Transcript Muscle Mechanics & Sliding Filament Theory

Exercise Science
Muscle Mechanics & Sliding Filament Theory
Functions of Muscles – Learning Targets
Be able to describe how the muscle contracts in an overview.
Learn the properties of muscles and how they work.
Understand that the brain has a direct link to the muscles through the “motor
unit”
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Functions of Muscles – Major Questions
1. Describe what is happening to the sarcomere during concentric and
isometric contractions.
2. List the 12 steps of contraction with as much detail as possible.
3. What chemicals are involved in muscle contraction?
4. What would happen if one of these chemicals (calcium, ATP) wasn’t
present during an athletic event?
Homework:
a) figure out the chemical composition of ATP and how it breaks down.
b) When it breaks down, what happens in the muscle?
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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
Major Functions of Muscles
 Movement
 Includes: breathing, eating, and
the beating of our hearts
 Support
 Heat production
There are over 600 muscles in the
human body.
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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.
Three Types of Muscle Tissue
 Skeletal muscles:
 Voluntary, striated, and attach
to bones by tendons and other
tissue
Skeletal muscle
 Cardiac muscles:
 Involuntary, striated, and
found in one place – the heart
 Smooth muscles:
 Involuntary, non-striated, and
Cardiac muscle
surround the body’s internal
organs
Smooth muscle
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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.
Properties of Muscle Fibre
Irritability
Refers to muscle responding to stimuli
Contractibility
Refers to muscle shortening in length
Elasticity
Refers to muscle stretching and returning to normal
position
Extensibility
Refers to muscle extending in length
Conductivity
Refers to muscle transmitting nerve impulses
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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.
Neuromuscular Junction
Axon
Neurotransmitter
acetylcholine (Ach)
Axon Terminal
Sarcolemma
Synaptic Cleft
Receptor
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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 Motor Unit
Dendrites
Neuron cell body
Axon hillock
Motor neuron
Direction of
action
potential
Myelin sheath
Neurolemma
Neuromuscular junction
Terminal branches
Motor end plate
Muscle
fibres
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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 Anatomy of Skeletal Muscle
 Muscle fibre looking outward:
 Perimysium
Muscle fibre
 Binds muscle fibres together
 Epimysium
Perimysium
 Sheath enveloping entire muscle
 Muscle fibre looking inward:
 Endomysium
Epimysium
 Sheath of connective tissue
surrounding muscle fibre
 Sarcolemma
 Contains cytoplasm (sarcoplasm)
 Myofibrils
 Contain actin and myosin
 Sarcomeres
 Contains myosin and actin
Endomysium
Muscle belly
Tendon
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Muscle Fibre
Muscle
belly
Epimysium
Perimysium
Sarcomere
Z line
Z line
Tendon
Muscle Fibre
Thick
filament
Sarcomere
Sarcolemma Sarcoplasmic
reticulum
Myofibril
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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.
Thin filament
The Sliding Filament Theory
 Myosin crossbridges (small “bridges” on the thick filaments that extend
to the thin filaments):
 Attach, rotate, detach, and reattach in rapid succession
 Results in the sliding or overlap of the actin and myosin filaments
 Causes sarcomere to contract (muscle contraction)
 Known as the sliding filament theory
©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 Sliding Filament Theory
 Myosin crossbridges (small “bridges” on the thick filaments that extend
to the thin filaments)
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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 Sliding Filament Theory
 Myosin crossbridges
 Attach, rotate, detach, and re-attach in rapid succession
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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 Sliding Filament Theory
 Myosin crossbridges
 Results in the sliding or overlap of the actin and myosin filaments
 Causes sarcomere to contract (muscle contraction)
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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 Role of Adenosine Triphosphate
 The sliding filament theory at the molecular level:
 Nerve impulse transmitted through the muscle fibre and releases
calcium ions
 Calcium (in presence of troponin and tropomyosin) facilitates
the interaction of myosin and actin molecules
 Adenosine triphosphate (ATP) is the energy source behind the
release of calcium
 ATP detaches myosin from the actin molecule
 ATP must be replaced through food metabolism for process to
continue
©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 Role of Calcium
Sarcolemma
Longitudinal
tubules of sarcoplasmic reticulum
Outer vessicle of
sarcoplasmic reticulum
(Terminal cisternae)
Transverse tubule
(T-tubule)
Triad
H zone
Z line
Terminal cisternae
Transverse tubule
Terminal cisternae
A band
I band
Myofibrils
©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.
Resources – lesson on SFT and video
 http://education.uoit.ca/lordec/ID_LORDEC/muscle/
 This resource will show you each step of the contraction and explain how
the sarcomere works
 Sliding Filament Theory Video:
Part 1: http://www.youtube.com/watch?v=EdHzKYDxrKc
Part 2:
http://www.youtube.com/watch?v=Vlchs4omFDM&feature=related
 Other sliding Filament Theory Video:
http://www.youtube.com/watch?v=0kFmbrRJq4w
©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.