1. 25
The Muscular System

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.

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.

4. Introduction Muscles contract and relax to cause movement
600 individual muscles in the body
Learning Outcome: Describe the functions of muscle.
You will focus on the differences among three muscle tissue types, the structure of skeletal muscles, muscle actions, and the names of skeletal muscles.

5. Functions of Muscle The ability to contract enables muscles to
Allow movement
Provide stability
Control body openings and passages
Warm the body
Learning Outcome: Describe the functions of muscle.

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
Learning Outcome: Describe the functions of muscle.
Movement
Skeletal muscles – cross joints. When these muscles contract, the bones they attach to move.
Smooth muscle is found in the walls of various organs.
Cardiac muscle of the heart produces the atrial and ventricular contractions that pump blood.
Refer to CONNECT to see an animation about Muscle Contraction

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
Learning Outcome: Describe the functions of muscle.

8. Control of Body Openings and Passages
Sphincters
Valve-like structures
Control movement in and out of passages
Learning Outcome: Describe the functions of muscle.
Muscles also form valve-like structures around various body openings and passages.

9. Apply Your Knowledge RIGHT! F T T F F 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:
tendons F T T
in and out
Learning Outcomes: Describe the functions of muscle. F
RIGHT! F
contract

10. Types of Muscle Tissue Muscle cells or myocytes – muscle fibers
Sarcolemma
Sarcoplasm
Sarcoplasmic reticulum
Myofibrils
Long structures in sarcoplasm
Striations – arrangement of filaments
Learning Outcome: Compare the three types of muscle tissue including their locations and characteristics.
Muscle cells or myocytes – called muscle fibers because of their long lengths.
Sarcolemma – cell membrane of a muscle fiber
Sarcoplasm – the cytoplasm of muscle fibers
Sarcoplasmic reticulum – endoplasmic reticulum
Myofibrils – long structures that fills most of the sarcoplasm
Striations – produced by the arrangement of filaments in myofibrils
Muscle structure

11. Back
Learning Outcome: Compare the three types of muscle tissue including their locations and characteristics.

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
Learning Outcome: Compare the three types of muscle tissue including their locations and characteristics.

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
Learning Outcome: Compare the three types of muscle tissue including their locations and characteristics.

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
Learning Outcome: Compare the three types of muscle tissue including their locations and characteristics.
Multiunit smooth muscle – found in the iris of the eye and the walls of blood vessels.
Visceral smooth muscle
Contains sheets of muscle cells that closely contact each other.
Muscle fibers tend to contract and relax together producing an action called peristalsis.
Found in the walls of hollow organs like the stomach, intestines, bladder, and uterus.

15. Cardiac Muscle Intercalated discs Self-exciting
Connect groups of cardiac muscle
Allow the heart to work as a pump
Self-exciting
Responds to neurotransmitters
Acetylcholine
Norepinephrine
Learning Outcome: Compare the three types of muscle tissue including their locations and characteristics.
Intercalated discs that have tunnels physically connect the cardiac muscle cells.
They allow the fibers in that group to contract and relax together allowing the heart to work as a pump.
The atria contract and relax together
Then the ventricles contract to send blood to the lungs and body, after which they relax and the cycle starts again.
Cardiac muscle is self-exciting and does not need nerve stimulation to contract.
Nerves only speed up or slow down the contraction of the heart.
Cardiac muscle responds to two neurotransmitters
Acetylcholine slows the heart rate
Norepinephrine speeds it up

16. Apply Your Knowledge Very Good! Match the following: ANSWER:
___ Self-exciting
___ Contract in response to acetylcholine ___ Stimulate each other to contract
___ Peristalsis
___ Slowed by acetylcholine
___ Voluntary movement
ANSWER:
Skeletal Muscle
Smooth muscle
Cardiac muscle C A B
Learning Outcome: Compare the three types of muscle tissue including their locations and characteristics. B
Very Good! C A

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
Learning Outcome: Explain how muscle tissue generates energy.
ATP (adenosine triphosphate) – a type of chemical energy needed for sustained or repeated muscle contractions.
Muscle cells make this energy in three ways:
Creatine phosphate production
When ATP is used during muscle contraction, it loses a phosphate and, therefore, energy.
Creatine phosphate donates a phosphate group, restoring energy potential.
Aerobic respiration
Cell breaks down the body’s store of glucose into pyruvic acid using oxygen stored in myoglobin to make ATP.
Pyruvic acid is converted to acetyl coenzyme A.
This begins a series of reactions called the Krebs cycle or citric acid cycle.
Lactic acid production
Occurs when cell is low on oxygen and must convert pyruvic acid to lactic acid which is a waste product.
This conversion produces a small amount of ATP for the cell.

