Week 6

Question 1

True/False
Lower Motor Neurons directly innervate skeletal muscle and have cell bodies in the anterior horn of the spinal cord (ventral horn) and at cranial nerve nuclei.

Answer 1

True

Question 2

Which motor neurons can exist in both the central and peripheral nervous system?
A. Upper Motor Neurons
B. Lower Motor Neurons
C. Somatic Motor Neurons
D. None of the Above

Answer 2

B. Lower Motor Neurons

Question 3

What will you see with hyporeflexia?

Answer 3

Muscle Weakness

Question 4

What will you see with hypospacity?

Answer 4

Fasciculations

muscle tremor

Question 5

What will you see with hypotonicity (flaccid)

Answer 5

Atrophy

Question 6

What are some signs of lower motor neuron lesions?

Answer 6

Decrease or loss of reflexes
Paresis or Paralysis
Atrophy
Decrease or loss of muscle tone
Fibrillations

Interrupting LMN signals to muscle decreases/prevents muscle contraction

Ex) result of trauma, demyelinating diseases, infection, or chronic neuropathy

Question 7

What is the function of reflexes?
A. Posture
B. Muscle Protection
C. Flexibility
D. Both A and B

Answer 7

D. Both A and B

Question 8

Muscle Protection

Answer 8

When a muscle length increases, the muscle spindle within that muscle stretches, and its nerve activity will increase - the muscle contracts, and therefore reduce the stretching of the muscle

Question 9

Posture

Answer 9

the result of a stretch reflex

Ex. Leaning to one side causes the opposite to stretch, and the stretch reflex kicks in keeping us upright.

Question 10

What are some causes of flaccidity and hypotonicity?

Answer 10

• LMN Lesions
• Developmental Disorders, usually caused by intracranial hemorrhage, immune, genetic, or metabolic disorders
• Acute UMN lesions that cause CNS shock