-
(gate theory) small unmyelinated C polymodal nociceptors responsible for transmission of
diffuse burning or aching sensations (slow pain)
-
(gate theory) Medium-sized A-delta fibers carry what kind of pain?
localized, sharp pain; important in initiating rapid reactions to stimuli (fast pain)
-
(gate theory) "gate" in the spinal chord regulates transmission of pain impulses that proceed _______ for further processing and interpretation in the ______
cephalad
brain
-
(gate theory) stimulation of ________________________ (which synapse in the dorsal horn of spinal cord along with their nociceptive Alpha-delta and C fiber counterparts) can close pain gates
large, fast, heavy myelinated Alpha-beta fibers
-
(gate therapy) what contributes to pain modulation (inhibition) in medulla and pons
norepi and epi
-
Endogenous opioids
morphine-like neuropeptides act as neurotransmitters by binding to one or more opioid receptors
-
_________ inhibit transmission of pain impulses in spinal cord and brain
endogenous opioids
-
4 types of endogenous opioids
- enkephalins
- endorphins
- dynorphins
- endomorphins
-
Acute pain
somatic, visceral or referred
-
Somatic pain
skin or close to surface, sharp and localized
-
Visceral pain
internal organs, abdomen, skeleton
-
Referred pain
area removed or distant from point of origin
-
in referred pain, the area is supplied by the
same segment as actual site of injury (i.e. upper adbomen-
-
example of referred pain
upper abdomen-- T8, L1, L2
-
In referred pain, ___________________ converge on same ascending neuron and brain cannot distinguish between origin of the two
cutaneous and visceral neurons
-
Steps of thermoregulation (5)
- 1. heat production begins in hypothalamus with release of TSH-RH
- 2. Results in release of TSH from anterior pituitary
- 3. TSH causes release of thyroxine from thyroid
- 4. Thyroxine causes release of epinephrine from adrenal medulla which causes vasoconstriction, glycolysis and increased metabolic rates
- 5. HEAT PRODUCTION OCCURS
-
Fever
failure of normal thermoregulatory mechanism
-
Fever begins with introduction of
exogenous pyrogens or endotoxins
-
In a fever, ______________ produced and released as exogenous bacteria are destroyed and absorbed by phagocytic cells in host. This raises the set point of the _________
Interleukin 1 (IL-1), IL-6, interferons and TNF
hypothalamus
-
heatstroke
potentially lethal consequence of thermoregulation
-
During heat stroke, ________________ center is overstressed
thermoregulatory
-
Brain cannot tolerate temperatures of more than
105
-
In heatstroke, the regulatory center may
cease to function
-
Sweating ________ during heatstroke because
ceases
core temp rises rapidly
-
The skin is dry and flushed during heatstroke because of
vascular collapse
-
the person becomes irritable, confused, stuporous and comatose during heatstroke due to
cerebral edema, degeneration of CNS, renal tubular necrosis
-
hypothermia
- slows chemical reactions
- increases blood viscosity
- slows blood flow
- facilitates blood coagulation
- stimulates profound vasoconstriction
-
body temp during hypothermia
less than 95
-
Hypothermia is secondary to
- hypothyroidism
- hypopituitarism
- malnutrition
- Parkinson's Disease
- rheumatoid arthritis
-
symptoms of of hypothermia
- shivering
- thinking becomes sluggish
- decreased coordination
- stuporous
- decreased HR and RR
- decreased cardiac output
- Moderate to severe acidosis
-
Consciousness
alertness with orientation to person, place and time
-
confusion
alteration of perception of stimuli
-
Confusion progresses in what steps
-
Lethargy
oriented x3 but slow vocalization, decreased motor skills
-
Obtundation
awakens in response to stimulation, continuous stimulation needed for arousal, eyes usually closed
-
Stupor
arouses only to painful stimuli
-
Coma
no arousal to any stimulus but brainstem reflexes intact
-
Progression of Nonresponsiveness:
1. Diencephalon (thalamus/hypothalamus):
dull, lethargic, obtundation, pupils respond briskly, full-range eye movements only on "doll's eyes"- none in direction of rotation on or after injection of hot or cold water in ear canal (caloric posturing)
2. Midbrain:
- stupor or coma
- neurogenic hyperventilation
- midposition fixed pupils (MPF)
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