What are the meninges?
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Several layers that protect the brain and spinal cord.
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What are the meninges?
Several layers that protect the brain and spinal cord.
What are the beneficial aspects of transient, low levels of neuroinflammation?
They can aid in repair after injury.
What role do Schwann cells play in axon regeneration?
They dedifferentiate, proliferate, form tubes, and release substances to guide re-growing axons.
What is a characteristic of the cell body in dorsal root ganglia?
It is large.
Where is the nucleus located in the dorsal root ganglia cell body?
In the center.
What are the criteria for diagnosing CTE?
Evidence of neuronal degeneration and an abnormal pattern of the microtubule-associated protein, Tau.
What is a synapse?
A site of communication between the axon and the next cell.
What happens to neurons in the CNS when they die?
They are gone because few neurons undergo mitosis.
What is typically the antigen in Multiple Sclerosis?
One of the myelin-associated proteins.
What role do specific proteins in neuronal cilia play?
They can contribute to obesity.
On average, how many synapses does each neuron have?
Approximately 7000.
What is the primary function of the meninges?
To provide protection for the brain and spinal cord.
What are plaques in Alzheimer's disease primarily made of?
Pieces of the protein Beta-amyloid that clump together.
Where are plaques found in relation to neurons?
Outside the neuron.
What is notable about the number of satellite cells in autonomic ganglia?
They are fewer in number.
What is the most common demyelinating disease in the CNS?
Multiple Sclerosis.
What is the primary function of a Schwann cell?
To myelinate a short portion of an axon (up to 0.1 mm).
Why is there limited regeneration in the CNS?
Due to differences in both glia and axonal response.
What does 'M' stand for in the context of peripheral nerves?
Myelin (space showing granularity).
What is Wallerian degeneration?
A process that occurs when a nerve fiber is cut or crushed, leading to the degeneration of the part of the axon distal to the injury.
What elements are important in dendritic spines?
Cytoskeletal elements and synaptic receptors.
What is the first step in the stretch reflex?
Extension of muscle sensed by receptors in the thigh.
What is a characteristic of the direct connection in the reflex arc?
It is fast.
What happens to injured axons in the PNS?
Sprouts appear from the end of the injured axons.
What type of axons are found in the PNS?
Both myelinated and unmyelinated axons.
What is the connective tissue that is continuous with the dura mater in the PNS?
Epineurium (dense irregular connective tissue).
What is the estimated total number of neurons in the human brain?
86 billion.
What are the meninges?
Connective tissue coverings that protect the brain and spinal cord.
What is a characteristic of the cell bodies in autonomic ganglia?
They are small.
What structure is formed by astrocytes that hinders regeneration in the CNS?
Glial scar.
What is one effect of plaques in Alzheimer's disease?
They block other processes.
What is the unique feature of neuronal morphology?
Neuronal processes.
What is Multiple Sclerosis thought to be?
An autoimmune disease.
What is the connective tissue associated with the pia mater in the PNS?
Endoneurium.
What is a ganglion in the peripheral nervous system?
A region with neuronal soma, dendrites, and some axons.
What type of cells are present around the neuronal cell body in dorsal root ganglia?
Satellite cells.
What happens to myelin during processing of peripheral nerves?
Myelin is removed, revealing spaces.
How does regeneration in the PNS differ from the CNS?
In the PNS, regeneration is more effective due to the presence of Schwann cells, which promote axonal growth, while in the CNS, regeneration is limited due to inhibitory factors and the absence of supportive cells.
Which neuropsychiatric diseases are associated with neuroinflammation?
Schizophrenia, Autism, and Depression.
What initiates the contraction of the flexor muscles in the stretch reflex?
Action potential at the neuromuscular junction.
What is the ultimate effect of amyloid plaques and neurofibrillary tangles in Alzheimer's disease?
They kill neurons in specific places.
What role do other glial cell types play in neuroinflammation?
They contribute alongside microglia.
What covers unmyelinated axons in the PNS?
Schwann cell cytoplasm.
What is Wallerian degeneration?
A process that occurs after an axon is damaged, leading to degeneration of the axon distal to the injury.
How can axonal transport be clinically significant?
It can be hijacked to transport substances into the CNS that shouldn't be transported.
