in humans?

Answer 1

-CNS & PNS

Question 2

A neuron has 3 general parts: cell body, dendrite, and axon. What are the specific parts of each of those? Where are they located? What do they do?

Answer 2

• cell body: nucleus and organelles
  
  • perikaryon: cytoplasm that contains organelles that provide energy & synthesize neurotransmitters (everything in cytoplasm)
  • neurofilaments: located in the cytoskeleton, neurofibrils are bundles of neurofilaments that extend into dendrites and axons to provide internal support
  • nissl bodies: clusters of RER and free ribosomes (makes proteins)
• dendrites: receives information
  
  • dendritic spines: long processes on dendrite branches
• axons: carries information
  
  • axon hillock: base of axon, connection point of cell body & axon
  • axolemma: specialized plasma membrane that surrounds the axoplasm
  • axoplasm- cytoplasm
  • telodendria: extensions of main axon, end in synaptic terminals

Question 3

What is a synapse? What is the difference between a pre and post-synaptic cell?

Answer 3

• specialized site where the neuron can communicate with other cells
• presynaptic: will always be a neuron
• postsynaptic: can be either to a muscle, gland, or another neuron

Question 4

There are three types of synapses. What are they?

Answer 4

• neuron to neuron
• neuron to muscle
• neuron to gland

Question 5

Why can’t CNS neurons repair themselves?

Answer 5

-they lack centrioles and therefore cannot divide to produce more cells

Question 6

Neurons are classified on structure and function. What are the 4 structural classes? Know the basics about each one. What are the three functional classes? How are they different?

Answer 6

• anaxonic: without distinguishable axon, in the brain & special sense organs
• bipolar: # of times something is leaving cell body, rare but in special sense organs
• unipolar: continuous dendrite & axon that leave from 1 place, in sensory neurons of PNS
• multiplar: typical neuron, most common neuron in CNS, in motor neurons
• sensory: monitoring our senses, bringing in info
• interneurons: bridge neurons in between motor and sensory
• motor neruons: going out & doing the job

Question 7

We have seen neuroglia before. How are they different between the CNS and the PNS?

Answer 7

• neuroglia of CNS
  
  • ependymal cells: forms lining that is filled with cerebrospinal fluid
  • microglia: small, clean neural tissue
  • astrocytes: do many functions
  • oligodendrocytes: produce myelin, think of as greasing the neuropathway
• neuroglia of PNS
  
  • schwann cells: produce myelin sheath around axons
  • satellite cells: surround neuron cell bodies in ganglia

Question 8

Generally describe Wallerian degeneration.

Answer 8

• the repair of damaged nerves
• schwann cells come in and lay a pathway for new growing axon to follow, axon starts to repair itself and follows pathway, axon reconnects to other cell/synapse and schwann cells will form around new axon and/or myelinate it depending on what kind of cell it is