Lab 9

Question 1

Which structure attached to the spinal cord is comprised functionally of motor fibers?

Answer 1

Ventral root

Question 2

Which structure attached to the spinal cord is comprised functionally of sensory fibers?

Answer 2

Dorsal root

Question 3

Which structure contains lower motor neurons?

Answer 3

Ventral gray horn

Question 4

Which structure contains first order sensory neurons?

Answer 4

Dorsal root ganglion

Question 5

Which structure contains second order sensory neurons?

Answer 5

Dorsal gray horn

Question 6

When a decussation of ascending or descending spinal tracts occur in the spinal cord level, at which of the structures above do sensory or motor signals cross contralaterally?

Answer 6

Anterior median fissure

Question 7

Name of ascending and descending tracts that do not decussate and ipsilaterally stay through their pathways

Just know one for each

Answer 7

Acsending – posterior spinocerebellar tract
Descending – lateral vestibulospinal tract

Question 8

After a concussion, Andria was asked by her athletic trainer to perform a single leg stance test to examine the ability of balance. While she was standing on right foot, which was an easy task to her before the concussion, she felt a little of shaking her body, which made her difficult to maintain the upright posture. Name one each of ascending and descending spinal tracts that might be associated

Answer 8

Ascending – posterior spinocerebellar tract (maintain balance/ posture)
Descending – lateral vestibulospinal tracts (neck and head extensors)

Question 9

Spinal Nerves found in the Cervical Plexus

1

Answer 9

1. Phrenic (S/M) – Diaphragm

Question 10

Spinal Nerves found in the Brachial Plexus

5

Answer 10

1. Musculocutaneous (S/M) – anterolateral forearm/ elbow/ upper arm muscles (biceps, brachialis, coravobrachialis)
2. Radial (S/M) – posterior arm/ lateral forearm/ hands
3. Median (S/M) – hands/ forearm flexors
4. Axillary (S/M) – shoulder/ deltoids + teres minor
5. Ulnar (S/M) – hands and elbows/ forearm flexors

Question 11

Spinal Nerves in the Lumbar Plexus

Answer 11

1. Femoral – (S/M) thigh/ knee/ foot/ hip and knee joints/ iliacus/ pectineus/ quads/ sartorius
2. Obturator – (S/M) thigh/ hip and knee joints/ obturator externus/ medial adductor

Question 12

Spinal Nerves found in Sacral Plexus

Answer 12

1. Tibial (S/M) – posterior leg, plantar skin, knee + foot joints
2. Common fibular (S/M) – short head of biceps femoris; fibular brevis/ longus, extensor hallicus longus; extensor digitorum longus, tibialis anterior
3. Sciatic (M) – hamstrings, adductor magnus