chapter 25 the muscular system 25-2 learning outcomes (cont.) 25.1 describe the functions of muscle....

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25The Muscular

System

25-2


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.

25-3


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.

25-4


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.

25-5


Functions of Muscle

• The ability to contract enables muscles to – Allow movement

– Provide stability

– Control body openings and passages

– Warm the body

25-6


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

25-7


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

25-8


Control of Body Openings and Passages

• Sphincters

– Valve-like structures

– Control movement in and out of passages

25-9


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.

tendons

in and out

contract

T

T

F

F

F

ANSWER:

25-10


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

25-12


Types of Muscle Tissue (cont.)

Muscle Group

Major Location

Major Function

Mode of Control

Skeletal Muscle

Attached to bones and skin of the face

Produces body movements and facial expressions

Voluntary

Smooth Muscle

Walls of hollow organs, blood vessels, and iris

Moves contents through organs; vasoconstriction

Involuntary

Cardiac Muscle

Wall of the heart Pumps blood through heart

Involuntary

25-13


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

25-14


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

25-15


Cardiac Muscle

• Intercalated discs– Connect groups of cardiac muscle– Allow the heart to work as a pump

• Self-exciting

• Responds to neurotransmitters– Acetylcholine– Norepinephrine

25-16



Match the following:

___ Self-exciting

___ Contract in response to acetylcholine

___ Stimulate each other to contract

___ Peristalsis

___ Slowed by acetylcholine

___ Voluntary movement

C

A

A

B

BVery

Good!

C

ANSWER: A. Skeletal Muscle

B. Smooth muscle

C.Cardiac muscle

25-17


Production of Energy for Muscle

• ATP

• Muscle cells make ATP by– Creatine phosphate ~ rapid production of

energy

– Aerobic respiration ~ uses body’s store of glucose

– Lactic acid production from pyruvic acid

25-18


Muscle fatigueMuscle fatigue

Oxygen Debt

Strenuous use of skeletal muscles depletes cells of oxygen

To liver for conversion to glucose, requiring more energy

and oxygen to make ATP

Pyruvic AcidPyruvic Acid Lactic acidLactic acid

Oxygen debtOxygen debt

25-19


Muscle Fatigue

• Loses ability to contract

• Causes– Accumulation of lactic acid

– Interruption of the blood supply

– Acetylcholine not released by motor neuron

25-20



___ Rapid production of energy

___ Needed for sustained or repeated muscle contractions

___ Uses body’s store of glucose

___ Muscle fatigue

___ With strenuous exercise, converts to lactic acid


A. Lactic acid

B. Pyruvic acid

C. ATP

D. Aerobic respiration

E. Creatine phosphate

C

A

D

B

E

ANSWER:

Yippee!

25-21


Structure of Skeletal Muscles

• Skeletal muscles – the major organs of the

muscular system

• Composition – Connective tissue– Skeletal muscle tissue – Blood vessels – Nerves

25-22


Structure of Skeletal Muscles (cont.)

• Connective tissue coverings

– Fascia

– Tendon

– Aponeruosis

– Epimysium

– Perimysium

– Endomysium

Muscle structure

25-23




__ 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

A. Tendon

B. Perimysium

C. Aponeurosis

D. Epimysium

E. Fascia

F. Endomysium

E

A

B

F

C

D

ANSWER:

25-24


Attachments and Actions of Skeletal Muscles

• Attachment types– Origin ~ for a less

movable bone

– Insertion ~ for a more movable bone

25-25


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

25-26



• Flexion

• Extension

• Hyperextension

• Dorsiflexion

• Plantar flexion

• Abduction

• Adduction

Figure of Body Movements

25-28



• Rotation

• Circumduction

• Pronation

• SupinationRotation Circumduction

Supination

Pronation

25-29



• Inversion

• Eversion

• Retraction

• Protraction

• Elevation

• Depression

Figure of movements

25-31



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.

T

F

T

T

antagonist

25-32


Major Skeletal Muscles

• Name often describes muscle by

– Location

– Size

– Action

– Shape

– Number of attachments

25-34


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

25-35


Arm Muscles

• Pectoralis major

• Latissimus dorsi

• Deltoid

• Subscapularis

• Infraspinatus

Skeletal muscles

25-36


Arm Muscles (cont.)

• Biceps brachii

• Brachialis

• Brachioradialis

• Triceps brachii

• Supinator

• Pronator teres Skeletal muscles

25-37


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

25-39


Respiratory Muscles

• Diaphragm – Separates thoracic and abdominal cavities– Contracts for inspiration

• External and internal intercostals – expand and lower the ribs

For diagram

25-40


Skeletal Muscles (cont.)

• Abdominal muscles– External and

internal obliques

– Transverse abdominis

– Rectus abdominis

• Muscles of the Pectoral Girdle– Trapezius

– Pectoralis minor

For diagram

25-42


Leg Muscles

• Iliopsoas major

• Gluteus maximus

• Gluteus medius and minimus

• Adductor longus and magnus

Skeletal muscles

25-43


Leg Muscles (cont.)

• Biceps femoris, semitendinosus, and semimembranosus

• Rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius

• Sartoris

Skeletal muscles

25-44


Ankle, Foot, and Toe Muscles

• Tibialis anterior

• Extensor digitorum longus

• Gastrocnemius

• Soleus

• Flexor digitorum longus

Skeletal muscles

25-45



Matching:

raises the eyebrows

chewing

expand and lower ribs

compress the abdominal wall

extends the thigh

extends the leg at the knee

A. Gluteus maximus

B. Intercostals

C. Frontalis

D. Quadriceps group

E. Obliques

F. Masseter

ANSWER:

Bravo!Bravo!

A

B

C

D

E

F

25-46


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

25-47


Diseases and Disorders of the Muscular System

Disease DescriptionBotulism 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

25-48


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

25-49


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

25-50



ANSWER: Speed and strength of muscle contractions decrease with aging.

The aging process results in: • Decreased dexterity and gripping ability• Decreased mobility

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

25-51



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.

ANSWER:

T

T

F

F

Fibromyalgia

Torticollis

25-52


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.

25-53


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.

25-54


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.

25-55


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.

25-56


Everyone has a ‘risk muscle.’ You keep it in shape by trying new things. If you don’t, it atrophies. Make a point of using it at least once a day.

~Roger von Oech

End of Chapter 25

chapter 25 the muscular system 25-2 learning outcomes (cont.) 25.1 describe the functions of muscle....

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