Sensory modalities

neuro

mechanoreceptors

type II fibers


1. pacinian corpuscles
2. ruffini corpuscles
3. meissner corpuscles
4. merkel’s disks

pacinian corpuscles

deep & rapid adapting

deep pressure and high frequency vibration

large receptive field

ruffini corpuscles

deep & slow adapting

slippage of objects along skin surface

skin stretching

large receptive field

meissner’s corpuscles

superficial & rapid adapting

light touch, light movement along skin

small receptive field

merkel’s disks

superficial & slow adapting

pressure & texture, edges, and corners

small receptive field

what happens during object slippage adjustment?

1. meissner detects start/stop of slippage
2. ruffini adjusts grip to counter slippage

mechanical nocioceptor

type III fiber

1st pain: sharp

polymodal nocioceptor

type IV

2nd pain: burning

cold receptor

type III

warm receptors

type IV

Thermoreceptos respond to __ in temperature, not ____ temperature

changes, absolute

golgi tendon

measures change in force/tension

type Ib fibers

muscle spindles

measures changes in length

type Ia and type II fibers

type Ia fibers activate

alpha motor neurons to contact extrafusal fibers and relax antagonist muscles to prevent further stretch

type II fibers activate

gamma motor neurons to contract intrafusal fibers to take out the slack when alpha motor neurons contract

nuclear bag fibers

intrafusal fiber

has type Ia fibers

nuclear bag 1 fibers

dynamic- fast for complex movements

increase stretch sensitivity

nuclear bag 2 fibers

static (slow for simple movements)

increasing firing rate

nuclear chain fibers

has type Ia and type II fibers

static only