Neural control of muscles and motor units

Question 1

Question: What is the order of the stages of neural control of muscle action?

Answer 1

Brain → Spinal cord → Motor neuron → Acetylcholine → Muscle contracts (all-or-nothing) → Motor unit recruitment (Henneman’s principle).

Question 2

Question: What is a motor unit?

Answer 2

A motor neuron + all muscle fibers it controls.

Question 3

What are Fine Motor Skills?

Answer 3

Small muscles, precise control, few fibers.

Question 4

What are Gross Motor Skills?

Answer 4

Large muscles, powerful, less precision, many fibers.

Question 5

What is the All or Nothing principle？

Answer 5

Muscle fibers contract fully or not at all once threshold is reached.

Question 6

intensity of muscular contractions (All or nothing principle)

Answer 6

More motor units = stronger contraction. Faster impulses = stronger force.

Question 7

Henneman Principles.

Answer 7

Small motor units activate first, large units later.

Question 8

Development of muscle force is dependent on (5)…

Answer 8

Motor units, muscle size, muscle length, joint angle, action speed.