The Muscular System

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25

• The Muscular System

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Learning Outcomes (cont.)

• 25.1 Describe the functions of muscle.
• 25.2 Compare the three types of muscle tissue
  including their locations and characteristics.
• 25.3 Explain how muscle tissue generates energy.
• 25.4 Describe the structure of a skeletal muscle.
  

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Learning Outcomes (cont.)

• 25.5 Recognize the terms origin and insertion.
• 25.6 Identify the major skeletal muscles of the
  body, giving the action of each.
• 25.7 Summarize the changes that occur to the
  muscular system as a person ages.
• 25.8 Describe the causes, signs and symptoms,
  and treatments of various diseases and
  disorders of the muscular system.

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Introduction

• Muscles contract and relax to cause movement
• 600 individual muscles in the body

You will focus on the differences among three
muscle tissue types, the structure of skeletal
muscles, muscle actions, and the names of
skeletal muscles.
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Functions of Muscle

• The ability to contract enables muscles to
• Allow movement
• Provide stability
• Control body openings and passages
• Warm the body

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Functions of Muscle (cont.)

• Skeletal muscles
• Attach to bones by tendons
• Contractions result in movement
• Smooth muscle contractions move organ contents
• Cardiac muscle contractions pump blood from the
  heart

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Functions of Muscle (cont.)

• Stability
• Hold bones tightly together
• Small muscles hold vertebrae together

• Heat Production
• Heat is released when muscles contract
• Helps maintain a normal temperature

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Control of Body Openings and Passages

• Sphincters
• Valve-like structures
• Control movement in and out of passages

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Apply Your Knowledge
True or False ___ Skeletal muscles are attached
to bones by ligaments. ___ Contractions of smooth
muscle produce movement of organ
contents. ___ Cardiac muscle produces atrial and
ventricular contractions. ___ Sphincters control
movement of substances out of passages. ___ Heat
is released as muscles relax.
ANSWER
F
T
T
F
RIGHT!
F
contract
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Types of Muscle Tissue

• Muscle cells or myocytes muscle fibers
• Sarcolemma
• Sarcoplasm
• Sarcoplasmic reticulum
• Myofibrils
• Long structures in sarcoplasm
• Striations arrangement of filaments

Muscle structure
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Back
12
Types of Muscle Tissue (cont.)
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Skeletal Muscle

• Skeletal muscle fibers
• Contract in response to the neurotransmitter
  acetylcholine
• After contraction, muscles release the enzyme
  acetylcholinesterase
• Breaks down acetylcholine
• Allows muscle to relax

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Smooth Muscle

• Multiunit smooth muscles respond to
  neurotransmitters and hormones
• Visceral smooth muscles
• Responds to neurotransmitters acetylcholine and
  norepinephrine
• Stimulate each other to contract peristalsis

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Cardiac Muscle

• Intercalated discs
• Connect groups of cardiac muscle
• Allow the heart to work as a pump
• Self-exciting
• Responds to neurotransmitters
• Acetylcholine
• Norepinephrine

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Apply Your Knowledge
Match the following ___ Self-exciting ___
Contract in response to acetylcholine ___
Stimulate each other to contract ___
Peristalsis ___ Slowed by acetylcholine ___
Voluntary movement
ANSWER

1. Skeletal Muscle
2. Smooth muscle
3. Cardiac muscle

C
A
B
B
Very Good!
C
A
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Production of Energy for Muscle

• ATP
• Muscle cells make ATP by
• Creatine phosphate rapid production of energy
• Aerobic respiration uses bodys store of
  glucose
• Lactic acid production from pyruvic acid

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Oxygen Debt

• Strenuous use of skeletal muscles depletes cells
  of oxygen

Pyruvic Acid
Lactic acid
Muscle fatigue
Oxygen debt
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Muscle Fatigue

• Loses ability to contract
• Causes
• Accumulation of lactic acid
• Interruption of the blood supply
• Acetylcholine not released by motor neuron

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Apply Your Knowledge
ANSWER

• Match the following
• ___ Rapid production of energy
• ___ Needed for sustained or repeated muscle
  contractions
• ___ Uses bodys store of glucose
• ___ Muscle fatigue
• ___ With strenuous exercise, converts to lactic
  acid

1. Lactic acid
2. Pyruvic acid
3. ATP
4. Aerobic respiration
5. Creatine phosphate

E
C
D
A
B
Yippee!
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Structure of Skeletal Muscles

• Skeletal muscles the major organs of the
  muscular system
• Composition
• Connective tissue
• Skeletal muscle tissue
• Blood vessels
• Nerves

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Structure of Skeletal Muscles (cont.)

