The Body Senses part 1 Flashcards
what are thermocepters known as & what are they
“free nerve endings” - signal skin temperature (warmth & cold fibres)
what are three parts of propriception/kinaethesia
- muscle spindles
- golgi tendon organs
- join receptors
what do muscle spindles do
respond to muscle length & rate of stretch
what do golgi tendon organs
respond to muscle tension
what do joint receptors do
respond to joint position
discuss the somatosensory hierachy
- two separate pathways that take signals up the to the brain
- spinothalamtic pathway
- lemniscal pathway
- both have branching circuits in the spinal cord that mediate reflex responses
what does the spinothalamtic pathway carry
relatively slow temperature signals from free nerve endings
what does the lemniscal pathway carry
relatively fast signals from mechanoreceptros
what is the primary somatosensory cortex
a thin strip running over the top of the head (ear to ear)
discuss somatotopic organisation
bits next to eat other on the body are represented next to each other in the cortex
discuss cortical magnification
some body parts (lips, hands) occupy a much greater cortical area than others (torso)
what is the somatosensory homunculus
the “little man” in your head
-illustrates somatopic organisation & cortical magnification
how did we find out about the somatosensory homunculus
derived from microstimulation during surgery for epilepsy
discuss receptive fields
- each cortical cell responds to stimulation in a small area of the body surface
- the area wherein touch affects activity in a given cell is known as its “receptive field”
what is the centre-surround antagonism (aka lateral inhbition)
there are two concentric zones in receptive field (RF)
