Central Nervous System Flashcards
What are the 2 divisions of the nervous system?
Central nervous system (CNS) and peripheral nervous system (PNS)
what does the CNS contain (2)
brain and spinal cord
what does the PNS contain (2)
nerves and ganglia
A. Functions of the brain range from life-sustaining activities to the most ________ neural functions.
complex
- The brain maintains internal environment through control of the ________ NS and the _______ system.
automatic NS and endocrine system
- The brain is involved in peripheral innervation through ______ ________
cranial nerves
The ________ performs tasks associated with intelligence, memory, emotion, behavior, and socialization.
brain
what is the brain the center for?
registering sensations, correlating w/ one another and w/ stored info, making decisions, and taking action
what are the four major parts the brain?
cerebrum
diencephalon
brain stem
cerebellum
which part of the brain contains cerebral hemispheres with various lobes of the brain?
cerebrum
which part of the brain contains the thalamus and the hypothalamus?
diencephalon
Which part of the brain is involved in balance?
cerebellum
which part of the brain contains the midbrain, pons, and medulla oblongata
brain stem
the brain, like the spinal cord, is composed of _______ and _________ matter
gray and white
what is the important distinction between the gray and white matter in the brain vs the spinal cord
- brain: gray on the outside, white on the inside
- spinal cord: gray butterfly in the middle, white on the outside
which matter is made up of myelinated nerve fibers (axons)
white matter
which matter is made of cell bodies of neurons
gray matter
What is the protective covering of the brain besides the cranial bones
the cranial meninges
How many connective tissue membranes are there?
3
What is the role of the meninges?
- cover and protect the CNS
- protect blood vessels
- enclose venous sinuses
- contain CSF
- partition the brain
- The cranial meninges, which lie between the nervous tissue and bone, are continuous with the spinal meninges and are named _______ ______, ________, and ______ _____
dura mater
arachnoid
pia mater
What two qualities best describe the dura which cover the brain and spinal cord
external and toughest
In some places of dura are separated by what?
dural sinuses
what are the two sinuses?
superior sagittal sinus and transverse sinus
meningeal and periosteal layers of dura mater separate to form this area - which sinus?
The superior sagittal sinus
paired venous sinuses - which sinuses?
The transverse sinus
C) These sinuses meet like an inverted T at the back of the brain and ultimately empty into the internal _____ _____
jugular veins
what are the 3 extensions of the dura meter that separate parts of the brain (cerebri)
- falx cerebri
- tentorium cerebelli
- falx cerebelli
which extension separates the hemispheres
falx cerebri
which extension seperates the cerebrum from the cerebellum
tentorium cerebelli
which extension separates the cerebellum (itself)
falx cerebelli
The arachnoid mater and pia mater are similar to those of the _______ ______
spinal cord
which mater is a weblike middle layer of the 3 meninges
arachnoid mater
what is the fluid-filled area between the arachnoid mater and the pia mater
subarachnoid space
which later is the most internal and most delicate of the 3 membranes (meninges) covering the brain and spinal cord
pia mater
The brain has 4 internal chambers called the
ventricles
what are these ventricles filled with?
cerebrospinal fluid
The ventricles are continuous with each other and the ______ _____ of the spinal cord
central canal
The ventricles are lined with ________ cells and are filled with cerebrospinal fluid (CSF)
ependymal
What are the 4 ventricles names?
lateral ventricles (2), third ventricle, and fourth ventricle
what is the thin median membrane that separates the 2 lateral ventricles
septum pellucidum
what connects the the left and right lateral ventricles to the 3rd ventricle
interventricular foramen
what is the narrow cavity of the midbrain that connects the 3rd and 4th ventricles
cerebral aqueduct
in the 4th ventricle, what allows the CSF to drain into the subarachnoid space?
lateral apertures
Is the subarachnoid space (4th ventricle) filled with CSF?
yes
What is the latin name for the central canal of the spinal cord
central cana
each ventricle has a mass of blood capillaries on the floor or wall called a ______ ______-
choroid plexus
what is the thin membrane that lines the brain ventricles
ependyma
what is special about the choroid plexuses?