• Connective tissue coverings
• Fascia
• Tendon
• Aponeruosis

• Epimysium
• Perimysium
• Endomysium

Muscle structure
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Apply Your Knowledge
Match the following __ Thin covering under the
fascia that surrounds the muscle __ Separates
muscles from each other __ Connects muscles to
bones __ Divides a muscle into sections called
fascicles __ Surrounds individual muscle
cells __ Attaches muscles to other muscles
ANSWER
D

1. Tendon
2. Perimysium
3. Aponeurosis
4. Epimysium
5. Fascia
6. Endomysium

E
A
B
F
C
Excellent!
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Attachments and Actions of Skeletal Muscles

• Attachment types
• Origin for a less movable bone
• Insertion for a more movable bone

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Attachments and Actions of Skeletal Muscles
(cont.)

• Movement
• Prime mover (agonist) responsible for most of
  the movement
• Synergists help the prime mover by stabilizing
  joints
• Antagonist produces movement opposite to prime
  mover

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Attachments and Actions of Skeletal Muscles
(cont.)

• Plantar flexion
• Abduction
• Adduction

• Flexion
• Extension
• Hyperextension
• Dorsiflexion

Figure of Body Movements
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Hyperextension
Extension
Dorsiflexion
Flexion
Plantar flexion
Extension
Adduction
Flexion
Abduction
Back
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Attachments and Actions of Skeletal Muscles
(cont.)

• Rotation
• Circumduction
• Pronation
• Supination

Supination
Pronation
Circumduction
Rotation
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Attachments and Actions of Skeletal Muscles
(cont.)

• Inversion
• Eversion
• Retraction

• Protraction
• Elevation
• Depression

Figure of movements
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Attachments and Actions of Skeletal Muscles
(cont.)
Protraction
Retraction
Elevation
Depression
Inversion
Eversion
Back
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Apply Your Knowledge
ANSWER
True or false? An agonist is the muscle
that produces a movement opposite to a
prime mover. Synergists stabilize joints.
Origin is an attachment site for the less
moveable bone during muscle
contraction. Insertion is an attachment
site for the more moveable bone during
muscle contraction.
F
antagonist
T
T
T
Correct!
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Major Skeletal Muscles

• Name often describes muscle by
• Location
• Size
• Action
• Shape
• Number of attachments

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Back
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Muscles of the Head

• Sternocleidomastoid
• Splenius capitis
• Muscles of the jaw
• Masseter
• Temporalis

• Muscles of facial expression
• Frontalis
• Orbicularis oris
• Orbiuclaris oculi
• Zygomaticus
• Platysma

Skeletal muscles
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Arm Muscles

• Pectoralis major
• Latissimus dorsi
• Deltoid

• Subscapularis
• Infraspinatus

Skeletal muscles
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Arm Muscles (cont.)

• Biceps brachii
• Brachialis
• Brachioradialis
• Triceps brachii
• Supinator
• Pronator teres

Skeletal muscles
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Muscles of the Wrist, Hand, and Fingers

• Flexor carpi radilas
• Felxor carpi ulnaris
• Palmaris longus
• Flexor digitorum profundus

• Extensor carpi radialis longus and brevis
• Extensor carpi ulnairs
• Extensor digitorum

Diagram of hand
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Back
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Respiratory Muscles

• Diaphragm
• Separates thoracic and abdominal cavities
• Contracts for inspiration
• External and internal intercostals expand and
  lower the ribs

For diagram
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Skeletal Muscles (cont.)

• Abdominal muscles
• External and internal obliques
• Transverse abdominis
• Rectus abdominis

• Muscles of the Pectoral Girdle
• Trapezius
• Pectoralis minor

For diagram
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Skeletal Muscles (cont.)
Back
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Leg Muscles

• Iliopsoas major
• Gluteus maximus
• Gluteus medius and minimus
• Adductor longus and magnus

Skeletal muscles
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Leg Muscles (cont.)

