2Essential QuestionHow does the muscular system support human life?
3Muscular SystemMuscles are responsible for all types of body movement.There are more than 600 individual muscles.Together muscles are about 40 % of our weight.
4Muscular SystemThree types of muscleSkeletalSmoothCardiac
5Skeletal Muscles Generally attached to bone by tendon Voluntary Muscle ~ controlled by choiceProduce movementMaintain body postureStabilize jointsProduce heat ~ thus help to maintain body temperature
6Skeletal Muscles Cell structure: LongShaped like cylinders or tubesComposed of proteins arranged to make the muscle appear striped or striated.Contraction ~ tightening of muscles to induce movementContraction can be slow or fast with no rhythm
7Smooth Muscle Found mainly in the walls of the viscera ~ hollow organs Often called visceral muscleFunctions automatically ~ involuntary muscleGoverns movement of respiration, urination and digestionNonstriated ~ does not appear striped
8Smooth MuscleSmooth muscle contraction slower and more rhythmic than skeletal muscleSmooth muscle more stretchy than skeletal muscleAllows for uterus, bladder and stomach to expandSmooth muscle has a better capacity for regeneration than does skeletal muscle.
9Cardiac Muscle Found only in the heart Cell structure Cells are long branching and fit together tightly at junctions.Classified as striated.
10Cardiac Muscle Involuntary contractions Contracts to pump blood throughout the body.Contractions are slowHave no capacity for regeneration
12How 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
14Muscle TermsOrigin and Insertion ~ refer to the sites of muscle attachmentWhen muscles contract across a joint, one bone remains relatively stationary or immovable.The ORIGIN attaches to the stationary boneThe INSERTION attaches to the more moveable bone.
15Muscle Terms Hypertrophy ~ increase in size of a muscle Due to overusePurposely done by athletesAtrophy ~ decrease in size of a muscleWasting awayLack of exercise : broken legNormal aging processDelayed with exercise
16Muscle TermsContracture ~ 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
17Muscle TermsMost 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 musclesAntagonists ~ oppose the action of another muscleMuscle pairs
19Types 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.
20Skeletal Muscle Movement Flexion ~ Bending of a joint that decreases the angle between the bones.Bending of a leg at the kneeExtension ~ Straightening of a joint so that the angle between the bones increases.Straightening the leg at the knee
21Skeletal Muscle Movement Plantar Flexion ~ Bending the foot downToe dancingDorsiflexion ~ Bending to the foot up towards the legHyperextention ~ Overextending the joint beyond its normally straightened position.Bending the wrist back
22Skeletal Muscle Movement Abduction ~ movement away from the midline of the body.Move leg sidewaysAdduction ~ movement toward the midline of the bodyMove leg toward your bodyInversion ~ turning the sole of the foot inward so it faces the opposite foot.
23Skeletal Muscle Movement Eversion ~ turning the sole of the foot outward.Supination ~ turning the hand so that the palm faces upwardPronation ~ turning the hand so that the palm faces downwardRotation ~ rotate or move around an axisCircumduction ~ combination of movements performed by extremities in a circular motion.
24How Skeletal Muscles are Named Skeletal muscles are generally named for one of the following characteristics.SizeShapeDirection of fibersLocationNumber of originsOrigin and insertionMuscle action
25Size Vastus ~ huge Maximus ~ large Longus ~ long Minimus ~ small Brevis ~ short
27Directions of FibersFibers are oriented or lined up, in several directionsRectus ~ straightOblique ~ diagonalTransverse ~ acrossCircularis ~ circular
28Location Pectoralis ~ chest Gluteus ~ buttock Branchii ~ arm Supra ~ aboveInfra ~ belowSub ~ underneathLateralis ~ lateral
29Number of OriginsMuscles can be named according to the number of sites to which it is anchored.BicepsTricepsQuadriceps
30Origin and InsertionNamed for sites of attachment both at their origin and insertionSternocleidomatoid ~ origin on the sternum and clavicle…..insertion on the mastoid process of the temporal bone
31Muscle Action How the muscle moves the body Abductor ~ moves the limb away from the midlineFlexor ~ causes flexionLevator ~ elevates
32The Facial MusclesInserted directly into the soft tissue of the skin and other muscles of the face.Contraction pulls on the soft tissueResponsible for our facial expressions
33Facial Muscles Frontalis ~ covers the frontal bone Contraction raises the eyebrows and wrinkles the forehead
34Facial MusclesOrbicularis oculi ~ sphincter muscle that encircles the eyes.Sphincter ~ a ring-shaped muscle that controls the size of an openingContraction closes the eye, winking, blinking
35Facial MusclesOrbicularis oris ~ sphincter muscle that encircles the mouth.Contraction assists in closing the mouth, forming words and pursing the lipsSometimes called the kissing muscle
36Facial MusclesBuccinator ~ origin is the mandible and maxilla. Inserts on the orbicularis oris.Used in sucking, whistling and playing the trumpet
37Facial MusclesZygomaticus ~ extends from the corners of the mouth to the cheekbonesSmiling muscle
38Facial MusclePlatysma ~ Originates in the fascia of the shoulder and inserts on the mandibleFascia ~ fibrous tissue enclosing a muscleResponsible for pouting and opening your mouth wide.
