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Muscular System.

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Presentation on theme: "Muscular System."— Presentation transcript:

1 Muscular System

2 Essential Question How does the muscular system support human life?

3 Muscular System Muscles are responsible for all types of body movement. There are more than 600 individual muscles. Together muscles are about 40 % of our weight.

4 Muscular System Three types of muscle Skeletal Smooth Cardiac

5 Skeletal Muscles Generally attached to bone by tendon
Voluntary Muscle ~ controlled by choice Produce movement Maintain body posture Stabilize joints Produce heat ~ thus help to maintain body temperature

6 Skeletal Muscles Cell structure:
Long Shaped like cylinders or tubes Composed of proteins arranged to make the muscle appear striped or striated. Contraction ~ tightening of muscles to induce movement Contraction can be slow or fast with no rhythm

7 Smooth Muscle Found mainly in the walls of the viscera ~ hollow organs
Often called visceral muscle Functions automatically ~ involuntary muscle Governs movement of respiration, urination and digestion Nonstriated ~ does not appear striped

8 Smooth Muscle Smooth muscle contraction slower and more rhythmic than skeletal muscle Smooth muscle more stretchy than skeletal muscle Allows for uterus, bladder and stomach to expand Smooth muscle has a better capacity for regeneration than does skeletal muscle.

9 Cardiac Muscle Found only in the heart Cell structure
Cells are long branching and fit together tightly at junctions. Classified as striated.

10 Cardiac Muscle Involuntary contractions
Contracts to pump blood throughout the body. Contractions are slow Have no capacity for regeneration


12 How muscles contract Muscles can only pull, not push!
To pull, muscles contract. When muscles contract they shorten. Muscles shorten because the muscles fibers slide past each other. The sliding is like a trombone

13 Handout How a Muscle Works Muscle Contraction

14 Muscle Terms Origin and Insertion ~ refer to the sites of muscle attachment When muscles contract across a joint, one bone remains relatively stationary or immovable. The ORIGIN attaches to the stationary bone The INSERTION attaches to the more moveable bone.

15 Muscle Terms Hypertrophy ~ increase in size of a muscle
Due to overuse Purposely done by athletes Atrophy ~ decrease in size of a muscle Wasting away Lack of exercise : broken leg Normal aging process Delayed with exercise

16 Muscle Terms Contracture ~ an abnormal formation of fibrous tissue within the muscle. Occurs when a muscle is immobilized for a prolonged period of time. “Freezes the muscle in a flexed position and severely restricts joint mobility

17 Muscle Terms Most movement is performed by groups of muscles working together; however, a single muscle is generally responsible for MOST of the movement. Prime mover ~ Chief muscle (responsible for movement) Snyergist ~ helper muscles Antagonists ~ oppose the action of another muscle Muscle pairs

18 Flashcards Smooth Muscle Prime mover Cardiac Muscle Snyergist
Skeletal Muscle Antagonist Hypertrophy Atrophy Contracture

19 Types of Muscle/Joint Movement
Movements at freely movable joints occur when the muscles that lie across the joints contract and exert pressure on the attached bone.

20 Skeletal Muscle Movement
Flexion ~ Bending of a joint that decreases the angle between the bones. Bending of a leg at the knee Extension ~ Straightening of a joint so that the angle between the bones increases. Straightening the leg at the knee

21 Skeletal Muscle Movement
Plantar Flexion ~ Bending the foot down Toe dancing Dorsiflexion ~ Bending to the foot up towards the leg Hyperextention ~ Overextending the joint beyond its normally straightened position. Bending the wrist back

22 Skeletal Muscle Movement
Abduction ~ movement away from the midline of the body. Move leg sideways Adduction ~ movement toward the midline of the body Move leg toward your body Inversion ~ turning the sole of the foot inward so it faces the opposite foot.

23 Skeletal Muscle Movement
Eversion ~ turning the sole of the foot outward. Supination ~ turning the hand so that the palm faces upward Pronation ~ turning the hand so that the palm faces downward Rotation ~ rotate or move around an axis Circumduction ~ combination of movements performed by extremities in a circular motion.

