chapter 14: spinal cord, part 2 - receptors

which nervous system provides links TO and FROM the world outside the body?

PNS

the "somatic nervous system" and "autonomic nervous system" (SNS and ANS) are components of?

the PNS's motor (efferent) division

the peripheral nervous system consist of?

ALL neural structures outside the brain and spinal cord

sensory receptors provide information about both ________ and ____________.

external & internal environments

each type of sensory receptor responds BEST to a type of?

stimulus

what is a sensation?

a stimulus we are CONSCIOUSLY aware of

to enter our consciousness, the signals we receive must reach the?

cerebral cortex

what is one way that we categorize sensory receptors?

by the modality of the stimulus, or the stimulating agent

receptors that detect chemicals dissolved in fluid

chemoreceptors

chemoreceptors include

both exteroceptors (eg smell of food) and interoceptors (eg O2 levels in blood)

receptors that detect changes in temperature

thermoreceptors

thermoreceptors can be found in

skin and hypothalamus

receptors that detect changes in light intensity, color, or movement

photoreceptors

photoreceptors are found in

retina of the eye

receptors that detect distortion of cell membrane

mechanoreceptors

mechanoreceptors include receptors for?

touch, pressure, vibration, stretch

baroreceptors

detect changes in blood pressure

proprioceptors

monitor the position and movement of skeletal muscles and joints

specialized receptors

in your skin sense touch; they pick up light touch, vibrations, temperature, and pain

mechanoreceptors can function as

baroreceptors, proprioceptors, tactile receptors, specialized receptors in inner ear

receptors that detect painful stimuli

nociceptors (noci-ceptors)

two divisions of nociceptors

somatic & visceral; chemical, heat, mechanical damage

other than the modality of the stimulus, what is another way we can categorize sensory receptors?

location

receptors that detect stimuli from the external environment

exteroceptors

receptors that detect stimuli from the internal organs

interoceptors

receptors that detect body & limb movements

proprioceptors

skin and mucus membrane receptors are

exteroceptors

special sense receptors are

exteroceptors

SOMATOSENSORY receptors of muscles, tendons, joints are

proprioceptors

other than the modality of the stimulus and location, what is another way we can categorize sensory receptors?

structure of the receptors

in terms of classification by receptor structure, we have two types. they are?

simple receptors for general senses, and receptors for special senses

general senses

TACTILE - temperature, pain, touch, pressure, vibration, proprioception, stretch

special senses

vision, hearing, taste, smell, equilibrium

what helps to determine stimulus duration?

receptor adaptation, the decreased sensitivity to continuous stimulus

a TONIC receptor shows _________ adaptation, and will respond ________________.

slow; continuously as long as the stimulus is present

a PHASIC receptor shows _________ adaptation, and will respond ________________.

rapid; briefly at the onset or offset of a stimulus

explain tonic vs phasic receptors

tonic = monitor steady, ongoing stimuli & thus help maintain awareness of CONSTANT conditions, such as balance or stretch

meanwhile, phasic = quickly respond to a new movement, but dont detect its persistence; ex when u wear a watch, u feel it at first, but after a short time, you stop noticing it unless the watch moves or you take it off

pressure receptors would count as

phasic

pain receptors & head position receptors would count as

tonic

the INACCURATE localization of sensory signals is called?

referred pain

why does referred pain happen?

basically, signals from the VISCERA are perceived as originating from the skin or muscle; this is bc somatic & visceral receptors often send signals via the SAME ascending tracts in the spinal cord, so sometimes the somatosensory cortex cant tell the tru source

referred pain: heart attack pain may be referred to? why?

pectoral region & medial arm; sympathetic innervation of the heart & innervation of these skin regions both come from T1-T5 segments of spinal cord

referred pain: kidney/ureter pain may be referred to? why?

INFERIOR abdomen, bc T10-L2 spinal nerves

referred pain: visceral pain is often conveyed along ________ nerves, but occasionally on ___________ nerves. for example

sympathetic, parasympathetic; bladder pain can be conveyed via sacral parasympathetic nerves = referred to buttocks