Neuroanatomy Overview Framework: Recovery Post Nervous System Function Loss

Recovery Post Nervous System Function Loss

Archer Bennett

Neuroanatomy Overview Framework

Patient Needs After Nervous System Function Loss

• What might a patient need?
• Re-learn how to regain function through its original means
• Learn to perform the same function using different components
• Learn a new way to function to compensate for a loss

Recovery Post Orthopedic Issue Comparison

• How might this be different from recovery post orthopedic issue?
• Using different positions, AD - rather than relying on the body's normal functions
• Ortho might have the ability to return to the original
• How might this be the same?

Nervous System Flow

• Flow of the Nervous system
• PNS - sensory input
• CNS - processing
• PNS - motor output

Signal Flow Through the Nervous System

• What is the flow of signals through the nervous system?
• PNS > CNS > PNS
• In > Process > Out
• Sensory > process both > Motor
• Afferent > process > Efferent
• Approach > process > Exit

Central Nervous System Components

• What makes up the central nervous system?
• Brain
• Spinal Cord

Peripheral Nervous System Components

• What makes up the peripheral nervous system?
• Cranial nerves
• Nerves to organs
• Spinal nerves

Spinal Nerves Components

• What makes up the spinal nerves?
• Dorsal rami
• Ventral rami
• Plexuses (peripheral nerves)

PNS Nerve Types

• What makes up the PNS nerve types?
• Sensory
• Motor

Sensory Components

• What makes up the sensory?
• Somatic Sensory Input
• Autonomic Sensory Input

Sensory Input Provided

• What is provided by the sensory input?
• Pain
• Touch
• Muscle stretch

Autonomic Sensory Input Provided

• What is provided by the autonomic sensory input?
• HR
• BP
• Bladder filling

Motor Outputs

• What are the motor outputs?
• Somatic motor output
• Autonomic motor output

Somatic Motor Output Function

• What does the somatic motor output do?
• Skeletal muscle activation

Autonomic Motor Output Function

• What does the autonomic motor output do?
• SNS - sympathetic nerve system
• PNP - parasympathetic nervous system

Afferent Nerves (Sensory Information "IN")

• What are the nerves for afferent: sensory - information "IN"?
• Peripheral nerves
• Cranial nerves
• Dorsal rami of spinal nerves (only carry sensory)

Afferent Nerves Information Source

• Where do the afferent nerves get information?
• Somatic sensory neurons
• Autonomic sensory neurons

Efferent Nerves (Motor Information "OUT")

• What are the nerves for efferent: motor - information "OUT"?
• Peripheral nerves
• Cranial nerves
• Ventral rami of spinal nerves (only carries motor sensory)

Motor Nerves Action

• What do motor nerves act on?
• Striated (somatic) - Muscle fibers
• Autonomic - Muscle fibers

Brain (Cerebrum) Components

• What is the "Brain" (cerebrum) made up of?
• Cortex
• Cerebellum
• Diencephalon (deep brain structures)

Cortex Components

• What is the cortex made up of?
• Hemispheres
• Lobes

Diencephalon Components

• What is the diencephalon (deep brain structures) made up of?
• Thalamus
• Hypothalamus
• Limbic system
• Basal Ganglia (basal nuclei)

Brainstem Components

• What is the brainstem made up of?
• Medulla
• Pons
• Midbrain

Brain Function

• What is the function of the brain?
• Receiving & relaying information
• Processing
• Planning & sending motor

Spinal Cord Functions

• What are the functions of the spinal cord?
• Sensory tracts
• Reflex loops
• Motor tracts

Cranial Nerves Fibers

• What are the fibers of the cranial nerves?
• Sensory fibers
• Motor fibers
• Some have a little bit of both

Nerves to/from Organs (ANS) Fibers

• What are the fibers of the nerves to/from organs (ANS)?
• Sensory fibers
• Motor fibers

PNS Spinal Nerves

• What are the spinal nerves of the PNS?
• Dorsal rami (sensory)
• Ventral rami (motor)
• Peripheral (sensory & motor)

NEUROANATOMY OVERVIEW FRAMEWORK POWERPOINT LAST PAGE

• Sensory - afferent , motor- efferent

Neurons

Neuron Functions

• What are the functions of neurons?
• Transmits signals between places in the nervous system
• Flow of information: chemical and electrical signals

What are Neurons?

