Chapter 16: Pain, Temp, Sleep Flashcards
Specificity theory of pain
Pain and touch are carried on distinct pathways that project to different brain centers
Intensity of pain is related to the amount of associated tissue injury
Pattern theory of pain
Different sense organs have different levels of responsiveness to stimuli with different spatial and temporal profiles firing
Gate control theory of pain
Gate either opens or closes
Nociception
the processing of potentially harmful stimuli through a normally functioning nervous system
Nociceptors
Free nerve endings in afferent PNS that selectively respond to stimuli
A delta fibers
Lightly myelinated, medium, fast transmission
Reflex withdrawal due to pain or heat
Fast like delta force
C fibers
Smaller and unmyelinated
Slow, dull, aching pain poorly localized
A beta fibers
Large and myelinated
Touch and vibration
Pain transduction
Tissue is damaged; activation of nociceptors
Pain transmission
Conduction of pain impulses along A delta and C fibers into dorsal horn of spinal cord up to cortex for interpretation
Pain perception
Conscious awareness
Occurs in reticular and limbic and cerebral cortex
Pain modulation
Increase or decrease in transmission of pain signals
Segmental inhibition of pain
Rubbing an area that is injured
A beta fibers stimulated and impulses arrive at same spinal level as A delta or C fibers
Conditioned pain modulation
Pain is relieved when 2 noxious stimuli occur at the same time from different sites
Perceptual dominance
Pain at one site may mask another painful area
Nociceptive pain
Pain with normal tissue injury from known cause
Normal protective mechanism
Acute pain
Can last up to 3 months
Increased HR, BP, Sweating, dilated pupils, increased glucose
Chronic pain
More than 3-6 months
Out of proportion to any tissue injury
Hyperalgesia
increased sensitivity to pain
Allodynia
Pain due to normally nonpainful stimuli
Myofascial pain syndrome
Injury to muscle fascia and tendons
Compression of trigger point causes referred pain and becomes more generalized
Normal body temp
97.2-99.9
What mediates temperature primarily
Peripheral thermoreceptors in skin and abdominal organs
Chemical thermogenesis
Hypothalamus stimulates release of TSH from anterior pituitary, thyroxine released, adrenal medulla releases epinephrine, leads to vasoconstriction, glycolysis and increased metabolic rate
Body heat conservation
Hypothalamus stimulates SNS, which stimulates adrenal cortex, increased skeletal muscle tone and shivering and vasoconstriction keeps heat from escaping
Radiation
Heat loss through electromagnetic waves
Conduction
Direct molecule to molecule transfer
Convection
Through currents of gases or liquid
Mechanisms to lose heat
Vasodilation, hyperventilation, sweating
Aging and temperature
Slowed blood circulation, decreased shivering, decreased metabolic rate, decreased sweating
Decreased or no fever response to infection
Pathogenesis of fever
Pathogens produce endotoxins; production of prostaglandin E2 in periphery and brain; Increased temperature, B cell proliferation, increased catecholamines, vasoconstriction, shivering
Benefits of fever
Kills microorganisms, decreases iron, zinc and copper, causes lysosomal breakdown and auto destruction of cells
Hyperthermia
Increase in body temperature without increase in hypothalamic set point
Can produce nerve damage, coagulation of cell proteins and death
Heat cramps
Severe, spasmodic cramps in abdomen and extremities due to prolonged sweating and Na loss
Fever, increased HR and BP
Heat exhaustion
Prolonged high core temperature; profound vasodilation and sweating
Leads to dehydration
Heat stroke
At 104 degrees, regulatory system stops and body’s heat loss mechanisms fail
Absence of sweating, increased HR, confusion
Malignant hyperthermia
Inherited muscle disorder triggered by anesthetics
increased intracellular Ca levels: sustained uncoordinated muscle contractions
No reflexes, fixed pupils, apnea
Hypothermia causes
Depression of CNS and resp system, vasoconstriction and ischemic tissue damage
Parodoxical undressing
as hypothermia deepens, there is a shift to vasodilation–patient feels hot
NREM sleep
Slow wave sleep
Decreased SNS and Increased PNS activity
Growth hormone released in N3
Decreased corticosteroids and catecholamine release
Aging and sleep
Total sleep time decreased
Decreased slow wave sleep
Dyssomnias
Difficulty in initiating or maintaining sleep or presence of excessive sleepiness
Types of dyssomnias
•Insomnia
•restless leg syndrome
•obstructive sleep apnea syndrome
•hypersomnia
•narcolepsy
•circadian rhythm disorders
Parasomnias
Awakening from REM or partial arousal form NREM
Examples of parasomnias
Sleep walking, night terrors, night cramps, SIDS
Touch and sedatives or prefrontal injury
Decreased interpretation of tactile sensations
Meniere disease
Episodic vestibular disorder due to neuroepithelial damage related to abnormalities in the quantity, composition and pressure of endolymph in the middle ear
Vertigo, hearing loss, tinnitus
Blepharitis
Inflammation of eyelids due to staph
Redness, edema, tearing, itching
External hordeolum
Stye
Infection of sebaceous glands
Entropion
Lid margin turns inward against eyeball
Ectropion
Lid margin turns outward
Trichasis
Eyelashes grow back towards eye
Acute bacterial conjunctivitis
Pinkeye
Usually self limiting
Viral conjunctivitis
Caused by adenovirus
Trachoma
Caused by chlamydia
Leading cause of preventable blindness
Keratitis
Inflammation of cornea
Can be noninfectious or infectious
Strabismus
Deviation of one eye from other when looking at object
Neuromuscular disorder of eye muscle
Primary s/s: diplopia
Nystagmus
May be due to imbalance in normally coordinated reflex activity of inner ear
Amblyopia
Lazy eye
Due to altered development of visual cortex
Scotoma
Circumscribed defect of central field of vision
Age related to do with this
Cataract
Cloudy/opaque area in ocular lens
Due to alterations of metabolism and transport of nutrients within lens
Glaucomas
Intraocular pressure >12-20
Degeneration of peripheral vision followed by central vision
Retinal detachment
Fluid separates photoreceptors from retinal pigment epithelium
Deprives outer retina of O2 and nutrients
Age related macular degeneration
Severe and irreversible loss of vision
Due to age, htn, smoking, diabetes, family hx
Presbyopia
(Nearsightedness)
Ocular lens becomes larger, firmer, less elastic
Occurs >45 years old
Decrease in near vision
Myopia
Nearsightedness
Hyperopia
Farsightedness
Astigmatism
Unequal curvature of corna
Light rays bent unevenly
Presbycusis
Loss of hearing in increased age
Loss of hearing high frequency common
Conductive hearing loss
Due to change in outer or middle ear
Sensorineural hearing loss
Impairment of organ of corti
Due to noise exposure, aging, meniere disease, ototoxicity, systemic disease
Risk factor for otitis externa
Swimming
Otitis media due to
HIB most commonly in children
Hyposmia
Impaired sense of smell
Hypoguesia
Impaired taste sensation
When does nocturnal angina occur
REM sleep
Visceral pain transmitted by
Sympathetic afferent nerves
Diabetic neuropathy causes
Chronic, peripheral pain
Due to damaged nerves–become hyper excitable and fire even when absence of pain signals