What is the first step in Schwann cell myelination?
The axon invaginates into the Schwann cell.
What is the function of dendrites?
Carry information TOWARDS the soma.
What does 'N' represent in the organization of peripheral nerves?
Nucleus of Schwann cell.
What is an example of a ganglion?
Dorsal Root Ganglion (DRG).
What are the gaps in the myelin sheath of peripheral nerves called?
Nodes of Ranvier.
What are the main components of the cytoskeleton in both axons and dendrites?
Microtubules and microfilaments.
How many neurons innervate each muscle fiber?
Each muscle fiber is innervated by 1 neuron.
What can be observed in neurodegenerative disorders?
Neuronal loss.
Can proteins be synthesized in dendrites?
Yes, proteins can be synthesized in dendrites.
What is a key reason for regeneration failure in the CNS?
Failure of oligodendrocytes to remove degenerating myelin.
What role does neuroinflammation play after an injury?
It is involved in the repair process.
What trophic support do microglia provide under normal conditions?
Secretion of factors.
How can CTE be definitively diagnosed?
Only at autopsy.
What is the role of the epineurium?
It surrounds the whole nerve and the spaces between fascicles.
Where are astrocytes found?
In the central nervous system (CNS).
Where do the lesions in Multiple Sclerosis typically radiate from?
From the ventricles (periventricular).
What are supporting cells in the nervous system primarily classified as?
Glial cells or neuroglia.
Which neurotransmitter is used at the neuromuscular junction?
Acetylcholine.
What types of glial cells are found in the Central Nervous System (CNS)?
Oligodendrocytes, astrocytes, and microglia.
How do dendritic spines vary?
They come in different shapes.
What type of neurons are found in dorsal root ganglia?
Sensory neurons that transmit sensory information to the central nervous system.
What is the role of ependymal cells?
Ependymal cells line the ventricles of the brain and the central canal of the spinal cord, but their importance is sometimes questioned.
What happens to microtubules if the neuron survives after injury?
They can fail to assemble in a linear manner.
How do the shapes of dendritic spines change?
They change over development.
What is often required to visualize many features of neurodegenerative disorders?
Special stains.
Why are microglia important in the CNS?
Because the CNS is protected from the immune system.
What is the effect of neurofibrillary tangles on axonal transport?
They block axonal transport.
What is the role of microglia in neuroinflammation?
They are part of the neuroinflammatory response.
What is a key factor in the failure of axonal regeneration?
Failure of molecules that guide the axon.
What is one function of satellite cells?
To maintain the environment around the neuron.
Are all synapses located on spines?
No, not all synapses are on spines.
Where is the action potential initiated in a neuron?
At the initial segment of the axon.
What is a hallmark of the pathogenesis of multiple sclerosis (MS)?
Breakdown of the blood-brain barrier (BBB) and increased immune cell trafficking into the CNS.
What is the appearance of microglia at the most severe part of an injury?
They become ameboid and phagocytose debris.
In which system is Wallerian degeneration better observed?
In the Peripheral Nervous System (PNS).
What are the two portions of an axon involved in Wallerian degeneration?
Proximal portion (near soma) and distal portion (below injury).
Why do we have unmyelinated axons?
To allow some signals to be slow and sustained rather than fast and transient.
What is the major cell type involved in neuroinflammation?
Microglia.
Where are the nuclei located in autonomic ganglia?
Eccentric.
What type of inhibitory molecules are increased due to glial scar formation?
Chondroitin sulfate proteoglycan.
What occurs in a normal PNS condition?
The axon contacts muscle or another cell type.
Which connective tissue is continuous with the arachnoid in the PNS?
Perineurium.
Why are microglia important during development?
They play a crucial role in the development of the nervous system.
What is the neuromuscular junction?
The connection between the axon of a motor neuron and a muscle cell.
Where is the axon open to the environment?
At the Nodes of Ranvier.
What are microglia?
Tiny cells found in the central nervous system (CNS).
What happens to the axon between the Nodes of Ranvier?
It is otherwise isolated.
What are neurodegenerative disorders characterized by?
Numerous different characteristics.
What does dendritic tree variability refer to?
