Chapter 5 The Muscular System Lesson 5 1

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Chapter 5: The Muscular System Lesson 5. 1 Muscle Tissue Categories and Functions

Chapter 5: The Muscular System Lesson 5. 1 Muscle Tissue Categories and Functions

Muscle Tissue • The three major categories of muscle fibers are: – Skeletal –

Muscle Tissue • The three major categories of muscle fibers are: – Skeletal – Smooth – Cardiac © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Muscle Tissue Categories • Skeletal Muscle (striated / voluntary muscle) – Attached to bones

Muscle Tissue Categories • Skeletal Muscle (striated / voluntary muscle) – Attached to bones and are largely responsible for body movements. – This type of muscle is stimulated by consciously directed nerve activity – These muscle fibers (cells) have many nuclei – The number of muscle fibers in a given person is genetically determined and does not change as we age, except for loss in fibers due to injury. © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

– Muscle fibers can increase in length and in diameter as we grow. –

– Muscle fibers can increase in length and in diameter as we grow. – Adults can increase their fiber diameter, and strength, by resistance training with just a few repetitions of heavy loads on a regular basis over a period of time © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Microscopic View of Striated Muscle © Goodheart-Willcox Co. , Inc. Permission granted to reproduce

Microscopic View of Striated Muscle © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Muscle Tissue Categories • Smooth muscle (visceral muscles) – These are small, spindle-shaped, nonstriated

Muscle Tissue Categories • Smooth muscle (visceral muscles) – These are small, spindle-shaped, nonstriated and involuntary (not under conscious control) – Found in the walls of many internal organs Ex. The stomach, intestines, blood vessels etc. © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

– Responsible for the propulsion of food in a wave -like motion down the

– Responsible for the propulsion of food in a wave -like motion down the digestive tract in a process called peristalsis – Peristalsis – Can sustain long periods of contraction without getting fatigued © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Microscopic View of Smooth Muscle © Goodheart-Willcox Co. , Inc. Permission granted to reproduce

Microscopic View of Smooth Muscle © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Muscle Tissue Categories • Cardiac Muscle – Is located solely in the walls of

Muscle Tissue Categories • Cardiac Muscle – Is located solely in the walls of the heart. – These muscle cells are branched, cross-striated, and involuntary—under the control of the autonomic nervous system © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

 • They have a distinguishing structure called intercalated disks which join spiral shaped

• They have a distinguishing structure called intercalated disks which join spiral shaped bundles of muscle. This enables simultaneous contraction of neighboring cells to produce the heartbeat. • Heartbeats • Heart Anatomy © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Microscopic View of Cardiac Muscle © Goodheart-Willcox Co. , Inc. Permission granted to reproduce

Microscopic View of Cardiac Muscle © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Side by Side Comparison © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for

Side by Side Comparison © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Skeletal Muscle Organization © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational

Skeletal Muscle Organization © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Review and Assessment True or False? 1. Smooth muscle is voluntary. False 2. Cardiac

Review and Assessment True or False? 1. Smooth muscle is voluntary. False 2. Cardiac muscle has branching fibers. 3. Smooth muscle is multinucleate. © Goodheart-Willcox Co. , Inc. True False Permission granted to reproduce for educational use only.

Behavioral Properties of Muscle • All muscle tissues have four behavioral characteristics in common:

Behavioral Properties of Muscle • All muscle tissues have four behavioral characteristics in common: – Extensibility – the ability to be stretched – Elasticity – the ability to snap back to normal length after a stretch – Irritability – the ability to respond to stimulus from the nervous system. – Contractility – the ability to shorten or contract. © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Muscle Tissue Functions • When a skeletal muscle develops tension, one of three actions

Muscle Tissue Functions • When a skeletal muscle develops tension, one of three actions can happen, the muscle can: – Shorten (concentric contraction) – Remain the same length (Isometric contraction) – Lengthen (eccentric contraction) © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Muscle Tissue Functions, cont. • Tension and types of skeletal muscle contraction – Agonist

