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Muscular System 2012-2013.

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Presentation on theme: "Muscular System 2012-2013."— Presentation transcript:

1 Muscular System

2 Vocab development Calat- something inserted Erg- work Fasc- bundle
-gram- something written Hyper- over, more inter;- between Iso-equal Laten- hidden Myo- muscle Reticul- a net Sarco- flesh Syn- together Tetan- stiff -tonic- stretched -troph- well fed Voluntar- of one’s free will

3 Introduction Muscles are organs made of cells that use chemical energy stored in nutrients to exert a force on the structures they are attached to. Muscle actions provide: Muscle tone Propel body fluids and food Generate the heartbeat Distribute heat

4 Introduction 3 types of muscle Skeletal Smooth Cardiac
We are going to focus mostly on skeletal muscle in this chapter Skeletal muscle attaches to bones and to the skin of the face and is under conscious control

5 Structure of Skeletal Muscle
Composed mostly of skeletal muscle tissue, nervous tissue, blood, and other connective tissues Layers of connective tissue enclose and separate all parts of a skeletal muscle allowing the parts to move somewhat independently.

6 Skeletal Muscle: Connective Tissue Coverings
Fascia Separates a muscle from its adjacent muscles; covers the whole muscle Tendon Connect a muscle to a bone Aponeuroses connects muscle to bone and other muscles

7 Skeletal Muscle: Connective Tissue Coverings
Epimysium Closely surrounds a skeletal muscle Perimysium Extends inward from epimysium & separates the muscle tissue into small sections called fascicles Endomysium Each muscle fiber within a fascicle is covered by this

8 Skeletal Muscle Fibers
Each muscle fiber forms from many undifferentiated cells that fuse together Each muscle fiber is multinucleate Shaped like a long, thin cylinder with rounded ends Sarcolemma- just beneath the muscle cell membrane Sarcoplasm- cytoplasm of the fiber

9 Skeletal Muscle Fibers
Myofibrils Bundles of threadlike structures found within muscle fibers Fundamental in the muscle contraction mechanism Consist of 2 types of proteins Myosin- thick filaments Actin- thin filaments Alternating of the myosin & actin causes the striations found in skeletal muscle Sarcomeres- repeating patterns of striations along each muscle fiber Alternating of myosin and actin produce the dark and light striations that you see in skeletal muscles

10 Skeletal Muscle Fibers
Striation Pattern Has 2 main parts I band (light bands) made of actin filaments connected to z lines A bands (dark bands) made of myosin filaments overlapping thin actin filaments Include an H zone which consists of only thick filaments (myosin)

11 Skeletal Muscle Fibers

12 Skeletal Muscle Fibers
Sarcoplasmic reticulum Within the sarcoplasm of a muscle fiber Network of channels that surrounds each myofibril Muscle fibers and the connective tissues associated with them are flexible but if they are overstretched they tear. The is commonly called a muscle strain.

13 Skeletal Muscle Contraction
Complex interaction of cellular and chemical pieces The result is movement within the myofibrils where the filaments of actin and myosin slide past each other causing the sarcomere to shorten

14 Skeletal Muscle Contraction
Energy Sources ATP Muscle fiber only has enough ATP to contract briefly so it must be able to regenerate ATP Creatine Phosphate Initial source of energy to regenerate ATP Much more abundant in muscle fibers than ATP, but it cannot supply energy directly to the cell Cellular Respiration ATP is decomposed to ADP, the energy from creatine phosphate molecules is transferred back to these ADP molecules, quickly phosphorylating them back into ATP . The amount of ATP and creatine phosphate is ususally not enough to support maximal muscle activity for more than 10 seconds…as a result the muscle fibers in an active muscle soon use cellular respiration of glucose to synthesize ATP

15 Skeletal Muscle Contraction
10 steps to muscle contraction 1. An action potential is conducted down a motor neuron axon 2. The motor neuron terminal releases the neurotransmitter acetylcholine (ACh) 3. ACh binds to ACh receptors on the muscle fiber 4. The sarcolemma is stimulated, an action potential is generated, and the impulse is conducted over the surface of the muscle fiber and deep into the fiber through the transverse tubules.

16 Skeletal Muscle Contraction
5. The impulse reaches the sarcoplasmic reticulum, and calcium channels open. 6. Calcium ions diffuse from the sarcoplasmic reticulum into the sarcoplasm and bind to tropin molecules. 7. Tropomyosin molecules move and expose specific sites on actin. 8. Actin and myosin link, forming cross-bridges. 9. Thin (actin) filaments are pulled toward the center of the sarcomere by myosin cross-bridges increasing the overlap of the thin and thick filaments. 10. The muscle fiber contracts.

17 Skeletal Muscle Relaxation
1. Acetylcholinesterase decomposes acetylcholine, and the muscle fiber membrane is no longer stimulated. 2. Calcium ions are actively transported into the sarcoplasmic reticulum. 3. ATP breaks linkages between actin and myosin filaments without breakdown of ATP itself 4. Breakdown of ATP “cocks” the myosin heads. 5. Troponin and tropomyosin molecules inhibit the interaction between myosin and actin filaments. 6. Muscle fiber remains relaxed until it is stimulated again.