The amazing range of variability in the structure of dendritic trees among different types of neurons.
Which pathway is implicated in the connection between neuronal cilia and obesity?
The leptin pathway.
What primarily forms the blood-brain barrier?
Complex tight junctions (TJ) between endothelial cells of capillaries.
What is the dura mater?
The thick outer layer of the spinal cord meninges.
How is the cytoskeleton organized in dendrites compared to axons?
The cytoskeleton in dendrites is less organized and more associated with branching.
What is a characteristic feature of each type of neuron?
Each type of neuron has its own characteristic dendritic tree.
What is the location of dorsal root ganglia?
Adjacent to the spinal cord, along the dorsal roots of spinal nerves.
What is the typical size of satellite cells?
They are small cells.
How does the number of branches in a dendritic tree affect a neuron?
More branches mean more opportunity for input.
Where is most protein made in a neuron?
In the soma.
What is the primary function of myelinated axons?
To facilitate faster communication of action potentials between neurons.
What organelles are mostly found in dendrites?
Mitochondria and rough endoplasmic reticulum (rER).
What type of disease is Guillain-Barre Syndrome?
A demyelinating disease in the peripheral nervous system (PNS).
Are there neurons with more than 7000 synapses?
Yes, some neurons have considerably higher synapse counts.
What are the characteristic features of Alzheimer's disease?
The presence of amyloid plaques and neurofibrillary tangles.
What do oligodendrocytes fail to form that impacts regeneration?
Tubes.
Which other immune cells can infiltrate the area of a lesion during neuroinflammation?
Lymphocytes.
What is the function of the endoneurium in the PNS?
It surrounds individual axons.
What does the perineurium encase?
Bundles of axons, known as fascicles.
What do axons do?
Carry information AWAY from the soma.
How do nerve fibers pass through the dorsal root ganglion?
They form bundles.
What are dendritic spines?
Protrusions that serve as sites of contact for synaptic communication.
Which virus is known to utilize axonal transport to enter the CNS?
Rabies virus.
What is the blood-brain barrier?
A theoretical barrier that selectively lets certain substances through while blocking others.
What type of neuron is found in the dorsal root ganglia?
Pseudounipolar neuron.
What types of cells can communicate at a synapse?
Another neuron or another type of cell, such as muscle or blood vessel.
What is the initial segment of the axon?
The part of the axon that is myelinated by Schwann cells.
What constitutes a nerve in the peripheral nervous system?
Regions with only axons and their glial cells, without soma or dendrites.
What is the specific process called that occurs during degeneration of the distal axon?
Wallerian degeneration.
Where are autonomic ganglia located?
Near or within the organs they innervate.
What is the primary function of dendrites?
To carry information towards the soma.
What underlies the formation of retraction bulbs in axonal regeneration?
Disorganized microtubules.
What type of synapses are most common in the mammalian brain?
Chemical synapses.
What is the innermost layer of the meninges?
Pia mater.
What is the primary function of Schwann cells?
To myelinate axons in the peripheral nervous system (PNS).
Why are branches important in the physiology of the neuron?
They allow maximum area to contact inputs.
What type of neurons are found in the ventral horn of the spinal cord?
Motor neurons.
What are oligodendrocytes?
Cells that provide myelin in the CNS.
What initiates the sequence of communication at a synapse?
An action potential coming down the axon.
What is an example of a reflex arc?
Stretch reflex.
What is the clinical implication of the highly metabolic state of neurons?
Neurons are highly sensitive to deprivation.
What are the detrimental effects of high levels or chronic neuroinflammation?
They can have harmful effects on the nervous system.
What is the final outcome of axon regeneration in the PNS?
Axons regrow and reach target cells again.
What does 'A' represent in the organization of peripheral nerves?
Axon (pink thread-like structure).
What are the main components of a peripheral nerve?
Axons and Schwann cells.
What is the unmyelinated region between adjacent Schwann cells called?
Node of Ranvier.
What happens if an axon in the PNS is damaged but the cell body remains intact?
Recovery can occur proximal to the site of injury while the distal part degenerates and then regenerates.
What is the primary function of myelinated axons?
To increase the speed of conduction up to 30 times.
What happens after the axon invaginates into the Schwann cell?
