OTD 341 - Neurons and Glia

neurons, glia

What are the two categories of cells in the nervous system?

glial cells, neuroglia

What are 2 other names for glia?

dendrites, cell body, axon

What are the 3 primary components of a neuron?

electrical

What type of signals are typically used within a neuron? (electrical or chemical)

chemical

What type of signals are typically used between neurons? (electrical or chemical)

soma, perikaryon

What are 2 other names for a neuron cell body?

cell body, soma

What are 2 other names for a perikaryon?

cell body, perikaryon

What are 2 other names for a neuron soma?

cell body

“Perikaryon” is another name for which part of the neuron? (dendrites, cell body, axon)

cell body

component of the neuron that is the site for synthesis of nearly all the neuron’s enzyme’s, structural proteins, membrane components, organelles, and some neurotransmitters

dendrites

component of the neuron that are tapering extensions of the cell body that are specialized to receive information and increase surface area available for synaptic inputs

increase

Dendrites _____ surface area available for synaptic inputs. (increase or decrease)

dendritic tree

total array of a neuron’s dendrites

dendritic spines

spiky protuberances that are preferred sites for synaptic inputs

dendritic spines

What part of the dendrite is the preferred site for synaptic inputs?

axon

single output unit of a neuron that transmits action potentials (APs) from cell body distallly

axon hillock

component of an axon that is actually in the cell body and gives rise to the initial segment

initial segment

component of an axon that is just distal to the axon hillock and is the most electrically excitable part of the neuron

initial segment

What is the most electrically excitable part of a neuron?

myelin

glial membranes that cover most axons and increase the speed of action potentials (APs)

axon hillock

What part of the axon is located in the cell body?

cytoskeleton

network of 3 kinds of protein filaments (microtubules, neurofilaments, microfilaments) contained within nearly all parts of neurons that give neurons their shape and assist in transport within the neuron

microtubules, neurofilaments, microfilaments

What are the 3 kinds of protein filaments that comprise the neuronal cytoskeleton?

axonal transport

active process of moving macromolecules and organelles along an axon; may be fast/slow, anterograde/retrograde

active

Is axonal transport an active or passive process?

anterograde transport

type of axonal transport in which macromolecules or organelles are moved from cell body to axon terminal along microtubules

retrograde transport

type of axonal transport in which macromolecules or organelles are moved from axon terminal to cell body along microtubules

poliovirus

What virus can gain access to the CNS through fast retrograde transport and cause poliomyelitis?

fast retrograde

Through what type of axonal transport does poliovirus gain access to the CNS?

retrograde

Through what type of axonal transport does herpes virus gain access to neuron cell bodies? (anterograde or retrograde)

True

True or false: chemotherapy can disrupt axonal transport, leading to neuropathies and cancer pain

Alzheimer’s disease (AD)

progressive degenerative brain disease marked by beta-amyloid plaques and neurofibrillary tangles that are caused by disruptions to tau protein on microtubules

beta-amyloid plaques, neurofibrillary tangles

What are the 2 defining neuroanatomical characteristics of Alzheimer’s disease (AD)?

microtubules

Neurofibrillary tangles, a defining neuroanatomical characteristic of Alzheimer’s disease (AD) is caused by disruptions to tau protein on what cytoskeletal element? (microtubules, neurofilaments, microfilaments)

chronic traumatic encephalopathy (CTE)

progressive degenerative brain disease found in athletes with a history of repetitive brain trauma, including symptomatic concussions as well as asymptomatic subconcussive hits to the head; marked by neurofibrillary tangles; symptoms include behavioral, mood, and cognitive impairments

Alzheimer’s disease (AD), chronic traumatic encephalopathy (CTE)

What 2 progressive degenerative brain diseases are marked by neurofibrillary tangles?

pseudounipolar, bipolar, multipolar

What are the 3 types of neurons when classifying according to shape?

multipolar

• neuron type with multiple dendrites and a single axon

• most common type of neuron in vertebrates

• designed to receive and accommodate large amounts of input

• examples: spinal motor cell, cerebral and cerebellar cortex

multipolar

What is the most common type of neuron in vertebrates? (pseudounipolar, bipolar, multipolar)

multipolar

Spinal motor neurons and those found in the cerebral and cerebellar cortices are mostly likely _____ neurons. (pseudounipolar, bipolar, multipolar)

bipolar

• neuron type with 2 primary processes that extend from cell body—dendritic root (that divides into multiple dendritic branches) and axon

• Exclusive to retina and olfactory epithelium

retina, olfactory epithelium

What are the only 2 locations in which a bipolar neuron would be found?

pseudounipolar

• subclass of bipolar neurons that appear to have a single projections from the cell body that divides into two axonal roots and no true dendrites

• example: peripheral sensory nerves

pseudounipolar

Peripheral sensory nerves are an example of what type of neuron?