Muscle Tissue Functions, cont. • Tension and types of skeletal muscle contraction – Agonist (prime mover) – moves bone – Antagonist – opposes the movement of the agonist © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Concentric Contraction • Shortening contraction of the biceps. • Agonist contracts, antagonist relaxes ©

Concentric Contraction • Shortening contraction of the biceps. • Agonist contracts, antagonist relaxes © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Eccentric Contraction • Lengthening contraction of the biceps. • Agonist contracts while lengthening, antagonist

Eccentric Contraction • Lengthening contraction of the biceps. • Agonist contracts while lengthening, antagonist relaxes © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Isometric Contraction • Contraction of both biceps and triceps. • No change in muscle

Isometric Contraction • Contraction of both biceps and triceps. • No change in muscle length occurs. • Both agonist and antagonist contract. © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Review and Assessment Match these words with 1– 5 below: extensibility, elasticity, irritability, contractility,

Review and Assessment Match these words with 1– 5 below: extensibility, elasticity, irritability, contractility, agonist, antagonist. 1. Respond Irritability Antagonist 2. Opposes movement 3. Stretch Extensibility 4. Shorten Contractility 5. Causes movement Agonist © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Chapter 5: The Muscular System Lesson 5. 2 Skeletal Muscle Actions

Chapter 5: The Muscular System Lesson 5. 2 Skeletal Muscle Actions

The Motor Unit • Muscle tissue is not able to develop tension unless stimulated

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 known as a motor neuron. • A motor unit is a group of muscle fibers under the control of one motor neuron © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Contraction of the Sarcomeres • Sarcomeres are units that shorten by actin filaments sliding

Contraction of the Sarcomeres • Sarcomeres are units that shorten by actin filaments sliding along myosin filaments within the muscle fiber. • Glucose stored within the muscle cell provides the energy for this contraction. © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Maximum Tension and Return to Relaxation • A signal (action potential) always causes entire

Maximum Tension and Return to Relaxation • A signal (action potential) always causes entire motor unit muscle fibers to contract. • This is the all-or-none law, after which the muscle fiber returns to its resting state. • Muscle Action © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Skeletal Muscle Fiber Types • Skeletal muscle fibers may be divided into two umbrella

Skeletal Muscle Fiber Types • Skeletal muscle fibers may be divided into two umbrella categories: – Slow – twitch (type I) fibers contract slowly – Fast – twitch (type II) fibers contract fast • Type IIa • Type IIb – Fast Twitch vs Slow Twitch • The fast- twitch/slow-twitch ratio varies from muscle to muscle and from person to person © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Skeletal Muscle Fiber Architecture (pattern) • Parallel fiber arrangements – Fusiform – Bundled –

Skeletal Muscle Fiber Architecture (pattern) • Parallel fiber arrangements – Fusiform – Bundled – Triangular • Pennate fiber arrangements – Unipennate – Bipennate – Multipennate © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Muscular Strength • Rotary force (force causing bone movement) that muscles can produce at

Muscular Strength • Rotary force (force causing bone movement) that muscles can produce at a joint – The maximum weight you can lift is a measurement of muscular strength • Force x velocity – How fast you can sprint is a measurement of muscle power © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Muscle Endurance • Muscle tension/time – How far you can run over a period

Muscle Endurance • Muscle tension/time – How far you can run over a period of time is a measurement of muscle endurance © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Chapter 5: The Muscular System Lesson 5. 3 The Major Skeletal Muscles

Chapter 5: The Muscular System Lesson 5. 3 The Major Skeletal Muscles

Skeletal Muscle Attachments • Skeletal muscles attach at either end of the muscle: –

Skeletal Muscle Attachments • Skeletal muscles attach at either end of the muscle: – Origin • The end of the muscle that attaches to a relatively fixed structure. – Insertion • The end of the muscle that attaches to a bone that typically moves when the muscle contracts. • When stimulated to develop tension, muscles can only pull. They are incapable of pushing. © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Skeletal Muscle Attachments • To describe the human body and its movements, we refer

Skeletal Muscle Attachments • To describe the human body and its movements, we refer to three major planes that pass through the center of the body: – Sagittal plane: forward and backward motions – Frontal plane: sideways movements – Transverse plane: rotational movements © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

© Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

© Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Sagittal Plane Movements • • • Flexion Extension Hyperextension Dorsiflexion Plantar flexion © Goodheart-Willcox

Sagittal Plane Movements • • • Flexion Extension Hyperextension Dorsiflexion Plantar flexion © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Sagittal Plane Movements © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational

Sagittal Plane Movements © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Frontal Plane Movements • • • Abduction Adduction Inversion Eversion Radial deviation Ulnar deviation

Frontal Plane Movements • • • Abduction Adduction Inversion Eversion Radial deviation Ulnar deviation © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Transverse Plane Movements • • Medial rotation Lateral rotation Pronation Supination © Goodheart-Willcox Co.

Transverse Plane Movements • • Medial rotation Lateral rotation Pronation Supination © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Multiplanar Movements • Circumduction • Opposition © Goodheart-Willcox Co. , Inc. Permission granted to

Multiplanar Movements • Circumduction • Opposition © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Chapter 5: The Muscular System Lesson 5. 4 Common Injuries and Disorders of Muscles

Chapter 5: The Muscular System Lesson 5. 4 Common Injuries and Disorders of Muscles

Muscle Injuries • Strain – This happens when a muscle is overstretched – Individuals

Muscle Injuries • Strain – This happens when a muscle is overstretched – Individuals with a large degree of flexibility at particular joints are at a lower risk – Strains are classified as: • Grade I (mild): tightness in the muscle • Grade II (moderate): pain cause by partial tear • Grade III (severe): tearing of muscle, loss of function & internal bleeding and swelling © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

– Hamstring strains are frequent for athletes. • Slow to heal • Tend to

– Hamstring strains are frequent for athletes. • Slow to heal • Tend to recur within the 1 st year of returning to the sport © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Muscle Injuries • Contusion – This is a bruise or bleeding within the muscle

Muscle Injuries • Contusion – This is a bruise or bleeding within the muscle resulting from an impact. • Myositis ossificans is a more serious condition due to repeated injury. • Cramps – These involve moderate to severe muscle spasms that cause pain – Causes are generally unknown, but may include electrolyte imbalance and dehydration © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Muscle Injuries • Delayed onset muscle soreness (DOMS) – Typically occurs 24 – 72

Muscle Injuries • Delayed onset muscle soreness (DOMS) – Typically occurs 24 – 72 hrs. after an unaccustomed activity – This involves multiple microscopic tears in muscle tissue causing inflammation, pain, swelling and stiffness © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Tendon Injuries • Tendons are tough fibrous connective tissues that connect muscle to bones

Tendon Injuries • Tendons are tough fibrous connective tissues that connect muscle to bones – Tendinitis is the inflammation of a tendon accompanied by pain and swelling – Tendinosis results when tendinitis remains untreated resulting in degeneration of the tendon and eventual rapture © Goodheart-Willcox Co. , Inc. Val Thoermer/Shutterstock. com Permission granted to reproduce for educational use only.

Joint Injuries • Rotational injury at shoulder – Swimmers shoulder • Overuse of elbow

Joint Injuries • Rotational injury at shoulder – Swimmers shoulder • Overuse of elbow – Tennis elbow • Shin splints – Pain localized to the medial lower leg. • Whiplash – Injury to the neck common as a result of automobile accidents resulting from an abnormal motion of the cervical vertebrae. © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Muscle Disorders • Muscular dystrophy – This is a group of similar, inherited disorders

Muscle Disorders • Muscular dystrophy – This is a group of similar, inherited disorders characterized by progressively worsening muscle weakness and loss of muscle tissue. – There are no known cures – Treatments are to control symptoms © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.

Muscle Disorders, cont. • Hernia – This is a balloon-like section of the abdominal

Muscle Disorders, cont. • Hernia – This is a balloon-like section of the abdominal cavity lining that protrudes through a hole or weakened section of the muscles in the abdomen. – May be caused by heavy lifting, increased pressure inside abdominal cavity or no specific cause. © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only.