Lecture 5: Introduction to Motor Control

Question 1

List and compare the 3 types of muscle.

Answer 1

1. skeletal (striated) - quick; discontinuous; voluntary
2. smooth (gut and lungs) - quick; continuous; involuntary
3. cardiac (heart) - weak; slow; involuntary

Question 2

Whats the difference between isometric and isotonic contraction?

Answer 2

Isometric - length of muscle stays the same

Question 3

What differs to afford a muscle fine vs. gross motor control?

Answer 3

Fibres per motor unit decreases for MORE control.

Question 4

Each muscle fibre innervated by (ONE/MANY) axon/s; one axon innervates (ONE/MANY) fibres.

Answer 4

One; Many

Question 5

What are two distinguishing features of muscle vs. synaptic transmission?

Answer 5

1. AP always causes muscle twitch (vs. threshold)

2. AP potential propogates in all directions

Question 6

The _________________ (full of calcium) surrounds the ____________ (many located in single muscle fibre).

Answer 6

Sarcoplasmic reticulum. Myofibrils.

Question 7

How is a muscle twitch triggered?

AP down motor neuron to i)_____________ which releases ii)_______________ which causes iii)______________.

Answer 7

i) neuromuscular cleft
ii) acetycholine
iii) electrical impulse

Question 8

How is the force of a contraction modulated?

Answer 8

1. No. of neurons activated

2. Rate of firing of motor neuron

Question 9

In Sliding Filament theory, the i)________ cannot attach to ii)________ binding site unless iii)________ is present.

Answer 9

i) myosin
ii) actin
iii) calcium

Thus, the myosin will keep pulling as long as the calcium is present (until APs stop)

Question 10

List two types of reflex control and their key differences.

Answer 10

1. muscle spindles - located on muscle, detects length change
2. golgi tendon organs - located on tendon, detects stretch