Neuromuscular Control of Movement

Organization of Brain Motor Centers

The -Motor Neuron

• Innervates skeletal muscle

• Receives input from higher centers

• Receives sensory input from muscle stretch and tension receptors

Motor Unit

The -Motor Neuron

• All or none

• Size principle

Motor Unit

Motor Unit

Motor Unit

• The ratio of nerves to muscle fiber is specific to a motor unit and defined by the task.

Fine movements (focusing eyes)

Gross movements (muscles involved in jumping)

Motor Unit

Motor Unit

Muscle Recruitment

• Training

• In the lab!

Motor UnitLarge Motor Unit, Brief Contraction Time

Small Motor Unit, Long Contraction Time

StimFreq

Neuromuscular Junction

Muscle Sensors

• Allow for fine control and adjustments of muscle movements.

• Protect musculoskeletal system from injury.

Fine Control of Motor Movements

Muscle Spindle

Golgi Tendon Organ

Chemical Feedback

Control of Breathing

“Muscle Memory”

“Muscle Memory”

“Muscle Memory”

“Muscle Memory” is a form of Neural Memory

Spinal Cord Autonomy

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Nerve determines Muscle Characteristics

Nerve determines Muscle Characteristics

S F

Sc

S F

Fc

mitochondrial -glycerolphosphate-dehydrogenase

Nerve determines Muscle Characteristics

S F

Sc

S F

Fc

mitochondrial -glycerolphosphate-dehydrogenase

Stimulation Frequency

Soleus by Soleus Nerve

FDL by Soleus Nerve

FDL by FDL Nerve

Soleus by FDL Nerve

Training the Motor Unit?