Chapter 9 Nervous System Flashcards
Functions of Neuroglial cells
fill spaces, provide structural frameworks, produce components of myelin (electrical insulator), carry on phagocytosis
Nervous tissue is composed of masses of nerve cells called
Neurons
Five types of Neuroglial cells
Microglial, Oligodendrocytes, Astrocytes, Ependymal, Schwann
Microglial cells
throughout nervous system - support neurons - phagocytize bacterial cells and cellular debris - form scars in areas of damage
Oligodendrocytes
form myelin in the brain and spinal cord
Astrocytes
part of blood-brain barrier near blood vessels - support structures, aid in metabolism, regulate ion concentration and respond to brain injury by filling in spaces
Ependymal cells
cover inside of ventricles and form choroid plexuses within the ventricles and central canal of spinal cord
Schwann cells
Peripheral nervous system Neuroglial cell - myelin-producing cells of the PNS
Dendrites
cytoplasmic extensions that provide the main receptive surfaces for neurons
white matter
myelinated neurons in the CNS
myelinating process in children
gradual and can be observed in child’s development - responses to impulses are delayed/stunted until myelination is complete
T or F Nodes of Ranvier occur between adjacent neurons
False - Nodes of Ranvier occur between adjacent Schwann cells
Gray Matter
Unmyelinated nerve tissue in the CNS is called
Interneurons
multipolar neurons within the CNS that form links between other neurons
T or F If fibers are cut in the ascending tract there will still be a motor response.
False - the ascending tract relays information of stimuli to the CNS
What is the function of the descending tract
The descending tract relays a response to the effector after the stimuli has been processed in the CNS
T or F You will have nerve damage below the cut if fibers in the ascending tract are cut.
False - b/c the impulse came from below and is ascending up
Cell Membrane potential
cell membrane is electrically charged with respect to the inside part of the cell (polarized membrane) due to uneven distribution of postitive and negative ions on each side of the membrane
Resting potential
potential energy - negatively charged on inside/positively charged on the outside
Action potential
a nerve impulse (wave of depolarization and repolarization) that moves away from the point of stimulation on a nerve
Synapse
the junction between the adjacent nerves where impulses pass
Polarized nerve fiber
The concentration of positive ions is higher on the outside and the concentration of negative ions is higher on the inside
synaptic cleft
the gap that separates two communication neurons
Action Potential
rapid sequence of depolarization and repolarization that occurs along the length of the nerve moving away from a point of stimulation
Saltatory conduction (myelinated fibers)
conduction is many times faster than conduction on unmyelinated fibers - speed of impulse conduction is proportional to the diamater of the axon - Motor neurons are larger/faster than sensory neurons
Reflex arc - order
Receptor - Sensory (afferent) neuron - Interneurons CNS - motor (efferent) neuron - effector
chromatophilic substance
membranous sacs similar to rough endoplasmic reticulum
meninges
layered membranes between the bony coverings and the soft tissues of the CNS protecting the brain and the spinal cord
subarachnoid space
space that contains the clear, watery cerebrospinal fluid (CSF)
mininges layers
Dura mater, arachnoid mater, pia mater
dura mater
outermost layer of meninges - tough, white, fibrous connective tissue containing many blood vessels and nerves
arachnoid mater
thin weblike membrane without blood vessels between the dura and pia layers
pia mater
very thin layer containing many nerves and blood vessels that nourish underlying cells of the brain and spinal cord
lumbar puncture position
puncture is placed in the subarachnoid space below the spinal cord between the first and second lumbar vertebrae
subdural hematoma
escaping blood collects beneath the dura mater (between the pia mater and the skull)
spinothalamic tract
begins in the spinal cord and carries sensory impulses associated with the sensations of pain, touch, and temperature to the thalamus of the brain
multipolar neurons
neuron with multiple dendrites - brain made up of billions of them & they communicate with one another and other parts of the CNS
cerebellum - function
coordinates muscular activity - voluntary movement
temporal lobe
associated with long term memory, concentration, planning and problem solving - area where you store your memories
Ependymal cells
Neuroglial cells form epithelial-like membrane to contain the fluid- filled cavity of brain or spinal cord
excite a neuron - definition
