Week 1 Reading- Ch. 2 Flashcards
Clinical localization of disease requires knowledge about ____________ and ____________
the affected functional system and its location within the nervous system
Function of the bones of the skull
non-yielding covering for adult brain, protective function against trauma.
Protection of brain by skull bones is offset somewhat by
the inability of the adult brain to expand in response to pressure from certain internal pathologic conditions (hemorrhage, hydrocephalus, tumor), a situation that can produce diffuse neurologic abnormalities due to mass effects and increased intracranial pressure
3 distinct shallow cavities at the base of the skull
anterior, middle, posterior fossae
The fossae help define what 2 major levels of the CNS?
posterior fossa level, supratentorial level (anterior and middle fossae)
The _______ and _______ fossae contain symmetrically oriented _________ through which the paired cranial nerves exit to innervate peripheral structures, including the speech muscles of the head and neck.
posterior and middle; foramina (holes),
The ___________ of the CNS consist of 3 layers: the _____, _______, and _______.
meninges (coverings); dura, arachnoid, and pia mater
Dura mater- define
Outmermost membrane (meningeal layer)
The dura mater consists of 2 layers of fused tissues that separate in certain regions to form the ___________ .
intracranial venous sinuses
Define: intracranial venous sinuses
areas where venous blood drains from the brain
The folds of the dura in the cranial cavity form what 2 layers?
falx cerebri
tentorium cerebelli
Define- falx cerebri
located between the 2 hemispheres
Define: tentorium cerebelli
separates the cerebellum from the cerebral hemispheres
Define: arachnoid mater
lies beneath the dura and is applied loosely to the surface of the brain
Define: pia mater
the thin innermost layer, closely attached to the brain’s surface
The ______ mater and _____ mater are collectively known as the __________.
pia and arachnoid; leptomeninges
Define: epidural space
located between the inner bone of the skull and the dura
Define: subdural space
beneath the dura
Define: subarachnoid space
beneath the arachnoid, surrounds the brain and spinal cord and is filled with cerebrospinal fluid
The subarachnoid space is filled with _________
cerebrospinal fluid
The subarachnoid space is connected to the interior of the brain through the ___________.
ventricular system
Most conditions capable of producing MSD’s that involve the meninges and meningeal spaces stem from what 4 things?
infection, venous vascular disorders, hydrocephalus, trauma with associated hemorrhage and edema
Supratentorial level includes what 6 structures?
hemispheres, lobes, basal ganglia, thalamus, CNI, CN II
Supratentorial level relationship with what parts of skeleton?
Skull- anterior and middle fossa
Supratentorial level- relationship to meninges
above tentorium cerebelli
lateral to falx cerebri
Supratentorial level- relationship to ventricular system
lateral and third ventricles, subarachnoid space
Supratentorial level- relationship to what 6 parts of vascular system
carotid arterial system, ophthalmic arteries, middle cerebral arteries, anterior cerebral arteries, vertebrobasilar system, posterior cerebral arteries
Posterior fossa level- includes what 2 structures?
Brainstem (pons, medulla, midbrain), cerebellum, origins of cranial nerves III- XII
Posterior fossa level- relationship to what skeletal structure?
skull -posterior fossa
Posterior fossa level- relationship to meninges
below falx cerebelli
Posterior fossa level- relationship to ventricular system
fourth ventricle, subarachnoid space
Posterior fossa level- relationship to vascular system
vertebrobasilar system, vertebral arteries, basilar artery
Posterior fossa level- involves what 5 motor speech disorders if dysfunctional?
spastic, unilateral UMN, hyperkinetic, ataxic, flaccid dysarthria
Supratentorial system- involves what 5 motor speech disorders if dysfunctional?
apraxia of speech,
spastic, unilateral UMN, hypokinetic, and hyperkinetic dysarthria
Spinal level- relationship to the skeleton
vertebral column
Spinal level- relationship to the meninges
spinal meninges
Spinal level- relationship to the subarachnoid system
spinal, subarachnoid space
Spinal level- relationship to vascular system
anterior spinal artery, posterior spinal arteries
Spinal level- involves what motor speech disorder?
flaccid dysarthria
Peripheral level- includes?
cranial and spinal nerves
Peripheral level- relationship to skeleton?
face and skull
non-cranial and non-spinal bones
Peripheral level- relationship to meninges
None
Peripheral level- relationship to ventricular system
None
Peripheral level- relationship to vascular system
Branches of major extremity vessels
Peripheral level- involves what motor speech disorder?
