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Exercise Science Section 6: The Nervous System and the Control of Movement

An Introduction to Health and Physical Education Ted Temertzoglou

Paul Challen

ISBN 1-55077-132-9 ©Thompson Educational Publishing, Inc. 2003. All material is copyright protected. It is illegal to copy any of this material. This material may be used only in a course of study in which Exercise Science: An Introduction to Health and Physical Education (Temertzoglou/Challen) is the required textbook.

The Components of the Nervous System

Nervous System

Peripheral Nervous System

Cranial Nerves

Spinal Nerves

Forebrain

Central Nervous System

Brain

Hindbrain

Spinal Cord

Midbrain

©Thompson Educational Publishing, Inc. 2003. All material is copyright protected. It is illegal to copy any of this material. This material may be used only in a course of study in which Exercise Science: An Introduction to Health and Physical Education (Temertzoglou/Challen) is the required textbook.

The Central Nervous System  The central nervous system (CNS) is divided into

two parts:  The vertebral column and the spinal cord:  Main pathway for information connecting the brain and peripheral nervous system  The brain:  Main control centre  Receives and interprets endless signals  Has six main parts:  Cerebrum  Cerebellum  Brain stem  Diencephalon  Limbic system  Reticular activating system

©Thompson Educational Publishing, Inc. 2003. All material is copyright protected. It is illegal to copy any of this material. This material may be used only in a course of study in which Exercise Science: An Introduction to Health and Physical Education (Temertzoglou/Challen) is the required textbook.

The Peripheral Nervous System  Peripheral nervous system (PNS):  Consists of those parts of the nervous system that lie outside the

CNS  Carries information in and out of the CNS  Includes:  12 pairs of cranial nerves  31 pairs of spinal nerves  Contains both autonomic and somatic components

©Thompson Educational Publishing, Inc. 2003. All material is copyright protected. It is illegal to copy any of this material. This material may be used only in a course of study in which Exercise Science: An Introduction to Health and Physical Education (Temertzoglou/Challen) is the required textbook.

The Autonomic Nervous System  Autonomic nervous system (ANS):  Comprised of two systems:  Sympathetic system:  Causes localized bodily adjustments to occur  Prepares body for emergencies (i.e. releases adrenaline,

increases heart rate)  Parasympathetic system:  Returns body to normal (after it’s been altered by the sympathetic system)  Systems work in unison

©Thompson Educational Publishing, Inc. 2003. All material is copyright protected. It is illegal to copy any of this material. This material may be used only in a course of study in which Exercise Science: An Introduction to Health and Physical Education (Temertzoglou/Challen) is the required textbook.

Somatic Nervous System  Somatic nervous system:  Handles the muscles in our extremities  Contains both afferent and efferent nerve fibres:  Afferent nerves:  Send information to the CNS

 Efferent nerves:  Send instructions to skeletal muscle  PNS receives and processes information

©Thompson Educational Publishing, Inc. 2003. All material is copyright protected. It is illegal to copy any of this material. This material may be used only in a course of study in which Exercise Science: An Introduction to Health and Physical Education (Temertzoglou/Challen) is the required textbook.

Autonomic and Somatic Nervous Systems

©Thompson Educational Publishing, Inc. 2003. All material is copyright protected. It is illegal to copy any of this material. This material may be used only in a course of study in which Exercise Science: An Introduction to Health and Physical Education (Temertzoglou/Challen) is the required textbook.

The Reflex Arc  Reflex arc:  Pathway in which the initial stimulus and the

corresponding response message travel  Five parts to a reflex arc:  Receptor  Sensory (or afferent) nerve  Intermediate nerve fibre

 Motor (or efferent) nerve  Effector organ

©Thompson Educational Publishing, Inc. 2003. All material is copyright protected. It is illegal to copy any of this material. This material may be used only in a course of study in which Exercise Science: An Introduction to Health and Physical Education (Temertzoglou/Challen) is the required textbook.

The Proprioceptor System  Proprioceptors:  Specialized receptors located within tendons, muscles, and joints  Provide sensory information (ex. state of muscle contraction)

through the primary use of two sensory receptors: golgi tendon organs and muscle spindles  Continuously monitor muscle actions  “Tell” the nervous system about the state of muscle contraction  Act as a kind of safety device allowing the nervous system to respond accordingly

©Thompson Educational Publishing, Inc. 2003. All material is copyright protected. It is illegal to copy any of this material. This material may be used only in a course of study in which Exercise Science: An Introduction to Health and Physical Education (Temertzoglou/Challen) is the required textbook.

