Sensation Pathways

Question 1

The Spinothalamic Pathways carry what sensory modalities?

Answer 1

Temperature, Pain, Pressure/Crude Touch

Question 2

The Dorsal Column Pathways carry what sensory modalities?

Answer 2

Vibration, Fine Touch, Propioception, 2-Point Discrimination

Question 3

What is the reason for the phenomenon where we wear clothes but become unconscious to it over time?

Answer 3

Rapidly Adapting Neurones. Starts with a High frequency and then slows down over time

Question 4

What is the course of second order sensory neurones?

Answer 4

They start at the spinal chord or brain stem, decussate then synapse on third order neurones in the thalamus

Question 5

Dorsal column sensory information from the upper half of the body synapse on what nuclei in the medulla?

Answer 5

Cuneate Nuclei

Question 6

Dorsal column sensory information from the lower half of the body synapse on what nuclei in the medulla?

Answer 6

Gracile Nuclei

Question 7

The path of second order neurones in the dorsal column system has what name?

Answer 7

Medial Lemniscus System. As it starts at the medulla and synapse on 3rd order neurones on the contra lateral thalamus

Question 8

Describe the general pathway of of the spinothalamic sensory system?

Answer 8

1st order neurones travel through the dorsal root and synapse at the dorsal horn. 2nd order neurones then decussate and travel ventrally up the spinothalamic tracts before synapsing on the thalamus. 3rd order neurones travel from the thalamus to the primary sensory cortex

Question 9

Describe the action of Lissauers Tract

Answer 9

1st order neurones of spinothalamic fibres can ascend up the spinal chord before synapsing and decussating.

Question 10

Describe how rubbing an area in pain can modulate the pain you feel?

Answer 10

Mechanoreceptors on the skin detect the rub activating A Beta fibres that activate an interneurone to inhibit the second order neurones

Question 11

Describe the action of cortical modulation of pain

Answer 11

Neurones from the cortex synapse of the periaquaductal Grey. Cell bodies then have axons that synapse on the Nuclei Raphe Magnus in the medulla. This sends a neurone that activates the inhibitory interneurone to the second order pain neurone

Question 12

Review your understanding of this transverse section of the spinal chord.

Question 13

What area along the homunculus of the primary sensory cortex is responsible for sensation to the face?

Answer 13

Lateral. As you go medially it gives sensation to the lower part of the body