Exam 1 Flashcards
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Mature nervous tissue has little capacity to store ______ or _____
oxygen, sugar (glucose)
Mature nervous tissue has little ______ capacity
mitotic
2 different components of the nervous system, broken up by structure
CNS, PNS
CNS is made up of what?
Brain (encephalon), Spinal cord (Medulla spinalis)
PNS is made up of what?
12 cranial nerve pairs, 31 spinal nerve pairs = 86 total nerve trunks and Ganglia
Groups of neuron cell bodies clustered together in the PNS
ganglia
Part of the N.S. that innervates the skeletal musculature “skeletal muscles”
Somatic component of the N.S.
Somatic component is synonymous with…
Voluntary component
Includes both efferent and afferent nerve fibers
Somatic component of the N.S.
The chemical released by the somatic axon endings (cholinergic)
Acetylcholine
2 different components of the N.S. broken up by function
Somatic and Autonomic
Part of the N.S. that innervates the glandular epithelium, smooth, and cardiac musculature
Autonomic (Visceral) Component of the N.S.
The involuntary portion of the N.S.
Autonomic
Parasympathetic subdivision of the visceral component of the N.S. is known as
Vegative
Autonomic component of the N.S. involves ____ and ____ structures
CNS and PNS
The nerves (PNS) that carry efferent parasympathetic fibers are limited to:
Cranial nerves: III, VII, IX, X
Sacral nerves 2, 3, 4
places where we find nerves that carry parasympathetic info is known as a
craniosacral subdivision
Two efferent neurons that are utilized to reach the gland cell or muscle cell involved are the
preganglionic (first) and postganglionic (second)
Autonomic preganglionic (___) neuron is _____
first, long
Autonomic postganglionic (____) neuron is _____
second, short
Preganglionic parasympathetic neurons release
acetylcholine
postganglionic parasympathetic neurons release
acetylcholine
Autonomic component of the N.S. is said to be a _____ system
cholinergic
Fight or flight
Sympathetic subdivision of the visceral component of the N.S.
Neurons of the sympathetic subdivision are located in…
both the CNS and PNS
PNS nerves that carry sypathetic efferent fibers are…
spinal nerves T1 through and including L2
Preganglionic sympathetic neurons are
short
Postganglionic sympathetic neurons are
longer
Preganglionic sympathetic neurons release
ACH
Postganglionic sympathetics neurons release
norepinephrine
Sympathetic subdivision of the Visceral component of the N.S. is said to be an
adrenergic system
In the sympathetic subdivision, exceptions, where ACH is released at the target, are known as:
sweat glands and arrector pili muscles
Slows heart rate / speeds peristalsis / constricts the pupil / constricts respiratory tree
parasympathetic
speeds heart rate / decreases peristalsis / dilates the pupil / dilates respiratory tree
sympathetic
Sympathetic ratio of preganglionic to postganglionic neurons
1:17
Parasympathetic ratio of preganglionic to postganglionic neurons
1:2
Neuron cell bodies in CNS trace origin to
neural tube
neuron cell bodies in PNS trace origin to
neural crest cells
The 3 primary brain vesicles
Prosencephalon (forebrain), mesencephalon (midbrain), and Rhombencephalon (hindbrain)
The 5 secondary Vesicles
Telencephalon, Diencephalon, Mesencephalon, Metencephalon, and Myelencephalon
Prosencephalon gives rise to
telencephalon and diencephalon
Mesencephalon gives rise to
Mesencephalon
Rhombencephalon gives rise to
metencephalon and myelencephalon
The 5 secondary vesicles give rise to
mature structures
Telencephalon gives rise to
cerebral cortex, basal ganglia, and lateral ventricles
Diencephalon gives rise to
Thalamus, Hypothalmus, Pineal Gland, and 3rd ventricle
Mesencephalon (Secondary vesicle) gives rise to
corpora quadrigemina, cerebral peduncles, and cerebral aqueduct (of sylvius)
Metencephalon gives rise to
cerebellum, pons, and 4th ventricle
myelencephalon gives rise to
medulla oblongata, 4th ventricle (continuous with spinal cord)
Brain at birth =
10% of body wt. / uses 50 - 60% of O2
Brain in adult =
2 - 2.5% body wt. / uses 20% of O2
Neuroepithelial cells (stem cells) give rise to
Neuroblast, Ependymal Cells, Glioblast
Neuroblasts give rise to
neurons
Glioblasts (or spongioblasts) give rise to
Astrocytes and oliodendrocytes
Glioblast cells can undergo
mitosis
The functional connective tissue of the CNS come from
glioblast and its derivations
Secrete chemicals that attract or repel migrating neurons
functional connective tissue
What cells help guide neurons
glioblast
It is estimated that in total there are 5 - 10 times as many ____ and _____ as neurons in the adult human brain
astrocytes / oliodendrocytes
Most numerous cell of the adult central nervous system
Astrocytes (stellate shape)
A stroke is most likely cause to move ______ around
astrocytes
Astrocytes are mostly not
mitotic
Protoplasmic astrocytes found in
gray matter
fibrous astrocytes found in
white matter
The primary job of astrocytes
structural support cell
Astrocytes are found between blood vessel capillaries and neuron cell bodies. Those in this position are said to be part of the ________ _______ ______
Blood Brain barrier
Astrocytes store
glucose (glycogen)
Astrocytes form (what) following a CNS injury.
