Flashcards in CNS Ch 12 Deck (56)
Specialized to respond to changes in environment called stimuli
Classification by stimulus type
Respond to mechanical force such as touch, pressure, vibration, and stretch
Respond to light, such as those in the retina.
Respond to chemicals in solution ( molecules smelled or tasted, or changes in blood or interstitial fluid chemistry)
Respond to potentially damaging stimuli that result in pain (extremes of cold and heat, excessive pressure and inflammatory chemicles
Classification by location
Exteroceptors: Outside the body
Internoceptors: Within the body
Occure in skeletal muscles, tendons, joints, ligaments and connective tissues or bones and muscles
Simple receptors of general sences
Non-encapsulated (free) nerve endings
Encapsulated nerve endings
Non-encapsulated nerve endings
Non-mylinated, small diameter and have knob like distal ends
Nearly everywhere, abundant in epithelial and connective tissue.
Examples: Tactile (merkel) disk in skin and Hair follicle receptors
Encapsulated nerve endings
ONe or more fiber terminal enclosed in connective tissue capsule
Joint kinethetic receptors
Part of the sensory system serving the ody wall and limbs. Receives input from exteroceptors, interoceptors and proprioceptors
3 levels of neural integration
Receptor level: sensory receptors
Circuit level: processing in ascending pathways
Perceptual level: processing in cortical sensory areas
Ability to detect that stimulus has occured
Ability to detect how intense the stimuli is
Ability to identify the site and pattern of stimuli
The ability to identify multiple features of an object
Ability to identify submodalities of a sensation, eg. sweet or bitter.
Ability to recognize a familiar or unfamiliar pattern, or a special significance.
Results from noxious stimulation of receptors in thorax or abdomen.
Vague, dull, aching or burning
Arises from one part of the body but is perceived in another part.
Cord like organ, consists of multiple fascicles full of axons and a blood supply
Endoneurium: encloses each axon
Perineurium: surrounds each fascicle
Epineurium: encloses all fascicles, outer sheath of nerve.
Regeneration of PNS nerves
1. Axon fragments at injury site
2. Macrophages clean out the dead axon
3. Schwann cells form regeneration tube and axon sprouts grow through tube.
4. Axon regenerates and new myelin sheath forms
Tiny nerve filaments of sense of smell
SENSORY ONLY, nerve of vision, outgrowth of the brain so it is actually a tract.
MOTOR ONLY, "eye mover", supplies the 4 extrinsic muscles that move the eyeball up down and inward.
MOTOR ONLY, "pulley" innervaed the extrinsic eye muscle that rotate eye inferolaterally
SENSORY & MOTOR to the face and chewing muscles