24 How Skeletal Muscles are Named
Skeletal muscles are generally named for one of the following characteristics. Size Shape Direction of fibers Location Number of origins Origin and insertion Muscle action

25 Size Vastus ~ huge Maximus ~ large Longus ~ long Minimus ~ small
Brevis ~ short

26 Shape Deltoid ~ triangular Latissimus ~ wide Trapezius ~ trapezoid
Rhomboideus ~ rhomboid Teres ~ round

27 Directions of Fibers Fibers are oriented or lined up, in several directions Rectus ~ straight Oblique ~ diagonal Transverse ~ across Circularis ~ circular

28 Location Pectoralis ~ chest Gluteus ~ buttock Branchii ~ arm
Supra ~ above Infra ~ below Sub ~ underneath Lateralis ~ lateral

29 Number of Origins Muscles can be named according to the number of sites to which it is anchored. Biceps Triceps Quadriceps

30 Origin and Insertion Named for sites of attachment both at their origin and insertion Sternocleidomatoid ~ origin on the sternum and clavicle…..insertion on the mastoid process of the temporal bone

31 Muscle Action How the muscle moves the body
Abductor ~ moves the limb away from the midline Flexor ~ causes flexion Levator ~ elevates

32 The Facial Muscles Inserted directly into the soft tissue of the skin and other muscles of the face. Contraction pulls on the soft tissue Responsible for our facial expressions

33 Facial Muscles Frontalis ~ covers the frontal bone
Contraction raises the eyebrows and wrinkles the forehead

34 Facial Muscles Orbicularis oculi ~ sphincter muscle that encircles the eyes. Sphincter ~ a ring-shaped muscle that controls the size of an opening Contraction closes the eye, winking, blinking

35 Facial Muscles Orbicularis oris ~ sphincter muscle that encircles the mouth. Contraction assists in closing the mouth, forming words and pursing the lips Sometimes called the kissing muscle

36 Facial Muscles Buccinator ~ origin is the mandible and maxilla. Inserts on the orbicularis oris. Used in sucking, whistling and playing the trumpet

37 Facial Muscles Zygomaticus ~ extends from the corners of the mouth to the cheekbones Smiling muscle

38 Facial Muscle Platysma ~ Originates in the fascia of the shoulder and inserts on the mandible Fascia ~ fibrous tissue enclosing a muscle Responsible for pouting and opening your mouth wide.

39 Chewing Muscles Muscles of mastication ~ chewing
All are inserted on the mandible Some are the strongest muscles of the body

40 Chewing Muscles Masseter ~ origin on the temporal bone
Contraction closes the jaw

41 Muscles of the Neck Sternocleidomastoid ~ extends from sternum and clavicle to the mastoid process of the temporal bone Contraction causes flexion of the head Praying muscle

42 Muscles of the Trunk Involved in breathing Form the abdominal wall
Move the vertebral column Form the pelvic region

43 Muscles for Breathing Intercostal Muscles ~ located between the ribs
Origin and insertion on the ribs Responsible for raising and lowering the rib cage during breathing

44 Muscles for Breathing Diaphragm ~ dome-shaped muscle that separates the thoracic cavity from the abdominal cavity Chief muscle of inhalation

45 Muscles of the Abdominal Wall
Consists of 4 muscles Muscles are layered at different depths Fibers of these muscles run in different directions Contain, support and protect abdominal organs Contraction causes flexion and rotation of vertebral column, urination, defecation, and childbirth.

46 Abdominal Muscles Rectus abdominis ~ fibers run up and down
Contraction flexes the vertebrae Increases intra-abdominal pressure

47 Abdominal Wall Muscles
External oblique ~ lateral walls of the abdomen Fibers run obliquely (slanted) Aids rectus abdominus (trunk rotation/lateral flexion)

48 Abdominal Wall Muscles
Internal oblique ~ add strength to the external oblique (crisscross with them)

49 Abdominal Wall Muscles
Transversus abdominis ~ fibers run horizontally Innermost layer of the abdominal muscles Responsible for compression

50 Muscles of the Vertebral Column
Attach to the vertebrae Move the vertebral column in numerous directions Numerous muscles….will not discuss in detail.