Flaccid dysarthria
Explain: supratentorial level
a nearly horizontal membrane that forms the upper border of the posterior fossa, covers the upper surface of the cerebellum, and separates the anterior and middle fossae from the posterior fossa
Define: tectum
the area of the posterior fossa dorsal to the aqueduct of Sylvius
The tectum includes what 2 structures?
the inferior and superior colliculi
The inferior and superior colliculi are known collectively as the __________
corpora quadrigemina
Define: inferior colliculi
midbrain structure that is a major relay station for the auditory system
Define: superior colliculi
midbrain structure that is a major relay station for the visual system
Define: tegmentum
the area ventral to the aqueduct of Sylvius and fourth ventrile; contains white matter and many nuclei, including the reticular formation.
The large cerebral and cerebellar pathways in the most ventral region below the tegmentum form the ________________.
Base region of the midbrain and pons
The cerebellum lies dorsal to the _________, _______, and ___________.
fourth ventricle, pons, and medulla
The cerebellum is comprised of what 3 structures?
A right and left hemisphere, and a midline vermis.
Of the 12 paired cranial nerves, ____ of them (All but ____ and _____) have their origin in and emerge from the _______.
10, I and II, brainstem
Define: final common pathway
the last neural link from the nervous system to the speech muscles
The cranial nerves serving speech are actually part of the ________ nervous system.
peripheral
The adult spinal cord begins at the ___________ and terminates at the level of the ___________.
foramen magnum, first lumbar vertebra
Define: foramen magnum
the large, central opening in the posterior fossa at the lower end of the medulla
The spinal cord is surrounded by the bony __________, which includes _______, ________, and _________.
vertebral column; 7 cervical, 12 thoracic, and 5 lumbar vertebrae
_____ pairs of spinal nerves are attached to it via ______ and _______ nerve roots.
31; dorsal (posterior) and ventral (anterior)
The dorsal roots are _______ in function; the ventral roots are _______.
sensory, motor
Define: major longitudinal systems
groups of structures that have specific functions
Why are the systems called longitudinal?
for the most part, the activities of the system are evident over the length of the nervous system (i.e. from the supratentorial to the peripheral level)
6 major functional longitudinal systems
Internal regulation system (visceral system), cerebrospinal fluid system (ventricular system), vascular system, consciousness system, sensory system, motor system
Define: internal regulation (visceral) system
contains afferent and efferent components to maintain a balanced internal environment (homeostasis) through the regulation of visceral glands and organs.
Define: CSF system
Primary function- to cushion the CNS against physical trauma and to help maintain a stable environment for neural activity
CSF is produced by ________ located in the ______/
choroid plexuses, each ventricle
Each cerebral hemisphere contains a _________ that is connected by the way of the ________ to the midline-located ________.
lateral ventricle, foramen of Monro, third ventricle
The third ventricle narrows into the _._________, which leads to the ___________ between the brainstem and cerebellum
aqueduct of Sylvius, fourth ventricle
The __________ and the _________ in the fourth ventricle link the ventricular system to the subarachnoid space.
foramen of Luschka, foramen of Magendie
__________ and ______________ comprise the CSF system.
ventricular system and subarachnoid space
CSF circulates throughout the _________ and _________ and is absorbed in the ___________ in the brain or in the __________ in the spinal cord’s subarachnoid space.
ventricles and subarachnoid space, arachnoid villi, leptomeninges.
