Download C5.2 PPT - Destiny High School

5
The Muscular
System
Lesson 5.1: Muscle Tissue Categories
and Functions
Lesson 5.2: Skeletal Muscle Actions
Lesson 5.3: The Major Skeletal Muscles
Lesson 5.4: Common Injuries and
Disorders of Muscles
Chapter 5: The Muscular System
Lesson 5.1
Muscle Tissue Categories
and Functions
Do Now
• Work on the “Learning the Key Terms”
Worksheet.
• Chapter 5 Lesson 1 begins on page 155.
• You have 10 minutes to complete the worksheet.
• Turn the worksheet in to Mr. B when you are
finished.
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Today’s Objectives
1. Discuss the structural and functional
characteristics of each of the three categories of
muscle.
2. Describe the four behavioral characteristics of all
muscle tissue.
3. Explain the roles of agonist and antagonist
muscles.
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Muscle Tissue
• Muscle is the only tissue capable of shortening, or
contracting.
• Muscles control movements of our body, move our
eyes, move our food through our digestive system
and beats our heart.
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Muscle Tissue
• categories
– skeletal
– smooth
– cardiac
• functions
– behavioral properties
– tension and types of skeletal muscle contractions
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Muscle Tissue Categories
• Skeletal
– Skeletal muscles attach to bones and are largely responsible for body
movements.
– Skeletal muscles are also known as striated muscles because of their crossstripes.
– Skeletal muscle is also known as voluntary muscle because these muscles
are stimulated consciously through nerve activity.
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Skeletal Muscle Organization
• The cell membrane of the muscle fiber is called
the sarcolemma.
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• perimysium bundles groups of
muscle fibers to make up a
fascicle
• epimysium encloses several
fascicles to make up a muscle
• aponeurosis connects muscle
to other tissues
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Skeletal Muscle Organization
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• Smooth Muscle
– Smooth muscle fibers are small, spindle shaped, and non-striated.
– Involuntary – not under conscious control.
– Found on the walls of many internal organs like the stomach,
intestines, bladder, and respiratory passages.
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• Cardiac
– Located solely in the walls of the heart.
– Cardiac cells are, involuntary and striated.
– Arranged in an interconnected network of figure-eight or spiralshaped bundles that join at the intercalated disks.
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Review and Assessment
True or False?
1. Smooth muscle is voluntary.
2. Cardiac muscle has branching fibers.
3. Smooth muscle is multinucleate.
4. Perimysium wraps fascicles to make a muscle.
5. Endomysium surrounds the muscle fibers.
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Behavioral Properties of Muscle
• All muscles have four behavioral characteristics in common:
– extensibility– the ability to be stretched.
– elasticity– the ability to return to normal length after a stretch.
– irritability– the ability to respond to a stimulus.
– contractility– the ability to contract or shorten.
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Muscle Tissue Functions
• tension and types of skeletal muscle contraction
– agonist– the prime mover, moves bone
– antagonist–opposes the movement of the agonist
• Example: Bicep Curls. The bicep acts as the agonist and
triceps acts as the antagonist.
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Concentric Contraction
• agonist contracts,
antagonist relaxes
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Eccentric Contraction
• agonist contracts while
lengthening, antagonist
relaxes
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Isometric Contraction
• both agonist and
antagonist contract
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Review and Assessment
Match these words with 1–5 below: extensibility,
elasticity, irritability, contractility, agonist, antagonist.
1. respond
2. opposes movement
3. stretch
4. shorten
5. causes movement
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END
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Exit Ticket
1) Which is not a category of muscle?
a. skeletal
b. smooth
d. rough
e. cardiac
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2) What is the only type of muscle found in the
heart?
a. smooth muscle
b. eccentric
c. cardiac
d. sarcolemma
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3) When you perform a bicep curl, there are two
muscles involved, the bicep and the tricep. Which of
muscle is the agonist and which is the antagonist?
Agonist = ________________
Antagonist = ________________
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Chapter 5: The Muscular System
Lesson 5.2
Skeletal Muscle Actions
Do Now
• Work on the “Learning the Key Terms”
Worksheet.
• Chapter 5 Lesson 2 begins on page 162.
• You have 10 minutes to complete the worksheet.
• Turn the worksheet in to Mr. B when you are
finished.
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Today’s Objectives
1. Describe a motor unit and explain the functional differences
between motor units that contain large and small numbers of
muscle fibers.
2. Explain how a nerve impulse generates an action potential in a
muscle fiber.
3. Explain how muscle contraction occurs at the level of the
sarcomere.
4. Describe the differences between slow-twitch and fast-twitch
skeletal muscle fibers.
5. Discuss the concepts of muscular strength, power, and
endurance.
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Skeletal Muscle
• Development of tension in a skeletal muscle is
influenced by a number of variables.
– Signals from the nervous system
– The properties of the muscle fibers
– The arrangement of fibers within the muscle
• the motor unit
• skeletal fiber types
• muscular strength, power, and endurance
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The Motor Unit
• group of muscle fibers under the control of one
motor neuron
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The Motor Unit
• Muscle tissue is not able to develop tension unless
stimulated by one or more nerves.
– A nerve that stimulates skeletal muscle, which is under
voluntary control is called a motor neuron.
– A single motor neuron and all of the muscle cells that it
stimulates is known as a motor unit.
– One motor neuron supplying impulses to a muscle may
connect anywhere between 100 to nearly 2000 skeletal
muscle fibers.
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Generating Action Potentials
• How does the motor neuron communicate with the
muscle cells in the motor unit to stimulate them?
