Download Muscle Properties

The Muscular
System Continued
Grade 12 Exercise Science
Mr. MacMillan
Review
O The characteristics of muscle
O Irritability
O Contractility
O Extendibility
O Elasticity
O Conductibility
O Muscle fibre types
O Fast glycolytic, fast oxidative, slow
O Muscle types
O Skeletal
O Smooth
O cardiac
The Neuromuscular System
O The complex linkages between the muscular system
O
1.
2.
3.
and the nervous system
Example: Preparing to Kick a Soccer Ball
Messages needed to execute the action are sent
from brain or spinal cord.
This causes a chemical reaction in the leg muscle
area
Muscles produce the force and you kick the ball
All of this happens in an instant with many nerves and
muscles being affected, yet kicking a soccer ball seems
so effortless
The Neuromuscular Junction
Motor Unit
O Nerves transmit impulses in waves that ensure
smooth movements.
O Muscle Twitch
O
A single nervous impulse and the resulting contraction
O Motor Unit
O
The motor neuron, its axon and the muscle fibre it stimulates
are together called the motor unit.
All-or-none Principle
O Whether or not a motor unit activates upon the
arrival of an impulse depends upon the so called
all-or-none principle
O An impulse of a certain magnitude (or strength)
is required to cause the innervated fibres to
contract
O Every motor unit has a specific threshold that
must be reached for such activation to occur
Anatomy of Skeletal Muscle
O Perimysium
O Sheath of connective tissues that binds groups of muscle fibres
together
O Epimysium
O Strong, connective sheath that envelopes the entire muscle
O Endomysium
O Sheath of connective tissues that surrounds the muscle fibre
O Tendon
O Attaches the muscle structure to the bone
O Blood vessel
O Supplies the muscle with blood and other nutrients
Microscopic Skeletal Muscle
O Using the microscopes in the back cupboard,
you will be examining skeletal muscle under a
light microscope
O Your task is to sketch what you see under all
three magnifications
O Your 3 sketches need the following
O A title
O Magnification listed
O Labeled components of sketch
O Each sketch should be on a separate piece of paper
High microscope magnification of a single
sarcomere within a single myofibril
Homework
O Finish labeled sketches of skeletal muscle
O Read pages 2-37 of textbook
O Make any necessary notes if needed.