Peripheral Nervous System Flashcards
Peripheral Nervous System
consists of cranial and spinal nerves that branch out from the brain and spinal cord to all body parts
divisions of peripheral nervous system
sensory (afferent) division
motor (efferent) division
motor (efferent) division
*motor neurons activate effectors by releasing neurotransmitters
*effectors include skeletal muscle, visceral muscle, and glands
sensory (afferent) division
specialized to respond to changes in environment
*awareness of stimulus (sensation) and interpretation of meaning of stimulus (perception) occur in brain
general senses
*receptors that are widely distributed throughout the body (skin, organs, joints)
*includes tactile sensation (touch, pressure, stretch, vibration) temperature, pain, muscle sense
special senses
more specialized receptors found in places like the eyes and ears
major types of receptors
chemoreceptors
pain receptors
thermoreceptors
mechanoreceptors
proprioceptors
baroreceptors
stretch receptors
photoreceptors
chemoreceptors
*respond to changes in chemical concentrations
*sense of smell and taste
*internal chemoreceptors detect changes in concentration of oxygen, hydrogen, ions, glucose, and other chemicals in the blood
pain receptors
*respond to tissue damage
*triggered by mechanical, electrical, thermal, or chemical energy
*receptors adapt poorly, may send impulse to CNS for some time
*may exhibit referred pain-pain that seems to come from another part of body
fast pain fibers
*thin, myelinated
*conduct impulses rapidly
*associated with sharp pain
*well localized areas of the skin
slow pain fibers
*thin, unmylinated
*conducts impulses more slowly
*associated with dull aching pain
*usually visceral and difficult to pinpoint
thermoreceptors
respond to changes in temperature
mechanoreceptors
respond to mechanical forces
proprioceptors
sense change in tension of muscles and tendons
baroreceptors
detect changes in blood pressure
stretch receptors
sense degree of inflation in lungs
photoreceptors
found in eyes, respond to light
sensory impulses
*stimulation of receptor causes local change in the receptor membrane
sensory adaptation
*ability to ignore unimportant or continuous stimuli
*involves decrease response to particular stimulus from the receptor
exteroceptive sense
sense associated with body surface
touch, pressure, temperature, pain
interoceptive sense
sense associated with changes in viscera
blood pressure, stretching blood vessels
proprioceptive sense
senses associated with changes in muscle and tendons
touch and pressure receptors
receptors sensitive to mechanical forces
*nonencapsulated nerve endings
*tactile (meissners) corpuscles
*lamellated (pacinian) corpuscles
nonencapsulated (free) nerve endings
*detect touch and pressure
*common in epithelial tissues
*responsible for the sensation of itching