CNS- 23

Question 1

CNS consists of

Answer 1

brain and spinal cord

Question 2

brain consists of:

Answer 2

cerebrum
cerebellum
brain stem (midbrain, pons, medulla)

Question 3

cerebrum consists of:

Answer 3

outer layer of gray matter (cortex)
deep gray matter
white matter

Question 4

cortex

Answer 4

replete with neurons that are employed for intellectual (cognitive) functions as well as for sensory and motor functions above the vegetative level

Question 5

deep gray matter

Answer 5

consists of groups of neurons such as the thalamus and basal ganglia that perform functions similar to the cortex, albeit at a much more primitive level

Question 6

white matter

Answer 6

composed primarily of the axons and their myelin sheaths.

Question 7

brain axons

Answer 7

long processes of neurons that connect with neurons in other prts of the brain and spinal cord.

Question 8

axons of spinal cord neurons

Answer 8

innervate skeletal muscles

*voluntary thought generated from neurons of the cerebral cortex can control skeletal muscle movement

some axons convey sensory impulses in the opposite direction- from the spinal cord to carious parts of the brain

Question 9

cerebellum

Answer 9

situated in the posterior inferior aspect of the skull

responsible for coordination of motor functions

Question 10

brainstem

Answer 10

a relay between brain and spinal cord and is also a control center for heart rate, respiration rate, sleep and wakefulness, integration of eye movements and other functions

Question 11

meninges

Answer 11

cover the brain
include an outer, tough membrane called the DURA (next to the skull), and an inner lace-like membrane= PIA-ARACHNOID (lies directly over the cortex

form a continuous covering over the spinal cord too

Question 12

cerebrospinal fluid

Answer 12

utilized for metabolic exchange, as an excretory vehicle and as a means to absorb pressure changes in the CNS

formed in the ventricles of the brain by secretion from the CHOROID PLEXUS and by filtration through the ependyma.
-flows from 3 ventricles in the anterior part of the brain, through a narrow aqueduct, to the medulla (area of brain stem). then passes out of the ventricular system and percolates between the layers of the pia-arachnoid membrane, bathing the brain and spinal cord before being absorbed back into veins.

Question 13

most blood flows to the brain through:

Answer 13

the 2 internal carotid arteries anteriorly and the paired vertebral arteries posteriorly

carotid to bulk of cerebrum
vertebral to brain stem, cerebellum and post cerebrum (supply control centers for respiration and consciousness)

Question 14

circle of willis

Answer 14

vessels all interconnect at the base of the brain

*so occlusion at one major artery to the brain may no necessarily result in deprivation of blood

Question 15

blood-brain barrier

Answer 15

selective exclusion of substances- brain capillaries are constructed to function in such a manner as to prevent passage of many substances into the brain that can easily reach tissues in other organs.

Question 16

important cellular constituents of the brain stem and spinal cord:

Answer 16

neurons
astrocytes
oligodendroglia

Question 17

neurons

Answer 17

large cells found in gray matter that conduct nervous impulses

• efferent processes (axons) may extend for long distances in gray and white matter
• short afferent processes (dendrites) connect to other neurons through synapses

Question 18

astrocytes

Answer 18

spider lie processes provide structural support to the CNS

regulate blood-brain barrier and tissue electrolytes

when brain is injured, astrocytes proliferate to form a glial scar composed of glial processes but lack collagen

Question 19

oligodendroglia

Answer 19

manufacture and maintain the myelin sheath that surrounds and protects axons and dendrites

Question 20

major brain diseases

Answer 20

CVAs/strokes- 3rd cause of death
traumatic injuries
infections (meningitis, encephalitis, abscess)
alzheimer disease
neoplasms
multiple sclerosis
parkinson's
senile dementia

Question 21

most common presenting symptoms

Answer 21

headache
diminution or loss of motor function
sensory loss
seizures
disturbances in intelectual or memory capabilities

Question 22

neurologic exam

Answer 22

exam of motor and sensory systems
testing cognitive function
special tests for ability to perform coordinated movements

Question 23

motor system exam

Answer 23

gait
posture
symmetry of muscle mass
muscle strength
coordination
quality of reflexes

Question 24

decreased reflux indicates:

Answer 24

lesion in peripheral nerve with resultant inability to either transmit the sensoryy impulse back to the spinal cord or to transmit the motor impulse out to the muscle

Question 25

hyperactive reflex

Answer 25

represents an intact nerve but without the modifying control normally mediated by the CNS

Question 26

focal vs general

Answer 26

focal= referable to a specific area of nervous system involvement general=involving integrated functions of the whole brain