when a neuron is more excitable as a result of incoming sub-threshold stimulation it is said to be facilitated
Ischemic
a cell lacking oxygen due to poor blood flow
lumbar puncture
hollow needle inserted between the 1st and 2nd lumbar vertebrae below the spinal cord - pressure
Diazepam is used for which - a. depresses activity in limbic system b. depresses activity in reticular formation c. increases activity or produces GABA d. All of the above
D - All of the above
facilitation in regard to impulse processing
when action potential is not triggered by an impulse to a neuron, but the neuron is left in a more excitable state to incoming stimulation than it was before
dendrites
part of neuron that provide receptive surfaces for impulses
axon
part of the neuron that conducts impulses away from the cell body
meninges
layered membranes that protect and cushion the brain and spinal cord (dura, arachnoid, pia)
where is CSF contained
the subarachnoid space
caffeine’s effect on synaptic transmission
lowers the threshold so neurons are more easily excited
action potential
nerve impulse (wave of depolarization and repolarization) that moves away from a point of stimulation on a nerve
chromatophilic substance in cell body of nerve cell
membranous sacs similar to rough endoplasmic reticulum in other cells & function in protein synthesis
where myelin is produced in the CNS
oligodendrocytes
where myelin is produced in the PNS
Schwann cells
root of spinal nerve containing motor nerves
descending tract
root of spinal nerve containing sensory nerves
ascending tract
describe the concentration of sodium and potassium ions in regard to the membrane of a polarized nerve
the outside membrane has an abundance of positive charge & high concentration of sodium ions (Na+) - the inside membrane has an abundance of negative charge (due to impermeable negative ions) & high concentration of potassium ions (K+)
Resting potential
The separation of charge (positive and negative), or potential difference
effectors
muscles or glands that motor nerves deliver impulses to
interneurons
form a link between other neurons
amphetamines affect the nervous system how?
cause the release of nor-epinephrin
During action potential what charge ions are moving into the nerve cell
positive sodium ions
which ions move outside of the nerve cell during repolarization
potassium ions
what age does myelin sheath begin to develop
14 week of prenatal development
how does an infant’s nervous system function in relation to myelin production
responses are course, undifferentiated and may involve the whole body
What drug decreases membrane permeability to sodium?
local anesthetics
Do local anesthetics prevent nerve impulses from passing
Yes, they stunt depolarization and prevent the action potential resulting in impulses no longer passing along the nerve
7th cranial nerve
Facial nerve
facial nerve
7th cranial nerve - (motor and sensory) muscles for facial expression and for taste
the radial nerve arising from the spinal plexus
brachial plexus
phrenic nerve arising from spinal plexus
cervical plexus
femoral nerve from spinal plexus
lumbosacral plexus
when sensory impulses reach the reticular formation of the brainstem what occurs
the impulses activate the cerebral cortex into a state of wakefullness
8th cranial nerve
vestibulocochlear nerve
vestibulocochlear nerve
sensory nerve for hearing and equilibrium
12th cranial nerve
hypoglossal nerve
hypoglossal nerve
12th cranial nerve - motor nerve for muscles that move the tongue
sympathetic tone
smooth muscles in the blood vessel walls continuously stimulated and in a state of partial contraction
transmitter substance released from preganglionic sympathetic and parasympathetic fibers
acetylcholine (autonomic neurotransmitter)
transmitter released from parasympathetic postgaglionic fibers
acetylcholine
sympathetic postgaglionic fibers release this transmitter substance
norepinephrine (adrenergic)
1st cranial nerve
olfactory - sensory for smell
if descending tract damaged what activity would be affected
motor movement of muscle/gland would be damaged
ascending fibers damaged affects this activity
sensory information to the brain would be impeded
fluid-filled interconnected cavities of the brain containing CSF
ventricles
part of brain coordinates voluntary movement and integrates sensory information to maintain posture
cerebellum
part of brain stem containing cardiac and vasomotor centers
medulla oblongata
part of brain responsible for initiation of voluntary muscle movement
cerebrum
how do you measure the pressure of the CSF
lumbar puncture into the subarachnoid space of the lumbar spine (spinal tap)
two major regions within the diencephalon
thalamus and hypothalamus