– acetylcholine crosses the synaptic cleft at the
neuromuscular junction
• Acetylcholine causes an influx of sodium ions into the cell
and potassium ions out of the cell.
– depolarization takes place on muscle fiber
– action potential begins as a result of positive sodium
ions.
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Contraction of the Sarcomeres
• sarcomeres shorten by actin filaments sliding
along myosin filaments
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Maximum Tension and Return to
Relaxation
• All-or-None Law
– An action potential always causes entire motor unit
muscle fibers to contract.
• Skeletal motor units develop tension in a twitchlike manner.
• The muscles will generate maximum tension very
briefly, then immediately go into a resting state.
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Review and Assessment
True or False?
1. An action potential causes one half of the fibers in
the motor unit to contract.
2. Acetylcholine crosses the synaptic cleft at the
neuromuscular junction.
3. The sarcomeres lengthen by myosin filaments
sliding over actin filaments.
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Skeletal Muscle Fiber Types
• Why are some athletes especially good at events
or tasks like running marathons or dunking a
basketball.
• Skeletal muscles are divided into two categories:
– slow-twitch
– fast-twitch
• type IIa
• type IIb
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• Slow-Twitch Fibers
– Muscle fibers that are found in people that are better
suited for endurance type activities.
• Fast-Twitch Fibers
– Contract much faster compared to slow-twitch.
– Type IIa
• Intermediate speed
– Type Iib
• Contract very rapidly
• About 1/7 the time required for slow-twitch fibers to
contract.
• Fatigue rapidly
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Skeletal Muscle Fiber Architecture
• Fiber architecture refers to the ways
in which muscle fibers are arranged.
• 2 Major Categories
– parallel fiber arrangements
• fusiform
• bundled
• triangular
– pennate fiber arrangements
• Unipennate – fibers aligned in
one direction to a central tendon
• Bipennate – fibers that are
attached to a central tendon.
• Multipennate – fibers that attach
to a central tendon in more than
two directions.
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Muscular Strength
• Muscular strength can be difficult to assess.
• More precise assessment of muscular strength is
torque.
– Torque is a rotary force that muscles can produce at a
joint
• the maximum weight you can lift is a measurement of
muscular strength
• The more toque a muscle generates at a joint, the greater
the tendency for movement of the bones.
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Muscle Power
• Muscular power is defined as muscle force
multiplied by muscle shortening velocity.
• Muscular power generated by several different
muscles working collectively.
• force x velocity
– how fast you can sprint is a measurement of muscle
power
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Muscle Endurance
• The ability of a muscle to produce tension over a
period of time.
• The longer the physical activity is maintained, the
greater the required muscular endurance.
• muscle tension/time
– how far you can run is a measurement of muscle
endurance
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END
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Exit Ticket
1) A nerve that stimulates muscle is call a(n) ____.
a. Motor Unit
b. Motor Neuron
c. Motor Home
d. Motor Muscle
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2) A(n) ___ is an electrical charge that creates
tension within a muscle fiber.
a. action mark
b. action speed
c. action potential
d. action spark
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• 3)
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Review and Assessment
Match these words with 1–5 below: muscle
endurance, muscular strength, muscle power,
Type I, Type IIb.
1. force x velocity
2. muscle tension/time
3. rotary force that muscles can produce at a joint
4. slow twitch, slow fatigue
5. fast twitch, fast fatigue
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Chapter 5: The Muscular System
Lesson 5.3
The Major Skeletal
Muscles
The Major Skeletal Muscles
•
•
•
•
•
directional motions
head and neck muscles
trunk muscles
upper limb muscles
lower limb muscles
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Skeletal Muscle Attachments
• origin
– fixed end of a muscle
• insertion
– movable end of a muscle
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Sagittal Plane Movements
•
•
•
•
•
flexion
extension
hyperextension
dorsiflexion
plantar flexion
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Frontal Plane Movements
•
•
•
•
•
•
abduction
adduction
inversion
eversion
radial deviation
ulnar deviation
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Transverse Plane Movements
•
•
•
•
medial rotation
lateral rotation
pronation
supination
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Multiplanar Movements
• circumduction
• opposition
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Review and Assessment
True or False?
1. Circumduction is a multiple plane movement.
2. Supination is a multiple plane movement.
3. The insertion is the fixed end of a muscle.
4. Extension is a sagittal plane movement.
5. Adduction is a frontal plane movement.
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Head and Neck Muscles
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Trunk Muscles
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Upper Limb Muscles
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Lower Limb Muscles
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Review and Assessment
Match these words with 1–4 below: head, trunk,
upper limb, lower limb.
1. temporalis
2. brachioradialis
3. external oblique
4. biceps femoris
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Chapter 5: The Muscular System
Lesson 5.4
Common Injuries and
Disorders of Muscles
Muscle Injuries
• strain–overstretched muscle
– grade I, II, III
• contusion–bruised muscle
– myositis ossificans
• cramps–spasming muscle
• delayed onset muscle soreness–tear
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Tendon Injuries
• tendinitis–
inflamed tendon
• tendinosis–
degeneration of
a tendon
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Joint Injuries
•
•
•
•
rotational injury at shoulder
overuse of elbow
shin splints
whiplash
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Muscle Disorders
• muscular dystrophy
• hernia
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Review and Assessment
True or False?
1. Tendinitis is muscle strain.
2. A contusion is a bruise.
3. Whiplash is a joint injury.
4. A hernia is a tendon injury.
5. A strain is an over stretch of a tendon.
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