Ch 10 Flashcards
characteristics of sensory receptors
-specialized cells that detect special kinds of stimuli
-able to produce an electric response
-not neurons or glia
-located in a variety of places within the body. Some are at the body’s surface to detect external stimuli, some are within the body to monitor
internal organ functions.
chemoreceptors
-respond to chemicals
ex: taste, smell, and pH levels
photoreceptors
-responds to light
ex: vision (rods, cones)
thermoreceptors
-responds to temp
ex: cutaneous receptors
mechanoreceptors
-responds to physical deformation
ex: hair cells (hearing; vestibular); (cutaneous receptors)
nociceptors
-responds to pain
-can be chemical, thermal or mechanical
all receptors have three general parts
-receptive area
-area rich in mitochondria
-synaptic area
-they must transduce (change) a physical stimulus into an electrical signal called a receptor potential
receptor potential
-a graded (added up), local (restricted to one place in
the sensory receptor) electrical response of a sensory receptor
generator potential
-receptor cells can propagate an electrical signal in the form of an action potential
sensory sys
-broken up into parts
(special sensory & somatosensory aka gen sensory)
special sensory
-sensations experienced by special sensory structure
special sensory example
-vision, hearing, smell, taste and balance
somatosensory (gen sensory)
-sensations experienced by the skin & subcutaneous tissue, muscles tendons, joints, bones, and viscera
somatosensory (gen sensory) example
-tactile (touch, pressure, vibration, etc)
-proprioception (position sense)
-pain & temp
first step in somatosensation
-sensory stimulus (external or internal)
second step in somatosensation
-picked up by a specialized sensory receptor wehre stimulus is transduced into an electrical impulse
third step in somatosensation
-receptor potential & sometime also an action potential
fourth step in somatosensation
-info travels toward the CNS via the peripheral process of a psudounipolar sensory neuron whose cell body is in the dorsal root ganglion
fifth step in somatosensation
-central process of pseudounipolar sensory neuron then transmits info to other parts of the CNS via various pathways & synapses
higher density of receptors lead to
-better tactile discrimination
better tactile discrimination
-lower 2 point discrimination value
pain receptors
-Some nociceptors are specialized to detect specific types of stimuli, such as temperature, mechanical, or chemical signals
-Others are polymodal, meaning they can respond to multiple types of stimuli
-Pain serves a crucial role by alerting us to potential danger or injury.
pain syndrome
-many different types
-congenital insensitivity to pain
-hyperalgesia/sensitization
-phantom limb pain
-neuralgia
congenital insensitivity to pain
-sometimes with anhidrosis (no sweating; CIPA): children born without ability to
perceive pain
hyperalgesia/sensitization
-enhancement of the sensation of pain
-pat on back after a sunburn
phantom limb pain
-the experience of pain emerging from an amputated limb
neuralgia
-severe persistent pain in the distribution of a cranial or
spinal nerve
three coverings
-perineurium
epineurium
-endoneurium
epineurium
-dense, loose connective layer enclosing each peripheral nerve
-continuous with dura mater
perineurium
-lies within epineurium
-sheath of connective tissue continuous with arachnoid enclosing each bundle of nerve fibers
endoneurium
-loose, delicate connection tissue within the perineurium
-indiv nerve fibers are enclosed
joint receptor
-located in the joints
-detects joint position & and movemement
golgi tendon organs
-able to detect & monitor muscle tension as a result of muscle contraction
-located at the junction btwn the muscles and the tendons
muscle spindles
-attached to ordinary muscle fibers, so when they stretch muscle stretches
-allows us to detect both length of muscle at rest and rate of length change
