quiz 1 Flashcards
List 8 sensations
touch
pressure
vibration
limb position
heat
cold
itch
pain
Information in skin and muscles from receptors goes where
central nervous system (CNS)
Is the somatosensory system specialized?
a) True
b) False
a) true
Cutaneous Mechanoreceptors
fine touch
vibration
pressure
Proprioception
the ability to sense the position of our own limbs and other body parts in space
Free Nerve Endings
pain
temperature
coarse touch
Dermatome
areas of skin on your body that rely on specific nerve connections on your spine
Ia, Ib, II afferents
largest and fastest, supply sensory receptors to muscles for proprioception
Aβ afferents
smaller, convey touch
Aδ and C afferents
small and slow, pain and temperature
Sensory Function: Proprioception
receptor type: muscle spindle
afferent: Ia, II
Sensory Function: Touch
receptor type: merkel, meissner,pacinian, ruffini
afferent: Aβ
Sensory Function: Pain and Temperature
receptor type: free nerve endings
afferent: Aβ
Sensory Function: Pain, Temperature, and Itch
receptor type: free nerve endings (unmyelinated)
afferent: C
Receptive FIelds
the area of the skin surface over which stimulation results in a significant change in the rate of action potentials
Slowly Adapting Afferents
generate sustained discharge during ongoing stimulus
provide spatial info: size and shape of stimulus
Rapidly Adapting Afferents
fire rapidly when a stimulus is first presented
fall silent with continual stimulation
convey changes (stimulus movement)
Epidermis Region
pain
motion detection & grip
shape & texture
Dermis Region
force, shape & internally generated motion
Subcutaneous Region
vibrations
Small Receptor Fields
merkel
meissner
Large Receptor Fields
pacinian
ruffini
Merkel
25% of mechanoreceptors in the hand
mainly in fingertips
highest spatial resolution of all sensory afferents
Meissner
40% of the mechanoreceptors in the hand
closest to the skin surface
textured objects that move across the skin
Pacinian
10-15% of the mechanoreceptors in the hand
detect vibrations transmitted through held objects
skilled use of tools (using a wrench, writing, cutting bread with a knife)
Ruffini
20% of the mechanoreceptors in the hand
sense skin stretching, movement, and finger position
least understood
internally generated stimuli: movement of fingers
Muscle Spindle
signal changes in muscle length
Primary Ending (Ia)
largest myelinated axons rapidly respond to changes in muscle length
transmits information on limb position and direction of movement
Secondary Endings (II)
produce sustained responses to static position of muscle length
Golgi Tendon Organs
signal change in muscle tension
Joint Receptors
relay finger position for range of motion
Central Pathway: Tactile from Body
