Somatosensory System - Part I

Front 1

Somatorysensory System - Part I
Which pathway do opiate drugs selectively block?
a. Neospinothalamic tract
b. Paleospinothalamic tract
c. both

Back 1

b. Paleospinothalamic tract

slide #26

Front 2

Using a single intracellular recording electrode, in what part of a sensory neuron could you simultaneously record both receptor potentials and action potentials?
a. in the cell body
b. at the node of Ranvier nearest the peripheral end
c. at the receptor membrand where the stimulus occurs
d. at the central axon terminals within the CNS
e. there is no single point where both can be measured

Back 2

b. at the node of Ranvier nearest the peripheral end

slide #4 & Vander's p.253

Front 3

The modality of energy a given sensory receptor responds to in normal functioning is known as the _____ _____ for that receptor.

Back 3

Adequate stimulus

slide #13 & Vander's p.253

Front 4

__ and __ of receptive field help CNS to locate a stimulus on the body, distinguish size and shape of the stimulus and resolve spatial resolution.

Back 4

size and density

Front 5

Modalities have separate populations of sensory neurons specialized in detecting what kinds of stimuli?

Back 5

touch, pain, temperature, etc
Thus they transform physical energy into neural signals

Front 6

Axons have membrane receptors that respond to specific stimuli delivered indirectly through _____ or modified epithelial cells, or directly through the membrane of ________.

Back 6

Indirectly: CT capsules or modified epithelial cells

Directly: free nerve endings

Front 7

Each Transient Receptor Type (TRP) ion channel responds maximally to one ____ and less to another.

Back 7

adequate stimulus, the energy that elicits the greatest response. It determines which neurons will be responsible for the sensory modality perception.

Front 8

___________refers to environmental stimuli of cutaneous receptors that mediate discriminative and non-discriminative touch, temperature and pain.

Back 8

Somatosensory exteroception

Front 9

Discriminative touch is mediated by which five exteroreceptive mechanoreceptors impedded in the CT or hair follicles?

Back 9

Merkel cells SA
Ruffini corpuscle SA
Meissner corpuscle FA
Pacinian corpuscle FA
Hair follicle FA

Front 10

_______ are most sensitive to light touch, such as scanning the surface.

Back 10

Merkel cells- SA, form and texture

Front 11

Which two discriminative touch mechanoreceptors are slow adapting?

Back 11

Merkel cells: form, texture: fingers scanning a surface

Ruffini corpuscle: skin stretch; perception of hand shape and position

Front 12

Which discriminative touch mechanoreceptor responds to vibratory stimuli?

Back 12

Pacinian corpuscle FA

Front 13

What part of the brain receives and perceives the information from the sensory receptive fields?

Back 13

cerebral cortex

Front 14

What is a mechanoreceptor receptive field?

Back 14

area of skin that when impacted can stimulate a single specific neuron/receptor

Front 15

What three slow adapting somatosensory modalities are mediated by free nerve endings?

Back 15

non-discriminative touch, temperature and pain- they are all slow conducting and slow adapting

Front 16

Interoreceptors mediate events from _________ structures or from ______ structures such as the muscles and CT.

Back 16

Visceral or somatic structures such as muscles and CT.

Front 17

What do the visceral afferent free nerve endings of axons within sympathetic nerves detect?

Back 17

Overwhelmed yet?!
These interoreceptors nociceptors detect tissue damage or irritation like bloating and cramping

Front 18

What do the parasympathetic visceral afferents detect?

Back 18

These are physiologic or specialized receptors in smooth muscle, mucosae, hypothalamus, etc that detect pressure, stretch, tension, bp, gas and heat.

Front 19

Proprioceptors mediate __________ and joint position and __________. They are ______ conducting (fast or slow)

Back 19

muscle and movement
They have large axons and are fast conducting

Front 20

Joint proprioceptors detect stretch of CT with which two receptors?

Back 20

pacinian and ruffini

Front 21

Muscle receptors detect changes in length with _________ and changes in ______ with Golgi tendon organs.

Back 21

Spindles detect changes in length
Golgi tendon detects changes in tension

Front 22

Modality depends on specific receptors and the _______ activated by the stimulus

Back 22

pathway

Front 23

Somatosensory modalities have specific receptors, conducting velocity and ascending pathways. What system do discriminative touch, vibration and proprioception share?

Back 23

the dorsal column-leminiscal system. This means they transfer a quantitative sense that provides localization of the stimulus

Front 24

The visceral sensory information ascends in the _____ system.

Back 24

Both the dorsal column and anterolateral systems

Front 25

In the Dorsal Column Lemniscal System, the ____, ______ and _____ neurons convey information through spinal cord, brain stem and thalamus to the ________.

Back 25

first, second and third order neurons deliver to the cerebral cortex

Front 26

Touch, vibration, proprioception and part of the visceral systems travel up the _______________ system.

Back 26

dorsal column-leminiscal system

Front 27

In the Dorsal Column Lemniscal System, _______ order neurons decussate in the medulla

Back 27

Second order neurons cross over in the medulla

Front 28

In the Dorsal Column-Lemniscal System, third order thalamic neurons form part of the _______ ____ and project to primary somatosensory cortex in the __________ ______.

Back 28

internal capsule
postcentral gyrus

Front 29

In the Dorsal Column-Lemniscal System, where do second order neurons synapse onto?

Back 29

neurons within the thalamus

Front 30

In the Dorsal Column-Lemniscal System, the _____ order sensory neuron axons synapse onto dorsal column (cuneate and gracile) nuclei in the _______.

Back 30

First order
Medulla

Front 31

The anterolateral system includes non-discriminative touch, pain and temperature. T/F

Back 31

TRUE!...just wait, I'll mix it up when I start understanding this better!