Question 27

hemiparesis

Answer 27

weakness of one side of the body | focal

Question 28

focal examples

Answer 28

hemiparesis localized areas of sensory deprivation abnormalities of 1 or 2 cranial nerves localized headaches

Question 29

general examples

Answer 29

intellectual impairment generalized headaches stupor loss of consciousness (coma)

Question 30

major cause of generalized s&s

Answer 30

increased intracranial pressure

Question 31

foramen magnum

Answer 31

only major opening in the skull- for spinal cord substance of the brain tends to be pushed toward this foramen as a consequence of any increased intracranial pressure

Question 32

treatment of increased intracranial pressure

Answer 32

removal of any space occupying lesion | steroid drugs and osmotic agents may help relieve brain edema by drawing fluid back to vascular system

Question 33

most important lab exam for CNS

Answer 33

analysis of cerebrospinal fluid usually by a needle into lumbar parachnoid space in sitting pressure is measured as fluid is being drawn.

Question 34

electroencephalogram (EEG)

Answer 34

evaluates electrical activity simultaneously in various areas of the brain

Question 35

developmental abnormalities of the CNS divided into:

Answer 35

1: malformations 2: destructive brain lesions

Question 36

malformations

Answer 36

result of deleterious forces acting upon the embryonic or fetal brain~1/2 gestation ``` down syndrome spina bifida meningomyelocele anencephaly hydrocephalus ```

Question 37

spina bifida

Answer 37

post arches and spines of some vertebrae are absent if severe a meningomyelocele results

Question 38

meningomyelocele

Answer 38

defect in the spinal column through which spinal cord and meninges protrude into the skin of the back. may result in severe paralysis of the legs

Question 39

anencephaly

Answer 39

severe malformation- entire forebrain is missing infants are stillborn or die soon after birth

Question 40

destructive brain lesions

Answer 40

occur in last 1/2 of gestation or during firth 2 years of life. most occur at time of labor - result of anoxia from prolonged/difficult labor or respiratory distress also common from infections. especially meningitis vary greatly in severity most pts have motor problems , 1/3 mentally retarded ``` cerebral palsy maternal diet drugs radiation toxins ```

Question 41

cerebral palsy

Answer 41

non-progressive condition manifested by motor retardation and sometimes mental.

Question 42

inflammatory diseases

Answer 42

meningitis encephalitis rabies myelitis

Question 43

meningitis

Answer 43

=inflammation of the pia-arachnoid most often caused by bacteria usually abrupt onset bacteria gains access to brain and spinal cord via blood. escherichia coli and group B streptococci cause majority of newborn cases haemophilus influenzae for small children

Question 44

s&s of meningitis

Answer 44

fever, headache, neck rigidity, pain caused by muscle spasm from nerve irritation

Question 45

neisseria meningitis

Answer 45

can occur in epidemics

Question 46

encephalitis

Answer 46

=diffuse inflammation of the brain usually caused by viral infections (mosquito borne) occur in epidemics *west nile, st louis, equine, venezuelan

Question 47

s&s of encephalitis

Answer 47

irritability drowsiness headache no tx. pts die, fully recover or recover with neurologic deficit

Question 48

rabies

Answer 48

the virus travels up the peripheral nerve to the brain and once infected death is practically inevitable.

Question 49

s&s of rabies

Answer 49

``` pain at bite site fever malaise vomiting progressing to delirium painful laryngeal spasm when attempting to drink (hydrophobia) ```

Question 50

myelitis

Answer 50

infection of the spinal cord

Question 51

poliomyelitis

Answer 51

specific infection of the gray matter of the spinal cord killing anterior horn motor neurons with resultant paralysis

Question 52

vascular disease and trauma

Answer 52

CVA (1/3 die, 1/3 serious neuro deficits) | trauma

Question 53

cerebrovascular accident (stroke)

Answer 53

=sudden neurologic deficit caused by either vascular occlusion from thrombosis or embolism, from hemorrhage to the brain, or from ruptured saccular aneurysm * majority from emboli * *common atherosclerotic vascular disease

Question 54

artery most occluded by emboli

Answer 54

middle cerebral artery: largest and a direct continuation of the carotid artery supplies the part of the cortex controlling motor function

Question 55

aphasia

Answer 55

impaired language function

Question 56

brain hemorrhage

Answer 56

rupture of vessels and bleeding into the brain

Question 57

saccular (berry) aneurysms

Answer 57

occur mostly in the circle of willis where vessels branch. deficiencies in the blood vessel walls result in outpouching.

Question 58

trauma

Answer 58

``` concussion contusion epidural hematoma subdural hematoma penetrating injuries ```

Question 59

why should a pt be watched closely after trauma?