“scar-like” tissue (this is where mobility potential may be of use)
Oligodendrocytes are found in the
white matter
Interfascicular oligodendrocytes form _____ ____ around most CNS neuron axons
myelin sheaths
Perineural oligodendrocytes are unclear but may serve a type of _____ ______ in the CNS
nutrient role
What cells line the central canal and ventricles of the CNS
Ependymal Cells
Most ependymal cells are classified as
simple cuboidal
Ependymal cells secrete CSF and form the
choriod plexus in each ventricle
Is there cilia present in Ependymal cells?
Yes, but NO. At first they are ciliated. but by the time we are adults they are lost.
Tanycytes are found in 1 place
3rd ventricle ependymal cells
Tanycytes are responsible for transporting things from the CSF to
hypophsial portal system
Most common brain tumor
astrocytoma
Most lethal primary brain tumor (more frequent in older people)
Glioblastoma
Most restrictive glioma?
ependymoma (derived from ependymal cells and restricts CSF, Blood flow down, and Intracranial pressure aka ICP is high)
This is mesodermally derived. They arise from fetal macrophages and invade from the bloodstream during embryonic and fetal development
Microglia
Microglia phagocytic function
responsible for clearing dead and damaged tissue and may even wall off damaged areas along with the astrocytes
Microglia also ______ ______ responses within the CNS
mediate immune
HIV infects
microglia
Neuroblast cells show little _____ activity but do undergo _____ / ______ and ______
mitotic, growth/maturation and adaption.
______ and _____ _____ during critical embryonic and foetal stages may cause under/over shooting of designated targets
radiation and alcohol exposure
The neuron is the _____, _____, and ______ _____ of the ner-vous system.
genetic, anatomical, and functional unit
Neurons are classified into ______ and _______
anatomical and physiological
Anatomicallyl neurons are based on _____ and generally designated as ____, _____, and _____
appearance, unipolar, bipolar, and multipolar
Physiologically neurons are based on ______ and _____ and generally designated as _____, _____ and _____
function, position, sensory, motor, internuncial
General sensory neurons in ganglia with one process =
unipolar/pseudounipolar
Special sensory organs (neurons with two processes)
Bipolar
Every neuron will have ____ axon process sending information away from the cell body
ONE
______ neurons have more than 2 processes, they are more in our CNS then anything else
Multipolar neurons
Most common type of neuron
multipolar
Neurons that carry information towards CNS
Sensory
Dendrites carry information
towards cell body
Axon carry information
away from cell body
Neurons that carrying information away from the CNS
motor
Neurons that are located entirely within the CNS structures. They are like messengers or connectors between incoming sensory and outgoing motor neurons. Terms associative or interneuron are sometimes used synonymously
Internuncial
An internuncial neuron that connects equivalent structures on opposite sides of the CNS
Commissural
An internuncial neuron that begins in one structure and terminates in a different structure of the CNS
Projection
A projection that stays on the same side
ipsilateral
a projection that crosses to the opposite side
contralateral
an internuncial neuron in the spinal cord that begins and ends at the same cord level
intra segmental
an internuncial neuron in the spinal cord that begins at one cord level and terminates at another cord level
inter segmental
Where ACH is stored
telodrenia
Where ACH would be released
Neuropodia
Where most action potentials happen
axon hillock
Axon of 1 neuron receives informatino from axon
Axoaxonic (least common)
dendritic of 1 neuron receives information from axon
axodendritic (most common)
cell body of 1 neuron receives information from axon
axosomatic
Where are mitochondra most abundant
cell body and telodendria
What are Nissil Bodies
(large neurons) Clumps of rough ER plus free ribosomes and iron deposits
What is another name for nissl bodies
tigroid bodies
When a neuron is injuried, the nissl bodies respond quickly disperse. This is called
chromotolysis
A fragmentation of the golgi apparatus under injurious condition, this process is called…
retispersion
Neurofibrils: largest give cell its shape
microtubules
Diameter of microtubules?
