Quiz 4 Flashcards
Two types of nerve cells
Neuron, neuroglia
Small cell that surrounds and wraps delicate neurons
Neuroglia (glial cells)
Excitable cells that transmit electrical signals
Neurons (nerve cells)
Four types of neuroglia in central nervous system
Astrocytes, microglial cells, ependymal cells, oligodendrocytes
Two types of neuroglia in peripheral nervous system
Satellite cells and Schwann cells
Most abundant neuroglia in CNS
Astrocytes
Small ovoid cells with thorny processes. Migrate toward injured neurons
Microglial cells
Line cerebrospinal fluid-filled cavities
Ependymal cells
Branched cells, processes wrap CNS nerve fibers. Forms insulating myelin sheath
Oligodendrocytes
Surround neuron cell bodies in PNS, function similar to astrocytes
Satellite cells
Surround peripheral nervous fibers, form myelin sheath, similar to oligodendrocytes
Schwann cells
Receptive regions
Dendrites
Impulse-generating and conductive region
Axon
Cone shaped area, start of an axon
Axon hillock
Long axons are called _______
Nerve fibers
Purpose of a myelin sheath
Insulate and protect nerve fiber, enhances impulse and speed.
Node of ranvier
Gap in myelin sheath between adjacent Schwann cells.
Ohm’s Law
Current (I) = Voltage (V) / Resistance (R)
Current is (directly/inversely) proportional to voltage
Directly
Current is directly/inversely) proportional to resistance
Inversely
Highest velocity (300mph), largest axon diameter, highly myelinated
Type A
Intermediate velocity (30mph), medium axon diameter, lightly myelinated
Type B
Slowest velocity (2mph), smallest axon diameter, unmyelinated
Type C
Four brain lobes
Frontal, parietal, occipital, temporal.