A rich membrane (rooftop) that FORMS THE CSF
what is the function of the blood-cerebrospinal fluid barrier
protects the brain from harmful substances
What is the clear, colorless liquid that protects the brain and sc against chemical and physical injuries, carries O, glucose, and other chems from the blood to the neurons/neuroglia
cerebrospinal fluid (CSF)
what are the 3 ways that CSF contributes to hemostasis?
- buoyancy: protect the brain, keep the sc suspended
- protection: shock absorption
- chemical stability: maintain homeostasis
What does the CSF circulate through?
brains surface, over the surface, and down the sc
what cues does CSF have to circulate thru the CNS
Its own pressure
- beating of the cilia of the ependymal cells
- rhythmic pulsations of the brain produced by the heartbeat
what 2 areas is most of the fluid absorbed into
arachnoid villi, superior sagittal sinus
where does this fluid go (which vein)
jugular veins
what is the volume of the cerebrospinal fluid?
volume is about 120 mL (about 1/2 cup); produced at a rate of 20 mL/hr = same as reabsorption rate
blood flows to the brain mainly via _______ _______
blood vessels
where doe these blood vessels brain from
cerebral arterial circle (circle of willis) at the base of the brain
These structures do what… internal carotid arteries and basilar artery
deliver blood to brain
These structures do what… dural sinuses and then into jugular veins
blood drainage
The brain is only 2% of the adult weight, but it receives ____% of the blood
15%
of this supply how much oxygen and glucose does the brain consume at rest?
20% oxygen, 50% glucose
- The brain is one of the most metabolically active organs of the body, and the amount of oxygen it uses varies with the degree of ________ activity
mental
Neurons depend on which energy production system?
aerobic glycolysis (need oxygen)
. Because carbohydrate storage in the brain is limited (No glycogen stores (some in glia)), the supply of glucose to the brain must be __________
continuous
Glucose ________ may produce mental confusion, dizziness, convulsions, and unconsciousness.
deficiency
Are fats typically used in the brains energy?
NO, under extreme circumstances, ketones are used
What can happen if there is any interruption of the oxygen supply to the brain?
weakening and even permanent damage = death of brain cells
Interruption of the mother’s ________ supply to a child during childbirth before it can breathe may result in paralysis, mental retardation, epilepsy, or death.
blood
How many seconds does an interruption of blood flow causes a loss of consciousness?
10 seconds
1-2 minutes = impairment of function, what minute causes irreversible brain damage?
4 minutes
What can cross the blood-brain barrier (BBB)
small, lipid-soluble molecules = oxygen, CO2, glucose (polar), certain hormones
________ head injuries can lead to brain injuries of varying severity: concussion, contusion, and subdural or subarachnoid hemorrhage – brain bleeds.
traumatic
what are the 2 types of brain bleeds
subdural and subarachnoid hemorrhage
what are strokes caused by
decreased blood supply
brain bleeds that occur in the epidural space effect what?
arteries
brain bleeds that occur in the subdural space effect what?
veins
which one is a medical emergency?
epidural space (arteries)
what two things could lead to a stroke that effects the cerebral blood vessel
occlusion (blockage) and hemorrhage (brain bleed)
what do brain bleeds increase?
intracranial pressure (ICP)
which one epidural space or subdural space is rapid bleeding
epidural space
what negative effect can increases ICP have
pushes brain outside of position
the displacement of the hemisphere under falx cerebri to ______ side of brain
opposite
increased causes downward or upward displacement of the hemisphere, diencephalon, and midbrain
downward displacement
The temporal lobe under the dura, the cerebral peduncle is _______
pinched
the brain tissue is ________ against the bone
compressed
The cerebrum is the center of what
intelligence and personality (THINKING)
what percentage of all neurons in the NS are housed in the cerebrum
75%
The cerebrum is about 83% of the brain’s volume and consists of two cerebral hemispheres which have an outer, superficial layer called the _____ and a deeper layer called the ______
cortex, medulla
. The cerebral hemispheres form the superior or inferior part of the brain.