51 Muscles of the Pelvic Floor
Assist in expelling contents from the urinary bladder and rectum Will not be discussed in detail

52 Muscles of the Shoulder
Trapezius ~ origin in bases of the occipital bone and inserts on the scapula and clavicle Hyperextends head Contraction allows for shrugging and rotating movement Right and left trapezius form the shape of a trapezoid

53 Muscles of the Shoulder
Pectoralis Major ~ forms the anterior chest wall Connects the humerus with the clavicle and sternum Contraction moves the arm across the chest Adducts the arm

54 Muscles of the Shoulder
Deltoid ~ forms the rounded portion of your shoulder (shoulder pad) Contraction abducts the arm

55 Muscles of the Shoulder
Latissimus dorsi ~ Broad muscle located in the middle and lower back region. Origin vertebrae, insertion humerus Adducts shoulders and extends arm back. “Swimmers muscle”

56 Muscles that Move the Forearm
Most are located along the humerus Triceps brachii ~ located on the posterior surface of the humerus. Prime mover of extension of the forearm Supports weight for push-ups Boxer muscle ~ packs the greatest punch

57 Muscles that Move the Forearm
Biceps brachii ~ located along the anterior surface of the humerus. Flexes the forearm “Make a muscle”

58 Muscles that Move the Forearm
Branchioradialis ~ synergist of biceps branchii Origin on humerus, Inserts on radius Flexes forearm at elbow

59 Muscles that Move the Wrist, Hand, and Fingers
More than 20 muscles Small which makes for delicate movement Generally located along the forearm The tendons of these muscles pass through the wrist into the hand and fingers.

60 Muscles that Move the Wrist, Hand, and Fingers
Flexor digitorum ~ flexes fingers Anterior muscle

61 Muscles that Move the Wrist, Hand, and Fingers
Extensor digitorum ~ extends fingers Posterior muscle

62 Carpal Tunnel Syndrome

63 Muscles that Move the Thigh, Leg, and Foot
Some of the largest and strongest muscles of the body Move the lower extremities Help maintain posture

64 Muscles that Move the Femur (thighbone)
All attach to some part of the pelvic girdle (coxal bones) and the femur. Contraction of these muscles moves the hip joint

65 Gluteal Muscles Located on the posterior surface
Gluteus maximus ~ forms the area of the buttocks Largest muscle of the body Rotates the thigh laterally and extends the thigh at the hip (walking, stair climbing)

66 Gluteal Muscles Gluteus medius ~ abduct and rotate the thigh medially at the hip

67 Muscles that Move the Leg
Located on the thigh Extensor muscles lie along the anterior and lateral surfaces. Flexors lie along the posterior and medial surfaces

68 Muscles that Move the Leg
Quadriceps Femoris ~ located on the anterior thigh Most powerful muscle in the body Contain four different parts Vastus lateralis Vastus intermedius Vastus medialis Rectus femoris All four parts cause extension of the leg at the knee

69 Quadriceps Femoris Vastus lateralis

70 Quadriceps Femoris Vastus intermedius ~ sits directly below the rectus femoris

71 Quadriceps Femoris Vastus medialis

72 Muscles that Move the Leg
Sartorius ~ crosses over anterior thigh Allows you to sit in cross leg position Laterally rotates thigh at hip

73 Muscles that Move the Leg
Hamstrings ~ located on the posterior surface of the thigh Contain three different parts Biceps femoris Semimembranosus semitendinosus

74 Hamstrings Flex the leg at the knee Extend the thigh
Strong tendons of these muscles can be felt behind the knee

75 Hamstrings Biceps femoris

76 Hamstrings Semimembranosus

77 Hamstrings Semitendinosus

78 Muscles that Move the Foot
Located on the anterior, lateral, and posterior surfaces of the leg Tibialis anterior ~ located on anterior surface Causes dorsiflexion and inversion of the foot

79 Muscles that Move the Foot
Gastronemius ~ forms the calf of the leg Attach to the heel bone by the Achilles tendon Strongest tendon in the body Causes plantar flexion Toe dancer muscle

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