Golgi Tendon Organs

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The Muscle Spindle

Sensory neuron (two branches within) Motor neuron

Muscle spindle within muscle fibre (magnified)

Muscle fibres

©Thompson Educational Publishing, Inc. 2003. All material is copyright protected. It is illegal to copy any of this material. This material may be used only in a course of study in which Exercise Science: An Introduction to Health and Physical Education (Temertzoglou/Challen) is the required textbook.

Golgi Tendon Organs & Muscle Spindles Golgi Tendon Organs

Muscle Spindles

Location

Where tendon meets muscle fibre

In belly of muscle fibre

Position

In series with muscle fibre

Parallel to muscle fibre

Respond to

Changes in muscle/tendon tension

Changes in muscle length

Sensory neurons

1

2

©Thompson Educational Publishing, Inc. 2003. All material is copyright protected. It is illegal to copy any of this material. This material may be used only in a course of study in which Exercise Science: An Introduction to Health and Physical Education (Temertzoglou/Challen) is the required textbook.

The Stretch Reflex  Stretch reflex:  Simplest spinal reflex  Depends on the single connection between primary afferent fibres

and motor neurons of same muscle  Sequence of nerve impulses and motions (e.g. tapping patella ligament):  Receptor muscle senses action of hammer against patella ligament through the muscle spindle’s sensory neuron  Message transmitted along afferent nerve axon to spinal cord  Afferent neuron synapses with the efferent pathway of same muscle  Impulse transmitted along efferent pathways to muscle  Motor units contract–brings about knee-jerk action

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Muscle Spindles at Work

Sensory neuron (two branches within) Motor neuron

Muscle fibres

©Thompson Educational Publishing, Inc. 2003. All material is copyright protected. It is illegal to copy any of this material. This material may be used only in a course of study in which Exercise Science: An Introduction to Health and Physical Education (Temertzoglou/Challen) is the required textbook.

Polysynaptic Reflexes  Withdrawal reflex:  Rapid and occurs before brain has time to interpret the information  Involves the withdrawal of a body part from a painful stimulus  Reflex action involves transferring impulse from a sensory neuron

to a motor neuron through a connecting interneuron  Crossed-Extensor Reflex:  Observed when one leg or arm automatically compensates for a reflex action in opposing leg or arm  Involves multiple synapses and muscle groups

©Thompson Educational Publishing, Inc. 2003. All material is copyright protected. It is illegal to copy any of this material. This material may be used only in a course of study in which Exercise Science: An Introduction to Health and Physical Education (Temertzoglou/Challen) is the required textbook.

The Withdrawal Reflex and the CrossedExtensor Reflex

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Spinal Cord and Head Injuries  Spinal cord injuries:  Damage to the spine can result in

©Thompson Educational Publishing, Inc. 2003. All material is copyright protected. It is illegal to copy any of this material. This material may be used only in a course of study in which Exercise Science: An Introduction to Health and Physical Education (Temertzoglou/Challen) is the required textbook.

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an inability to send impulses to body parts  Nerves above injury keep working, nerves below may not  Paraplegia:  Injury prevents use of legs but not arms  Quadriplegia:  Injury prevents movement of both arms and legs

Spinal Cord and Head Injuries 

©Thompson Educational Publishing, Inc. 2003. All material is copyright protected. It is illegal to copy any of this material. This material may be used only in a course of study in which Exercise Science: An Introduction to Health and Physical Education (Temertzoglou/Challen) is the required textbook.

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Head injuries:  Most common head injury is a concussion:  Occurs when brain literally hits the skull; often involves injury to nerve fibres  Ranges from mild to severe  Symptoms can include: headaches, fatigue, memory problems, or slurred speech

©Thompson Educational Publishing, Inc. 2003. All material is copyright protected. It is illegal to copy any of this material. This material may be used only in a course of study in which Exercise Science: An Introduction to Health and Physical Education (Temertzoglou/Challen) is the required textbook.