superior
what is the difference between gyri and sulci
- gyri = ridges
- sucli = shallow grooves
The deep longitudinal fissure separates which two things?
left and right cerebral hemispheres
At the bottom of this fissure the hemispheres are connected by the _______ _______
corpus callosum
which gender has a larger corpus callosum?
females
what does the transverse cerebral fissure seperate
the thalamus from the parahippocampal gyrus and the fornix of the corpus callosum
e. The five lobes of the cerebral hemispheres separated by specific sulci are:
frontal, parietal, temporal, occupital, and insula
Each cerebral hemisphere has three regions:
-the superficial cortex of gray matter
- internal white matter (medulla),
- areas of gray matter deep within the white matter, the basal nuclei.
The _______ _________ is the location of the conscious mind
cerebral cortex
in addition to being 40% of the brain mass, what does the cerebral cortex allow us to do?
communicate, remember, and understand
The differences in the cerebral hemispheres function is called what
cerebral lateralization
Each hemisphere has contralateral control over sensory and motor functions, meaning that each hemisphere controls the ________ side of the body.
opposite
The left hemisphere is more important for:
language abilities, math, and logic
The right hemisphere is more important for:
visual-spatial skills, reading facial expressions, intuition, emotion, and artistic and musical skills
- Specialization of hemispheres is more pronounced in males or females
males
What are the main functions of the cerebrum
- interpreting impulses
- vol mvmt
- storing info as memory
- retrieving stored info
- reasoning
- intelligence and personality
T or F: 1. The cerebral cortex, is 2-4 mm thick and is composed of gray matter and is the outermost portion of cerebrum.
true
The cerebral cortex is the location of the “conscious mind” and is composed primarily of what 2 things
- cell bodies
- dendrites
Does the cortex contain a lot of neurons?
YES BILLIONS
What are the 3 functional areas of the cerebral cortex
motor area, sensory areas, and association areas
- The cortex contains gyri (convolutions), deep grooves called _______, and shallower sulci.
fissures
Certain prominent ______ divide each hemisphere into five distinct lobes: temporal, parietal, occipital and frontal. Deep to these lobes lies the insula.
sulci
Which lobe is involved in voluntary motor functions and higher mental functions
frontal
What gyrus of the frontal lobe controls voluntary movement on the opposite side of the body
precentral gyrus
Which sulcus separates the frontal and parietal lobe
central sulcus
what area in the frontal lobe is a region of the brain that controls voluntary movement (hint: a primary)
primary motor cortex
what gyrus (frontal lobe) processes general somatic sensations such as touch, pressure, temperature, and pain
postcentral gyrus
What area controls motor movements necessary for speaking (speak production)
Broca area
memory, planning, and decision-making in the prefrontal cortex is also known as the
anterior association area
What lobe forms the uppermost part of the brain and extends caudally to the parieto-occipital sulcus. It is involved in general sense, taste, equilibrium, and some visual processing.
Parietal
what region of the brain that processes sensory information from the body, including touch, pain, temperature, and pressure (hint: a primary) in the parietal lobe
Primary somatosensory cortex
What is the name for representation of the body’s sensory or motor distribution along the brain’s cerebral cortex.
homunculus
what are the signals called for the conscious awareness of taste stimuli
gustatory (taste) signals
Which lobe: interprets hearing & smell and language. The temporal lobe is a lateral, horizontal lobe deep to the temporal bone and separated from the parietal and frontal lobes by a deep lateral sulcus. Auditory signals are received by in the superior region of the temporal lobe and in the nearby insula.
temporal
Temporal lobe, what is the conscious awareness of sound (hint it is a primary)
primary auditory cortex
What area tells you what the sound is you are hearing (ie horn)
the auditory association area
which area is conscious awareness of smells
primary olfactory cortex
What area deals with speech comprehension (understanding language)
Wernicke area
Which lobe: Interprets vision. At the rear of the head, caudal to the parieto-occipital sulcus and underlying the occipital bone. Visual signals are received by the primary visual cortex in the posterior region.
