characteristics and function of astrocytes - ANSWER--most abundant, versatile,
and highly branched glial cells
-cling to neurons, synaptic endings, and capillaries
-functions: support and brace neurons; play role in exchanges between capillaries
and neurons through BBB; guide migration of young neurons; respond to nerve
impulses and neurotransmitters; influence neuronal functioning
characteristics and function of microglia - ANSWER--small, ovoid cells with thorny
processes that touch and monitor neurons
-migrate toward injured neurons
-can transform to phagocytize microorganisms and neuronal debris
characteristics and function of ependymal cells - ANSWER--range in shape from
squamous to columnar
-may be ciliated (cilia beat to circulate CSF)
-line the central cavities of the brain and spinal column
characteristics and function of oligodendrocytes - ANSWER--branched cells
-processes wrap CNS nerve fibres, forming insulating myelin sheaths thicker
nerve fibres
,myelin sheath - ANSWER-lipid protein material that acts as an insulator of nerve
cells and speeds up nerve conduction
structure and function of satellite cells - ANSWER--cover surface of nerve cell
bodies
-regulation of extracellular environment of PNS neurons
characteristics and function of Schwann cells - ANSWER--wrap around axon in
jelly roll fashion
-one cell forms one segment of myelin sheath
myelination of neurons in CNS vs myelination of neurons in PNS - ANSWER-CNS: an
oligodendrocyte puts forth about 15 broad, flat processes that spiral around CNS
axons, forming myelin sheath
PNS: a Schwann cell spirals around an axon many times, forming myelin sheath.
The outer nucleated cytoplasmic layer of the Schwann cell is the neurolemma,
found only in PNS
,organization of nervous system - ANSWER-1) central nervous system = brain and
spinal cord
-processes many different kinds of incoming sensory information
-source of thoughts, emotions and memories
-produces signals causing muscles to contracts and glands to secrete
2) peripheral nervous system = consists of all nervous tissue outside the CNS
-further divided into sensory (afferent) division [provides information about
somatic senses] and motor (efferent) division [conveys output from CNS to
effectors]
-efferent division is further divided: somatic nervous system (conveys output
from CNS to skeletal muscle) and autonomic nervous system (conveys output
from CNS to smooth muscle, cardiac muscle, and glands)
-autonomic nervous system is further divided: sympathetic nervous system and
parasympathetic nervous system (usually have opposing actions)
structural classification of neurons - ANSWER--multipolar: have several dendrites
and one axon; brain and spinal cord
-bipolar: one main dendrite and one axon; retina of eye, inner ear, olfactory area
of brain
-unipolar: have dendrites and one axon that are fused together to form a
continuous process that emerges from the cell body; function as sensory
receptors
, functional classification of neurons - ANSWER--sensory: afferent neurons; either
contain sensory receptors at their distal ends or are located just after sensory
receptors that are separate cells; forms action potentials; most are unipolar
-motor: efferent neurons; convey action potentials away from CNS to effectors;
most are multipolar
-interneurons: association neurons; mainly located within CNS between sensory
and motor neurons; process incoming sensory information and elicit motor
response by activating motor neurons; most are multipolar
composition of white and gray matter - ANSWER--white matter: regions of the
brain and spinal cord with dense collections of myelinated fibres
-gray matter: mostly neuron cell bodies and nonmyelinated fibers
organization of white and gray matter in brain and spinal cord - ANSWER-brain:
white matter = deep; gray matter = superficial
spinal cord: white matter = superficial; gray matter = deep
resting membrane potential - ANSWER--charge of plasma membrane at rest;
potential difference across membrane of resting cell