Answer 59

late deterioration- subdural or epidural bleed developed immediately following injury but did not affect the pt until a critical amount of blood accumulated

Question 60

concussion

Answer 60

momentary loss of consciousness and loss of reflexes following head trauma amnesia for the traumatic event and complete recovery no structural damage in the brain

Question 61

contusion

Answer 61

bruises of the surface of the brain from time of impact "coup lesions"-contusion of same side "contrecoup lesions"- opposite side result in hemorrhages from small blood vessels in the brain can cause further vessel occlusion and edema- vulnerable for intracranial pressure

Question 62

epidural hematoma

Answer 62

epidural hemorrhage occurs between dura and skull associated with severe trauma- skull usually fractured. bc artery is ruptured (middle meningeal) the blood accumulates rapidly and pt will die w/in hours unless hematoma is removed.

Question 63

subdural hematoma

Answer 63

=collection of blood beneath the dura rupture of veins on the dorsum of the brain bc bleeding is venous- does not accumulate as rapidly as epidural so not as life threatening but bleed still needs to be removed surgically to prevent compression of brain

Question 64

penetrating injuries

Answer 64

bullets fractured bone splinters herniation- spinal cord *infection to wound

Question 65

degenerative diseases

Answer 65

``` multiple sclerosis creutzfeldt-jakob disease senile dementia parkinsons hydrocephalus epilepsy ```

Question 66

multiple sclerosis

Answer 66

women>men =focal loss of myelin sheath (demyelination)- appears to render axons incapable of properly transmitting a nervous impulse. can occur anywhere in the brain and spinal cord so varies with pt visual impairment unknown cause 5-25 lifespan. remission and relapse pt becomes debilitated from muscle weakness dx: increased immunoglobin G (IgG) protein in cerebrospinal fluid MRI-may see lesion

Question 67

creutzfeldt-jakob disease (CJD)

Answer 67

human prototype of a group of diseases in animals and humans that result in brain degeneration. rare "slow virus" diseases "mad cow" pt becomes rapidly demented and usually die 4-6 months after dx w/ severe brain degeneration

Question 68

cause of CJD

Answer 68

appears to be the result of transformation of a normal brain protein into an abnormal configuration allowing it to replicate. protein PRION builds up in the brain- associated with gray matter degeneration

Question 69

senile dementia

Answer 69

=decrease in cognitive function, memory loss -pick at their clothes, get lose easily, often irritable degree depends on loss of substance in the frontal lobes, the region of that brain associated with higher cognitive function

Question 70

alzheimer's disease

Answer 70

dementia accompanied by certain microscopic brain changes disease of age large number of plaques, tangles and amyloid are found in hippocampal formation in the temporal lobe- explaining loss of recent memory

Question 71

parkinson's disease

Answer 71

-caused by degeneration of certain portions of the extrapyramidal (involuntary) motor system, especially the substantia nigra nucleus in the midbrain classic inclusion= LEWY BODY tremors at rest, masklike facial expression, shuffling gait, rigidity of skeletal muscles

Question 72

hydrocephalus

Answer 72

="water brain" ventricles enlarge bc of block in the flow of cerebrospinal fluid at some level. stenosis of aqueduct btwn 4and 5th ventricles- head may enlarge if pressure is not released brain may herniate toward foramen magnum

Question 73

epilepsy

Answer 73

=recurrent seizures seizures=focal or generalized disturbances of neuronal electrical activity, may manifest abnormal movements or sensations and loss of reflexes, memory or consciousness

Question 74

seizures may be caused by

Answer 74

electrolyte imbalance, high fever, uremia

Question 75

generalized brain neoplasms symptoms

Answer 75

headaches vomiting blurred vision seizures from intracranial pressure

Question 76

astrocytomas

Answer 76

slower growing brain tumors from astrocytes

Question 77

glioblastoma

Answer 77

fast growing malignant brain tumor most common in adults result in death w/in 1-2 years

Question 78

meningioma

Answer 78

2nd most common brain tumor | benign neoplasm that arises from dura and slow growing

Question 79

adenomas

Answer 79

pituitary tumors difficult to remove some secrete growth hormone and result in gigantism or acromegaly

Question 80

medulloblastoma

Answer 80

arises in cerebellum in children from primitive cells that are neuronal precursors malignant but do respond well to radiation