The Muscular System 5 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

Muscle Tissue Categories and Functions 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.

Today’s Objectives Discuss the structural and functional characteristics of each of the three categories of muscle. Describe the four behavioral characteristics of all muscle tissue. Explain the roles of agonist and antagonist muscles.

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.

Muscle Tissue categories functions skeletal smooth cardiac behavioral properties tension and types of skeletal muscle contractions

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 cross-stripes. Skeletal muscle is also known as voluntary muscle because these muscles are stimulated consciously through nerve activity.

Skeletal Muscle Organization The cell membrane of the muscle fiber is called the sarcolemma.

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

Skeletal Muscle Organization

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.

Cardiac Located solely in the walls of the heart. Cardiac cells are, involuntary and striated. Arranged in an interconnected network of figure-eight or spiral-shaped bundles that join at the intercalated disks.

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.

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.

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.

Concentric Contraction agonist contracts, antagonist relaxes

Eccentric Contraction agonist contracts while lengthening, antagonist relaxes

Isometric Contraction both agonist and antagonist contract

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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Exit Ticket Which is not a category of muscle? a. skeletal b. smooth d. rough e. cardiac

2) What is the only type of muscle found in the heart. a 2) What is the only type of muscle found in the heart? a. smooth muscle b. eccentric c. cardiac d. sarcolemma

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 = ________________

Skeletal Muscle Actions 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.

Today’s Objectives Describe a motor unit and explain the functional differences between motor units that contain large and small numbers of muscle fibers. Explain how a nerve impulse generates an action potential in a muscle fiber. Explain how muscle contraction occurs at the level of the sarcomere. Describe the differences between slow-twitch and fast-twitch skeletal muscle fibers. Discuss the concepts of muscular strength, power, and endurance.

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

The Motor Unit group of muscle fibers under the control of one motor neuron

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.

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.

Contraction of the Sarcomeres sarcomeres shorten by actin filaments sliding along myosin filaments

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 twitch-like manner. The muscles will generate maximum tension very briefly, then immediately go into a resting state.

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.

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

Slow-Twitch Fibers Fast-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

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.

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.

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

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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Exit Ticket A nerve that stimulates muscle is call a(n) ____. a. Motor Unit b. Motor Neuron c. Motor Home d. Motor Muscle

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

3)

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

The Major Skeletal Muscles 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

Skeletal Muscle Attachments origin fixed end of a muscle insertion movable end of a muscle

Sagittal Plane Movements flexion extension hyperextension dorsiflexion plantar flexion

Frontal Plane Movements abduction adduction inversion eversion radial deviation ulnar deviation

Transverse Plane Movements medial rotation lateral rotation pronation supination

Multiplanar Movements circumduction opposition

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.

Head and Neck Muscles

Trunk Muscles

Upper Limb Muscles

Lower Limb Muscles

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

Common Injuries and Disorders of Muscles Chapter 5: The Muscular System Lesson 5.4 Common Injuries and Disorders of Muscles

Muscle Injuries strain–overstretched muscle contusion–bruised muscle grade I, II, III contusion–bruised muscle myositis ossificans cramps–spasming muscle delayed onset muscle soreness–tear

Tendon Injuries tendinitis–inflamed tendon tendinosis–degeneration of a tendon Val Thoermer/Shutterstock.com

Joint Injuries rotational injury at shoulder overuse of elbow shin splints whiplash

Muscle Disorders muscular dystrophy hernia

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.