The Schwann cell membrane wraps concentrically around the axon.
What factors influence the speed of conduction in myelinated axons?
The diameter of the axon and the thickness of the myelin.
How do astrocytes interact with neurons?
They communicate with neurons.
What can reactive astrocytes form?
A scar.
What are neurofibrillary tangles?
They occur when microtubules are disrupted in Alzheimer's disease.
What gases can penetrate the blood-brain barrier?
Oxygen (O2) and carbon dioxide (CO2).
What occurs to the distal part of a damaged axon in the PNS?
It degenerates and then regenerates.
What is the function of excitatory neurotransmitters?
They facilitate the firing of an action potential in the connected cell.
Which substances are transported across the blood-brain barrier by carrier proteins?
Glucose, amino acids (aa), and vitamins.
What do inhibitory neurotransmitters do?
They prevent the firing of an action potential in the connected cell.
What are dendritic branches classified based on?
Their origin and structure.
How does the dendritic tree typically relate to the soma?
It typically stays close to the soma.
Where do primary dendritic branches originate from?
From the soma.
How do autonomic ganglia differ from dorsal root ganglia in terms of function?
Autonomic ganglia control involuntary functions, while dorsal root ganglia process sensory information.
How do satellite cells contribute to neuronal health?
By providing electrical insulation.
What type of neuron is responsible for processing information in the CNS?
Multipolar neurons (Integrative function).
What is thought to be the cause of Guillain-Barre Syndrome?
It is believed to be an autoimmune disease that attacks myelin.
Which motor protein is responsible for binding cargo during axonal transport?
Kinesin.
How do sensory neurons contribute to the reflex arc?
They transmit information to motor neurons in the ventral horn of the spinal cord through synaptic connections.
What type of signals are typically transmitted by unmyelinated axons?
Signals related to pain.
What morphological change occurs in microglia during neuroinflammation?
They can change to an amoeboid shape.
How do nerve fibers behave in autonomic ganglia?
They do not tend to form bundles.
What causes Chronic Traumatic Encephalopathy (CTE)?
Repeated blows to the head.
What is one of the key functions of microglia related to synapses?
Synaptic pruning.
What is indicated by 'NR' in peripheral nerve organization?
Node of Ranvier.
What are reactive astrocytes?
Astrocytes that respond following injury or in disease states.
Where are synapses found?
At the distal end of the axon.
What is the approximate rate of nerve regeneration in the PNS?
Approximately 1 inch per month.
What was the initial belief about how West Nile Virus enters the CNS?
It was originally thought to work the same way as rabies virus.
What role do Schwann cells play in the PNS?
They support the regeneration of damaged axons by forming a regeneration tube and secreting growth factors.
What are the Nodes of Ranvier?
Gaps in the myelin sheath that allow for saltatory conduction.
What specific intermediate filament protein is associated with astrocytes?
Glial fibrillary acidic protein (GFAP).
What is the significance of the Nodes of Ranvier in neuronal function?
They facilitate faster nerve impulse conduction through saltatory conduction.
What is the function of the arachnoid layer?
It has projections (trabeculae) that extend inward.
What does the white space at the Nodes of Ranvier indicate?
The absence of myelin due to processing.
What type of neurons are primarily found in autonomic ganglia?
Postganglionic neurons that innervate target organs.
Are drugs able to cross the blood-brain barrier?
Many drugs are blocked by the barrier.
What characterizes the pia mater?
It is the delicate inner-most membrane resting on the surface of the spinal cord.
What is the composition of gray matter in the spinal cord?
It is based on neurons, not glia.
Where is white matter located in the brain and spinal cord?
Inside the brain and outside in the spinal cord.
What types of cargo are transported in anterograde transport?
Proteins, synaptic vesicles, and organelles (like mitochondria).
What is the synaptic cleft?
The space where neurotransmitters diffuse across.
How is an action potential defined?
As a change in electrical potential caused by ions moving across the membrane.
What is the appearance of Lewy bodies?
Typically eosinophilic with a pale halo.
How do microglia affect the vascular system during severe injury?
They can make it permeable to recruit new immune cells.
How do myelin-reactive T cells breach the blood-brain barrier?
With the help of upregulated cell adhesion molecules and MMPs.