20-30 nm
Neurofibrils: Smallest size and run longitudinally and cercumferentially and are often associated with the axolemma?
Microfilaments
Size of Microfilaments?
3-5 nm diameters
Neurofibrils: These are moderat diameter filaments
Neurofilaments
size of neurofilaments?
9-10 nm
What is axoplasmic (cell) transport?
movement of “raw materials” within the cell
Axoplasmic flow is only
away from the cell body
____ ____ is intracellular (intraneuronal) movement of such items as protein building blocks for the neurofibrils and mitochondria.
Slow transport of (axoplasmic transport)
Slow transport is _______ mm/day. Speed of flow is directly related to axon length but _____ energry is required.
0.1 - 3.0, little
____ ______ is intracellular (intraneuronal) movement of such items as synaptic vesicles (or precursors), lysosomes, and certain enzymes.
fast transport of (axoplasmic transport)
Fast transport is _______ mm/day. May occur in the anterograde or ______. Speed of transport is not related to axon length and is _____ ______.
100-400. retrograde. energy dependent
_____ can die as a result of slow transport because of SUBLUXATION.
Neurons
Made by a surrounding cell. Not the neuron, and is always white
Myelin coverings
Myelin is made by a surrounding cell
interfascicular digodenrocytes
fibers < 1 micron
not myelinated
fibers > 2 microns
are myelinated
fibers > 1m but > 2m
may be myelinated
There is not myelin over _____, ______, or_______
telodendra, perikaryon or hillock
The ______ the myelin the _____ an impulse will be conduced along the neuron fiber
thicker, faster
_____ _____ _____ is one mechanism used by the nervous system to achieve coordination
variable conduction speed
two things that determine conduction velocity
- fiber diameter
2. myelation (has a dramatic effect on C.V. w/out taking up much [conduction velocity] space
Every PNS nerve fiber has a covering (what cell)?
Schwann Cell
There are ______ PNS nerve fibers. They do have a Schwann cell covering but are not ______.
unmyelinated, myelinated
An example of an unmyelinated PNS nerve fiber
post-ganglionic sympathetic neuron
The _____ the neuron fiber diameter the _____ each schwann cell will be
thicker, longer
Where one schwann covering cell meets another is called
Node of Ranvier
Where the schwann covering cell exists, you have an _____
internode
_____ ______ will begin at the Node of Ranvier
Collateral branch
This highly vascular, fibrous and cellular matrix is around each neurilemma
Endoneurium
This coat wraps around groups of fibers (fasciculi).
Perineurium
Perineurium is the most _____ of the mesodermal covers and it is continuous with the ____ and the ____ ____ as it approaches the CNS structures
elastic, pia, arachnoid maters
The ______ is the outer coat of a nerve
epineurium
The epineurium adds _____, _____ and ______ to the fasciculi within.
protection, strength and support
Epineurium may occupy ____% to ____% of the cross sectional area of the nerve. It is continuous with the ____ ___ as it approaches the CNS structures
25 - 85, dura mater
Each schwann cell forms
1 internode
CNS myelin coverings are
interfascicular digodendrocytes
Are Nodes of Ranvier/Internodes present in the CNS?
Yes, but you must substitute the oligodendrocyte in place of the schwann cell
What attacks schwann cells?
Guillain Barré Syndrome
Multiple sclerosis destroy’s ______
oligoderadrocytes
The first chemical transmitter identified
ACH
Most widespread inhibitory neurochemical
GABA
The most abundant neurochemical (generally excitatory)
Glutamate
Covers the entire CNS and the roots of the PNS within the vertebral canal and cranial vault.
