Somatosensory Terms

Question 1

Anterior Spinocerebellar Tract

Answer 1

axons that transmit info about the activity of spinal interneurons and of descending motor signals from the cerebral cortex and brainstem

• The neurons arise in the thoracolumbar SC and end in the cerebellar cortex
• The info does not reach consciousness and is used to adjust movements

Question 2

Anterolateral Columns

Answer 2

white matter in the anterior and lateral SC that contains spinothalamic and motor axons

Question 3

Conscious Relay Pathways

Answer 3

3-neuron series that transmits somatosensory info about location and type of stimulation to the cerebral cortex

Question 4

Crossed Analgesia

Answer 4

Pain sensation is lost on one side of the body and on the opposite side of the face

Question 5

Cuneocerebellar Pathway

Answer 5

transmits proprioceptive info from the arm and upper half of the body to the cerebellum

Question 6

Divergent Pathway

Answer 6

series of neurons that transmits somatosensory info to the BS and cerebrum

Question 7

Dorsal Column-Medial Lemniscus System

Answer 7

pathway that transmits info about discriminative touch and conscious proprioception to the cerebral cortex

Question 8

Dorsolateral Tract

Answer 8

white matter dorsal to the dorsal horn in the SC

- axons of first-order nociceptive neurons ascend or descend in this tract before synapsing in the dorsal horn lamina

Question 9

Extrafusal Fibers

Answer 9

contractile skeletal muscle fibers outside of the muscle spindle

Question 10

Gamma motor neurons

Answer 10

lower motor neurons that innervate intrafusal fibers in skeletal muscle
- when these neurons fire, the ends of intrafusal fibers contract, stretching the central region of muscle fibers within the muscle spindle

Question 11

High-fidelity tracts

Answer 11

• 2 groups of axons that relay accurate, detailed, somatotopically arranged tactile and proprioceptive info from the SC to the cerebellar cortex
  1) posterior spinocerebellar
  2) cuneocerebellar
• the info does not reach consciousness and is used to adjust mov’ts

Question 12

Homunculus

Answer 12

a figure representing the parts of the body controlled by or transmitting sensory info to a specific part of the cerebral cortex

Question 13

Internal feedback tract

Answer 13

axons of neurons that monitor the activity of:

1) spinal interneurons
2) descending motor signals from the cerebral cortex and BS
- the info is transmitted to the cerebellum
- the info does not reach consciousness and is used to adjust mov’ts

Question 14

Intrafusal fiber

Answer 14

specialized muscle fiber inside the muscle spindle

Question 15

Muscle Spindle

Answer 15

sensory organ embedded in muscle that responds to stretch of the muscle

Question 16

Nociceptors

Answer 16

Receptor sensitive to information about tissue damage or potential tissue damage

Question 17

Nucleus Cuneatus

Answer 17

site of synapse bw fasciculus cuneatus and medial lemniscus neurons

• Relays discriminative touch and conscious proprioceptive info
• Located in the dorsal part of the lower medulla

Question 18

Nucleus Dorsalis

Answer 18

Site of synapse bw first- and second-order neurons that convey unconscious proprioceptive info to the cerebellum

• The second-order axon is in the posterior spinocerebellar tract
• The nucleus dorsalis is located in the medial dorsal horn of the SC, from T1-L2 spinal segments

Question 19

Nucleus Gracilis

Answer 19

Site of synapse bw fasciculus gracilis and medial lemniscus neurons
- Relay discriminative touch

Question 20

Posterior spinocerebellar pathway

Answer 20

Transmits proprioceptive info from the legs and lower half of the body to the cerebellum

Question 21

Primary Sensory (Somatosensory) Cortex

Answer 21

Cerebral cortex that receives somatosensory info from the body and face
- located posterior to the central sulcus

Question 22

Rostrospinocerebellar Tract

Answer 22

Axons that transmit info about the activity of spinal interneurons and of descending motor signals from the cerebral cortex and BS

• the neurons arise in the cervical SC and end in the cerebellar cortex
• the info does not reach consciousness and is used to adjust mov’ts

Question 23

Somatosensory Association Area

Answer 23

A region of the cerebral cortex that analyzes info from the primary somatosensory cortex and from the thalamus

• provides stereogenesis and memory of the tactile and spatial environment
• located posterior to the primary somatosensory cortex

Question 24

Spinocerebellar Tracts

Answer 24

Groups of axons that convey proprioceptive info or info from spinal interneurons to the cerebellum
- the info does not reach consciousness and is used to adjust mov’ts

Question 25

Spinoreticular Pathway

Answer 25

Series of neurons that convey nonlocalized nociceptive info to the reticular formation - the info is transmitted to the medial and intralaminar nuclei of the thalamus

Question 26

Stereogenesis

Answer 26

Ability to use manipulation, touch, and proprioceptive info to identify an object

Question 27

Substance P

Answer 27

NT produced by primary nociceptive neurons - Also produced in other areas of the CNS - Produces Enkephalin (Dorsal horn)

Question 28

Unconscious Relay Tracts

Answer 28

Neurons that convey proprioceptive info from the SC or info from spinal interneurons to the cerebellum - the info does not reach consciousness and is used to adjust mov'ts

Question 29

Ventral Posterolateral Nucleus of the Thalamus

Answer 29

Site of synapse bw neurons that convey somatosensory info from the body to the cerebral cortex - the neospinothalamic and medial lemniscus axons end in this nucleus