Neuroanatomy - 08 Somatosensory Systems

made from pptx 8a - 2025 somatosensory I & II

haptic exploration

____________ uses tactile, proprioceptive and kinesthetic exploration to determine the characteristics of an object, like shape, size, and texture

somatic sensations

______________ are determined in the environment around us via haptic exploration

cutaneous, proprioception

_________ sensations from the foot and ____________ from joint receptors helps us with balance

cerebellum

the ___________ helps smooth out movements

stimulus, sensation, perception

first, a ________ occurs where an external event applies some sort of energy. then, __________ is awareness of the situation, and ___________ is the awareness plus and internal construct of the sensory experience

discriminative

(discriminative/nondiscriminative) touch is fine touch, with precise detection of location and modality

nondiscriminative

(discriminative/nondiscriminative) touch is crude touch or light touch

touch

_______ can be nondiscriminative, discriminative, vibration, or pressure

proprioception

____________ is the sense of positioning

kinesthesia

___________ is the sense of joint movement

sensory receptors

____________ are modified axon terminals of sensory neurons that may be associated with non-neural structures

stimulus energy

each sensory receptor is responsive to a specific type of _______________-

mechanical pressure, distortion

mechanoreceptors are responsive to __________ and __________

taste, smell

chemoreceptors are responsive to __________ and __________

hot, cold

thermoreceptors are responsive to __________ and __________

pain, high intensity stimulus, chemicals

nociceptors are responsive to _____ via __________ or __________

high intensity stimulus

nociceptors need a ______________ because they have a higher threshold

somatic

exteroceptors and proprioceptors are (somatic/visceral)

visceral

interoceptors are (somatic/visceral)

somatic, skin

exteroceptors are (somatic/visceral) receptors found in the _______

somatic, muscle and joint

proprioceptors are (somatic/visceral) receptors found in the _______

visceral, organs

interoceptors are (somatic/visceral) receptors found in the _______

POORLY LOCALIZED

visceral interoceptors provide general sensation that is ________ _________

auditory, visual, olfactory, vestibular, taste

other special sensory receptors are:

lateral

at the DRG, the (medial/lateral) group is small fibers for pain and temperature

medial

at the DRG, the (medial/lateral) group is larger fibers for touch and proprioception

lateral

at the DRG, the (medial/lateral) group is headed to the ALS

medial

at the DRG, the (medial/lateral) group is headed to the P/DCML

F; small stimuli may not generate response bc of threshold required

T/F: all sensory stimuli generate an action potential

density, field size, processing in CNS

the ability to localize a stimulus depends on the receptor ________ and _________, and the ____________

receptor density

a higher ___________ allows closer stimuli to be distinguishable as two pins

inversely

receptor density is (directly/inversely) proportional to receptor field size

myelinated

A class sensory fibers are (myelinated/unmyelinated)

unmyelinated

C class sensory fibers are (myelinated/unmyelinated)

A alpha

_____ fibers do proprioception from muscle and tendon

Ia and Ib

A alpha fibers are also called ______ fibers

very fast

A alpha fibers have a _________ conduction velocity

A alpha, A beta

______ and ______ fibers travel to the P/DCML

A delta, C

______ and ______ fibers travel to the ALS

A beta

_______ fibers do discriminative touch, two-point discrimination, and vibration

A delta

_______ fibers do temperature and faster pain

C pain

______ fibers do slow pain and temperature

C tactile

_______ fibers do light stroking and gentle touch

C autonomic

_______ fibers do autonomic functions, sweat glands, and vasculature

slower

C fibers have a _________ conduction velocity

IV

C fibers are also called ____ fibers

II

A beta fibers are also called ____ fibers

III

A delta fibers are also called ____ fibers

A-C

the ______ classifications of sensory nerve fibers are typically used for cutaneous and visceral afferents

I-IV

the ______ classifications of sensory nerve fibers are typically used for joint and muscle afferents

free nerve endings

nociceptors, thermoreceptors, mechanoreceptors, and chemoreceptors are all types of ____________

nociceptors

_________ are free nerve endings that are slowly adapting and widely distributed in most tissues and organs for the sensing of pain

mechanical injury

mechanical nociceptors detect _____________

heat injury (>45c/113f) and cold injury (<5c/41f)

thermo-nociceptors detect _________and _________

chemical irritation

chemo-nociceptors detect ____________

mechanical injury, thermal injury, and chemical irritation

polymodal nociceptors can detect ________, _________ and ________

A delta

stimulation of ___ fibers FNE is from sharp pain, fast pricking pain, and is localized