Dura Mater
Dura mater is ____ ____ of the nervous system
not part
The outer highly vascular layer of the dura mater
endosteal dura
Endosteal dura is ____ to the cranial bones
fused
Inner more fibrous layer of the dura mater
menigeal dura
The menigeal dura is separate from the endosteal dura only where a ____ or ____ ____ ___ is created
falx, or dural venous sinus
Within the ______ ______ the dura has only one layer
vertebral canal
The one layer in the vertebral canal of dura mater is
inner meningeal dura
An actual _____ space is created along the vertebral canal
epidural
Epidural space is filled with
areolar and adipose connective tissue
Epidural space holds a complex which is?
internal vertebral venous plexus
What structures does the dura mater fuse too?
Foramen magnum, dorsal surface of the lower sacrum and first coccygeal segment
Slips of dura making attachment into the ligaments or periosteum of the axis, lower cervical and occasionally thoracic vertebrae. These are sometimes called what?
meningovertebral legaments
Dural falces are _____ layers of _____ dura extending into a few ____ of the brain
double, meningeal, fissures
Dural falces are _____ shaped, for the most part, therefore called ___ = _____
sickle, falx = sickle
_____ ______ is located in the great longitudinal cerebral fissure between the Rt/Lt cerebral hemispheres
Falx Cerebri
Falx cerebri extends from the ____ _____ of the ethmoid bone to the ______ _______ ______ of the occipital bone
Crista Galli, Internal Occipital Protuberance (IOP)
_____ separates your cerebellum
falx cerebelli
Falx Cerebelli: The fixed portion of the falx lies along the what?
Internal occipital crest
The tentorium cerebelli is built like a ____ over the _____ and under the ____ ____ of the cerebrum.
tent, cerebellum, occipital lobes
The opening left in the middle between LT. and Rt. tentorial wings are called the…
tentorial hiatus
The brain stem comes up through what opening?
tentorial hiatus
Meningeal dura that forms a “roof” over the sella turcica (pituitary fossa) & is perforated in the middle by the infundibular stalk (to the pituitary).
diaphragma sellae
Supratentorial cranial nerves
5 & 7
Infratentorial cranial nerve
10
Cephalgia means
headache
many throbbing headaches are located where?
meningeal arteries
Non-vascular membrane, and inner and outer walls are composed of simple squamous cell lining
arachnoid mater
Simple squamous cells are unusual in that some are capable of becoming _____and _____
motile and phagocytic
tumors on the arachnoid but originate from the arachnoid
meningiomas
Arachnoid mater follows the path of _____
dura
The largest cranial cistern
cerebellomedullary cistern (Cisterna Magna)
The fourth ventricle opens into _____ _______ via the median foramen
cerebellomedullary cistern (cisterna magna)
Cistern of the great cerebral vein is deep within the
transverse (horizontal) cerebral fissure
Anterior aspect of Pons
Pontine Cistern
A pair of opening enter the pontine cistern laterally from the fourth ventricle called the…
lateral foramina (of luschka)
What is the region between the cerebral peduncles on the anterior aspect of the midbrain?
Interpeduncular Cistern
Much of the (what?) is found along the epipia of the interpeduncular cistern?
cerebral arterial circle (of willis) vascularization
This cistern extends around the tapering end of the spinal cord?
Lumbar Cistern
The _____ Cistern is where CSF is removed during a lumbar spinal tap? Needle generally inserted between spinous process of ___ and ____
Lumbar, L4 and L5
Also called pacchionian bodies (when calcified)
Arachnoid nilli
Arachnoid villi is most prominent along the
superior sagittal dural sinus
(This) allows used CSF to be removed from the subarachnoid space and carried out of the cranial vault by way of the dural venous sinuses
Arachnoid Villi
The innermost meninx, it is a vascular transparent membrane and is lumped with the arachnoid as part of the leptomeninx
Pia mater
The pia mater does dip into all _____ and _____ of the brain
fissures and sulci
The denticulate ligaments in the vertebral canal are formed by the _____
pia
The ____ ____ ____ is formed primarily by the outer pial layer of the pia mater.
