PATHOPHYSIOLOGY MOD8

what makes up the central nervous system

• brain

• spinal cord

what makes up the peripheral nervous system

the peripheral nerves

function of the nervous system

receives and reacts to environmental stimuli on a physiologic and cognitive level

what are the three main components of the nervous system

the brain, spinal cord, nerves

the ___ houses and protects the brain

skull

the ___ houses and protects the spinal cord

vertebral column

the membrane that encase the CNS

meninges

what are the three protective layers of the meninges

• dura matter: the outer and toughest layer

• arachnoid layers: the middle layer with a spider web- like vascular system

• pia matter: the innermost layer

when we think of fuel sources, what are the two sources we think about (what does the nervous system need to perfrom)

oxygen and glucose

what is the cerebrospinal fluid

plasma like liquid that fills the space between the arachnoid and the pia mater layers to provide additional cushion and support

• it provides a “cushion” to the brain and all its related structures

what are ventricles

interconnected, hollow areas of the brain where CSF is produced, fills, and flows

what do neurons do

send electrical signals ** generate and trasmit bioelectrical

neurons do not have the ability to what

divide

** losses due to aging or injury cannot be replaced

severed brain and spinal cord axons cannot be ___

repaired

severed spinal cord nerves result in ___ and ____

result in paralysis and loss of sensation BELOW the area of damage

neurons require constant what ___. and what does this make it vulnerable to

require a constant oxygen and glucose supply, making neurons vulnerable to hypoxia and hypoglycemia

what are the parts of the neuron and their function

• dendrites: receive signal

• axon: sends signal

• myelin: speeds up signal

• synapse: gap between neuron

• Schwann cells: produce the myelin sheath

when you think neuro think 2 things which are

1. motor (movement)

2. sensory (can you feel ex. can you feel pain can you feel sensation)

action potential of electrical impulses

ability to CREATE a charge

resting potential of electrical impulses

charge at REST

what are electrical impulses

neural impulses are generated by small ionic changes

** it is a signal created by small changes in ions (like sodium and potassium) moving across the neuron membrane

cerebrum does what

controls the higher thought processes

how is the cerebrum divided and each of those contain subdivisions called

into the right and left hemispheres and each hemisphere contains subdivisions called lobes

the frontal lobe facilitates

voluntary motor activity and plays a role in personality traits

function of the parietal lobe

receives and interprets sensory input with the exception of smell, hearing, and vision

what does the occipital lobe process

visual information

what is the temporal lobe essential for

hearing and memory

motor function

stimulates muscle activity

sensory function

receives sensory information

function of the thalamus

receives and relays most of the sensory input, affects mood, and initiates body movements

the most inferior portion of the dicencephalon

hypothalmaus

what are 2 examples of the major regions in the diencephalon

thalamus and hypothalamus

what are the major regions of the brainstem

pons, midbrain, medulla

purpose of the brain stem

connects the brain to the spinal cord

injury of the brainstem can result in

death

the brainstem collaborates with the hypothalamus to regulate vital activities such as

• regulate body temperature

• regulate breathing

• regulate the heart

__ of __ cranial nerves exit from brainstem

10 of 12

pons contain nerves that regulate

sleep and breathing

midbrain is the smallest region of the brain that acts as a relay station for ___ and controls ___

acts as a relay station for auditory and visual information and controls the visual and auditory systems as well as eye movement

medulla is a conduction pathway for ascending and descending nerve tracts that coordinates

heart rate, peripheral vascular resistance, breathing, swallowing, vomiting, coughing, and sneezing

major regions of the cerebelleum

basal ganglia and limbic system

basal ganglia plays a pivotal role in

coordination, motor movement, and posture

the limbic system works in conjunction with the hypothalamus to infleunce

intrinsic behavior, emotions, motivation, mood, pain, and pleasure

ascending fibers (afferent) does what

carries sensory information in the form of action potential from the periphery back to the brain

descending fibers (efferent) does what

carries motor impulses in the form of action potential from the brain to the fibers of the PNS

sympathetic nervous system is responsible for

fight or flight response

parasympathetic nervous system is responsible for the

rest and digest response

most sensitive identification of altered brain function is

altered level of consciousness

hydrocephalus is seen more often in

pediatric patients

what happens in hydrocephalus

the ventricles dilate and the brain and blood vessels become compressed

in hydrocephalus, pressure thins the cortex causing severe

brain damage

hydrocephalus manifestations in infants

• eyes that gaze downward (because of intercranial pressure)

• high pitched cry

• unusually large head (macrocephalic)