18. Oxygen Debt Strenuous use of skeletal muscles depletes cells of oxygen
Pyruvic Acid
Lactic acid
To liver for conversion to glucose, requiring more energy and oxygen to make ATP
Muscle fatigue
Learning Outcome: Explain how muscle tissue generates energy.
When pyruvic acid is converted to lactic acid for energy production, the lactic acid builds up and causes muscle fatigue.
The lactic acid is brought to the liver via the bloodstream to be converted back into glucose, which requires more energy.
The amount of oxygen the liver cells need to make enough ATP for this conversion results in the oxygen debt.
This process explains why your body still burns energy even after you are done exercising.
Oxygen debt

19. Muscle Fatigue Loses ability to contract Causes
Accumulation of lactic acid
Interruption of the blood supply
Acetylcholine not released by motor neuron
Learning Outcome: Explain how muscle tissue generates energy.
Cramps often accompany muscle fatigue.

20. Yippee! Apply Your Knowledge ANSWER:
Match the following: ___ 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
Lactic acid
Pyruvic acid
ATP
Aerobic respiration
Creatine phosphate E C D
Learning Outcome: Explain how muscle tissue generates energy. A B
Yippee!

21. Structure of Skeletal Muscles
Skeletal muscles – the major organs of the muscular system
Composition
Connective tissue
Skeletal muscle tissue
Blood vessels
Nerves
Learning Outcome: Describe the structure of a skeletal muscle.

22. Structure of Skeletal Muscles (cont.)
Connective tissue coverings
Fascia
Tendon
Aponeruosis
Epimysium
Perimysium
Endomysium
Learning Outcome: Describe the structure of a skeletal muscle.
The following connective tissue coverings are associated with skeletal muscles
Fascia
Covers entire skeletal muscles
Separates muscles from each other.
Tendon
Tough, cord-like structure made of fibrous connective tissue
Connects muscles to bones
Aponeurosis
Tough, sheet-like structure made of fibrous connective tissue.
It typically attaches muscles to other muscles.
Epimysium
A thin covering just deep to the fascia of a muscle.
It surrounds the entire muscle.
Perimysium – connective tissue that divides a muscle into sections called fascicles.
Endomysium – connective tissue that surrounds individual muscle cells.
Muscle structure

23. Apply Your Knowledge Excellent! D E A B F C 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
Tendon
Perimysium
Aponeurosis
Epimysium
Fascia
Endomysium E A B
Learning Outcome: Describe the structure of a skeletal muscle. F C
Excellent!

24. Attachments and Actions of Skeletal Muscles
Attachment types
Origin ~ for a less movable bone
Insertion ~ for a more movable bone
Learning Outcomes: Recognize the terms origin and insertion. .

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
Learning Outcome: Recognize the terms origin and insertion.
Most of the time, body movement is produced by a group of muscles.
An antagonist – must relax in order to produce a smooth body movement.

26. Attachments and Actions of Skeletal Muscles (cont.)
Plantar flexion
Abduction
Adduction
Flexion
Extension
Hyperextension
Dorsiflexion
Learning Outcome: 25.5 Recognize the terms origin and insertion.
Flexion – bending a body part; decreasing the angle of a joint
Extension – straightening a body part; increasing the angle of a joint
Hyperextension – extending a body part past the normal anatomical position
Dorsiflexion – pointing the toes up
Plantar flexion – pointing the toes down
Abduction – moving a body part away from the midline of the body
Adduction – moving a body part toward the midline of the body
Figure of Body Movements

27. Hyperextension Extension Dorsiflexion Flexion Plantar flexion
Learning Outcome: Recognize the terms origin and insertion.
Extension
Adduction
Flexion
Abduction
Back

28. Attachments and Actions of Skeletal Muscles (cont.)
Rotation
Circumduction
Pronation
Supination
Learning Outcome: Recognize the terms origin and insertion.
Rotation – twisting a body part; for example, turning your head from side to side
Circumduction – moving a body part in a circle; for example, moving your arm in a circular motion
Pronation – turning the palm of the hand down or lying face down
Supination – turning the palm of the hand up or lying face up
Supination
Pronation
Rotation
Circumduction