C

stimulation of ___ fibers FNE is from itch, burning pain, or dull aching pain

A delta, C

when you bang your thumb with a hammer, the initial sharp pain is carried by ____ fibers, but then the dull aching pain after is carried on the ____ fibers

glutamate

________ is the excitatory transmitter/neuropeptide of fast pain

substance P

________ is the excitatory transmitter/neuropeptide of slow pain

dorsal horn

glutamate and substance P are found in the _________ for primary afferent nociceptor axons

withdrawal reflexes, conscious perception of pain, emotional effects, behavioral changes

pain activation via ALS can lead to a variety of responses including:

5 - 40

thermoreceptors (non-noxious) for cold detect temps between ___-___ deg C

29 - 45

thermoreceptors (non-noxious) for heat detect temps between ___-___ deg C

A beta

hair follicle receptors have ___ nerve fiber terminals surrounding the hair follicle that are sensitive to the displacement of hair

A delta and C

mechanoreceptors (non-nociceptive) for crude and light touch use ________ fibers

larger

touch fibers in the ALS system have (smaller/larger) receptive fields than those of the P/DCML

smaller

touch fibers in the ALS system have (smaller/larger) diameter than those of the P/DCML

A beta

the four types of discriminative mechanoreceptors are all terminal endings of ____ afferent nerve fibers

T

T/F: fibers coming from mechanoreceptors for discriminative aspects of tactile sensation pretty much avoid the DRG

slow, small

merkel receptors have a (slow/fast) adaptation rate and a (small/large) receptive field

slow, large

ruffini endings have a (slow/fast) adaptation rate and a (small/large) receptive field

fast, small

meissner corpuscles have a (slow/fast) adaptation rate and a (small/large) receptive field

fast, large

pacinian corpuscle have a (slow/fast) adaptation rate and a (small/large) receptive field

merkel receptors

______________ are slow adapting type I (SA I)

ruffini endings

______________ are slow adapting type II (SA II)

meissner corpuscles

______________ are fast adapting type I (FA I)

pacinian corpuscles

______________ are fast adapting type II (SA II)

encapsulated, unencapsulated

receptor and/or peripheral nerve terminal endings may be __________ or ___________

encapsulated

___________ receptors/peripheral nerve terminal endings are surrounded by a non-neural (cellular or CT) capsule

unencapsulated

___________ receptors/peripheral nerve terminal endings are not surrounded by a non-neural capsule

unencapsulated

free nerve endings are (encapsulated/unencapsulated)

unencapsulated

merkel endings are (encapsulated/unencapsulated)

deep epidermis, fingertips

merkel endings are found in the _________ and the highest concentration is in the _________

merkel

(merkel/ruffini/meissner/pacinian) detect form, texture, points and edges, and touch pressure

encapsulated, by CT capsule

meissner’s corpuscles are (encapsulated/unencapsulated)

dermal papillae glabrous skin, fingertips

meissner’s corpuscles are found in the _________ and are most numerous in the _________

meissner

(merkel/ruffini/meissner/pacinian) detect changes in pressure/sudden forces on the skin, including form, tapping, vibration, skin indentation, and motion detection object slip and grip control

encapsulated by CT capsule

ruffini’s endings are (encapsulated/unencapsulated)

deep dermis, sub Q tissue; palms, joint lines, under fingernails

ruffini’s endings are found in the _________ and ________ the especially in the _________

ruffini

(merkel/ruffini/meissner/pacinian) detect tissue stretch and skin stretch, including joint position of the fingers and hand and detecting object motion

T

T/F: ruffini’s endings are also found in joint tissues and bone

encapsulated, CT capsule

pacinian corpuscles are (encapsulated/unencapsulated)

concentric rings, collagen

pacinian corpuscles have a CT capsule made of ___________ of cells with small ______ fibers and gelatinous material

deep dermis, sub Q tissue, joints, viscera; deeper

pacinian corpuscles are found in the ____,________,______,____ and are ______ compared to other tissues

pacinian

(merkel/ruffini/meissner/pacinian) detect high frequency and rapid changes in vibration, pressure, and texture

F; MORE THAN ONE TYPE

T/F: natural stimuli activate multiple receptors of one type

T

T/F: receptors have a lower threshold to certain stimuli, but can often respond to many stimuli

intensity

stimulus _________ is coded to the CNS by the number of receptors activated and the action potential frequency