• bulging fontanelle

• lethargy

• feeding difficulties

• development delay

cerebral palsy is

nonprogressive

** once the damage is done

cerebral palsy is ___ damage to the ___ during the ___ but can occur any time during the first ___

irreversible damage to the cerebellum, during the prenatal period (often during childbirth), but can occur any time during the first 3 years of life, where the brain is developing

cerebral palsy manifestations

• vary in severity

• may affect the entire body or one area

• may affect one side or both sides of the body

• spasticity

• excessive drooling

what is meningitis

inflammation of the meninges and subarachnoid space, usually resulting from an infection

#1 cause of bacterial meningitis

streptococcus pneumoniae

a patient with bacterial meningitis is going to be ____ vs. viral

acutely/ more severely ill

it is important that nurses who caring for a meningitis patient must

wear a mask

risk factors of meningitis

• younger than 25 years if age

• living in a community setting (college dorms)

• pregnancy

• working with animals

• immunodeficiency

meningitis can be ___ (viral) or ____ (acute bacterial)

self limiting or life threatening

clinical manifestations of meningitis

• fever

• photophobia (light sensitivity)

• severe headache

• nuchal rigidity (stiff neck)

• decreased consciousness

• opisthotonos (extreme background arching of the body due to severe neurologic irritation)

what causes a traumatic brain injury

usually caused by a sudden violent blow to the head (closed injury) or a penetrating (open injury) head wound that disrupts the normal brain function

conditions associated with closed TBIs

concussion and cerebral contussion

what is a concussion

momentary interruption of brain function

what is a cerebral contusion

bruising of the brain

when it comes to traumatic brain injury the manifestations may be __

vague and develop slowly, or may be sudden and severe

• symptoms may improve and then suddenly worsens

• the outward appearance of the head IS NOT an indication of the injury severity

normal range of intracranial pressure

0-15 mmHG

clinical manifestations of increased intracranial pressure

• vomiting (often projectile)

• increasing blood pressure

• fixed and dilated pupils

• headache (early manifestation)

• blurred vision

clinical manifestations of increase intracranial pressure in infants

• separated sutures

• bulging fontanelle

herniation refers to

displacement of brain tissue

spinal cord injuries result from

direct injury to the spinal cord or indirectly from damage to surrounding bones, tissues, or blood

“shock” means you are having some type of problem with

perfusion

direct damage can occur in spinal cord injuries if

the spinal cord is pulled, pressed sideways, or compressed

the accumulation of ____ can compress the spinal cord and damage it

blood or fluid

what is spinal shock

temporary suppression of neurologic function because of spinal cord compression; neurologic function gradually returns

the clinical manifestations of spinal cord injury depends on what

the level of injury to the spinal cord

autonomic dysrflexia/ hyperreflexia is

a massive sympathetic response that can cause headaches, hypertension, tachycardia, seizures, stroke and death

• most commonly associated with injuries above T6

what is a neurogenic shock

an abnormal vasomotor response secondary to disruption of sympathetic impulses

quadriplegia is paralysis of

4 extremities

paraplegia is loss of

motor and sensory control of the trunk and lower extremities

cervical injuries can affect

both the upper and lower extremities

thoracic injuries affect the

lower extremities

lumbar sacral injuries can affect

the lower extremities

• loss of deep tendon reflexes and flaccid paralysis

when thinking about end stage neuronal activity, we look at patient ____ which are

posturing

• decorticate

• decerebate

between decorticate or decerebate, which is worse

decerebate

transient ischemic attack is

a temporary episode of cerebral ischemia that results in symptoms of neurologic deficits

hyperflexion

decorticate

hyperextending position is

decerebrate

transient ischemic attack are known as

ministroke (because these neurologic deficits mimic a cerebrovascular accident)

the symptoms of TIA resolve in __ in most cases

1-2 hours

why is the patient having a TIA

lack of blood flow to part of the brain or a stroke

in TIA, ischemia can occur because of

a cerebral artery occlusion, cerebral artery narrowing, or cerebral artery injury

aphasia

difficulty talking

dysphagia

difficulty swalloing

TIA manifestations

** begins suddenly and last for a short period

** manifestations are the same as for a stroke

** reflects the location of the ischemia

• muscle weakness or paralysis of the face, arm, leg (usually unilateral)

• unilateral paresthesia

• aphasia

• dysphagia

• changes in sensation

• change in level of consciousness

• confusion

• vision issues

cerebrovascular accident are an interruption of

cerebral blood supply

what are the major types of CVA

• ischemic strokes (most common)

• hemorrhagic stroke (most fatal)

what are the complications of CVA

neurologic deficits and death

____ may be present with hemorrhagic strokes because of increasing ICP

headaches