29. Attachments and Actions of Skeletal Muscles (cont.)
Inversion
Eversion
Retraction
Protraction
Elevation
Depression
Learning Outcome: Recognize the terms origin and insertion.
Inversion – turning the sole of the foot medially
Eversion – turning the sole of the foot laterally
Retraction – moving a body part posteriorly
Protraction – moving a body part anteriorly
Elevation – lifting a body part; for example, elevating your shoulders as in a shrugging gesture
Depression – lowering a body part; for example, lowering your shoulders
It is important to understand these movements to assist with judging and measuring the patients’ abilities to perform range of motion (ROM) exercises when assessing injuries and illnesses.
Figure of movements

30. Attachments and Actions of Skeletal Muscles (cont.)
Protraction
Retraction
Learning Outcome: Recognize the terms origin and insertion.
Elevation
Depression
Inversion
Eversion
Back

31. Correct! Apply Your Knowledge F T T T 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.
ANSWER: F
antagonist T T
Learning Outcome: Recognize the terms origin and insertion. T
Correct!

32. Major Skeletal Muscles
Name often describes muscle by
Location
Size
Action
Shape
Number of attachments
Learning Outcome: Identify the major skeletal muscles of the body, giving the action of each.

33. Learning Outcome: 25.6 Identify the major skeletal muscles of the body, giving the action of each.
Back

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
Learning Outcome: Learning Outcome: Identify the major skeletal muscles of the body, giving the action of each.
Sternocleidomastoid – pulls the head to one side and also pulls the head to the chest (sterno = sternum, cleido = clavicle, mastoid = mastoid).
Splenius capitis – rotates the head and allows it to bend to the side. (capit = head)
Muscles of facial expression include the following:
Frontalis – raises the eyebrows.
Orbicularis oris – allows the lips to pucker (oris = oro or mouth).
Orbicularis oculi – allows the eyes to close (oculi = eye).
Zygomaticus – pulls the corners of the mouth up (zygomat = cheekbone).
Platysma – pulls the corners of the mouth down.
The muscles of the jaw allow for mastication and include:
Masseter – close the jaw (masseter – mastication or chewing).
Temporalis. –close the jaw (temporo = temple).
Skeletal muscles

35. Arm Muscles Pectoralis major Latissimus dorsi Deltoid Subscapularis
Infraspinatus
Learning Outcome: Learning Outcome: Identify the major skeletal muscles of the body, giving the action of each.
Muscles that move the arm include:
Pectoralis major – pulls the arm across the chest; it also rotates and adducts the arms (pectoro = chest).
Latissimus dorsi – acts to extend, adduct, and rotate the arm inwardly (latissimus = butterfly, dorsi = back).
Deltoid – acts to abduct and extend the arm at the shoulder.
Subscapularis – muscle rotates the arm medially (sub = below, scapulo = shoulder blade).
Infraspinatus – rotates the arm laterally (infra = below, spinat = spine).
Skeletal muscles

36. Arm Muscles (cont.) Biceps brachii Brachialis Brachioradialis
Triceps brachii
Supinator
Pronator teres
Learning Outcome: Learning Outcome: Identify the major skeletal muscles of the body, giving the action of each.
Muscles that move the forearm include the following:
Biceps brachii – flexes the arm at the elbow and rotates the hand laterally (bi = two, ceps = insertion, brachii = arm).
Brachialis – flexes the arm at the elbow (brachii = arm).
Brachioradialis – flexes the forearm at the elbow (brachii = arm, radio = radius).
Triceps brachii – extends the arm at the elbow (tri = three, ceps = insertion, brachii = arm).
Supinator – rotates the forearm laterally (supination) (supine = palm up).
Pronator teres – rotates the forearm medially (pronation) (prone = palm down).
Skeletal muscles

