chapter 9
the greater the diameter of an axon, the ____ the impulse
faster
the nervous system contains specialized communicating nerve cells called and supporting cells called
neurons and neuroglia
narrow gaps in the myelin sheath are called
nodes
what is the function of the autonomic nervous system
not-controlled, involuntary, smooth muscle
_______ form myelin in the central nervous system
oligodendrocytes
the internist layer, the ___ _____, is thin and contains many blood vessels and nerves
pia matter
in the autonomic motor system, motor pathways include two fibers: a _______ leaves the CNS, and a _______ fiber that innervates the effector
preganglionc, postganglionic
_____ axons conduct impulses over their entire membrane surface
unmyleinated
an _____ _____ is not graded, therefore it is an all-or-none response. a greater intensity of stimulation does not produce a stronger response, instead; it produces more _____ _____ per second
action potential, action potentials
the middle layer, the ____ _____, is thin and lacks blood vessels and looks like a spider web
arachnoid matter
function of the neurolimma?
assist in repairing damaged axons
_____ are near blood vessels and support structures, aid in metabolism, and respond to brain injury by filling in spaces
astrocytes
in what structure is the cell body of the second neuron located?
automatic ganglion
nerve fibers contain a solitary outgoing ___ and numerous _____ which bring in impulses from receptors
axon and dendrite
Nerves are bundles of
axons
the central nervous system is composed of the
brain and spinal cord
fibers in the parasympathetic division arise from the _____ and the ____ region of the spinal cord, and synapse in the ganglia close to the effector organ.
brainstem and sacral
1. structure: a neuron has a ____ ____ with mitochondria, lysosomes, a golgi apparatus, chromatophillic substance (nissil bodies) containing rough endoplasmic reticulum, and neurofibrils
cell body
neuroglia fills spaces, support neurons, provide structural frameworks, produce myelin, and carry phagocytosis. four types are found in the and one main type is found in the.
cns and pns
what is the function of the somatic nervous system
controlled movements
A single neuron within a pool may receive impulses from two or more fibers. This is called __________, and makes it possible for the neuron to summate impulses from different sources.
convergence
impulses leaving a neuron in a pool may be passed into several output fibers. this is called _____ and serves to amplify an impulse.
divergence
the brain and spinal cord are surrounded by membranes called meninges that lie between the bone and the soft tissues. the outermost later is made up of tough dense connective tissue, contains many blood vessels, and is called the ______ _____
dura matter
_____ cover choroid plexuses and form inner linings that enclose ventricles of the brain
ependyma
the stealth around the spinal cord is separated from the vertebrae by a ____ space
epidural
the outer layer of covering in the mylienated pherphrial neurons called the ______
neurolimma
what are the general functions of the nervous system
gather information, connect it to the nerve impulses, infrigerate sensory impulses in the brain as perceptions, desisions leading to motor skills
_______ are multipolar neurons within the cns that forms links between other neurons
interneurons
what is the function of the autonomic nervous system
maintain homeostasis of visceral activities without conscious effort
______ cells are small cells that phagocytize bacterial cells and cellular debris
micrological
Nerves containing both sensory and motor fibers are called _____________ nerves.
mixed
____ neurons are multipolar neurons that conduct impulses from the cns to effectors
motor
_____ nerves carry impulses from the CNS.
motor
2. classifications of structures: name the 3 types of neurons as classified by structure. how do they differ?
multipolar-many nerve fibers. bipolar, single axon and single dendrite unipolar
larger axons in the PNS are enclosed by _____ sheaths provided by _____ cells
myelin and schwann
____ axons conduct impulses from node of Raniver to node of Ranvier, a phenomenon called ___ conduction. this conduction is many times faster.
myelinated , saltatory
the pheripheral nervous system is composed of pheriprial
nerves
a reflex arc includes a sensory ____, a ____ neuron, one of more _____ that serve as a reflex center, a _____ neuron whose axons pass out of the CNS, and a ____ ____ that carries out the reflex response.
receptor, sensory, effectors, interneuron, motor neuron
______ cells are the myelin-producing neuroglia of the pheriphal nervous system
schwann cells
nerves that bring sensory information into the CNS are called ______ neurons
sensory
3. classification by function: _____ neurons (affrent neurons) conduct impulses from pheriphereal receptors to the cns, and usually have a ______ stricture, but may also have a ____ structure.
sensory, unipolar, bipolar
between the middle and the innermost layers is a ____ space containing _____ fluid.
subarachnoid, cerebrospinal
a particular neurons of a pool may receive excitatory or inhibitory stimulation; if the net effect is excitatory but _____ the neuron becomes more excitable to incoming stimulation (a condition called facilitation)
subthreshold
What are the 2 divisions of the autonomic nervous system?
sympathetic and parasympathetic
fibers in the sympathetic division arise from the ____ and ___ regions of the spinal cord, and synapse in ____ ganglia close to the vertebral column.
thoracic, lumbar, paracertabral