• Biceps femoris, semitendinosus, and
  semimembranosus
• Rectus femoris, vastus lateralis, vastus
  medialis, and vastus intermedius
• Sartoris

Skeletal muscles
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Ankle, Foot, and Toe Muscles

• Tibialis anterior
• Extensor digitorum longus
• Gastrocnemius
• Soleus
• Flexor digitorum longus

Skeletal muscles
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Apply Your Knowledge
ANSWER

• Matching
• raises the eyebrows
• chewing
• expand and lower ribs
• compress the abdominal wall
• extends the thigh
• extends the leg at the knee

1. Gluteus maximus
2. Intercostals
3. Frontalis
4. Quadriceps group
5. Obliques
6. Masseter

C
F
B
E
A
D
Bravo!
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Aging and the Musculoskeletal System

• Speed and strength of muscle contractions
  decrease
• Aging
• Decreased dexterity and gripping ability
• Decreased mobility
• Assistive devices helpful
• Routine exercise

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Diseases and Disorders of the Muscular System
Disease Description
Botulism Affects the gastrointestinal tract and various muscle groups
Fibromyalgia Fairly common condition that causes chronic pain primarily in joints, muscles, and tendons
Muscular dystrophy Inherited disorder characterized by muscle weakness and a loss of muscle tissue
Myasthenia gravis Autoimmune condition in which patients experience muscle weakness and loss of muscle tissue
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Diseases and Disorders of the Muscular System
(cont.)
Disease Description
Rhabdomyolysis Kidneys become damaged because of toxins released from muscle cells after serious muscle injuries
Tendonitis Painful inflammation of a tendon and the tendon-muscle attachment to a bone
Tetanus (lockjaw) Muscle spasms in the jaw, keck and facial muscles high mortality rate
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Diseases and Disorders of the Muscular System
(cont.)
Disease Description
Torticollis (wryneck) A cervical deformity in which the head bends toward the affected side while the chin rotates to the opposite side
Trichinosis An infection caused by parasites ingested by eating undercooked meat
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Apply Your Knowledge

1. What changes occur to the muscular system as a
   result of aging?

• ANSWER Speed and strength of muscle contractions
  decrease with aging.
• The aging process results in
• Decreased dexterity and gripping ability
• Decreased mobility

Good Job!
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Apply Your Knowledge
ANSWER

• True or False
• Botulism is a condition resulting in
  chronic pain in joints, muscles and
  tendons.
• Kidney damage due to toxins released by
  serious muscle injuries is the condition
  called rhabdomyolysis.
• Tetanus is caused by a toxin and causes
  muscle spasms in the jaw, neck, and facial
  muscles.
• Lockjaw is caused by spasm or shortening of
  the sternocleidomastoid muscle.

Fibromyalgia
F
T
T
Torticollis
F
Good Job!
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In Summary

• 25.1 The functions of muscles include movement,
  stability, control of body openings and
  passages, and the production of heat.
  Valve- like muscular structures called sphincters
  control passage of substances into and out of
  organs like the stomach and bladder.
• .25.2 The three types of muscle tissue are
  striated, voluntary skeletal muscle smooth,
  involuntary visceral muscle and specialized
  striated and involuntary cardiac muscle.

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In Summary (cont.)

• 25.3 There are three ways muscles create energy.
  Creatine phosphate, aerobic respiration, and
  lactic acid production.
• 25.4 Skeletal muscle is composed of connective
  tissues, skeletal muscle tissue, blood vessels,
  and nerves. The coverings of skeletal muscles
  include fascia, tendon, aponeurosis, epimysium,
  perimysium, and endomysium.

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In Summary (cont.)

• 25.5 The origin of a muscle is the attachment
  site of the muscle to the less moveable bone
  during muscle contraction. The insertion of a
  muscle is the attachment site for the muscle to
  the more moveable bone during muscle contraction.
  
• 25.6 The major muscles of the head and the upper
  extremity, major respiratory muscles, abdominal
  muscles, pectoral girdle muscles and those of the
  lower extremity are covered in this learning
  outcome.

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In Summary (cont.)

• 22.7 The common diseases of aging include
  arthritis, fractures, osteoporosis, and
  muscular decline. Aging causes a decline in
  strength and speed of muscle contractions.
  Dexterity and gripping abilities lessen and
  mobility often decreases related to skeletal
  and muscular decline.
• 22.8 There are many common diseases and
  disorders of the muscular system with varied
  signs, symptoms, and treatments.

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End of Chapter 25
Everyone has a risk muscle. You keep it in
shape by trying new things. If you dont, it
atrophies. Make a point of using it at least once
a day. Roger von Oech