Exam 2 - Ch. 16 Flashcards
- Begin in the PNS, travel to the spinal gate in the dorsal horn, and then ascend to higher centers in the CNS.
- Somatic pain • Visceralpain
Afferent pathways
Are located in the brainstem, midbrain, diencephalon, and
cerebral cortex
Interpretive centers
Descend from the CNS to the dorsal horn of the spinal cord
Efferent pathways
The processing of pain
Nociception
Transduction, transmission, perception, modulation
Phases of nociception
begins when tissue is damaged by exposure to noxious (chemical, mechanical, or thermal) stimuli, and is converted to electrophysiologic activity.
Transduction
conduction of pain impulses along the
A and C fibers into the dorsal horn of the spinal cord and eventually to the reticular formation, hypothalamus, thalamus, and limbic system
Transmission
is the conscious awareness of pain
a. Sensory-discriminating system
b. Affective-motivational system
c. Cognitive-evaluative system
Perception
process of increasing or decreasing transmission of
pain signals throughout the nervous system
Modulation
nociceptors
Stimulated by severe mechanical deformation, mechanical deformation, and/or temperature extremes.
1st order neurons
transmission is fast → reflex withdrawal of affected body part from stimulus before pain sensation is perceived.
Myelinated A-delta fibers
stimulated by mechanical, thermal, and chemical nociceptors
Transmissionisslowerandconveysdull, aching, or burning sensations.
Unmyelinated C polymodal fibers
large myelinated fibers that transmit touch and vibration sensations
A-beta fibers
are interneurons in the dorsal horn of the spinal column
2nd-order neurons
are afferent neurons in the spinothalamic tract
Carry information to reticular formation,
hypothalamus, thalamus, and limbic system to interpret pain location and intensity
3rd-order neurons
Is the lowest intensity of pain that a person can recognize
Pain threshold
Is the greatest intensity of pain that an individual can endure
Is very individualized
Pain tolerance
Thermoregulation is controlled by this
hypothalamus
Radiation • Conduction • Convection • Evaporation • Vasodilation • ↓ muscle tone • ↑ pulmonary ventilation • Voluntary mechanisms • Heat adaptation
Heat Loss
Vasoconstriction
Voluntary mechanisms
Heat Conservation
Infants produce sufficient body heat (brown fat) but are unable to conserve the heat produced
Inability to shiver
Pediatric considerations temp regulation
Slower circulation and vasoconstriction/vasodilator responses.
Aging considerations in temp regulations
Fever is stimulated by this
Tumor necrosis factor-α
