Ch. 15 Pain, Temperature, Sleep, and Sensory Fxn Flashcards
What is the difference between A-delta and C fibers?
Both are primary types of nociceptors. A-delta are larger myelinated fibers that transmit sharp, well-localized “fast” pain sensations (e.g. intense heat or a pinprick to the skin). Activate spinal reflex. C fibers are smaller, unmyelinated, and located in m., tendons, body organs, and skin. Slowly transmit dull, aching, or burning sensations that are poorly localized and often constant.
Give 2 examples of pain excitatory and inhibitory neurotransmitters
For excitatory neurotransmitters:
1. glutamate and aspartate in the CNS
2. GABA and glycine in the CNS
How do A-delta fibers inhibit pain and cause pain?
When activated, these fibers cause a spinal reflex withdrawal of the affected body part from the stimulus before the pain sensation is perceived.
What are 2 differences between nociceptive pain and neuropathic pain?
Nociceptive pain includes somatic, visceral, and referred pain, meanwhile neuropathic includes central and peripheral pain. Nociceptive pain is acute and a normal protective mechanism that alerts the body of a condition/experience that is harmful to the body, mobilizing the individual. Neuropathic pain is chronic pain initiated/caused by a primary lesion or dysfxn in NS, leads to long-term changes in pain pathway structures (neuroplasticity) and abnormal processing of sensory info.
What does GABA stand for?
gamma-aminobutyric acid
What are the principal heat production and heat loss methods?
Heat production: chemical rxns of metabolism and skeletal m. tone and contraction. Distributed by the circulatory system.
Heat loss: radiation, conduction, convection, vasodilation, evaporation, decreased m. tone, increased respiration, voluntary measures, and adaptation to warmer climates.
How does the hypothalamus alter its set point to change body temperature?
Fever involves the “resetting of the hypothalamic thermostat” to a higher level. When it breaks the set point returns to norm. It is triggered by release of endogenous pyrogens from phagocytic cells
Compare and contrast hyperthermia and hypothermia and their effects on the body.
Hyperthermia can produce n. damage, coagulation of cell proteins, and death. Hypothermia slows the rate of cell metabolism, increases the viscosity of the blood, slows blood flow through the microcirculation, facilitates blood coagulation, and stimulates profound vasoconstriction.
Describe REM and non-REM sleep
REM sleep is controlled by the mechanisms in the pons and mesencephalon. It is known as paradoxical sleep because EEG pattern resembles waking pattern and brain is active with dreaming. Non-REM sleep is controlled by release of inhibitory signals from the hypothalamus and and accounts for 75-80% of sleep time. Body is in state of reduced activity.
What’s the major difference between the dyssominias and parasomnias?
Dyssomnias are disorders of initiating or maintaining sleep (i.e. insomnia, OSAS, hypersomnia, sleep-wake cycle disorders) meanwhile parasomnias (i.e. sleepwalking, nights terrors, and RLS) are unusual behaviors during sleep.
How are different touch receptors distributed over the body?
The sensation of touch is a function of receptors present in the skin, and the sensory response is conducted to the brain through the dorsal column and anterior spinothalamic tract.
What are 2 causes of alterations in proprioception?
Disorders of proprioception can occur at any level of the nervous system and result in impaired balance and lack of coordinated movement. Vestibular nystagmus is the constant, involuntary movement of the eyeball and develops when the semicircular canal system is overstimulated. Vertigo is the sensation of spinning that occurs with inflammation of the semicircular canals in the ear.
List the major structures of the eye
- Sclera (thick white, outermost layer)
- Cornea ( slera portion in central ant. region that allows light to enter the eye)
- Choroid (deeply pigmented middle layer; prevents light from scattering inside eye)
- Iris (part of choroid)
- Pupil ( round opening of iris)
- Retina (innermost layer w/ millions of rods and cones)
Name the different categories of visual disorders
- alterations in visual acuity (e.g. cataracts, glaucoma, macular degeneration ..)
- alterations in accommodation aka changes in lens shape (e.g. presbyopia)
- alterations in refraction (e.g. myopia, hyperopia, astigmatism)
- alterations in color vision
How does fluid accumulate in the middle ear during otitis media?
Otitis media is an infection of the middle ear that is common in children. Accumulation of fluid (effusion) behind the tympanic membrane is a common finding
