Lecture 1

Question 1

What is the somatic nervous system?

Answer 1

Part of the peripheral nervous system that controls voluntary movement and movement through involuntary reflex arcs

Question 2

A motor unit is the final common pathway between the _____ and ______:

Answer 2

Nervous system, generation of force

Question 3

What is a motor unit?

Answer 3

The cell body and dendrites of an alpha motor neuron, the axon, and all the muscle fibres it innervates

Question 4

Cell bodies reside where?

Answer 4

Ventral horn of the spinal cord

Question 5

Cell bodies in spinal cord form ____?

Answer 5

Motor neuron pools

Question 6

Motor neurons exit from anterior/ventral horn via?

Answer 6

Ventral root

Question 7

______ carries sensory or afferent neurons:

Answer 7

Dorsal root

Question 8

Cervical enlargement is in what position?

Answer 8

C4-T1

Question 9

Lumbar enlargement is in what position?

Answer 9

T11-L1

Question 10

Cervical enlargement serves as motor neuron pools for what limb?

Answer 10

Arms

Question 11

Lumbar enlargement serves as motor neuron pools for what limb?

Answer 11

Legs

Question 12

What is the output of spinal cord and brainstem circuits?

Answer 12

Skeletal muscles

Question 13

What is the input of spinal cord and brainstem circuits?

Answer 13

Sensory inputs

Question 14

How many muscle fibres are innervated by a single motor neuron?

Answer 14

It differs across motor units

Question 15

What is the innervation ratio?

Answer 15

The number of muscle fibers innervated by a single motor neuron

Question 16

How does the innervation ratio change with age?

Answer 16

No. of motor units declines, but No. of fibers per motor unit increases

Question 17

Three types of skeletal muscle fiber:

Answer 17

• Slow oxidative (SO) fibres (Type I)
• Fast oxidative-glycolytic (FOG) fibers (Type IIa)
• Fast glycolytic (FG) fibers (Type IIx)

Question 18

Which skeletal muscle fiber has the highest innervation ratio?

Answer 18

FG

Question 19

Which skeletal muscle fiber has the lowest innervation ratio?

Answer 19

SO