Occpital
What is the 5th part of the cerebrum (DEEP) that has a role in language, sense of taste, and integrating visceral sensory information
insula
Beneath the cortex lies the cerebral ______ ______
white matter
The cerebral white matter makes up most of the volume of the cerebrum and is composed of glia and myelinated nerve fibers organized into _______ kinds of tracts
3
Cerebral white matter is responsible for ________ between cerebral areas and the cerebral cortex and lower CNS centers.
communication
What are the 3 fibers of the cerebral medulla?
association fibers, commissural fibers, and projection fibers
which fibers connect different parts of the same hemisphere
association fibers
which fibers interconnect corresponding gray areas of the right and left cerebral hemispheres, allowing them to function together
commissural fibers
which fibers have sensory information that reaches the cerebral cortex, connection to brain stem and spinal cord
projection fibers
what are areas of gray matter located deep within the white matter of the cerebral hemispheres; regulate certain aspects of movement
basal nuclei
What would be an example of how the basal nuclei help program habitual or automatic sequences and set appropriate amts of muscle tone
activities like walking, typing, tying shoes = basal nuclei
Nearly all areas of cerebral cortex, except for primary ______ and _________ cortices, send signals to the basal nuclei.
visual and auditory
Basal nuclei (ganglia) also selectively _______ other motor neuron circuits that are intrinsically active or excitatory
inhibit
Impairment of the basal nuclei results in uncontrollable, abnormal body movements, often accompanied by muscle rigidity and tremors -> what diseases are effected by this
Dyskinesia “bad movements” Parkinson disease, Huntington disease, and tourette syndrome
what is the main difference between parkinsons and Huntington
loss of input from the substanta nigra -> slow, jerky mvmts (P)
overstimulation and jerky movements (H)
___________ brain systems are networks of neurons that work together and span large distances in the brain.
functional
what are the two functional brain systems
reticular formation and limbic system
medial portions of the cerebral cortex, the fornix, and parts of the diencephalon -> these make up the
limbic system
a white matter bundle in the brain that plays a key role in memory and cognition
fornix
- The limbic system is known as the “_________ brain”
emotional
So the limbic system
functions in emotional aspects of behavior and memory, and is associated with pleasure and pain and contains structures for both gratification and aversion. Controls emotions, produces feelings, and interprets sensory impulses.
what does the limbic system associate smells with
emotions and memories
The __________ lies medial to the cerebral hemispheres and superior to the brainstem.
diencephalon
What are the 3 components of the diencephalon
- thalamus
- hypothalamus
- epithalamus
a peanut-sized structure in the thalamus that relays visual information from the retina to the visual cortex
lateral geniculate nucleus
a part of the thalamus that plays a key role in motor control and the coordination of movement
ventral lateral nuclei
rounded little bumps that bulge (hypothalamus)
mammillary bodies
a cross shaped structure anterior to the diencephalon of the brain, representing the point of crossover of half the axons of the optic nerve (hypothalamus)
optic chiasm
in the hypothalamus, what structure is in charge of the secretion of hormones
pituitary glands
a group of brain cells in the hypothalamus that regulates the body’s circadian rhythms
- Suprachiasmatic Nucleus:
a funnel shaped cavity in the hypothalamus
infundibulum
what is the difference between the paraventricular vs the arcuate nucleus in the hypothalamus
- paraventricular nucleus: regulates CV and osmotic homeostasis
- arcuate nucleus: regulates E balance, food intake, and reproduction
- The hypothalamus is the ______ CONTROL CENTER of the body
visceral
what two systems does the hypothalamus link
nervous and endocrine -> neuroendocrine
What structure is in the epithalamus that is a hormone that controls sleep and wakefulness, cone shaped area
pineal gland
what is the sleep hormone associated with the pineal gland
melatonin
The _______ ________ is the most caudal of the four major brain regions. Its primary functions are to produce programmed automatic behaviors, provide a passageway for fiber tracts running between the cerebrum and spinal cord, and innervation for CNs
brain stem
The major parts of the brain stem are the _______ _______, ________ and __________ and produces rigidly programmed automatic behaviors necessary for survival.