Front 32

What travels along Lissauers tract?

Back 32

First order Aδ and C neurons branch rostrally and caudally along the dorsolateral fasciculus.

Note: Anterolateral System

Front 33

____ lamina consist of neuronal groups segregated by modality. lamina I and II sense ____ and lamina IV senses touch

Back 33

Rexed
Pain

Front 34

The Paleospinothalamic tract projects to the __________, medial thalamus and ________, communicating aspects of pain, ______ and ______.

Back 34

reticular formation, medial thalamus and cortex
temperature and non-discriminative touch

Front 35

In the Dorsal Column Lemniscal System, the ____, ______ and _____ neurons convey information through spinal cord, brain stem and thalamus to the ________.

Back 35

first, second and third order neurons deliver to the cerebral cortex

Front 36

Touch, vibration, proprioception and part of the visceral systems travel up the _______________ system.

Back 36

dorsal column-leminiscal system

Front 37

In the Dorsal Column-Lemniscal System, ___________ order neurons decussate in the medulla

Back 37

In the Dorsal Column-Lemniscal System, second order neurons cross over in the medulla

Front 38

In the Dorsal Column Leminscal System, third order thalamic neurons form part of the _______ ____ and project to primary somatosensory cortex in the __________ ______.

Back 38

internal capsule
postcentral gyrus

Front 39

In the Dorsal Column-Lemniscal System, where do second order neurons synapse?

Back 39

thalamus

Reminder: 2nd order neurons of The Dorsal Column Leminscal System decussate in the medulla

Front 40

In the Dorsal Column-Lemniscal System, the _____ order sensory neuron axons synapse onto dorsal column (cunate adn gracile) nuclei in the _______.

Back 40

first order in medulla

Front 41

The anterolateral system includes non-discriminative touch, pain and temperature. T/F

Back 41

TRUE!...just wait, I'll mix it up when I start understanding this better!

Front 42

What travels along Lissauers tract?

Back 42

First order Adelta and C neurons branch rostrally and caudally along the dorsolateral fasciculus.

Front 43

____ lamina consist of neuronal groups segregated by modality. lamina I and II sense ____ and lamina IV senses touch

Back 43

Rexed
Pain

Front 44

The Paleospinothalamic tract projects to the __________, medial thalamus and ________, communicating aspects of pain, ______ and ______.

Back 44

reticular formation, medial thalamus and cortex
temperature and non-discriminative touch

Note: opiate drugs selectively block this pathway.

Front 45

The ________ tract projects to lateral thalamus and _______ cortex.

Back 45

Neospinthalamic tract
to the somatosensory cortex
communicates localization of sensation

Front 46

Lateral and medial thalamic neurons are ____ order neurons of the Anterolateral System.

Back 46

third

Front 47

The reticular formation generates/communicates _______ and _______ in wide areas of the thalamus and cortex.

Back 47

alerting and wakefullness

Front 48

Sensation involves _____ ______ sampling small amounts of energy from the environment.

Back 48

Sensory receptors

Slide 2

Front 49

CNS activity can produce _____ that regulates sensory activity at all levels, including the receptors themselves.

Back 49

Feedback. Maintains a tolerable range of sensory stimulation.

Slide 1

Front 50

What type of somatosensory receptors respnd to external stimuli and include those mediating touch, pain & temp?

What type detect internal changes of the body & include those responsive to tissue stretch or chemical changes?

Back 50

Exteroreceptors
Interoreceptors

Slide 3

Front 51

Receptors translate environmental E into _____ which in turn trigger ____ ____.

Back 51

Generator (receptor) potentials
Action potentials

Slide 4

Front 52

Myelinated axons have larger total diameters and faster conduction velocities. True or False?

Back 52

True.

Slide 5

Front 53

Recordings of the summed APs measured over time at a particular site on the nerve are called __________.

Peaks in these recordings correspond to what?

Back 53

Compound Action Potentials
Axonal clusters (population size of axons with a specific degree of myelination & velocity)

Slide 5

Front 54

In classification of nerve compound action potentials, Roman numerals apply to what type of nerves? How about letters?

Back 54

Roman numerals- Motor nerves
Letters- Sensory nerves

Slides 5 & 6

Front 55

Sensory systems mediate what four attributes of stimuli that can be correlated with sensation?

Back 55

Intensity
Sensory Adaptation
Localization
Modality

Slide 8

Front 56

According to intensity coding,
Does increased stimulus decrease or increases the AP frequency?

Does a decrease in intensity reduce or increase the AP frequency?

Back 56

↑ intensity = ↑ AP

↓ intensity = ↓ AP

Slide 9

Front 57

The decrease in neural activity with sustained stimulation is called ______.

Back 57

Sensory adaptation

Slide 10

Front 58

What type of sensory adaptation alerts the CNS of a change in sensory environment, ie, something is occurring?

Mechanism usually involves ion channel inactivation or receptor ______.

Back 58

Rapid adaptation
Deformation

Slide 10

Front 59

What type of sensory adaptation communicates the status of a stimulus, ie, what is occurring?

Mechanism usually involves inactivation of what ion channels?

Back 59

Slow adaptation
Ca or Na channels

Slide 10

Front 60

______ is the area of skin innervated by the branching of a single sensory neuron.

Back 60

Cutaneous Receptive Field (RF)

Slide 11

Front 61

Are densely innervated Receptive Fields large or small in area?

Back 61

Small

Slide 11

Front 62

Membrane receptors of axons respond indirectly through ________ and directly through ________.

Back 62

CT capsules or modified epithelial cells,
Free nerve endings

Slide 12