• What are neurons?
• Neural cell that receives and/or sends signals to other cells
• Structure includes:
• Dendrites
• Cell body (soma)
• Axon

What is a Nerve?

• What is a nerve?
• A collection of nerve fibers (neurons)

What are Dendrites?

• What are dendrites?
• An extension of the cell body (of a neuron) that receives signals from other neurons
• "Receptors"

What is the Cell Body?

• What is the cell body?
• "Brain" of the neuron

What is an Axon?

• What is an axon?
• A projection of a nerve from the cell body that conducts impulses away from the cell body
• Can be very short or very, very long

What is Myelin?

• What is myelin?
• Insulating layer, or sheath that forms around nerves including those in the brain and spinal cord

What is the Synaptic Cleft?

• What is the synaptic cleft?
• Small gap, or space, between two neurons at a synapse where a nerve impulse is transmitted by a neurotransmitter

What is a Neurotransmitter?

• What is a neurotransmitter?
• Chemical messengers that transmit signals across a synapse (the gap between the nerve cells) from one neuron to another
• Enables communication within the nervous system and affecting various bodily functions

Neuron Shapes

• What are the shapes of the neurons?
• Pseudo-unipolar
• Multipolar *
• Bipolar

Nuclei (Groups of Cell Bodies)

• What is nuclei (groups of cell bodies)?
• Group of cell bodies with similar functions in the CNS
• E.g. basal nuclei

Ganglion (Groups of Cell Bodies)

• What is ganglion (groups of cell bodies)?
• Group of cell bodies in the PNS
• E.g. dorsal root ganglion

If you have a group of cell bodies, it is called the nuclei in the CNS If you have a group of cell bodies, it is called the ganglion in the PNS

Tract (Bundles of Axons)

• What is the tract (bundles of axons)?
• Group of axons in the CNS
• E.g. corticospinal tract in the spinal cord

Nerve (Bundles of Axons)

• What is the nerve (bundles of axons)?
• Group of axons in the PNS
• E.g. ulnar nerve, Cranial n. XI, spinal n.

Glial Cells in CNS

• What are the glial cells in CNS?
• Astrocytes: perform metabolic, structural, homeostatic, and neuroprotective tasks such as clearing excess neurotransmitters, stabilizing and regulating blood-brain barrier, and promoting synapse formation.
• Microglia: central nervous systems primary defense against pathogens and debris, also playing a crucial role in the brain development, synaptic pruning, and maintaining neuronal health.
• Ependymal: playing a crucial role in cerebrospinal fluid (CSF) dynamics, forming a barrier, and potentially contributing to CNS development and regeneration.
• Oligodendrocytes: produces the myelin sheath, an insulating layer that wraps around axons, facilitating fast and efficient nerve impulse transmission.
• Myelin sheath in CNS

Glial Cells in PNS

• What are the glial cells in PNS?
• Schwann cells: to form the myelin sheath around axons, providing insulation and promoting rapid nerve impulse conduction, as well as supporting axon health and regeneration.
• Myelin sheath in PNS

Myelin Definition and Function

• What is myelin?
• An insulating layer, or sheath that forms around nerves, including those in the brain and spinal cord.
• Increases speed of nerve conduction
• Thickness determines speed
• Thicker myelin = faster nerve impulse

Myelin Composition

• What is myelin made up of?
• Proteins and lipids that form to create sheath around particular nerves

Myelin Structure

• What is myelin structure?
• Cells that surrounds (sheath) axons of neurons
• Different types of myelin cells
• PNS - schwann cells
• CNS - oligodendrocytes

Myelin Dysfunction/Damage

• What is myelin dysfunction/damage to myelin?
• Problems with transmission of nerve signals
• Poor transmission then creates movement dysfunction

Demyelination Condition Examples

• Examples of conditions with demyelination
• Multiple Sclerosis (MS)
• Guillain Barre Syndrome (GBS)

Nodes of Ranvier

• What is the nodes of Ranvier?
• Brief gasps in myelin of an axon
• Helps to "boost" or speed up the signal conduction between segments of myelin

