Introduction to Nervous System Flashcards
• Describe the basic cells of the central and peripheral nervous system • Differentiate between a typical motor versus sensory neuron • Explain the role of myelin, and define white matter versus grey matter • Describe the structural and functional differences between the central and peripheral nervous systems, as well as the somatic versus autonomic nervous systems
What are the components of the central nervous system (CNS)?
brain, spinal cord
What are the components of the peripheral nervous system (PNS)?
nerves
What are the basic functional units of the nervous system?
neurons
What cells are non-neuronal, non-excitable, that provide support?
neuroglia
Excitable cells that receive and transmit electrical impulses
neurons
what are the 2 types of neurons?
multipolar motor neurons , pseudounipolar sensory neurons
how do pseudounipolar sensory neurons differ in function from multipolar motor neurons?
Multipolar motor neurons: SEND signals FROM CNS to TARGET ORGANS
Pseudounipolar sensory neurons: BRING signals FROM PERIPHERY to CNS
Dendrites
Collect information from other neurons/cells
Trigger Zone
(axon hillock) signals build up until a threshold is reached, creating an action potential
Axon
transmits action potential down to the axon terminal
Nodes of Ranvier
active sites; generate action potentials
Myelin Sheath
insulate axon, allowing for quicker action potential generation
Axon Terminal
where synapsing w/ receptor organ/dendrites of another neuron occurs
Peripheral process
part of a pseudounipolar sensory neuron that is distal to the cell body (nucleus)
Central process
part of the axon on a pseudounipolar sensory neuron that is proximal to the cell body
What 4 types of neuroglia occur in the central nervous system (CNS)?
oligodendrites, microglia, astrocyte, ependymal cells
Oligodendrocyte
CNS-bound neuroglia that creates the myelin sheath for axons ; can myelinate multiple neurons w/ a single oligodendrocyte
Microglia
CNS-bound neuroglia that acts as a waste collector to keep cell healthy
Astrocyte
CNS-bound neuroglia that contains tight-junctions preventing toxins from circulation from entering blood-brain-barrier (BBB) ; a bouncer
Ependymal Cells
A CNS-bound neuroglia that produces cerebral spinal fluid (CSF) ; important for ventricular system
What do Schwann Cells do?
produces myelin sheath* for neurons in the peripheral nervous system (PNS) ; similar to an oligodendrocyte
**Schwann cells can only myelinate one part of an axon per Schwann cell
Multiple Sclerosis is associated w/… What are the symptoms? Why?
Degradation of oligodendrocytes ; symptoms vary based on location (if degradation of myelin in area of brain associated w/ motor function, patient would have impaired motor skills)
Guillian-Barre Syndrome is associated w/… what are the symptoms, why?
Degradation of Schwann cells, weakness and paralysis, due to lack of myelin in axons, lowering action potential rates
is myelin considered white or gray matter?
white matter