Why can't action potentials cross myelin?
Because myelin acts as an insulator, preventing the flow of ions.
What happens to the distal axon during Wallerian degeneration?
It breaks up into short segments.
What role does the nervous system play in physical activity?
It allows movement.
What is an SSRI?
A selective serotonin reuptake inhibitor, a class of antidepressants.
How does regeneration in the CNS compare to the PNS?
There is little regeneration in the CNS compared to the PNS.
What happens to myelin in Multiple Sclerosis?
It is destroyed in focal lesions.
What is a characteristic feature of Schwann cells in peripheral nerves?
They have a membrane that surrounds the axons.
What are the processes of astrocytes that contact blood vessels called?
End feet.
What diseases are neuroinflammation linked to?
Most neurodegenerative diseases like Alzheimer’s and Parkinson’s.
What structures can astrocytes contact?
Neuronal soma and myelin.
From what do microglia develop?
From the same precursors as other macrophages.
What does the blood-brain barrier regulate?
The passage from the vascular system to the nervous system.
What is the outermost layer of the meninges?
Dura mater.
What do we now understand about the mechanism of West Nile Virus entry into the CNS?
It involves a combination of axonal transport and other mechanisms.
Which meningeal layer is the thickest?
Dura mater.
What happens to the protein Tau in neurofibrillary tangles?
Tau becomes dissociated from the microtubule and clumps together.
What is observed in the center of the Nodes of Ranvier?
The axon, represented as a dark line.
Where is the arachnoid layer located?
Between the red and black lines in the spinal cord meninges.
What happens to bigger molecules at the blood-brain barrier?
They are often blocked.
What is retrograde transport?
Transport towards the soma and away from the synapse at the end of the axon.
What are the main components of the spinal cord's organization?
Dorsal horn, ventral horn, white matter, and gray matter.
What is the role of sensory neurons in dorsal root ganglia?
To relay sensory information from the periphery to the central nervous system.
What is the process of transporting materials away from the soma called?
Anterograde transport.
How do different types of neurotransmitters vary at the EM level?
They have slightly different synaptic morphologies.
What is myelin composed of?
Lipid-rich layers formed by concentric layers of Schwann cell plasma membranes.
What do antibodies attack in Myasthenia Gravis?
The ACh receptor.
How is cargo transported along the axon?
Along microtubules.
What type of neurons are found in the dorsal horn of the spinal cord?
Sensory neurons.
Who conducted research on dendritic spine abnormalities in childhood disorders?
Marin-Padilla, 1976.
What are primary cilia morphologically similar to?
Typical cilia.
Where are the cell bodies of motor neurons found?
In the ventral horn of the spinal cord.
What is neuroinflammation?
An inflammatory response in the central nervous system (CNS).
What are ciliopathies?
Disorders caused by defects in the structure or function of cilia.
What internal processes does the nervous system control?
The functioning of internal organs.
What higher order functions are associated with the nervous system?
Cognition.
What emotional aspect is regulated by the nervous system?
Emotions.
What structures cover the apical surfaces of ependymal cells?
Cilia and microvilli.
What morphological changes occur in reactive astrocytes?
Increase in size and branch thickness.
What does 'NF' denote in the context of peripheral nerves?
Nerve fiber, which includes axon and its myelin sheath.
What occurs to the Schwann cell cytoplasm and nucleus during myelination?
They are pushed to the edge and remain around the axon.
What role do astrocytes play in the blood-brain barrier?
They play a significant role in the functioning of tight junctions of endothelial cells.
Where are satellite cells located?
In the peripheral nervous system (PNS).
What happens to the neuronal cell body during Wallerian degeneration?
It undergoes changes such as chromatolysis, which is the breakdown of the cell's Nissl bodies.
What constitutes gray matter in the CNS?
Regions with neuronal soma, dendrites, and some axons.
What causes some neurodegenerative disorders?
Aggregation of abnormal proteins.
Where do neurofibrillary tangles occur?
Inside the cell.
What is the state of microglia in a quiescent state?
They have thinner, longer processes.
What does the pia mater do in relation to the spinal cord?
It dips into the fissures (clefts) in the cord.
Which motor protein is involved in retrograde transport?
