Organization and Basic Anatomy/Physiology of Neurons - Study Guide for Neurophysiology Section Winter 2026

What are the major divisions of the nervous system?

The Peripheral Nervous System and the Central Nervous System

What is the function of the central nervous system?

The central nervous system is the “master computer” for sensory and motor data. It receives signals, processes information, and sends signals.

What are nuclei? (How are the defined?)

Nuclei are clusters of neuron cell bodies found within the central nervous system

What is the function of the peripheral nervous system?

The peripheral nervous system is the “master highway” for sending sensory info to the central nervous system and and sending motor info from the central nervous system.

What are ganglia?

Ganglia are clusters of neuron cell bodies found within the peripheral nervous system.

What are the divisions of the peripheral nervous system?

The peripheral nervous system is divided into

afferent sensory neurons which carry sensory information to the central nervous system

and

efferent motor neurons which carry motor information away from the central nervous system

How are the afferent and efferent divisions different?

• What else are the afferent and efferent systems called?

• What are the two types of the afferent and of the efferent systems?

afferent (sensory) sensory neurons which carry sensory information to the central nervous system

and

efferent (motor) motor neurons which carry motor information away from the central nervous system

Each is divided into visceral and somatic

What are the divisions of the efferent nervous system?

The efferent nervous system is divided into the autonomic nervous system and the somatic nervous system

What are the divisions of the autonomic nervous system?

The autonomic nervous system is divided into the sympathetic nervous system “fight or flight” and the parasympathetic nervous system “rest and digest”. There is also the enteric nervous system “digest”

What are the two different types of neural tissue?

• What are the functions of each type?

Neurons send and receive electrical signals

Neuroglia are the “support” cells

-separate

-provide structural framework

-regulate immediate environment

Be able to identify the anatomical features/structures (like dendrites…) of a neuron covered in lecture and to describe the function of each feature/structure.

• Know what types of channels, gates and pumps are located in each part of a neuron.

Dendrites, dendritic spines, and soma, contain: CGC of cations, potassium, and chloride

Axon hillock, initial segment, and axon contain: VGC of Sodium (Na+) and Potassium (K+)

Synaptic knob / synaptic terminal / axon terminal’s contain: VGC Calcium (Ca2+) and Ca2+ pump

The entire neuron contains: Na+ / K+ pumps and Na+ leak channels and K+ leak channels

Be able to describe what a synapse, synaptic cleft, synaptic vesicles, pre/postsynaptic cells are

Synapse: where a neuron talks to another cell

Synaptic cleft: the space between the pre and post synaptic cells

Synaptic vesicles: are organelles created by the golgi apparatus that release neurotransmitter when stimulated by calcium

Presynaptic cell: the cell before the synapse

Postsynaptic cell: the cell after the synapse

What are neurotransmitters?

• What is the function of neurotransmitters?

Neurotransmitters are chemicals that open chemical gated channels

Where are neurotransmitters synthesized (produced) in a neuron?

Mostly in the soma’s sometimes in the synaptic knobs

How are neurotransmitters transported in a cell?

Axoplasmic transport

Neurotransmitters are transported from the soma to the axon terminal via motor proteins kinesins across neurotubules which is called anterograde.

Neurotransmitters are transported from the axon terminal to the soma via the motor proteins dyneins across neurotubules which is called retrograde.

How are anterograde axoplasmic transport and retrograde axoplasmic transport different?

During anterograde axoplasmic transport: Neurotransmitters are transported from the soma to the axon terminal via motor proteins kinesins across neurotubules.

During anterograde axoplasmic transport: Neurotransmitters are transported from the axon terminal to the soma via the motor proteins dyneins across neurotubules.

What are kinesins and dyneins?

• What does each specifically do?

• What intracellular structures do they work with?

Kinesins (anterograde to axon terminal) and dyneins (retrograde from axon terminal) are motor proteins that do axoplasmic transport across neurotubules.

What structures are involved in transporting the secretory vesicle in axoplasmic transport?

Motor proteins: Kinesins and Dyneins

Neurotubules (microtubules)

What are the different structural classifications of neurons and where would we find examples of them?

Anaxonic: brain

Unipolar: dorsal root ganglion (often sensory neurons)

Bipolar: sensory organs (often sensory neurons)

Multipolar: anterior grey horn (often motor neurons)

What are the different functional classifications of neurons?

• What is the function of each type?

Sensory: “afferent” carries visceral and somatic sensory information

Motor: “efferent” carries visceral and somatic motor information

Interneuorons: “between / association” neurons connects motor and sensory neurons

What types of sensory neurons do we have?

visceral and somatic

What types of motor neurons do we have?

visceral and somatic

List the different types of neuroglia cells found in the CNS.

Astrocyte: (blood brain barrier) it’s cytoplasmic extension cover the capillary to maintain blood brain barrier, preventing pathogens invading also the most abundant

Ependymal cells: (CSF) produces cerebral spinal fluid for transport of gases and nutrients and physical protection of tissues

Microglia: (killas) phagocytize cell debris and waste, and attack pathogens

Oligodendrocytes: (CNS myelinating cells) wrap their axolemma around exons and form a “myelin layer” to isolate that part of the nerve membrane from the extracellular environment - a single Oligodendrocyte wraps around multiple regions of an axon

What are the functions of the different types of neuroglia cells found in the CNS?

Astrocyte: (blood brain barrier) it’s cytoplasmic extension cover the capillary to maintain blood brain barrier, preventing pathogens invading also the most abundant

Ependymal cells: (CSF) produces cerebral spinal fluid for transport of gases and nutrients and physical protection of tissues

Microglia: (killas) phagocytize cell debris and waste, and attack pathogens

Oligodendrocytes: (CNS myelinating cells) a single Oligodendrocyte wraps multiple times (~200) around multiple regions of an axon to form a “myelin layer” isolating that part of the nerve membrane from the extracellular environment.

List the different types of neuroglia cells found in the PNS.

Schwann cells: (PNS myelinating cells) a single schwann cell’s phospholipid bilayer wraps multiple times around one region of an axon. They’re capable of repairing damaged nerves of PNS.

Satellite cells: (soma protector) covers soma / cell body in the ganglia to protect from the environment and regulate the environment.

What are the functions of the different types of neuroglia cells found in the PNS?

Schwann cells: (PNS myelinating cells) a single schwann cell’s phospholipid bilayer wraps multiple times around one region of an axon. They’re capable of repairing damaged nerves of PNS.

Satellite cells: (soma protector) covers soma / cell body in the ganglia to protect from the environment and regulate the environment.

What do the terms internode and node refer to in relation to myelination of a nerve?

The internode is where the phospholipid bilayer of the myelinating cell is wrapped around the axon of a neuron. The node is the space between internodes.

How are Oligodendrocytes and Schwann cells different?

Oligodendrocytes are found in the CNS and Schwann cells are found in the PNS

Oligodendrocytes wrap around multiple areas of the axon Schwann cells wrap around a single area of the axon

Oligodendrocytes cannot repair damaged nerves, Schwann cells can

Which type of myelinating cells assists in the repair of peripheral nerves?

Schwann cells

How is the myelination layer created?

The myelinating cell wraps it’s phospholipid bilayer around the axon

What are the myelination layers made up of?

The myelinating cells phospholipid bilayer

How is white matter different from gray matter?

white matter is myelinated

grey matter is unmyelinated