CSF can be found in what 3 major anatomic levels of the nervous system?
supratentorial, posterior fossa, spinal levels
All blood vessels that supply the brainstem and cerebral hemispheres arise from the _________ in the chest.
aortic arch
Blood enters the brain by way of the __________ and the ___________
carotid system, vertebrobasilar system
The carotid and vertebrobasilar systems are capable of some communication with each other through connecting channels to the brainstem known as the ______________.
circle of Willis
Each internal carotid artery separates at the ______________ into what 2 of the 3 major paired cerebral arteries?
circle of willis; anterior cerebral arteries, middle cerebral arteries.
The anterior cerebral arteries are connected to eachother by the ______________.
anterior communicating artery
The vertebrobasilar system begins with the paired _______________, which enter the brainstem through the foramen magnum and join at the lower border of the pons to form the ____________.
vertebral arteries, basilar artery
Consciousness system structures are found only at the ___________ and ____________ levels.
supratentorial and posterior fossa
Consciousness system includes:
reticular formation and its ascending projection pathways, portions of the thalamus, pathways to the widespread areas of the cerebral cortex, and portions of all lobes of the cerebral cortex
Consciousness system is crucial to what 4 things?
maintaining wakefulness, consciousness, awareness of the environment, and (on a higher level) selective and sustained attention
Malfunctions within the consciousness system can cause
cognitive deficits (including language and commuication) and the adequacy of motor actions (including speech)
The sensory system includes:
peripheral receptor organs, afferent fibers in cranial spinal and peripheral nerves, dorsal root ganglia (spinal level), ascending pathways in the spinal cord and brainstem, portions of the thalamus, and thalamocortical connections (primarily to sensory cortex in the temporal, parietal, and occipital lobes).
Motor system directly responsible for:
all motor activity involving striated muscle
Motor system primary function
Essential to normal reflexes, to maintaining normal muscle tone and posture, and to the planning, control, and execution of voluntary movement, including speech
The nervous system is composed of _______, or _________, and considerably more numerous ________, or _________.
neurons, or nerve cells; supporting cells, or glial cells
Define: neuron
the most important cellular element of the nervous system because its electrochemical activities drive the receipt, transmission, and processing of information.
Many diseases affecting neurons result in their _______, _________, or ________, whereas others prevent normal _________ or _________ of neurons
malfunction, degeneration, or loss; normal structural or functional development of neurons
Neurons in different parts of the nervous system vary in _______ and _______, but they all contain a _______, __________, and _________.
size and shape; cell body, dendrites, axon
Define: cell body
central processing unit responsible for neuronal metabolic functions.
Define: dendrite
responsible for gathering information transmitted from surrounding neurons.
Axon diameter generally varies with its ________
length.
Define: axon
conducts signals away from the cell body to other neurons or to muscles or glands
Most communication among neurons, or between muscles and neurons, takes place at regions known as _________. In neuron to neuron communication, the ________ usually communicates with the __________ or __________ of another neuron.
synapses; axon, cell body or dendrites
In most instances the axon and dendrite (or muscle fibers) are separated by a ______________.
synaptic cleft
At the tip of the axon are tiny ___________ containing a chemical neurotransmitter that carries the axon’s signal to ________________ that mediate excitatory, inhibitory, or modulatory effects on the receiving cell.
synaptic vesicles; neurotransmitter receptors
The message carried by a single axon to another neuron is ultimately simple: it either ____ or ______ the neuron receiving it from firing a message of its own.
facilitates or inhibits
The “decision” of a neuron to fire or not reflects ________________.
a summation of the messages it receives from multiple sources.
Define: glutamate
primary excitatory neurotransmitter for all CNS neurons
Define: GABA (gamma-aminobutyric acid)
primary inhibitory neurotransmitter in the mature CNS and plays a role in the regulation of muscle tone; important in motor control activities of the basal ganglia and cerebellum
Define: dopamine
crucial neurotransmitter that originates in the substantia nigra and ventral tegmental area in the midbrain and projects to many areas of the brain.