medulla oblongata, pons, and midbrain
The ______ _______ is the inferior part of the brain stem
medulla oblongata
the point at which the right and left corticospinal tracts cross over in the medulla oblongata
decussation of pyramids
what centers in the MO control HR, blood pressure, and breathing
cardiac center, vasomotor center, and respiratory center
The ______ is about 2.5 cm long and appears as a broad anterior bulge rostral/superior to the medulla. It connects the spinal cord with the brain and links parts of the brain with one another by way of tracts.
pons
- The pons also contains the ______ and _______ areas, which help control and regulate rate and depth of breathing along with the respiratory center in the medulla.
pneumotaxic and apneustic areas
a pair of structures that connect the cerebellum to the pons
middle cerebellar peduncles
It contains nuclei for which cranial nerves (Pons)
CN V
The __________ is the most rostral of the three parts of the brain stem. The midbrain conveys motor impulses from the cerebrum to the cerebellum and spinal cord, sends sensory impulses from the spinal cord to the thalamus, and regulates auditory and visual reflexes (corpora quadrigemina).
midbrain
midbrain: what is the difference between the superior colliculi and the inferior colliculi
- superior colliculi = process visual info
- inferior colliculi = process auditory info
Anterior to the cerebral aqueduct, the midbrain consists mainly of the two cerebral _________ that anchor the cerebrum to the brain stem. (CN III and IV)
peduncles
The _________ ___________ is a complex network of nerve fibers scattered throughout the brain stem that consists of small areas of gray matter interspersed among fibers of white matter and has both sensory and motor functions.
reticular formation
what network of neurons in the brainstem that regulates sleep-wake cycles, arousal, and attention (reticular formation)
reticular activating system, or RAS
what modulation is reticular formation best known for
pain modulation
The cerebellum contains how many hemipsheres
2; right and left
What is the largest part of the hindbrain?
cerebellum
what are the cerebellar hemispheres connected by
wormlike bridge called the vermis
three pairs of white matter bundles that connect the cerebellum to the brain stem
cerebellar peduncles
The cerebellum is 10% of the brain’s mass but has _____% of the surface area of the cerebral cortex and contains more than half of all brain neurons.
60%
What are the 4 aspects of cerebellar functioning (like how would you know that someones cerebellum is impaired)
- monitoring intent for movement
- monitoring actual movement
- comparing intent with actual performance
- sending out corrective signals
The cerebellum receives information from the _________ on planned movements, compares planned movements with current body position, and sends instructions to the cerebral cortex.
cerebrum
The ___________ is involved in learning new motor skills and motor memory, and it also plays some role in language, problem solving, and task planning.
cerebellum
All fibers to and from the cerebellum are ipsilateral or contralateral
ipsilateral
The cerebellum integrates _________ input from the eyes, ears, joints, & muscles about the present position of body parts.
sensory
The cerebellum functions in the coordination of skeletal muscle contractions and in the maintenance of normal muscle tone, posture, and _________
balance
The cerebellum does what to voluntary mvmts
makes them smooth and coordinated
what are some examples of the cerebellum learning new motor skills
playing the piano or hitting a baseball
A) The spinal cord and spinal nerves mediate reactions to environmental ________
changes
B) The spinal cord has several functions and can function __________ from the brain.
independently
what are the 3 functions of the spinal cord
- rely sensory info from the body to the brain
- send motor commands from brain to body
- coordinate reflexes
The spinal cord is a cylinder of nervous tissue that arises from the brainstem at the foramen _________, and then passes through the vertebral canal as far as the inferior margin of the first lumbar vertebra or slightly beyond.
