Ch. 15, 16, 17 Exam 2 patho prep

CNS

brain and spinal cord

PNS

spinal and cranial nerves

ANS

involuntary (visceral), voluntary (skeletal muscle, somatic), sympathetic and parasympathetic

ascending peripheral pathway

afferent, towards CNS

descending peripheral pathway

efferent, away from CNS to muscle and effector organs

main cell types of nervous tissue

neurons, neurological CNS, Schwann PNS

nerve regeneration depends on

type of injury, location, inflammation, scarring (affected by myelin differences)

3 main divisions of brain

forebrain, midbrain, hindbrain

forebrain

cerebral cortex, hypothalamus, thalamus, cerebral hemispheres

midbrain

cerebral peduncles, corpora quadrigemina, tegmentum

hindbrain

cerebellum, pons, medulla

brainstem

midbrain, pons, medulla oblongata

reticular formation

nerve bodies in brainstem, involved with vital reflexes, wakefulness (reticular activating system RAS)

gyri

convolution

sulci

grooves between gyri

fissures

Deep grooves

grey matter

cell bodies of neurons on cerebral cortex

white matter

myelinated nerve fibers underneath grey matter

lobes of cerebral hemisphere

occipital, frontal, parietal, temporal

thalamus

center for afferent impulses to cerebral cortex

hypothalamus

homeostasis, behavioral pattern implementation

2 main divisions of hindbrain

metencephalon (cerebellum, pons) and myelencephalon (medulla oblongata)

cerebellum

reflexive, involuntary fine tuning of motor behavior, balance and posture

pons

send info from cerebellum to brain stem and between hemispheres, respiratory control center

medulla oblongata

controls coughing, sneezing, HR, respirations, swallowing, vomiting

structures that protect CNS

cranium, bones cerebrospinal fluid, vertebrae

autonomic nervous system function

maintains steady state among visceral organs

neurons in ANS

preganglionic (myelinated) and postganglionic (unmyelinated)

sympathetic nervous system

fight or flight, uses energy stores in times of need

parasympathetic nervous system

rest and digest, conserve and restore energy

sympathetic preganglionic fibers

acetylcholine and cholinergic receptors

sympathetic postganglionic fibers

noepinephrine and adrenergic receptors

parasympathetic pre and post ganglionic fibers

acetylcholine and cholinergic receptors

somatogenic

pain with a cause

psychogenic

pain where there is no known cause

chronic pain

persistent, lasting over 6 months

acute pain

superficial, sudden onset

pain threshold

point when a person feels pain

pain tolerance

time/intensity of pain a person can endure

neuroanatomy of pain (4 phases)

transduction, transmission, perception, modification

transduction

tissue damage to stimuli becomes electrophysiologic activity

transmission

pain impulse conduction

perception

awareness of pain

modification

suppressing or facilitating pain

4 theories of pain

specificity, pattern, gate, neuromatrix

specificity

specific pain receptors

pattern

pattern of stimulation interpreted as painful

gate-control

gates in spinal cord open and close letting painful stimuli in

neuromatrix theory

patterns of nerve impulses drawn from various inputs

endorphines

natural pain killer released in body

somatic pain

superficial, sharp, well localized, dull, with n/v

visceral pain

internal organs, abdomen, skeleton, poorly localized, low blood pressure, often radiate

referred pain

pain present in area is removed or distant from point of origin

chronic vs physiologic responses to pain

acute: increased HR, RR, BP, flush, BS. Chronic: normal HR, RR, BP, but pain is not relieved, behavioral changes

hypothalamus regulates temperature by

hormones, peripheral and central thermoreceptors, TSH

mechanisms of heat production

chemical reactions of metabolism, skeletal muscle tone and contraction, thermal thermogenesis

heat conserving mechanisms

hypothalamus stimulates SNS, skeletal muscle tone increases (shivering and vasoconstriction), hypothalamus sends info about being cold

pathogenesis of fever

resetting of hypothalamic thermostat to higher level. thermoregulatory center adjusts heat production, conservation, and loss to maintain core body temp

benefits of fever

kills many microorganisms, affects growth and replication, lysosmal breakdown, autodigestion of infected cells

general causes of altered awareness

structural problems, infectious, cardiovascular, congenital, metabolic problems, hypoxia, electrolyte imbalances, low BS, drugs and toxins

5 parameters commonly assessed in patients with potential CNS dysfunction

LOC, breathing pattern, pupils, eye position and reflexes, skeletal muscle motor responses

confusion

cannot think fast and clear, impaired judgement and decision making

disorientation

beginning loss of consciousness, disorientation to place and impaired memory, loss of self recognition

lethargy

limited spontaneous speech and movement, arouses with speech or touch

obtundation

mild to moderate reduction in arousal, asleep if not stimulated

stupor

deep sleep or unresponsiveness, aroused with vigorous/repeated stimulation

coma

no response to stimuli, even if stimulus is noxious

Cheyne-Stokes respirations

caused by increased ventilatory response to CO2 stimulation, cycle in which over breathing causes pCO2 to be low, then breathing stops until pCO2 increases

what causes wide, fixed pupils

severe ischemia/hypoxia

cerebral death

death of cerebral cortex, exclusive of brainstem and cerebellum, may maintain homeostasis

brain death (brain stem death)

brain damage so great that homeostasis is not maintained

vegetative state

may occur with cerebral death, complete unawareness of self and surroundings, no cerebral function

locked in syndrome

content of though and arousal present, efferent pathways disrupted, person cannot communicate but conscious

dysphasia

impairment of comprehension/production of written/verbal language

aphasia

loss of comprehension/production of language

expressive dysphasia

primarily verbal expression deficits (Broca's area)

receptive dysphasia

impaired verbal comprehension and reception (Wernicke's area)

range for normal intracranial pressure (ICP)

5-15 mmHg

4 causes of increased ICP

increased intracranial contents, edema, excess CSF, bleeding

stage 1 of intracranial hypertension

vasoconstriction and venous system compression to reduce pressure, ICP may not change

stage 2 intracranial hypertension

continued expansion and increased pressure exceed compensatory mechanisms, neuronal oxygenation compromised, confusion, restlessness, drowsiness

stage 3 intracranial hypertension

brain hypoxic and hypercapneic as ICP approaches arterial pressure, rapid deterioration

stage 4 intracranial hypertension

brain herniates, high to low pressure, blood supply compromised, high ICP

cerebral edema

increase fluid content in brain, may involve extracellular or intracellular fluid

paresis

weakness with incomplete loss of muscle power

paralysis

loss of motor function

hemiparesis

weakness on one side of body

hemiplegia

paralysis on one side of body

paraplegia

paralysis of lower extremities

quadriplegia

paralysis of all four extremities

decorticate posture

upper extremity flexion with/without leg extensor responses

decerebrate posturing/rigidity

extension, abduction, and hyperpronation of arm