Dynein.
What are Lewy bodies?
Small inclusions within the cytoplasm of neurons.
What distinguishes different types of neurotransmitters?
They use different neurotransmitters.
What happens to precursor T cells in MS?
They become myelin-reactive after interacting with antigen presenting cells displaying myelin-cross-reactive antigens.
What happens to myelin in Guillain-Barre Syndrome?
Myelin is destroyed in focal lesions.
What is one primary function of the nervous system?
Allows for rapid response to the environment.
How does Myasthenia Gravis affect muscle function?
It prevents muscle contraction due to impaired transmission at the neuromuscular junction.
What occurs after neurotransmitters diffuse across the synaptic cleft?
They interact with the next cell.
How does the process of myelination by oligodendrocytes differ from that in the PNS?
It is wrapped in a different fashion.
What happens to neurons if they die?
They are not replaced.
Where are the cell bodies of autonomic neurons located?
In the lateral horn of the spinal cord.
How do SSRIs like Prozac affect neurotransmitters?
They allow neurotransmitters to stay longer in the synapse.
Where are multipolar neurons primarily found?
All over the central nervous system (CNS).
What is the primary function of autonomic ganglia?
They are involved in the autonomic nervous system, controlling involuntary functions.
What types of glial cells are found in the Peripheral Nervous System (PNS)?
Schwann cells and satellite cells in the dorsal root ganglia (DRG).
When do microglia enter the brain?
Very early in brain development.
Is neuroinflammation a cause or a consequence of diseases?
It is still under investigation whether it is a cause or a consequence.
What is an axosomatic synapse?
A synapse where an axon connects to the cell body of another neuron.
What is a potential approach to managing neuroinflammation?
Various treatments are being explored.
What occurs at the end of the axon that prevents growth?
A mass of structures forms due to continued axonal transport.
Where do the original branches of dendrites arise from?
From the soma.
What is found in the subarachnoid space?
Dorsal and ventral roots.
What is an axoaxonic synapse?
A synapse where the axon of one neuron connects to the axon of another neuron.
What types of cargo are transported to the soma during retrograde transport?
Proteins, synaptic vesicles, and organelles like mitochondria.
Where is the pia mater located?
Right on the surface of the brain.
What happens to microglial processes after CNS injury?
They become shorter and thicker.
What is the relationship between the arachnoid and subarachnoid space?
The subarachnoid space is located beneath the arachnoid layer and contains dorsal and ventral roots.
What are protrusions on dendrites called?
Spines.
What components make up the cytoskeleton in dendrites?
Actin filaments, microtubules, and intermediate filaments.
Which chemokine receptors may myelin-reactive T cells express?
CCR2, CCR5, and CXCR3.
What is the role of the cytoskeleton in dendrites?
It maintains shape and branches.
What is the function of the lateral horn in the spinal cord?
It contains autonomic neurons.
How does the nervous system contribute to perception?
It allows detection of the world around.
What does 'Den' represent in the morphology of a synapse?
Dendrite.
What is the length characteristic of primary cilia?
Small and variable length.
What is the role of primary cilia in neuronal function?
They are involved in signaling pathways that affect neurodevelopment and neuronal health.
Can Wallerian degeneration affect the neuronal soma?
Yes, it can affect the neuronal soma.
What is the shape of ependymal cells?
Cuboidal to columnar.
Describe the nucleus of a neuron.
It is large with an obvious nucleolus and mostly euchromatin.
What factors can influence the speed of nerve regeneration?
Age, health, and other factors.
Is neuroinflammation linked to COVID-19?
Yes, it is being studied in relation to COVID-19.
What inhibits regeneration in the CNS?
The presence of myelin-associated inhibitors and the formation of a glial scar.
What role do microglia play in the CNS?
They function as resident macrophages.
What defines regions of the CNS at a gross level?
Regions defined based on neuronal soma, not glia.
What is axonal transport?
A bidirectional process for transporting materials along the axon.
How is the cytoskeleton arranged in axons?
It is more polarized and arranged in bundles for transport.
What does the subarachnoid space contain?
Cerebrospinal fluid (CSF) and blood vessels.
What is the role of the Schwann cell sheath in relation to the Nodes of Ranvier?