sensory neuron

type of neuron that is receptive to sensory input either directly or through connections with receptor cells

motor neuron

type of neuron that ends on muscles, glands, or other neurons

interneurons, projection neurons

99% of all neurons in our bodies are what 2 types of neurons? (classifying according to function)

interneurons

neurons located in a small area in CNS

projection neurons

neurons in the CNS with long axons that project to another part of CNS

sensory neurons, motor neurons, interneurons, projection neurons

What are the 4 types of neurons when classifying according to function?

interneurons, projection neurons

What 2 types of neurons are located exclusively in the CNS? (classifying according to function)

sensory neurons, motor neurons

What 2 types of neurons are located partially in the CNS and partially in the PNS?

synaptic transmission

mechanism by which neurons communicate (transfer signals) with each other, glands, or muscles

synapse

special zone of “contact” in which one neuron communicates with another

axodendritic

What is the most common type of CNS synapse?

axodendritic, axosomatic, axoaxonic, dendrodendritic

What are the 4 types of CNS synapses discussed in lecture?

axodendritic

type of CNS synapse which involves axon of one cell communicating with dendrite of another

axosomatic

type of CNS synapse which involves axon of one cell communicating with soma of another

axoaxonic

type of CNS synapse which involves axon of one cell communicating with axon of another

dendrodendritic

type of CNS synapse which involves dendrite of one cell communicating with dendrite of another

PNS

Are Schwann cells located in the CNS or PNS?

Schwann cells

• principle PNS glia

• provide electrical insulation (creates myelin)

• facilitate regrowth of axons after peripheral nerve injury

• regulate extracellular ionic environment

• provide metabolic support

electrical, myelin, regrowth, axon, ionic, metabolic

Fill in the blanks of the following functions of Schwann cells:

• provides _____ insulation (creates _____)

• facilitates _____ of _____ after peripheral nerve injury

• regulates extracellular ______ environment

• provides ______ support

myelin

lipid-based substance that insulates axon to improve velocity and efficiency of an action potential

Schwann cell

Which type of glial cell creates myelin in the PNS?

oligodendrocyte

Which type of glial cell creates myelin in the CNS?

Schwann cells, oligodendrocytes

_____ create myelin in the PNS; _____ create myelin in the CNS.

True

True or false: all PNS glial cells are variants of Schwann cells.

True

True or false: satellite cells are flattened out Schwann cells.

nodes of Ranvier

Areas along an axon in which myelin sheath is interrupted

internode

Area of myelin between nodes of Ranvier on an axon

1

How many internodes does 1 Schwann cell myelinate?

False

True or false: one Schwann cell myelinates multiple internodes.

satellite cells

Flattened out Schwann cells that surround cell bodies in the PNS

oligodendrocytes, astrocytes, microglia, ependymal cells

What are the 4 types of CNS glial cells?

oligodendrocyte

CNS glial cell found in white and gray matter that form myelin sheaths

astrocytes

CNS glial cells found in gray and white matter that provide mechanical, structural, and metabolic support and respond to injury

microglia

CNS glial cells found in gray and white matter that perform phagocytosis and respond to injury

ependymal cells

CNS glial cells found on walls of ventricles that line ventricles and choroid plexus and secrete cerebrospinal fluid (CSF)

True

True or false: one oligodendrocytes myelinates multiple internodes.

False

True or false: one oligodendrocyte myelinates only one internode

astrocyte

What is the largest CNS glial cell?

astrocyte

Which CNS glial cell is associated with the blood-brain barrier?

microglia

What is the smallest CNS glial cell?

glioma

tumor of glial cell origin

Schwannoma

Type of PNS glioma of Schwann cell origin that is usually encapsulated with no nerve fiber involvement and is easily removed

neurofibroma

type of PNS glioma of Schwann cell origin that is encapsulated but infiltrating nerves and is difficult to remove

astrocytoma

The majority of brain tumors are what type?

glioblastoma multiforme

grade IV astrocytoma

astrocyte

What type of CNS glial cell is associated with the majority of brain tumors?

demyelinating diseases

• conditions that result in damage to the myelin sheath, causing nerve impulses to slow or stop

• may be causes by autoimmune disorders, metabolic abnormalities, viruses, trauma, or toxic chemicals

• examples: multiple sclerosis (MS), guillain-barre syndrome (GBS)

multiple sclerosis (MS)

What is an example of a demyelinating disease of the central nervous system (CNS)?

Guillain-Barre syndrome (GBS)

What is an example of a demyelinating disease of the peripheral nervous system (PNS)?

CNS, PNS

Multiple sclerosis is a demyelinating disease of the ____; Guillain-Barre syndrome (GBS) is a demyelinating disease of the _____.

multiple sclerosis (MS)

demyelinating autoimmune disease of the CNS in which antibodies attack oligodendrocytes, producing patches of demyelination that are replaced by astrocytic plaques

Guillain-Barre syndrome (GBS)

demyelinating autoimmune disease of the PNS in which antibodies attack Schwann cells, causing acute inflammation and demyelination of peripheral sensory and motor nerve fibers

motor

What type of peripheral nerve fibers are most affected by Guillain-Barre syndrome (GBS)?