Sensory System ppt 9-11

Question 1

What are characteristic of sensory stimuli?

Answer 1

modality location intensity duration

Question 2

What is modality?

Answer 2

General class of stimulus, General (somatic and visceral) Special (smell,tast etc.)

Question 3

What are free nerve ending sensory receptors?

Answer 3

bare dendrites associated with pain, thermal, tickle, itch and some touch sensations PAIN TEMPERATURE throughout the skin

Question 4

What are encapsulated nerve endings sensory receptors?

Answer 4

dendrites enclosed in connective ties. Pressure, vibration and some touch sensation

Question 5

What type of stimulus do mechanoreceptors detect?

Answer 5

Mechanical stimuli. touch, pressure, vibration, proprioception. hearing and equilibrium. monitor stretch of blood ves.

Question 6

What type of stimulus do thermoreceptors detect?

Answer 6

changes in temp

Question 7

What type of stimulus do nociceptors detect?

Answer 7

painful stimuli from physical or chemical damage

Question 8

What type of stimulus do photoreceptors detect?

Answer 8

direct light the strikes the retina of the eye

Question 9

What type of stimulus do chemoreceptors detect?

Answer 9

chemicals in the mouth (taste), nose (small) and body fluids

Question 10

What type of stimulus do osmoreceptors detect?

Answer 10

sense osmotic pressure of body fluids

Question 11

Where are proprioceptors located? What to they relay?

Answer 11

in the muscles, tendons, joints and inner ear. provide information about position, movement and equilibrium.

Question 12

What do messier corpuscles sense?

Answer 12

Dynamic, fine/light touch, position sense

Question 13

What do Pacinian corpuscles sense?

Answer 13

Vibration and Pressure in the deep skin layers, ligaments and joints

Question 14

What do Merkel discs sense?

Answer 14

Pressure, deep static touch, position sense. at the finger rips and superficial skin

Question 15

What do Ruffini corpuscles sense?

Answer 15

pressure, slippage of objects, joint angle change at the the fingertips and joints.

Question 16

What is the receptive field?

Answer 16

an area of the body that when stimulated results in a change in firing rate of a sensory neuron.

Question 17

How to neighboring receptive field interact?

Answer 17

Receptive field of neighboring afferent neurons usually overlap. *Degree of over lap varies in different part of body.

Question 18

What is acuity?

Answer 18

the precision of stimulus localization or the ability to distinguish fine details smaller field higher density less convergence overlap lateral inhibition

Question 19

What is a lateral inhibition (sensory)?

Answer 19

capacity of an excited neuron to reduce the activity of its neighbors.

Question 20

Two point discrimination

Answer 20

minimum distance between 2 caliper points , perceived as separate points of stimulation test the integrity of the dorsal column and proprioception.

Question 21

What is spatial summation

Answer 21

intensity can be transmitted by increasing number of parallel fibers

Question 22

What is temporal summation?

Answer 22

intensity can be transmitted by sending more ap along a single fiber

Question 23

What is a receptor potential?

Answer 23

initial response of a receptor- voltage across the receptor membrane intensity determines the frequency of action potentials

Question 24

SLOW adapting Receptors TONIC

Answer 24

Adapt very little over time and remain responsive during long stimuli. Pressure.

Question 25

RAPIDLY adapting receptors PHASIC

Answer 25

Adapt very quickly and essentially detect only the onset of a stimulus. Vibration.

Question 26

Dermatome Reflex mnemonic

Answer 26

s1-2 buckle my show l3-4 kick the the door c5-6 pick up sticks c7-8 lay them straight

Question 27

What is the arrangement of neuron in the sensory pathway?

Answer 27

1. from receptor to spinal cord (dorsal root ganglion) 2. first order to thalamus. (cross midline) 3. Thalamus to sensory cortex

Question 28

What does the Fasciculus gracilis receive?

Answer 28

sensory from the ipsilateral lower limb

Question 29

What does the fasiculus cuneatus receive?

Answer 29

sensory from ipsilateral upper limb

Question 30

What does the spinothalamic tract receive?

Answer 30

pain and temp from the contralateral side of the body

Question 31

What are the anterolateral pathways?

Answer 31

Anterior spinothalamic- crude touch Lateral spinothalamic- pain temp (lisseaur tract)

Question 32

What does the Posterior column (Dorsal medial lemniscus) sense?

Answer 32

fine touch vibration tactile location/ discrimination streognosis proprioception

Question 33

Medial Lemniscus Pathway

Answer 33

1.Axon enters to the fasiculus. 2. Terminate in the nuc gracilis or cuneatus. CROSS MIDLINE at MEDULLA 3. up medulla, pons and midbrain. 4. end in the VPL of the thalamus

Question 34

Anterolateral (Spinothalamic) Pathways

Answer 34

1. Axon enters the spinal cord in spinothalamic tract. CROSS MIDLINE in the SPINAL CORD. 2. Anteriolatertract in medulla. 3. up medulla, pons and midbrain. 4. end in the VPL of the thalamus

Question 35

Tract of Lissauer

Answer 35

Lie's Hurt PAIN a spinal ganglion enters the spinal cord and before it synapse with gives fibers to the above and bellow segments

Question 36

What is the first modulator of pain?

Answer 36

Substantia gelatinosa jello to relieve pain

Question 37

Spinocerebellar Pathway

Answer 37

1. Proprioceptive info enters spinal cord. Travels fascicles cutaneous. 1b. Clark Nuc L3-C8 2.Posterior Spino cerebellar tract brainstem, medulla 3. Ipsilateral cerebellum

Question 38

Which spinocerebellar pathway crosses over twice?

Answer 38

ventral (anterior) spinocerebellar

Question 39

Romber Sign

Answer 39

lesion in the dorsal columns

Question 40

Which lesion affects only the spina cerebellar tract

Answer 40

Fridreich Ataxia

Question 41

Aδ mechanical nociceptors

Answer 41

Myelinated axons respond to COLD fast paint

Question 42

Polymodal C fiber Nociceptors

Answer 42

UNmyelinated Response to hot temp slow pain.

Question 43

Vanilloid Receptors

Answer 43

VR-1 Capsaicin VRL temp \>50\*C

Question 44

Mechanism of Pain

Answer 44

Breadykinin, 5HT, Prostaglandin and Histamine active nociceptors. Noci. releace Sub. P with causes more realest of histamine

Question 45

What is the dual pathway for pain?

Answer 45

Paleospinothalamic (C fibers)- slow Neospinothalamic (Aδ fibers)- fast

Question 46

Unmodulated Pain

Answer 46

Unmodulated pain- excitation of the second order neuron- inhibition of the inhibitory interneuron.- pain passes to thalamus ![]()

Question 47

Gate theory of pain modulation

Answer 47

Aβ fibers carrying sensory information about mechanical stimuli help block pain transmission

Question 48

Referred pain

Answer 48

painful sensation in site other than the injured one. Dermatome theory Convergence Theory

Question 49

Hyperalgesia:

Answer 49

increased sensitivity and lower threshold to painful stimuli.

Question 50

Hypoalgesia:

Answer 50

decreased sensitivity and raised threshold to painful stimuli.

Question 51

Analgesia:

Answer 51

complete loss of pain sensation

Question 52

Allodynia:

Answer 52

the state in which there is excessive response to even mild stimuli.