It curves around the axon, contributing to the formation of the myelin sheath.
What is the role of modulatory neurotransmitters?
They influence how excitatory and inhibitory signals are integrated.
What is observed in dendritic spines in Fragile X syndrome?
More spines and a higher number of immature spines.
What is the presynaptic bouton?
The axon terminal that contains neurotransmitters in synaptic vesicles.
How do dendritic spines differ in individuals with Down's syndrome?
There are fewer spines.
What is the significance of classifying dendritic branches?
It helps in understanding their functions and roles in neural circuits.
Why is myelin not visible at the light level?
Due to its high fat content, which makes it appear as empty space.
How many axons does each neuron typically have?
Each neuron has one axon.
What is the cell body of a neuron called?
Cell Soma.
Do axons have branching?
They have little branching until they reach the end, but can have a collateral.
Where are primary cilia located on a neuron?
On the soma.
What happens to neurotransmitters after they have interacted with the next cell?
They are recycled to end the communication.
Can the blood-brain barrier be compromised in other neurological diseases?
Yes, it can happen in other neurological diseases.
What are typical organelles found in the neuron cell body?
Golgi apparatus and mitochondria.
What do ependymal cells line within the CNS?
Spaces filled with cerebrospinal fluid (CSF), such as ventricles and the central canal.
What is the primary function of the rough ER in neurons?
Active in making protein.
How do oligodendrocytes differ from Schwann cells?
Oligodendrocytes can myelinate multiple axons or parts of the same axon, while Schwann cells myelinate only one axon.
What is the outcome of Wallerian degeneration in the PNS?
It often leads to successful regeneration of the nerve fiber.
What is the significance of MC4R and ADCY3 in the context of obesity?
Their subcellular localization at neuronal primary cilia underlies a common pathway for genetic predisposition to obesity.
Why were supporting cells originally not viewed as important?
They were not considered particularly important for nervous system functioning.
What are pericytes' role in the blood-brain barrier?
They also have a significant role in the barrier's functioning.
What is an axodendritic synapse?
A synapse where an axon connects to a dendrite, typical and most common in the CNS.
Where are satellite cells commonly found?
In ganglia, often close to the neuronal soma.
What constitutes white matter in the CNS?
Regions with only axons and their glial cells (no neuronal soma or dendrites).
Do immune system cells routinely cross the blood-brain barrier?
No, they don’t routinely cross the barrier.
What type of disease is Myasthenia Gravis?
An autoimmune disease.
Why are dendritic branches important?
They play a crucial role in the physiology of neurons.
What is Wallerian degeneration?
A process that occurs in both CNS and PNS, characterized by the degeneration of axons after injury.
What is the primary function of axons?
To carry information away from the soma.
How does the myelin in the CNS compare to that in the PNS?
Morphologically the same, including having Nodes of Ranvier.
Can Guillain-Barre Syndrome cause damage to axons?
Yes, it can cause damage to axons.
Is recovery possible in Guillain-Barre Syndrome?
Yes, recovery is possible, although some recoveries can be long.
How can neurons be classified based on their processes?
By the number and arrangement of their processes.
What organelles do axons lack?
Most organelles for making proteins.
What type of dementia is associated with Lewy bodies?
Lewy Body dementia.
Who are the authors of the study on primary cilia in neurodevelopmental disorders?
Enza Maria Valente, Rasim O. Rosti, Elizabeth Gibbs, and Joseph G. Gleeson.
What is the significance of primary cilia in neurodevelopment?
They play a crucial role in the development and functioning of the nervous system.
What is the primary function of ependymal cells?
To move cerebrospinal fluid (CSF).
What was the original thought about astrocytes?
They were considered more of a connective tissue type of cell.
How do astrocytes regulate blood flow?
They help regulate blood flow in the brain.
How do astrocytes affect neurotransmitter concentration?
They regulate the concentration of neurotransmitters, such as glutamate.
What type of exchange do satellite cells facilitate?
Metabolic exchange.
What is the significance of dendritic spine abnormalities in clinical disorders?
They are associated with various disorders, including Fragile X and Down's syndrome.
Where are the cell bodies of sensory neurons located?
