UNIT 7

CNS

• integrating center of body

• neuron cluster are nuclei

• chained neurons are tracts

PNS

• info relay system of body

  • afferent and efferent

• neuron cluster are ganglia

• chained neurons are nerves

MS

• damage of oligodendrocytes can lead to

Guillan-Barre syndrome

• damage to schwann cellls

formation of the CNS

• first the formation of the neural plate and the neural crest occurs forming the neural tube, the lumen which becomes the CNS

• neural crest cells lining the dorsum of the tube becomes the PNS

4 weeks

• time when we start to develop the forebrain, midbrain, and hindbrain and spinal cord

6 weeks

• forebrain consists of diencephalon and cerebrum

11 weeks

• time of when cerebrum is most pronounced and embryo takes human shape

40 weeks

• time of fetus ready for birth

• cerebrum takes shape of brain

directionality

• use of directional words changes depending on reference to brain or spinal cord

• rostral, dorsal, ventral, and caudal

anencephaly

• occurs when forebrain fails to fully close and develop

• most fetuses ultimately die

• linked partially to folic acid deficiency

spina bifida

• occurs when spinal cord region of neural tube does not close/develop properly

spina bifida occulta

• incomplete fusion of the posterior vertebral arch

• usually benign

spinal bifida aperta

• results in a protruding sac from the spinal cord

SBA meningocele

• a protruding CSF-filled sac

• contains fluid and meninges only

• cauda equina stays intact

SBA myelomeningocele

• most severe form

• around L2 and L3

• protruding sac with CSF, meninges, AND cauda equina

• paralysis below lesion

• clubfoot, hip dysplasia, arnold-chiari malformation, hydrocephalus

gray matter

• nerve cell bodies, dendrites, and unmyelinated axons

• nuclei

• information processing

  • amazon warehouse

nuclei

• clusters of cell bodies in brain and spinal cord

white matter

• mostly myelinated axons

• tracts

• information delivery

• efferent and afferent

  • highways

tracts

• bundles pf axons in the brain and spinal cord

multiple sclerosis

• auto-immune disease of CNS affecting white matter tracts/axons

• type 4 hypersensitivity, cell mediated

• T cells inappropriately activated by myelin

• antibodies target oligodendrocytes

• sensory and motor abnormalities

remissions

• mediated by regulatory T cells

exacerbations

• occur due to eventual oligodendrocyte death → no myelin

protects the CNS

• bone

• cerebrospinal fluid

• blood brain barrier

meninges

• bone and connective tissue that protects CNS

• pia mater

• arachnoid membrane

• dura mater

hemorrhage

• acute/severe blood loss

hematoma

• enclosed bleeding within tissue usually resulting in clotting

epidural hematoma

• arterial bleeding between dura mater and skull

• usually due to head trauma

• headache, vomiting, confusion, seizures

subdural hematoma

• venous bleeding between dura mater and arachnoid membrane

• typically head trauma

• similar s/s to epidural, potential coma

subarachnoid hemorrhage

• within subarachnoid space

• due to ruptured aneurysm of cerebral artery

intracerebral hemorrhage

• bleeding within brain

• 2nd leafing cause of stroke

• aneurysm, brain tumor, bleeding disorder

choroid plexus

• secretes cerebrospinal fluid

• helps bathe the CNS

arachnoid villi

• reabsorbs cerebrospinal fluid

• helps bathe the CNS

ventricles

• where the CSF is produced and stored

• hollow spaces within CNS

cerebrospinal fluid

• provides physical protection and chemical protection

• regulates ECF environment

• solute exchange

• waste removal route

• adequate sleep is IMPORTANT, when waste removal occurs

meningitis

• inflammation of meninges

• infection, autoimmune disease

encephalitis

• viral inflammatory condition of brain

• HSV and influenza

myelitis

• inflammation of spinal cord

• infection, autoimmune disease

blood brain barrier

• goal to protect integrating center against harmful substances

• more than 400 miles of capillaries with low permeability

• tight junctions secure the barrier

• allows for necessary oxygen, specific nutrients, and waste removal

oxygen and glucose

• main sources of ATP production for the brain

• brain uses 1/5 of bodys oxygen supply and 50% of glucose

hypoglycemia

• can lead to confusion, unconsciousness, and death if glucose in brain is low

white matter tracts

• can ascend or descend along specific regions of spinal cord

ascending tracts

• sensory, from body to brain

• posterolateral aspects of spinal cord

• DCML

• spinothalamic of ALS

descending tracts

• motor, from brain to body

• ventral/interior aspects of spinal cord

• corticospinal tract

DCML

• an ascending tract

• fine touch, proprioception and vibration

spinothalamic of ALS

• an ascending tract

• pain, temperature changes, and crude generalized touch

corticospinal tract

• a descending tract

• general motor abilities of the body but not the face

tetraplegia

• quadriplegia

• spinal injury to C1-C8

• all extremities and trunk

paraplegia

• spinal injury to T1-S5

• trunk and/or LE involvement