Filum terminale internum
Melanophores occasionally give rise to _____
Melanomas
the perivascular space is found between the ____ and the ___ ____
pia, blood vessel
Epidural hematoma is located where?
between the skull and the periosteal dura (above the dura)
Epidural hematoma is most commonly due to a rupture of the ____ ____ ____ due to head trauma
middle meningeal artery
Epidural hematoma results in an increase in _____ ____ and ____ ____
intracranial compression and bran compression
Subdural hematoma is most commonly due to a rupture of ____ ____ due to a ____ ____
bridging veins, shear injury
Subarachnoid hemorrhage is ___-_____
non-tramatic (spontaneous)
Subarachnoid hemorrhage is usually associated with a ruptured ______ or ____ ______
aneurysm or A-V malformation
What is usually presented as “worst headache of my life”
subarachnoid hemorrhage
Mature brain weight is about ____ of our body weight
2-2.5%
Mature brain utilizes about _____ of the oxygen and sugar used per unit time at rest
20%
most common form of a stroke is an
aneurysm
80% of stroke or cerebrovascular accidents have already reported signs of
transient ischemic attacks (TIA’s) in the last 24 hours
The middle cerebral arty and its branches are the most common reported sites for ____
strokes
The ____ ____ _____ supply the majority of blood to the brain (2/3rds)
internal carotid arteris
Vertebral artery travels through ____ ____
tranvers foreman (C1-C6)
This small artery sends nearly 200 branches into the ventral aspect of the spinal cord
anteromedial longitudinal artery trunk (AMLAT)
This artery consists of 2 arteries that contribute to the blood supply to the spinal cord
Posterolateral longitudinal artery trunks (PLLAT)
This artery supplies more total blood to the cord then do the three longitudinal vessels
semental artery
Areas of the cord that are vulnerable due to minimal anastomoses between vessles are?
Posterior surface of T1-T3 and anterior surface near T4 and L1
Vessels must eventually reach the white and gray matter of the CNS. They penetrate inward from the pia mater with a slight cuff of pia called the…
pial coat
The space between the blood vessel and the pia is the
perivascular space or verchow robin space
The perivasculare space or verchow robin space contains a mix of _____ and ____ _____
CSF and interstitial fluids
The CNS has a new supply of blood every ____
6 seconds
There is _____ mL of blood present in the brain and ____mL of blood passes thru the brain in one minute
75, 800
The most common capillary type is the
continuous capillary
Continuous capillary lacks
holes
continuous capillary does not have
fenestrae “windows”
Continuous capillariers have the ____ wall construction. Junctions between cells are tight and the basement membranes are ____.
think, thick.
Choroid plexus makes
CSF
_____ are present up to 85% of the capillary surfaces
astrocyte (this is not part of BBB)
Some substances that cross the BBB
lipid-soluable, L-dopa (amino acid)
Some substances that do not cross the BBB
water-soluable (Botox, dopamine)
_____ and ____ of the CNS usually do not follow back the same course the arteries and arterioles follwed inward
venules and veins
Most cerebral veins penetrate the _____ ____ and ____ ____ to drain into the ____ ____ ____.
arachnoid mater and meningeal dura, dural venous sinuses
Vault drainage of dural venous sinus blood is into the rt./ or lt. ____ ____ ___ at the jugular foramina
internal jugular veins
What is the longest dural venous sinus?
superior sagittal dural venous sinus
Most blood in the superior sagittal dural venous sinus flows into the ___________________ after passing through the confluence of the sinuses.
right transverse dural venous sinus
This DVS runs along the posterior two-thirds of the falx cerebri (unattached/free margin)
inferior sagittal dural venous sinus
The inferior sagital DVS and great cerebral vein (of Galen) epties blood into the
straight dural venous sinus
This DVS is at the junction of falx cerebri, tentorium cerebelli and falx cerebelli. It also runs in a posterior inferior direction to the confluence of the sinuses
Straight (rectus) DVS
Straight DVS drainage is usually into the
left transverse DVS
This DVS runs along the attached margin of the falx cerebelli into the confluence of the sinuses.
Occipital dural venous sinus
Occipital DVS flow is usually into the
left transverse dvs
Also known as the torcular herophili
Confluence of the sinuses
This DVS has large sinuses and is bilateral
transverse dvs
This DVS is bilateral and begins when the transverse sinus leaves the tentorium cerebelli
sigmoid dural venous sinuses
This DVS is continuous with the internal jugular vein
sigmoid dural venous sinuses
