1. Neural Control of Movement
Chapter 2

2. CENTRAL NERVOUS SYSTEM
Brain
Cerebral Cortex/Cerebrum
Motor cortex
Basal Ganglia/Diencephalon – sensory input
Cerebellum – motor control
Brain stem – sensory input
Spinal Cord

3. CENTRAL AND PERIPHERAL NERVOUS SYSTEM
Central nervous system
Peripheral nervous system

4. PERIPHERAL NERVOUS SYSTEM
Somatic
Sensory (Afferent) Neuron
Motor (Efferent) Neuron
Autonomic [FYI]
Parasympathetic
Sympathetic

5. SENSORY NEURONS
Carry impulse towards the CNS
Towards CNS

6. MOTOR NEURONS Carry impulse away from the CNS (e.g. motor nerves)
Stimulatory
Inhibitory

8. Spinal Nerves
Cervical spinal nerves (C1 to C8) These nerves (eight pairs) supply the back of the head, the neck and shoulders, the arms and hands, and the diaphragm.
Thoracic spinal nerves (T1 to T12) These nerves (12 pairs) supply the chest, some muscles of the back, and parts of upper abdomen.
Lumbar spinal nerves (L1 to L5) These nerves (five pairs) supply parts of the lower abdomen and the back.
Sacral spinal nerves (S1 to S5) These nerves (five pairs) supply the thighs and parts of lower legs, and the feet.

10. NEURON ANATOMY
Dendrite
Cell Body
Axon

11. NEURON ANATOMY Neuron …a single nerve cell Nerve
….a bundle or group of neurons
A nerve contains both motor and sensory neurons

12. Proprioception and Kinesthesis
What is kinethesis?
…awareness of the position and movement of the body
What is proprioception?
…ability to regulate posture and movement by responding to stimuli from receptors throughout the body

13. MUSCLE SPINDLES

16. MUSCLE SPINDLES Provide proprioception
Sense the amount of stretch and the rate of stretch
Reflexes involving the muscle spindles is how we ‘feel’ a movement was done correctly
Spindles are a part of learning; we develop such reflexes as we practice skills and movements

17. GOLGI TENDON ORGAN

19. GOLGI TENDON ORGAN Sensitive to muscle tension and active contraction
Protect muscle from excess contraction force
Stimulation of GTO an afferent impulse is sent to the central nervous system
In turn, efferent impulses are sent to the…
…Agonist muscle causing it to relax
…Antagonist muscle causing it to contract

20. Other Receptors Proprioceptors of the joints and skin
Examples: Meissner’s corpuscles, Ruffini’s corpuscles, Pacinian corpuscles, Krause’s end-bulbs

22. NEUROMUSCULAR CONCEPTS

23. Motor Unit One motor neuron and all the muscle fibers it innervates
All-or-none principle

24. Factors Affecting Muscle Tension
The number of motor units activated
Type of motor units activated (fast or slow twitch)
The frequency of stimulation of the motor units

25. Factors Affecting Muscle Tension
Stimulation
Subthreshold stimulus
Threshold stimulus
Submaximal stimulations
Maximal stimulation

26. Factors Affecting Muscle Tension
Twitch
Summation
Tetanus

27. Neuromuscular Summary
An example from baseball.
A pitcher throws a curve ball to Derrek Lee
Derek’s eyes see the ball coming towards him and is able to identify the pitch as a curve ball
Sensory nerves (afferent) send that information to the CNS
In the CNS the sensory nerve synapses with motor nerves
The motor nerves in turn stimulates the muscles (deltoid and pectoralis major) required to swing the bat in the proper position to hit the ball

28. Neuromuscular Summary
Inside the fibers of the deltoid and pectoralis major, calcium is released
The calcium allows myosin heads to attach to actin
When the heads swivel the fibers of the deltoid muscle will shorten
The shortening of the fibers will pull on the humerus causing Derrek to swing the bat
The muscle spindles “tell” the CNS when the arm is in the correct position
If all goes as planned, the deltoid and pectoralis major will move his arms into a position to hit the ball

29. Neuromuscular Summary
An example from weight training.
A man is having his muscular strength tested on the bench press
For his first lift, 50 pounds is put on the bar
He will be using his pectoralis major muscle with has 500 motor units (300 slow twitch and 200 fast twitch) and his triceps muscle
His CNS stimulates 280 motor units leading to his pectoralis major muscle (180 slow twitch and 100 fast twitch)
Remember, each nerve ending stimulates a separate muscle fiber

30. Neuromuscular Summary
The pectoralis major and triceps muscles shortens and his arm extends outward raising the bar with 50 pounds on it.
After a few minutes of rest, 100 pounds is place on the bar
This time he stimulates 380 motor units (260 slow twitch and120 fast twitch)
The weight is successfully lifted
After a few minutes of rest, 150 pounds is place on the bar

31. Neuromuscular Summary
This time he stimulates 460 motor units (280 slow twitch and 180 fast twitch)
As the pectoralis major muscle contracts the GTO in the pectoralis major are stimulated
They stimulate a sensory nerve leading to the CNS
In the CNS, the sensory nerve synapses with a motor nerve that will inhibit (relax) the pectoralis major muscle
The man is unable to lift the 150 lb