magnum
B. The spinal cord is protected by two connective tissue coverings, the ________ and __________, and a cushion of cerebrospinal fluid.
meninges and vertebra
The protective _________ are three coverings that run continuously around the spinal cord and brain.
meninges
_________ is the inflammation of the meninges – can be caused by a virus or bacteria
meningitis
Are the layers of the meninges the same as the meninges lining the brain? if so what are they
dura mater, arachnoid (subarachnoid space), and pia mater
Where is a lumbar puncture taken from and what is the purpose (arachnoid)
in between vertebrae, taking a sample of CSF
In the pia mater (most internal and delicate), what tethers the spinal cord to the dorsum of the coccyx
terminal filum
what ligaments extends laterally from between the dorsal and ventral spinal nerve roots, pierces through the arachnoid membrane, and securely attaches to the thick spinal dura mater
denticulate ligaments
the tapered, cone-shaped end of the spinal cord that terminates near the first two lumbar vertebrae
conus medullaris
external sc: a swelling in the neck or an expansion in the spinal cord
cervical enlargement
external sc: a section of the spinal cord that’s wider than normal and contains more nerve fibers and cell
lumbar englargement
external sc: a bundle of nerves at the end of the spinal cord that provides movement and sensation to the lower body
cauda equina
external sc: a fibrous band that extends from the conus medullaris to the periosteum of the coccyx
filum terminale
inside the spinal cord, what does the shape of the gray matter make?
butterfly
what is gray matter made up of and whats its purpose
neuron cell bodies and dendrites -> processing info + motor responses
what are the 3 regions that make up the gray matter
2 dorsal (posterior) horn, 2 ventral (anterior) horn, and lateral horn
This region receives sensory information entering the spinal cord via the dorsal roots and is primarily responsible for processing sensory data like pain, temperature, and touch
dorsal (posterior) horn
This region contains the cell bodies of motor neurons that send axons out via the ventral roots to control muscle movement
ventral (anterior) horn
Primarily found in the thoracic region, this area houses neurons involved in the autonomic nervous system, regulating visceral functions
lateral horn
a thin band of gray matter within the spinal cord that surrounds the central canal and connects the left and right sides of the gray matter
gray commissure
a cerebrospinal fluid (CSF)-filled space that runs through the center of the spinal cord and connects to the brain’s ventricle
central canal
a collection of nerve fibers that cross the midline of the spinal cord and brain, enabling communication between the two sides of the body
anterior white commissure
a deep groove in the spinal cord that divides the white matter in half and contains a fold of pia mater
anterior median fissue
a shallow groove in the midline of the spinal cord, medulla oblongata, and pons that separates the two posterior funiculi
posterior median sulcus
Are the names the same for white matter?
yes: dorsal, ventral, and lateral
The ______ matter consists of bundles of myelinated axons of motor and sensory neurons.
white
The white matter is divided into columns. Each column contains distinct bundles of nerve axons that have a common origin or destination and carry similar information -> These bundles are called ________
tracts
All major spinal tracts are part of _______ multi-neuron pathways that mostly cross from one side to the other, and consist of a chain of two or three neurons.
paired
___________ pathways conduct sensory impulses upward through a chain of three neurons.
ascending
Somatic sensory pathways relay information from somatic receptors to the primary ___________ area in the cerebral cortex.
somatosensory
what is the order of neurons
first-order, second-order, third-order
______________ signals are an exception, as second-order fibers carry these to the cerebellum.
proprioceptive
For signals below the head, first-order fibers enter the_________ horn of the spinal cord.
posterior
Signals ascend via the __________ and other pathways.
spinothalamic
first order: These pathways decussate at or near the point of entry into the spinal cord or in the brainstem, so the primary somesthetic cortex in each hemisphere receives ____________ signals.
contralateral
Signals from the thoracic and abdominal viscera travel to the _______ _________ by way of sensory fibers in the vagus nerve (CN X).
medulla oblongata
2nd order: Several tracts undergo ____________, meaning that they cross over from one side of the body to the other side.
