Somatic Sensory System

Question 1

The medial lemniscal tracts carry…

Answer 1

Mechanoreceptive and proprioceptive signals to the thalamus

Question 2

The spinothalamic tract carries…

Answer 2

Pain and temperature signals to the thalamus

Question 3

Sensory information travels through 3 neurons to reach higher centres

Answer 3

• First order neurons - detect the stimulus and transmit it to the spinal cord
• Second order neurons - relay the signal to the thalamus (cross the midline)
• Third order neurons - carry signal from the thalamus to the cortex

Question 4

1st order axons from the upper body follow the _____ and synapse on ____ neurons in the _____ _____

Answer 4

• Lateral pathway
• 2nd order
• Cuneate nucleus

Question 5

1st order axons from the lower body follow the _____ and synapse on neurons in the ______ _______

Answer 5

• Medial pathway

- Gracile nucleus

Question 6

Cuneate and gracile nucleus are together known as…

Answer 6

The dorsal column nuclei

Question 7

2nd order axons cross _____ and ascend in the _____ _____. Their lower body axons are more _____ on reaching the thalamus

Answer 7

• The midline
• Medial lemniscus
• Lateral

Question 8

3rd order axons in the lower body synapse on more _____ _____ neurons

Answer 8

Medial cortical

Question 9

The result of topographic projection is…

Answer 9

A map of the body in the cortex

Question 10

Where do dermatomes originate?

Answer 10

Embryonic structures called somites

Question 11

More cortex is dedicated to areas where the receptive field is?

Answer 11

Small

Question 12

1st order neurons are located in the?

Answer 12

Dorsal root ganglion

Question 13

Second order neurons are located in the?

Answer 13

Dorsal column nuclei

Question 14

3rd order neurons are located in the?

Answer 14

Thalamus