NeuroAnatomy/NeuroPathology Lecture 6 Cells of Nervous System

Question 1

What are the two types of cells of the nervous system?

Answer 1

Neurons & glial cells

Question 2

What is the structure of a neuron?

Answer 2

cell body/soma, dendrite, axon, terminal axons, node of ranvier

Question 3

What is the function of a neuron?

Answer 3

responsible for neurotransmitter signaling in the nervous system

Question 4

What is the function of the cell body?

Answer 4

“production factory” for all neuron components

Question 5

What is the function of the dendrites?

Answer 5

sensory input

Question 6

What is the function of the axons?

Answer 6

conduct action potentials for signaling

Question 7

What does the Node of Ranvier allow?

Answer 7

faster transmission of action potentials

Question 8

What is the anterograde axon transport pathway?

Answer 8

cell body to terminal axon and transports molecular building blocks

Question 9

What is the retrograde axon transport pathway?

Answer 9

terminal axon to cell body and transports molecular byproducts

Question 10

What are the five types of glial cells?

Answer 10

astrocytes, oligodendrocyte, microglial cells, ependymal cells, Schwann cells

Question 11

What are the four functions of an astrocyte?

Answer 11

regulate the blood brain barrier, transport nutrients, regulates synapses, and remodeling

Question 12

What is the function of an oligodendrocyte?

Answer 12

myelinating axons of the CNS

Question 13

What are the functions of a microglial cell?

Answer 13

clear toxic material, secrete neurotrophic factors, increase clearance of glutamate, secretes potentially neurotoxic molecules

Question 14

What is the function of an ependymal cell?

Answer 14

responsible for secreting/absorbing nutrients into the CSF and protects the blood brain barrier

Question 15

what is the function of a Schwann cell?

Answer 15

responsible for myelinating axons of nerves in the PNS

Question 16

What causes the symptoms of Alzheimer’s disease?

Answer 16

the progressive widespread atrophy of the cerebral cortex

Question 17

Where does atrophy begin in Alzheimer’s disease?

Answer 17

the temporal lobe

Question 18

What causes Alzheimer’s?

Answer 18

astrocyte dysfunction – disrupted glutamine/protein clearance // leads to formation of neuritic plaques neurofibrillary tangles, and neuron death

Question 19

What types of proteinopathy are found in Alzheimer’s?

Answer 19

beta amyloid proteins, Tau proteins, α-synuclein

Question 20

Neuritic plaques are formed by….

Answer 20

abnormal extracellular accumulation of beta amyloid proteins that surround and damage the axon

Question 21

Neurofibrillary tangles are formed by….

Answer 21

abnormal accumulation of Tau proteins in FLAME-shaped neurofibrillary tangles that disrupt microtubule highway and leads to cell death

Question 22

What causes Pick’s disease?

Answer 22

abnormal accumulation of Tau proteins in ROUND neurofibrillary tangles

Question 23

Which cell is targeted/damaged that leads to Multiple Sclerosis?

Answer 23

Oligodendrocytes

Question 24

What happens if oligodendrocytes are damaged?

Answer 24

there is damage to the myelin sheath

Question 25

What are the four types of MS?

Answer 25

Clinically Isolated Syndrome, Relapsing-Remitting, Secondary Progressive, Primary Progressive

Question 26

What are the three causes that lead to injury for concussions?

Answer 26

transient microscopic disruption, astrocytes are unable to maintain CNS homeostasis, and there is a mismatch of cerebral blood flow that is inadequate for metabolic demands of jolted neurons

Question 27

What is the proteinopathy involved in CTE?

Answer 27

abnormal accumulation of Tau proteins which form neurofibrillary tangles

Question 28

How does the Tau proteinopathy differ between Alzheimer’s and CTE?

Answer 28

CTE has a different regional distribution pattern of the Tau accumulations in the brain than Alzheimer’s

Question 29

What are the three layers of tissue covers of the peripheral nerves listed from outer most to inner most?

Answer 29

Epineurium, Perineurium, and Endoneurium

Question 30

What is Wallerian Degeneration?

Answer 30

the process of degeneration that provides opportunity for regeneration to occur

Question 31

What are the three phases of Wallerian degeneration?

Answer 31

acute nerve injury, degeneration(immune response), regeneration

Question 32

What is the Seddon classification of nerve injuries ordered from least to most severe?

Answer 32

Neuropraxia, Axonotmesis, Neurotmesis

Question 33

What is the Seddon classification of Neuropraxia?

Answer 33

• least severe injury with good prognosis
• focal demyelination but no axonal loss so Wallerian degeneration does NOT occur
• complete recovery within 3-6 weeks

Question 34

What is the Seddon classification of Axonotmesis?

Answer 34

• disruption of axons with perineruium and epineurium still intact
• Wallerian degeneration DOES occur
• variable prognosis and can require many months

Question 35

What is the Seddon classification of Neurotmesis?

Answer 35

• complete transection of all nerve components
• Wallerian degeneration DOES occur
• requires surgical repair or NO chance for improvement

Question 36

What is the rate of peripheral nerve recovery?

Answer 36

• axonal regeneration = 1-2mm/day or 0.04-0.08in/day
• 1-2in/month

Question 37

What is the rate of motor recovery in peripheral nerve injuries?

Answer 37

12–18 months before irreversible motor end plate degeneration occurs

Question 38

What is the rate of sensory recovery in peripheral nerve injuries?

Answer 38

Longer than motor but eventually plateaus/stops