2 Flashcards
what is a receptor?
peripheral ending of sensory neuron
what is a neural pathway?
axons of sensory neurons enter CNS and connect to other neurons
neurons with same function are grouped into bundles(pathways)
how are pathways specific?
modality- eg. touch, pain, vision
where do neural pathways terminate?
particular areas of the brain-primary receiving areas
what’s in a peripheral nerve?
some contain sensory axons only, other have both motor and sensory
what is the brachial plexus?
innervation of the upper limb axillary musculocutaneous radial ulnar median
describe an A alpha axon
large diameter 13-20 microm
fast conduction (80-120m/sec)
innervates muscle
describe an A beta axon
diameter 6-12
conduction fact but slower than alpha (35-75 m/sec)
mechanoreceptors in skin
describe an A delta axon
diameter 1-5
speed 5-30
pain/temperature
describe a C axon
diameter 0.2-1.5
speed 0.5-2
dull, ache pain
itch, temperature
describe the trigeminal nerve
ophthalmic branch & maxillary branch = sensory
mandibular branch = sensory & motor
what is mechanoreception?
touch
what is nociception?
pain
give the sensory pathway to the cerebral cortex
primary sensory pathway -periphery secondary sensory pathway -CNS tertiary sensory neuron -thalamus
why is the brain image distorted?
areas with high density of receptors (small receptive field) are represented more widely in the cortex
what is stereognosis?
ability to recognise objects by feel alone requires: 3D mental image + previous experience =memory co-ordinated cortical processing
what is proprioception
perception of position and movement of the body
where body parts are w/o visual