Role in movement, motivation and reward, cognition and learning, attention, mood, and sleep. Its modulatory actions in the basal ganglia aid the initiation and control of skilled motor acts (including speech)
Define: acetylcholine; only neurotransmitter involved in what?
only neurotransmitter involved in the PNS control of skeletal muscle functions. excitatory effects, leads to movement by contraction of muscle fibers, modulatory effects in areas relevant to speech motor control and learning
Actions of neurotransmitters at any given point in time must _____. Mechanisms that accomplish this depend on the type of neurotransmitter and include _______________(3 things).
end/turn off; uptake by astrocytes or presynaptic terminals, enzyme metabolism, or diffusion out of the synaptic cleft.
Examples of neurochemical abnormalities leading to motor speech issues
- dopamine implicated in hypokinetic dysarthria associated with Parkinson’s disease
- acetylcholine is implicated in the flaccid dysarthrias associated with myasthenia gravis
- GABA is implicated in the spastic dysarthria associated with the spastic cerebral palsy
Use of __________ to influence neurochemical systems is crucial to the management of many diseases associated with MSD’s
pharmacological agents
5 types of supporting (glial) cells
oligodendroglia and schwann cells, astrocytes, ependymal cells, microglia, connective tissue
Define: blood-brain barrier
mechanism that prevents the passage of many metabolytes from the blood into the brain, thereby protecting it from toxic compounds and variations in blood composition
Define: astrocytes
assist neuronal migration during development; help regulate neuronal metabolism, the chemical microenvironment, and synaptic transmission; contribute to mechanisms of repair in response to injury
Define: oligodendroglia
source of myelin in the CNS
Define: schwann cells
source of myelin in the PNS
Define: myelin
insulation that surrounds axons
Define: nodes of Ranvier
small gaps between each myelinated segment of peripheral nerve fibers
Define: saltatory conduction
electrical signals traveling down axons skip from node to node with a resulting increased speed of transmission
Define: ependymal cells. Also form the?
line ventricular system and form a barrier between ventricular fluid and the neuronal substance (parenchyma) of the brain. also form the choroid plexuses that produce ventricular and cerebrospinal fluid
Define: microglia
respond to destructive CNS processes by proliferating and transforming into macrophages
Define and function: macrophages
scavenger cells, ingest pathogens and remove damaged tissue
Define: connective tissue
make up the meninges . In PNS, form thin layers on myelinated nerve fibers, help bind fibers together within nerves, cover areas at the trunks of nerves. Analogous to meninges that surround CNS.
Define: nerve
collection of axons (nerve fibers) bound together by connective tissues; groups of fibers that travel together in the PNS
Peripheral nerves travel between ______ and ________.
CNS (where cell bodies reside) and peripheral end organs
Define: peripheral end organs
sensory, motor, and visceral structures that nerves innervate
Major distinction between PNS nerves and CNS tracts
CNS tracts transmit impulses to other neurons, while PNS nerves transmit impulses from nerves to end organs (such as muscle)
Fiber tracts in the CNS are organized according to the _____________.
areas they connect
Define: association tracts
connect cortical areas within a hemisphere to one another
Define: projection tracts
contain afferent and efferent fibers that connect higher and lower centers in the CNS
Projection tract names, such as extrinsic muscles, usually reflect ______.
the names of the areas they connect
Define: ischemia. Reversible?
deprivation of oxygen and cessation of oxidative metabolism, as occurs in stroke. Not reversible
Within as little as ________ of ischemia, _____, followed by _________ and _________ may occur
2-5 minutes; acute swelling of neurons followed by shrinkage and eventual cell loss
Define: central chromatolysis/axonal reaction. Reversible?
