the cytoplasmic extensions that together with the cell body, provide the main receptive surfaces for neurons is?
masses of myelinated nerve fibers apper what color?
name the types of neuroglial cell 4
astrocytes, oligodendrocytes, microglial, ependyma
connects neurons to blood vessels and provides growth factors
support neurons and phagocytize
lines ventricles of the brain
when a nerve fiber is polarized the concentration of ________ ion is higher on the outside and the concentration of ______ ion is higher on the inside
saltatory conduction in myelinated neuron is _______
(faster/slower) in terms of conduction compared to the unmyelinated neuron.
what produces myelin in the brain and spinal cord?
which neurotransmitter functions to relieve pain sensations?
which ions pass through cell membranes most readily?
if a resting potential becomes more negative, the membrane is said to be?
when an action potential passes over the surface of a synaptic knob, the contents of the vesicles are released in response to the presence of _____ ions
if a neuron receives a series of stimuli whose effect is excitatory but subthreshold, the meuron is more excitable to incoming stimulation than before and is said to be?
ischemic cell change is caused by a lack of ____ gas?
an infants responses to stimuli are coarse and undifferentiated because its nerve fibers are not yet _____?
role of calcium ions in action potential?
calcium ions cause potassium channels to close
three general functions of the nervous system are?
integrative, motor, sensory
neurons are _______, whereas neurogical cells are ________
nerve cells; structural and functional units of the nervous system
Myelin is defined as ______
fatty material that forms a sheath like covering around certain nerve fibers
a myelinated nerve fiber is characterized by being ______, whereas an unmyelinated nerve fiber is characterized by being _______
white, and composing the white matter of the brain and spinal cord; gray and composing the gray matter of the brain an spinal cord
action potentials are related to nerve impulses because propagation of action potential along the fiber constitutes a ______ impulse
if the body had a low calcium level then this could affect the release of neurotransmitters by causing a _______ in the amount released from the synaptic knob.
the process of transmitting a nerve impulse from one neuron to another involves a
nerve impulse stimulating presynaptic axons to release a neurotransmitter into a synaptic cleft
the cells within the nervous system that fill spaces and give support to neurons are called _____ ______
sheaths of ______ cells often enclose the larger axons outside of the brain and spinal cord
the difference in electrical charge between the inside and outside of a polarized nerve cell membrane is called the _____ ______
a nerve impulse consists of a wave of ____ ______ moving away from a point of stimulation
a _____ is the junction between the parts of two neurons
body parts such as muscles and glands that are capable of responding to nerve impulses are called ______
if a neurotransmitter causes a cell membrane to become hyperpolarized and an action potential is less likely to occur the change is called _____ ______ ______
local potential change