decussation
(2) When the origin and destination of a tract are on opposite sides of the body, they are said to be ___________
contralateral
(3) When a tract does not decussate, its fibers are said to be ________
ipsilateral
3rd order: Axon collaterals of somatic sensory neurons simultaneously carry signals into the cerebellum and the reticular formation of the _______ _______
brain stem
what are the 2 names of the major ascending tracts
- fasciculus gracilis and cuneatus
- spinothalamic
what are the subgroups of the spinothalamic
lateral spinothalamic tract and anterior tract
which one is a sensory pathway in the spinal cord that carries information about pain, temperature, and possibly itch to the brain
lateral spinothalamic tract
which one carries sensory information from the skin to the brain
anterior tract
___________ tracts conduct motor impulses down to targets.
descending
T or F: All nerve fibers in a particular tract have similar origin, destination, and function.
True
Many of these fibers have their origin in a region called the _________, a vertical stalk that supports the large cerebellum and the two even larger cerebral hemispheres.
brainstem
Several tracts decussate: A stroke that damages motor centers of the right side of the brain can cause paralysis of the left or right limbs
left
what are the 2 upper motor neurons
basal ganglia and cerebellum
which on is a group of brain structures that are primarily responsible for controlling movement
basal ganglia
which one is responsible for coordination of movement, maintaining posture and balance, muscle tone, and motor learning
cerebellum
neurons that connect the central nervous system (CNS) to the muscles, allowing the muscles to be innervated, what type of neurons?
lower motor neurons
is spastic paralysis due to the damage of upper or lower motor neurons
upper motor neurons (contralateral)
is flaccid paralysis due to damage of upper or lower motor neurons
lower motor neurons (ipsilateral)
corticospinal tracts are from the cerebral cortex to the ______ _______
spinal cord
The fibers form ridges called pyramids on the anterior surface of the medulla oblongata and so were once called ___________ tracts.
pyramidal
Most of these fibers decussate in the lower medulla and form the lateral corticospinal tract on the __________ side of the spinal cord.
contralateral
_______ ________ _______ is a disease that attacks motor areas of the cerebral cortex, axons of upper motor neurons and cell bodies of lower motor neurons. It causes progressive muscle weakness due to degeneration of motor neurons in cord, brainstem and cortex by free radicals.
amyotrophic lateral sclerosis (ALS)
The lateral and medial reticulospinal tracts : pathways that control motor neurons in the spinal cord, and are involved in posture, orientation, and the _____ _______ reflex
knee jerk
Spinal cord injuries result in loss of voluntary movement and _______ in regions inferior to the transection.
sensation
Any localized damage to the spinal cord is its roots leads to __________ which is the loss of motor function
paralysis
What is the term for loss of sensory function
paresthesias
Severe damage to the ________ root or________ horn results in FLACCID PARALYSIS, since nerve impulses are not transmitted to the skeletal muscles.
ventral
When ______ motor neurons of the primary motor cortex are damaged, SPASTIC
PARALYSIS occurs, in which voluntary control over skeletal muscle is lost
upper
If damage to the spinal cord occurs between T1 and L1, lower limbs are affected,
resulting in _________
paraplesia
but if the damage occurs in the cervical region, all four limbs are affected, resulting in __________
quadriplegia
Poliomyelitis results from destruction of ventral horn motor neurons by ______
polio
D. Examples of brain disorders are traumatic brain injuries
such as concussion and contusion, and degenerative brain diseases, including cerebrovascular accidents (strokes) and Alzheimer’s disease.
A blow that causes unconsciousness _______ the brain stem, depressing the activity of the reticular formation.
twists
F. Amyotrophic lateral sclerosis (ALS), or Lou Gehrig’s disease, is a neuromuscular condition that involves progressive destruction of ventral horn motor neurons and fibers of the _________ tracts.
pyramidal
G. Postnatal changes in the brain represent many neuronal connections during childhood that are based on early experiences; brain growth stops in early _______
adulthood
cognitive functions _______ with age.
decrease