spinal cord injury autonomic dysfunction

• orthostatic hypotension

• autonomic dysreflexia

• bowel and bladder dysfunction

• thermoregulation changes

cerebellum

• region of brain responsible for movement coordination

• little brain

midbrain

• brain region responsible for eye movement

pons

• relay station between cerebrum and cerebellum

• coordination of breathing

medulla oblongata

• control of involuntary functions

reticular formation

• arousal

• sleep

• muscle tone

• pain modulation

CN 1

• olfactory

• sensory

CN 2

• optic

• sensory

CN 3

• oculomotor

• motor

CN 4

• trochlear

• motor

CN 5

• trigeminal

• mixed

CN 6

• abducens

• motor

CN 7

• facial

• mixed

CN 8

• vestibulocochlear

• sensory

CN 9

• glossopharyngeal

• mixed

CN 10

• vagus

• mixed

CN 11

• spinal accessory

• motor

CN 12

• hypoglossal

• motor

diencephalon

• thalamus

• pineal gland

• hypothalamus

• pituitary gland

thalamus

• integrating center and relay station for sensory and motor info

• olfactory and smell info. does not relay hear

pineal gland

• melatonin secretion

hypothalamus

• homeostasis

• behavioral drives

pituitary gland

• hormone secretion

basal ganglia

• filtration of movement signals

• termed ganglia even in the CNS

• substantia nigra

  • produces dopamine

parkinson’s disease

• degeneration of dopamine producing cells in basal ganglia

• decreased initiation and inhibition of movement

• TRAP → tremor, rigidity, akinesia/bradykinesia, postural instability

• stooped posture, shuffling gait, freezing of gait, depression, anxiety

limbic system

• most primitive region of cerebrum

• linked between reasoning and fear

• amygdala

• cingulate gyrus

• hippocampus

amygdala

• part of limbic system

• center of emotion

• memory

cingulate gyrus

• part of limbic system

• emotion and memory

hippocampus

• part of limbic system

• learning and memory

• associative/non-associative learning

• pictures and sounds stored in cerebral cortex

alzheimer’s disease

• limbic system

• progressive neurodegenerative disease of cognitive impairment, most common cause of dementia

• memory loss, personality changes, communication failure

• neurofibrillary tangles and amyloid plaques

frontal lobe

• skeletal muscle movement

• origination of efferent signals

• primary and premotor cortex

parietal lobe

• where sensory is processed

• primary somatic sensory cortex

• sensory association area

occipital lobe

• vision

• visual association

• visual cortex

temporal lobe

• olfactory cortex

• auditory cortex

• auditory association area

primary somatic sensory cortex

• located in post-central gyrus of parietal lobe

• sensory info from skin, musculoskeletal system, and viscera

• where ascending pathways form spinal cord synapse for signal processing

primary motor cortex

• located in pre-central gyrus of frontal lobe

• voluntary movements by cognitive system

• provide efferent responses via descending pathways

  • synapse spinal cord → spinal nerve → tissue

CVA stroke

• causes loss of neurologic function due to impaired blood flow to the brain lasting >24 hrs.

• contralateral hemiparesis (partial weakness)

• hemiplegia (loss of function/paralysis)

• contralateral sensory deficits

• gait, balance, speech, cognitive deficits

transient ischemic attack

• focal episode of neurologic dysfunction lasting <24 hrs.

ischemic stroke

• a clot blocking blood flow to an area of the brain

• 85%

hemorrhagic stroke

• bleeding inside or around brain tissue

middle cerebral artery CVA

• contralateral motor and sensory deficits

• mainly UE and face

• L hemisphere →speech/comprehensive deficits

• brocas aphasia

• wernickes aphasia

brocas aphasia

• circulatory insult in frontal lobe

• motor ability to speak

• expressive aphasia

• difficulty forming sentences

wernicke’s aphasia

• circulatory deficit in temporal lobe

• impacts cognitive ability to comprehend language

• receptive aphasia

• speech is nonsense

anterior cerebral artery CVA

• contralateral motor and sensory deficits

• mainly LE

• L CVA maintain awareness of deficits, regardless of artery

  • higher instances of depression and inability to communicate

• R CVA lack awareness of injury. regardless of artery

  • higher impulsivity, poor judgment, and emotional liability

  • higher safety concern

posterior cerebral artery

• temporal and occipital lobes

• hemianopia, loss of contralateral visual field

• dyslexia

• color agnosia

basilar artery

• carries oxygenated blood to brainstem

• locked in syndrome

  • can do anything but has cognition

cerebellar arteries

• group of arteries that supply cerebellum

• impaired balance and coordination

• often serious due to neighboring cranial nerves and/or multiple signal pathways

special senses

• vision

• hearing

• taste

• smell

• equilibrium

somatic senses

• touch

• temperature

• pain

• itch

• proprioception

perceptual threshold

• busy environment, stress or distracted → may not feel same touch

• level of stimulus is too low to notice without focusing on it

chemoreceptors

stimuli

• oxygen

• pH

• glucose