In dorsal root ganglia (DRGs) or specialized sensory organs.
What happens to synaptic vesicles during synaptic communication?
They fuse with the membrane and release neurotransmitters (NT).
What structural features do oligodendrocytes retain?
They have a nucleus and cytoplasm on the edge.
Do most neurons divide?
No, most neurons do not divide except in a few specific places.
What do autonomic neurons control?
Internal organs.
What does 'sp' stand for in synaptic morphology?
Spine.
Are primary cilia motile or non-motile?
Non-motile.
What do the neuroimmune system and immune responses in other parts of the body have in common?
They use many of the same pathways.
What is euchromatin associated with in the neuron nucleus?
Active transcription.
What is a notable feature of many axons in the CNS?
Many axons are unmyelinated.
What do astrocytes produce that is beneficial for neurons?
They produce growth factors.
What is the consequence of ACh not being able to bind?
The action potential does not get transmitted to the muscle fibers, preventing muscle contraction.
What is the primary function of motor neurons?
To move muscles.
Along what structures is cargo transported in axonal transport?
Microtubules.
Can microglia proliferate after CNS injury?
Yes, they can proliferate.
What is a significant risk associated with Myasthenia Gravis?
It often affects the muscles of respiration, leading to a typically short survival.
What role do macrophages play in Wallerian degeneration?
They come into the area and phagocytose debris.
What is a bipolar neuron?
A neuron with 1 axon and 1 primary dendrite (with many branches), found in sensory neurons in the eye and ear.
What is one of the functions of primary cilia?
To monitor the environment.
What are oligodendrocytes primarily responsible for?
Myelinating axons in the central nervous system (CNS).
What is a key structural feature of oligodendrocytes?
They have multiple processes.
In what way do astrocytes protect neurons?
By assisting in the metabolic processing of various substances.
What is found on the postsynaptic membrane?
Receptors that interact with neurotransmitters.
What is the process called when action potentials jump from node to node?
Saltatory conduction.
What protein is primarily associated with Lewy bodies?
Alpha synuclein.
What do myelin-reactive T cells encounter in the brain?
Myelin antigens presented mainly by microglia.
How far can axons travel?
They often travel long distances.
How is Lewy Body dementia definitively diagnosed?
At autopsy.
How do Schwann cells contribute to Wallerian degeneration?
They assist in the degeneration process, particularly in myelin breakdown.
What is indicated by 'At1' in the context of a synapse?
Presynaptic bouton.
What do the arrows point to in the morphology of a synapse?
Postsynaptic density.
Why is the morphology of a synapse not visible with regular microscopy?
It requires electron microscopy (EM) for visibility.
What is a characteristic of myelin associated proteins in oligodendrocytes?
They differ from those in Schwann cells.
How is myelin observed at the electron microscopy (EM) level?
As concentric circles.
What is the first process that occurs during Wallerian degeneration?
Cytoskeletal breakdown.
In which diseases are Lewy bodies commonly seen?
Parkinson’s disease and Lewy Body dementia.
What is the result of the inflammatory response incited by myelin-reactive T cells?
Damage or destruction of oligodendrocyte-formed myelin sheaths and underlying neurons.
How is the CNS described in terms of immune response?
The CNS is considered immune-privileged.
What is the typical presence of immune cells in the CNS under normal circumstances?
Few immune cells are present within the CNS.
What characterizes a pseudounipolar neuron?
It has 1 process with no true dendrite, consisting of 1 axon with branches going to the periphery and CNS, typically sensory to skin and muscle.
What is the structure of a multipolar neuron?
It has 1 axon and multiple primary dendrites, making it the most common type of neuron.
What critical roles do primary cilia have?
They can have critical roles in development.
Can axons perform any protein synthesis?
Yes, some local synthesis can occur.
What indicates high levels of rough ER in neurons?
Purple spots called Nissl Bodies.
What is localized to primary cilia?
Specific proteins.
What are modified ependymal cells part of?
The choroid plexus that produces cerebrospinal fluid (CSF).
What role do astrocytes play in the blood-brain barrier?
They contribute to the formation and regulation of the blood-brain barrier.
What types of homeostasis do astrocytes regulate?
Ionic and water homeostasis, including ions like H+ and K+.