Saltatory Conduction

• What is saltatory conduction?
• An action potential (nerve impulse) moving along an axon from node to node with "boosts" of speed at the Nodes of Ranvier
• "Jumping from node to node"

Nerve Conduction Velocity

• What is nerve conduction velocity?
• A measurement of the speed of a nerve impulse along the axon of a nerve

Gray Matter

• What is gray matter?
• Cell bodies & dendrites grouped together
• Connections and processing
• "intersections" & "cities"

White Matter

• What is white matter?
• Bundles of myelinated axons
• Transmits nervous system signals from one place to another
• "highways"

White Matter Location

• Where is white matter located?
• Outer layer of spinal cord
• Center of brain

Gray Matter Location

• Where is gray matter located?
• Center of spinal cord
• Outer layer of brain

Center of Spinal Cord Components

• What is in the center of the spinal cord?
• Cell bodies & dendrites
• Synapses
• Motor neuron cell bodies in anterior horn
• "Butterfly" & "intersections"

Outer Layer of Brain Components

• What is in the outer layer of the brain?
• Cell bodies & dendrites
• Synapses
• Functional processing areas
• Cortex

Outer Layer of Spinal Cord Components

• What is in the outer layer of spinal cord?
• Bundles of axons
• Tracts
• Corticospinal tract (motor)
• Vestibulospinal tract (motor)
• Spinocerebellar tract (sensory)
• Dorsal column (sensory)
• "elevators" & "highways"

Center of Brain Components

• What is in the center of brain?
• Bundles of axons
• Pathways for flow of information

White Matter Bundles Structure

• What is the structure of white matter bundles?
• Large bundles of white matter deep within the brain
• Myelinated axon of neurons

White Matter Bundles Function

• What is the function of white matter bundles?
• Connects various parts of the brain
• Communicates information
• Allows brain higher-order processing

Types of White Matter Connection Bundles

• What are the three types of white matter connection bundles in the brain?
• Association (green)
• Connects areas nearby
• Commissural (blue)
• Connects hemispheres
• Corpus callosum
• Projection
• Project to/ from cortex
• Internal capsule

Progressive vs. Acute Conditions

• How does a progressive condition differ from a condition such as post stroke (CVA) or traumatic brain injury (TBI)?

Progressive changes over time One you have injured the spinal cord, there is no changing the injury. How might it be similar?

Progressive Neurologic Conditions

• CNS - progressive neurologic conditions
• Parkinson's Disease (PD)
• Multiple sclerosis (MS)
• Amyotrophic lateral sclerosis (ALS)
• Post polio syndrome (PPS)
• PNS - progressive neurologic conditions
• Guillain-Barre syndrome (GBS)

Restorative Care

• What is restorative?
• Improving impairments, activity limitations and participation restriction

Compensatory Strategies

• What is compensatory?
• Modifying the task, activity, or environment to improve function

Preventive Measures

• What is preventive?
• Minimizing potential complications and indirect impairments

Palliative Care

• What is palliative care?
• Focus on relief of symptoms, pain, and stress of a serious illness
• Not necessarily = end of life (hospice)

Guillain-Barre Syndrome Symptoms

• Symptoms of guillian-barre syndrome?
• Sudden onset
• Hours to 1-2 days
• Acute polyneuropathy
• Suddenly, many peripheral nerve issues
• Temporary inflammation
• Demyelinating

Guillain-Barre Syndrome Location

• Where GBS?
• Lower motor neurons affected
• PNS
• ANS (50% cases)
• CN (50% cases)

Guillain-Barre Syndrome Etiology

• GBS etiology (why)?
• No confirmed cause
• Suspected trigger from bacteria or viruses
• Autoimmune response to a previous infection now attacking the myelin of peripheral nerves

Guillain-Barre Syndrome Pathology

• GBS pathology (whats wrong)?
• 2-4 weeks after an infection
• Macrophages rapidly destroy myelin > reduction in nerve conduction
• A few weeks of demyelination
• Myelin then starts to regenerate
• If axon is injured before new myelin can regenerate, recovery time will be longer

Types of Guillain-Barre Syndrome

• Types of GBS
• Acute inflammatory demyelinating polyradiculoneuropathy
• Most common
• Myelin injured