39Chewing Muscles Muscles of mastication ~ chewing All are inserted on the mandibleSome are the strongest muscles of the body
40Chewing Muscles Masseter ~ origin on the temporal bone Contraction closes the jaw
41Muscles of the NeckSternocleidomastoid ~ extends from sternum and clavicle to the mastoid process of the temporal boneContraction causes flexion of the headPraying muscle
42Muscles of the Trunk Involved in breathing Form the abdominal wall Move the vertebral columnForm the pelvic region
43Muscles for Breathing Intercostal Muscles ~ located between the ribs Origin and insertion on the ribsResponsible for raising and lowering the rib cage during breathing
44Muscles for BreathingDiaphragm ~ dome-shaped muscle that separates the thoracic cavity from the abdominal cavityChief muscle of inhalation
45Muscles of the Abdominal Wall Consists of 4 musclesMuscles are layered at different depthsFibers of these muscles run in different directionsContain, support and protect abdominal organsContraction causes flexion and rotation of vertebral column, urination, defecation, and childbirth.
46Abdominal Muscles Rectus abdominis ~ fibers run up and down Contraction flexes the vertebraeIncreases intra-abdominal pressure
47Abdominal Wall Muscles External oblique ~ lateral walls of the abdomenFibers run obliquely (slanted)Aids rectus abdominus (trunk rotation/lateral flexion)
48Abdominal Wall Muscles Internal oblique ~ add strength to the external oblique (crisscross with them)
49Abdominal Wall Muscles Transversus abdominis ~ fibers run horizontallyInnermost layer of the abdominal musclesResponsible for compression
50Muscles of the Vertebral Column Attach to the vertebraeMove the vertebral column in numerous directionsNumerous muscles….will not discuss in detail.
51Muscles of the Pelvic Floor Assist in expelling contents from the urinary bladder and rectumWill not be discussed in detail
52Muscles of the Shoulder Trapezius ~ origin in bases of the occipital bone and inserts on the scapula and clavicleHyperextends headContraction allows for shrugging and rotating movementRight and left trapezius form the shape of a trapezoid
53Muscles of the Shoulder Pectoralis Major ~ forms the anterior chest wallConnects the humerus with the clavicle and sternumContraction moves the arm across the chestAdducts the arm
54Muscles of the Shoulder Deltoid ~ forms the rounded portion of your shoulder (shoulder pad)Contraction abducts the arm
55Muscles of the Shoulder Latissimus dorsi ~ Broad muscle located in the middle and lower back region.Origin vertebrae, insertion humerusAdducts shoulders and extends arm back.“Swimmers muscle”
56Muscles that Move the Forearm Most are located along the humerusTriceps brachii ~ located on the posterior surface of the humerus.Prime mover of extension of the forearmSupports weight for push-upsBoxer muscle ~ packs the greatest punch
57Muscles that Move the Forearm Biceps brachii ~ located along the anterior surface of the humerus.Flexes the forearm“Make a muscle”
58Muscles that Move the Forearm Branchioradialis ~ synergist of biceps branchiiOrigin on humerus, Inserts on radiusFlexes forearm at elbow
59Muscles that Move the Wrist, Hand, and Fingers More than 20 musclesSmall which makes for delicate movementGenerally located along the forearmThe tendons of these muscles pass through the wrist into the hand and fingers.
60Muscles that Move the Wrist, Hand, and Fingers Flexor digitorum ~ flexes fingersAnterior muscle
61Muscles that Move the Wrist, Hand, and Fingers Extensor digitorum ~ extends fingersPosterior muscle
63Muscles that Move the Thigh, Leg, and Foot Some of the largest and strongest muscles of the bodyMove the lower extremitiesHelp maintain posture
64Muscles 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
65Gluteal Muscles Located on the posterior surface Gluteus maximus ~ forms the area of the buttocksLargest muscle of the bodyRotates the thigh laterally and extends the thigh at the hip (walking, stair climbing)
66Gluteal MusclesGluteus medius ~ abduct and rotate the thigh medially at the hip
67Muscles that Move the Leg Located on the thighExtensor muscles lie along the anterior and lateral surfaces.Flexors lie along the posterior and medial surfaces
68Muscles that Move the Leg Quadriceps Femoris ~ located on the anterior thighMost powerful muscle in the bodyContain four different partsVastus lateralisVastus intermediusVastus medialisRectus femorisAll four parts cause extension of the leg at the knee