when axons are severely injured, cell bodies may swell and lose some of their internal components; process is reversible
Define: wallerian degeneration
degeneration of the axon distal to the point of separation
Functionally significant regeneration of axons (does, doesn’t) occur in the CNS
doesn’t
Define: neurofibrillary degeneration
characterized by the formation of clumps of neurofibrils in the cytoplasm of CNS neurons. Most common form of dementia associated with clinical dementia (particularly Alzheimer’s disease)
Define: Senile plaques
related pathologic changes where deposits of a fibrous protein (amyloid) in cell bodies and degenerated nerve processes characterize them
Define: inclusion bodies
abnormal, discrete deposits in nerve cells. their presence may identify specific diseases (Parkinson’s, Pick’s, certain viral infections)
Define: storage cells
abnormal accumulations of metabolic products in nerve cells
Define: atrophy
when lower motor neuron innervation of muscle cells is destroyed, the muscle will waste away
Define: diaschisis
process in which neurons function abnormally because influences necessary to their normal function have been removed by damage to neurons to which they are connected
Define: positron emission tomography (PET)
has demonstrated that neuronal cell death in one region of the brain can lead to changes in metabolic functions of adjacent and even distant regions to which the damaged area has important anatomic connections
Define: demyelinating disease
myelin is attacked by some exogenous agent, broken down, and absorbed
The most common demyelinating disease is ____, but demyelinization also occurs in other CNS And PNS diseases, such as _________.
multiple sclerosis (MS), Guillain-Barre syndrome
The terms _____, ______, and ______ refer to the nonspecific process of astrocytes reacting to many CNS injuries by forming scars in injured neural tissue.
gliosis, astrocytosis, astrogliosis
Neurologic signs and symptoms generally reflect the ________, not and not necessarily its specific ______.
location of a lesion, cause.
Disease can often be localized on the basis of _____ and _______.
history and clinical examination
LDE Chart- degenerative disease
Diffuse-focal,
chronic,
progressive
LDE Chart- inflammatory disease
Diffuse-focal
subacute
progressive- exacerbate or remit
LDE Chart- toxic or metabolic disease
Diffuse,
acute subacute chronic
progressive- stationary
LDE Chart- neoplastic disease
Focal
Chronic Subacute
Progressive
LDE Chart- traumatic disease
Diffuse, multifocal, focal
Acute
Improving, stationary
LDE Chart- vascular disease
Focal, multifocal, diffuse
Acute
Improving, stationary, transient, progressive
3 types of localization
Focal, multifocal, diffuse
Define- focal
involving a single circumscribed area or contiguous group of structures (e.g.left frontal lobe)
Define- multifocal
involving more than one area or more than one group of contiguous structures (e.g. cerebellar and cerebral hemisphere plaques associated with MS
Define- diffuse
involving roughly symmetric portions of the nervous system bilaterally (e.g. generalized cerebral atrophy associated with dementia)
3 types of development; time span of course for each
acute (within minutes), subacute (within days), chronic (within months)
5 types of evolution
Transient, Improving, Progressive, Exacerbating-remitting, Stationary
Define: Development
establishing the course or temporal profile of the disease
Define: Evolution
course of the disease after symptoms have developed
Define: transient
when symptoms resolve completely after onset
Define: improving
when severity is reduced but symptoms are not resolved
Define: progressive
when symptoms continue to progress or new symptoms appear
Define: exacerbating-remitting
when symptoms develop, then resolve or improve, then recur and worsen, and so on
Define: stationary (or chronic)
when symptoms remain unchanged for an extended period of time
MSD’s can appear at any point during the __________ and _________ of neurologic disease.
development and evolution
6 broad etiologic categories of MSD’s
degenerative, inflammatory, toxic-metabolic, neoplastic, trauma, vascular
Degenerative diseases are characterized by what?
a gradual decline in neuronal function of unknown cause
Neurons may either _______ or _______.
atrophy and disappear, endure more specific changes (e.g. neurofibrillary tangles)
Define: degenerative diseases
genetically determined biochemical disorders that share basic mechanisms that lead to neuronal death.
Clinical differences in degenerative diseases reflect the _________ and ________.
localization of the affected neurons, order and pace at which degeneration proceeds
Degenerative disease are most often _____, _____, and _____, but they sometimes begin with ______.
chronic, progressive, and diffuse; focal manifestations
Inflammatory diseases: include? Characterized by? Pathologic Hallmark?
Include (not limited to) infectious processes
Characterized by: inflammatory response to microorganisms, toxic chemicals, or immunologic reactions.
Pathologic hallmark: outpouring of white blood cells
Development of clinical signs and symptoms in degenerative diseases is usually ________.
subacute
