Functional Neuroanatomy

Week 1

What are the major components of the Central Nervous System (CNS)?

Cerebrum, diencephalon, cerebellum, brainstem, and spinal cord

What 3 structures make up the brainstem?

Midbrain, Pons, and Medulla Oblongata

What structures make up the Peripheral Nervous System (PNS)?

Processes of the CNS that form the cranial nerves and spinal nerves

Cranial Nerves are associated with what CNS structure

Brainstem

Spinal Nerves are associated with what CNS structure?

Spinal Cord

What are the meninges?

3 connective tissue membranes surrounding the CNS

Name the meninges from inside → outside

Pia Mater, Arachnoid mater, Dura Mater

(PAD)

Which meninges are considered the leptomeninges?

Pia Mater and arachnoid mater

Which Meninx is called the pachymeninx?

Dura Mater

How many layers does the crainal dura have?

Two, Outer and Inner

The spinal dura is continous with which portion of the cranial dura?

the inner cranial duraWhat

What is the space between the pia and arachnoid called?

subarachnoid space

What fills the subarachnoid space?

Cerebral spinal fluid (CSF)

What is between the arachnoid and dura?

Subdural Space

What is the epidural space?

the space outside the dura

Which spaces are described as potential spaces?

subdural and epidural spaces

What connective tissue surrounds an individual myelinated neuron/nerve fiber?

Endoneurium

Group of nerve fibers form what?

Fasicles

What surrounds a fascicle?

Perineurium

Fascicles bound together form what?

A nerve

What surrounds the entire nerve?

Epineurium

What tissue does ‘somatic’ refer to?

Skin, skeletal, muscle and bone

What is somatic afferent information?

sensory information gathered by receptors in somatic tissues and sent to the brain for analysis

How is visceral efferent information disseminated?

through the endocrine and autonomic nervous system

afferent

arrives at the brain

efferent

exits the brain

what is visceral afferent information

information gathered by receptors in visceral tissues and sent to the brain for analysis

What are the two major classes of nervous-system cells?

Gilia and neurons

What are Glia?

Support cells of the CNS

What is the neuron?

The functional unit of the nervous system

How much more numerous are glia than neurons

10-50x more

What is the general role of glia?

support neuronal function and structure

What are the major glial categories discussed?

microglia and macroglia

Which cells are included under macroglia?

Oligodendrocytes/Schwann cells, astrocytes, and ependymal/choroidal cells

What are microglia?

mononuclear phagocytes derived from macrophages

What activates microglia?

injury, infection, or disease

What do microglia express?

a range of antigens

What diseases are associated with microglial activation?

multiple sclerosis, AIDs- related dementia, Parkinson’s, Alzheimer’s

Microglia

immune/cleanup crew

What produces myelin in the CNS?

Oligodendrocytes

How many axonal internodes can one oligodendrocyte envelop?

15

What produces myelin in the PNS?

Schwann cells

How many internodes does a Schwann cell envelop?

One

Which Cells are implicated in the ability of the PNS to regenerate after injury?

Schwann Cells

Oligodendrocyte

Location: CNS

Function: Myelin

Internodes: ~15

Regeneration: n/a

Schwann Cell

Location: PNS
Function: Myelin

Internodes: 1

Regeneration: PNS Regeneration

What do ependymal/choroidal cells line?

ventricles and choroid plexus

What are ventricles?

cavities in the CNS filled with CSF

What is the choroid plexus?tro

a collection of vessels within the ventricles that secretes CSF

What can astrocytes influence during embryonic development?

Growth or retraction of neurites

What do astrocytes regulate in extracellular space?

chemical contents

What do astrocytes do to neurotransmitter spread?

restrict it

What important ion concentration do astrocytes regulate?

Potassium (K+)

Do astrocytes possess neurotransmitter receptors?

yes

What do astrocytes end feet on CNS neurons form?

glial limiting membranes that regulate nutrient passage

What do astrocyte end feet do at CNS capillaries?

induce tight junctions that create the blood brain barrier (BBB)

What types of substances can readily enter the CNS through the BBB?

small, highly lipid-soluble substances

What does the BBB prohibit?

passage of large, complex objects

What substances are selectively transported across the BBB?

glucose, electrolytes, and amino acids

What is another name for the soma?

cell body

what structures are found in the soma?

nucleus, rough ER/Nissl bodies, smooth ER, mitochondria, and cytoskeleton

What are the 3 cytoskeletal components listed?

microtubules, microfilaments, and intermediate/neurofilaments

What is a neurite?

a neuronal process; dendrite and axon under neurite

Where does the axon begin?

axon hillock

Is rough ER present in the axon?

no

Why is the absence of Rough ER in the axon important?

there is no protein synthesis in the axon

What is a bouton?

axon terminal/presynaptic terminal

What does the bouton contain?

Synaptic Vesicles

What are the directions of axoplasmic transport?

anterograde and retrograde

Where do myelin sheaths envelop an axon?

at the internodal spaces

What are nodes of ranvier?

points on the axon that are not insulated by myelin

What is saltatory conduction?

the action potential proceeding from node to node ‘jumping’

What are the 4 functional components of neurons?

1. Input

2. trigger/integrative

3. conductile

4. output

What does the input component do?

receives information that will be propagated

What type of signal does the input component produce?

a graded local signal

what determines the intensity of a receptor potential?

stimulus intensity

What determines the intensity of a synaptic potential?

amount of neurotransmitter released

what occurs at the trigger or integrative component?

the all - or - none action potential is generated

what is another name for the trigger region?

spike initiation zone

what does the conductive component do?

propagates the action potential

What does the output component do?

Releases neurotransmitters

What determines how much neurotransmitter is released?

the number and frequency of action potentials

Input, trigger, conductile, output

Receive, generate, propagate, release

What is a unipolar neuron

a neuron with one process that gives rise to many branches

What is a bipolar neuron?

a neuron with 2 processes, a dendrite and an axon

what is a pseudounipolar neuron?

a neuron with 2 processes that both function as axons

What is a multipolar neuron?

a neuron with 1 axon and many dendrites