Nervous System and Neurons

7 Questions

What is the primary function of astrocytes in the central nervous system?

To maintain the chemical environment of CNS

Which type of cell is responsible for producing the myelin sheath in the peripheral nervous system?

Schwann cell

What is the main difference between afferent and efferent divisions of the peripheral nervous system?

Afferent sends signals to CNS, efferent sends signals away from CNS

What is the function of ependymal cells in the central nervous system?

To circulate cerebrospinal fluid

What is the main characteristic of neurons in the central nervous system?

They cannot replicate

What is the function of microglia in the central nervous system?

To dispose of debris

What is the characteristic that distinguishes neuroglia from neurons?

Neuroglia can replicate, neurons cannot

Study Notes

Central Nervous System (CNS)

Consists of the brain and spinal cord

Peripheral Nervous System (PNS)

Comprises nerves outside the brain and spinal cord

Afferent Division (PNS)

Nerves that send signals to the CNS
Composed of sensory neurons

Efferent Division (PNS)

Nerves that send signals away from the CNS
Composed of motor neurons

Neurons

Nerve cells specialized to transmit signals
Cannot replicate

Nervous Tissue: Support Cells

Astrocytes (CNS)

Abundant in CNS
Star-shaped
Provide structural support to neurons
Form blood-brain barrier (BBB) between capillaries and neurons
Maintain chemical environment of CNS
Remove waste

Ependymal Cells (CNS)

Line cavities of the brain and spinal cord
Circulate cerebrospinal fluid

Oligodendrocyte (CNS)

Produce myelin sheath around nerve fibers in CNS
Insulate nerve fibers

Microglia (CNS)

Spider-like phagocytes
Dispose of debris

Satellite Cells

Believed to provide nutrients to neurons

Schwann Cells (PNS)

Form myelin sheath in PNS
Insulate nerve fibers

Neuroglia

Do not transmit signals
Can replicate
Support neurons
Over-replication can cause most brain tumors