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
Learning Outcome: Learning Outcome: Identify the major skeletal muscles of the body, giving the action of each.
Muscles that move the wrist, hand, and fingers include the following:
Flexor carpi radialis and flexor carpi ulnaris – flex and abduct the wrist (radio = radius, ulna = ulna).
Palmaris longus – flexes the wrist.
Flexor digitorum profundus – flexes the distal joints of the fingers but not the thumb (digits = fingers).
Extensor carpi radialis longus and brevis – extend the wrist and abduct the hand (carpo = wrist, radio = radius, long = long, brev = brief or short).
Extensor carpi ulnaris – extends the wrist (carpo = wrist, ulna = ulna).
Extensor digitorum – extends the fingers but not the thumb (digit = finger).
Diagram of hand

38. Learning Outcome: Learning Outcome: 25
Learning Outcome: Learning Outcome: Identify the major skeletal muscles of the body, giving the action of each.
Back

39. Respiratory Muscles Diaphragm
Separates thoracic and abdominal cavities
Contracts for inspiration
External and internal intercostals – expand and lower the ribs
Learning Outcome: Identify the major skeletal muscles of the body, giving the action of each.
External and internal intercostals – inter = between, costo = rib
For diagram

40. Skeletal Muscles (cont.)
Abdominal muscles
External and internal obliques
Transverse abdominis
Rectus abdominis
Muscles of the Pectoral Girdle
Trapezius
Pectoralis minor
Learning Outcome: Identify the major skeletal muscles of the body, giving the action of each.
Abdominal Muscles
The muscles of the abdominal wall include the following:
External and internal obliques – compress the abdominal wall. (oblique = diagonal)
Transverse abdominis – also compresses the abdominal wall. (transverse = across)
Rectus abdominis – acts to flex the vertebral column and compress the abdominal wall. (rectus = erect)
Muscles of the Pectoral Girdle
The muscles that move the pectoral girdle (shoulder) include:
Trapezius – raises the arms and pulls the shoulders downward. (trapezius = trapezoid)
Pectoralis minor – pulls the scapula downward and raises the ribs. (pectoro = chest, minor = smaller)
For diagram

41. Skeletal Muscles (cont.)
Learning Outcome: Identify the major skeletal muscles of the body, giving the action of each.
Back

42. Leg Muscles Iliopsoas major Gluteus maximus Gluteus medius and minimus
Adductor longus and magnus
Learning Outcome: Identify the major skeletal muscles of the body, giving the action of each.
The leg muscles include muscles of the thigh and lower leg
Iliopsoas major – flexes the thigh.
Gluteus maximus – extends the thigh.
Gluteus medius and minimus – abduct the thighs and rotate them medially.
Adductor longus and magnus – adduct the thighs and rotate them laterally (adduct = toward the midline).
Skeletal muscles

43. Leg Muscles (cont.)
Biceps femoris, semitendinosus, and semimembranosus
Rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius
Sartoris
Learning Outcome: Identify the major skeletal muscles of the body, giving the action of each.
The leg muscles include muscles of the thigh and lower leg
Biceps femoris, semitendinosus, and semimembranosus
These are known as the hamstring group.
They act to flex the leg at the knee and extend the leg at the thigh.
Rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius
These four muscles are known as the quadriceps group.
They act to extend the leg at the knee.
Sartorius
Flexes the leg at the knee and thigh
Abducts the thigh, rotating the thigh laterally but rotating the lower leg medially
It carries out the act of sitting cross-legged.
Skeletal muscles

44. Ankle, Foot, and Toe Muscles
Tibialis anterior
Extensor digitorum longus
Gastrocnemius
Soleus
Flexor digitorum longus
Learning Outcome: Identify the major skeletal muscles of the body, giving the action of each.
Muscles that move the ankle, foot, and toes include:
Tibialis anterior – inverts the foot and points the foot up (dorsiflexion).
Extensor digitorum longus – extends the toes and points the foot up.
Gastrocnemius – calf muscle
Flexes the foot
Flexes the leg at the knee.
Soleus – also flexes the foot.
Flexor digitorum longus – flexes the foot and toes.
Skeletal muscles

45. Bravo! Apply Your Knowledge C F B E A D
Matching: raises the eyebrows chewing expand and lower ribs compress the abdominal wall extends the thigh extends the leg at the knee
ANSWER:
Gluteus maximus
Intercostals
Frontalis
Quadriceps group
Obliques
Masseter C F B E
Learning Outcome: Identify the major skeletal muscles of the body, giving the action of each. A D
Bravo!

