Functional Anatomy (2113 Exam 1)

Central Nervous System (CNS)

Brain & Spinal Cord

Peripheral Nervous System (PNS)

Everything outside of the brain & spinal cord

Neurons

Most basic cell in the nervous system that work electrically and communicate chemically

Neurotransmitter

Chemical messengers that transmit signals between neurons (nerve cells) in the brain and other parts of the nervous system

Dendrites

Branch-like extensions that extend from the cell body / Receive electrical signals from other neurons or sensory receptors / Transmit these signals to the cell body

Cell Body (Soma)

Contains the nucleus, mitochondria, and other organelles essential for cell survival / Houses the genetic material and controls the neuron's activities

Myelin Sheath

A lipid-rich material that in most vertebrates surrounds the axons of neurons to insulate them and increase the rate at which electrical impulses pass along the axon

Axon

A long, slender extension that carries the electrical signal, or action potential, away from the cell body

Terminal/Synapse Button

Located at the end of the axon, these terminal buttons store and release neurotransmitters

Synapse

The space between the terminal button on a neuron and the dendrite of another

Nodes of Ranvier

Gaps in the myelin sheath

Spines

Increases the surface area of the dendrites

Collaterals

Branches that diverge from the main shaft of a neuron's axon. They function to allow a single neuron to transmit information to multiple target cells

Vesicles

Small, membrane-bound, spherical organelles located in the axon terminals of neurons that store and release neurotransmitters into the synapse

Multipolar Neurons (Motor / Pyramidal / Purkinje Neurons)

The most common type of neuron in the central nervous system, characterized by having one single axon and multiple dendrites extending from the cell body (soma)

Bipolar Neurons (Retinal / Olfactory Neurons)

Specialized sensory nerve cells featuring two extensions—one dendrite and one axon—emerging from opposite ends of the cell body

Unipolar Neurons

Sensory neurons characterized by a single process extending from the cell body (soma) that divides into two branches: one acting as a dendrite (receiving signals) and the other as an axon (transmitting signals)

Anaxonic Neurons

Small, local interneurons in the central nervous system (brain, retina) that lack a distinguishable axon, featuring multiple dendrite-like processes that function as both input and output

Sensory Neurons (Afferent)

Specialized nerve cells in the peripheral nervous system that convert external and internal stimuli

Motor Neurons (Efferent)

Specialized nerve cells that transmit electrochemical signals from the central nervous system (brain and spinal cord) to muscles, organs, and glands, initiating voluntary and involuntary movement

Interneurons

Specialized neurons located exclusively within the central nervous system (brain and spinal cord) that act as intermediaries, connecting sensory and motor neurons

Reflex Arc

The neural pathway, consisting of sensory neurons, interneurons, and motor neurons, that controls involuntary, rapid, and automatic responses to stimuli

Glial Cells

Non-neuronal cells in the nervous system that provide essential structural support, metabolic nourishment, insulation, and immune defense for neurons

Astrocytes (CNS)

The most numerous, star-shaped glial cells (non-neuronal support cells) in the central nervous system (CNS), responsible for maintaining homeostasis, protecting neurons, and regulating brain metabolism

Oligodendrocytes (CNS)

Specialized glial cells in the central nervous system (CNS) that produce myelin, a fatty substance wrapping around axons to insulate them and accelerate electrical signal transmission

Microglia (CNS)

The primary resident immune cells of the central nervous system (CNS), functioning as specialized macrophages that constantly survey the brain and spinal cord

Ependymal Cells (CNS)

They are critical for producing, circulating, and absorbing cerebrospinal fluid (CSF), maintaining brain metabolism, and providing a barrier between CSF and neural tissue

Schwann Cells (PNS)

They accelerate neural impulse conduction, provide metabolic support, and are critical for nerve regeneration, distinguishing them functionally from oligodendrocytes in the central nervous system