Receptors Flashcards
what do receptors do
convert stimuli to action potentials
what are receptors
nerve endings
3 types of sensory receptors
mechano receptors
proprioceptors
nociceptors
what do mechanoreceptors sense
touch and pressure
what do proprioceptors sense
touch and pressure in muscle and joints- limb position
what do nociceptors sense
pain- heat and tissue damage
sensory modality
stimulus type that activates a receptor
sensory receptor specificity
highly sensitive to a specific energy form
but can be activated by other INTENSE stimuli
stimulus in mechano receptors and propioceptors
membrane deformation
sensory receptor transduction involves
ion channels opening
an adequate stimulus creates
a graded membrane potential
called: receptor potential/ generator potential
what does membrane deformation lead to in mechanoreceptors and proprioceptors
it activates stretch sensitive ion channels
so ions flow across the membrane and change the local membrane potential
after the local membrane potential is changed what happens
depolarisation travels and reaches a node of ranvier, opening voltage gated ion channels
firing and action potential
what happens after the local membrane potential is changed
frequency coding of stimulus intensity
a large stimulus causes
a LARGER RECEPTOR POTENTIAL and
a higher frequency of action potentials
mechano receptors: what do merkel receptors sense
steady pressure and texture
mechano receptors: what do meissner’s corpuscle sense
flutter and stroking movements
mechano receptors: what do ruffini corpuscles sense
stretch in skin
mechano receptors: WHAT DO PACINIAN CORPUSCLE SENSE
VIBRATION
mechano receptors: what do free nerve endings of hair roots sense
hair movement
nociceptors are made of ____ and sense___
free nerve endings
noxious stimuli
what carries the signal from skin receptors
sensory nerves- to spinal cord
mechano receptors and constant stimulation
some continue to produce AP’s
others drop and only produce AP’s if the stimulus changes
rapid/moderatly adapting receptors
pacinian corpuscles
meissner’s corpuscles
(corpuscles are very fast)
slowly adaoting receotors
merkel’s discs
ruffini endings
receptors that don’t adapt
nociceptors
mechanoreceptors that sense body or limb position
muscle spindles
golgi tendon organs
muscle tension
joint receptors
what do muscle receptors do
monitor muscle length
and
rate of change of muscle length
what do golgi tendon organs monitor
tension of tendons
what do joint receptors monitor
joint angle
rate of angular movement
tension of joints
what provides info to spinal cord for reflex movements
muscle spindles
and
golgi tendon organs
what are muscle spindles
specialised muscle fibres with its own sensory and nerve innervation- intrafusal muscle fibres
2 types of intrafusal fibre
nuclear bag- bag shaped with nuclei collected together
nuclear chain- nuclei lined in a chain
annulospiral endings
primary endings from Ia afferent nerves that wrap around intrafusal fibres
what parts of intrafusal fibres contract
and what innervates them
just the ends (middle gets stretched)
gamma motoneurons
muscle spindles lie in ___ with extrafusal muscle fibres
parallel
golgi tendon organs lies in ___ with extrafusal muscle fibres
series