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
Learning Outcome: Summarize the changes that occur to the muscular system as a person ages.
Aging of the skeletal system
Causes difficulties for patients with diseases and conditions like arthritis, fractures, and osteoporosis. Muscular decline often goes hand-in-hand with these changes.
May cause
Increasing difficulty with dexterity and gripping ability.
Decreasing mobility related to the combined decline of the musculoskeletal system.
Diet, exercise history, and family history have a direct impact on the patient’s mobility and activity level as the patient ages.
Assistive devices can help patients who are experiencing difficulties.
Exercise routines, particularly pool exercises like swimming and physical therapy, are often helpful in maintaining strength and mobility.

47. Diseases and Disorders of the Muscular System
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
Learning Outcome: Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the muscular system.
Botulism
Caused by the bacterium Clostridium botulinum which produces a toxin that can lead to a type of food poisoning.
It may have long-lasting effects.
Fibromyalgia
The causes are poorly understood.
May be caused or exacerbated by sleep disturbance, emotional distress, decreased blood flow to muscles, a virus, or any combination of these factors.
Muscular dystrophy (MD)
The causes are primarily hereditary.
Genetic fetal testing is available.
Myasthenia gravis – an autoimmune condition in which a person produces antibodies that prevent muscles from receiving neurotransmitters from neurons.

48. Diseases and Disorders of the Muscular System (cont.)
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
Learning Outcome: Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the muscular system.
Rhabdomyolysis – excessive amounts of myoglobin are released, which is then broken down into harmful chemicals.
Tendonitis – usually occurs after a sports-related activity that results in injury to the muscle-tendon or tendon-bone attachment.
Tetanus – a toxin produced by the bacterium Clostridium tetani which enters through open wounds caused by objects contaminated with soil.

49. Diseases and Disorders of the Muscular System (cont.)
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
Learning Outcome: Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the muscular system.
Torticollis
Caused by spasm or shortening of the sternocleidomastoid muscle.
Acquired or congenital
Breech or other difficult birth is often the cause of the congenital form
The acquired form is the result of underlying disease, cervical spine injury, or chronic muscle spasms.
Trichinosis
An infection caused by parasites
Worms are usually ingested by eating undercooked meat
Worms can leave the digestive tract and infect skeletal muscles, the heart, the lungs, and the brain.

50. Apply Your Knowledge Good Job!
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
Learning Outcome: Describe the changes that occur to the muscular system as a person ages.
Good Job!

51. Apply Your Knowledge Good Job! 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
Learning Outcome: Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the muscular system.
Torticollis F
Good Job!

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.
The three types of muscle tissue are striated, voluntary skeletal muscle; smooth, involuntary visceral muscle; and specialized striated and involuntary cardiac muscle.

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.
25.3 There are three ways muscles create energy. Creatine phosphate is a rapid method for muscles to create energy; aerobic respiration uses stored glucose to produce ATP in the Krebs cycle; and lactic acid production occurs when a cell is low in oxygen and converts pyruvic acid to lactic acid.

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.
25.7 The major muscles of the head are sternocleidomastoid, splenius capitis, frontalis, orbicularis oris and oculi, zygomaticus, platysma, masseter, and temporalis.
The upper extremity muscles include pectoralis major, latissimus dorsi, deltoid, subscapularis, biceps brachii, brachialis, brachioradialis, triceps brachii, supinator, pronator teres, flexor carpi radialis and ulnaris, plamaris longus, flexor digitorum profundus, extensor carpi radialis longus and brevis, extensor carpi ulnaris, and extensor digitorum.
The major respiratory muscles are the diaphragm and the external and internal intercostals.
The abdominal muscles include external and internal obliques, transverse abdominis, and rectus abdominis.
The pectoral girdle muscles include trapezius and pectoralis minor.
The muscles of the lower extremity include iliopsoas major; gluteus maximus, medius, and minimus; adductor longus and magnus; biceps femoris; semitendinosus and semimembranosus; rectus femoris; vastus lateralis, medialis, and intermedius; sartorius; tibialis anterior; extensor digitorum longus; gastrocnemius; soleus; and flexor digitorum longus.

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.
22.8 There are many common diseases and disorders of the muscular system with varied signs, symptoms, and treatments. Some of these include: botulism, fibromyalgia, muscular dystrophy, myasthenia gravis, rhabdomyolysis, tendonitis, tetanus, torticollis, and trichinosis.

56. End of Chapter 25
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