18 Muscle Fatigue Caused by Decreased blood flow
Ion imbalances due to repeated stimulation Psychological loss of desire to continue Lactic acid accumulation Oxygen debt Accumulates in the muscles when ATP production goes from aerobic to anaerobic

19 Muscular Responses Threshold Stimulus
A muscle fiber remains unresponsive until a certain strength of stimulation is reached, once this is reached an action potential is generated and the process of muscle contraction begins When an isolated muscle fiber is exposed to a series of stimuli of increasing strength, the fiber remains unresponsive until a certain strength of stimulation called the threshold stimulus is applied. Once the threshold is reached, an action potential is generated, resulting in an impulse that spreads throughout the muscle fiber, releasing enough calcium ions from the sarcoplasmic reticulum to activate cross-bridge formation and contract the fiber. A single action potential conducted down a motor neuron normally releases enough Ach to bring the muscle fibers to threshold, generating an impulse in the muscle fiber.

20 Muscular Responses Recording a Muscle Contraction
Twitch- contractile response of a single muscle fiber to a muscle impulse A twitch consists of a period of contraction, during which the fiber pulls at its attachments, followed by a period of relaxation, during which the fiber pulls at its attachments, followed by a period of relaxation, during which the pulling force declines. These events can be recorded in a myogram. A twitch has a brief delay between the time of stimulation and the beginning of contraction. This latent period, which in human muscle may be less than 2 milliseconds. The length to which a muscle fiber is stretched before stimulation affects the force it will develop. If a skeletal muscle fiber is stretched well beyond its normal resting length the force will decrease. This is because the sacaromeres of that fiber become so extended that some myosin heads cannot reach binding sites on the thin filamnets and cannot contribute to contraction. Conversely at very short fiber lengths, the sarcomeres become compressed, and further shortening is not possible. During normal activities muscle fibers contract at optimal lengths.

21 Muscular Responses Summation
The force that a muscle fiber can generate is not limited to the maximum force of a single twitch. A muscle fiber exposed to a series of stimuli of increasing frequency reaches a point when it is unable to completely relax before the next stimulus in the series arrives. When this happens, the individual twitches begin to combine, and the contraction becomes sustained. In such a sustained contraction, the force of individual twitches combines by the process of summation. At higher frequencies of stimulation, as the time spent in relaxation becomes very brief, a condition called incomplete tetanus or partial tetany. When the resulting forceful, sustained contraction lacks even partial relaxation, it is called complete tetanus or complete tetanic contraction.

22 Muscular Responses Types of Contractions
Isotonic Contractions (equal force –change in length)—allow you to move things Concentric-muscle contracts with greater force than resistance and shortens Eccentric- muscle contracts with less force than resistance and lengthens Isometric Contractions – (equal length- change in force) – allow you to sit and hold your posture In an isotonic contraction the length of the muscle changes but the amount of force does not…in an isometric contraction the length of the muscle doesn’t change but the muscle still contracts Most body movements require both isotonic and isometric contractions. In walking for example certain leg and thigh muscles contract isometrically and keep the limb stiff as it touches the ground, while other muscles contract isotonically bending and lifting the opposite limb.

23 Muscular Responses Fast & Slow Twitch Muscle Fibers 3 types
Slow twitch fibers (red fibers) Produce ATP from oxygen making them more resistant to fatigue These fibers can contract for long periods of time without fatigue Fast twitch fibers (white fibers) Produce ATP primarily through glycolysis Can contract rapidly but also fatigue rapidly as lactic acid accumulates in them Intermediate Fibers (white fibers) Can contract rapidly and also have a larger respiratory capacity so they don’t fatigue like fast-twitch fibers Muscle fibers vary in contraction speed and in whether they produce ATP oxidatively or glycolytically. There are atleast three types of muscle fibers found in humans. Slow Twitch Fibers- called red fibers because they contain the red, oxygen storing pigment called myoglobin. These fibers are well supplied with oxygen carrying blood. In addition red fibers, contain more mitochondria, which is an adaptation for the aerobic reactions of cellular respiration. These fibers have a high respiratory capacity and can generate ATP fast enough to keep up with the ATP breakdown that occurs when they contract. Fast twitch fibers- White fibers because they have less myoglobin and have a poorer blood supply than red fibers. These fibers have fewer mitochondria and so the have a reduced respiratory capacity. Intermediate Fibers - A type of white fiver, the fast twitch fatigue resistant fibers. These fibers have the fast twitch speed associated with white fiber with substantial amount of oxidative capacity more characteristic of red fibers

24 Smooth Muscles Smooth muscles lack striations
Cells have only one nucleus 2 major types of smooth muscles Multiunit Visceral Smooth muscle cells are shorter than the fibers of skeletal muscle and they have a single centrally located nucleus. Remember skeletal muscle cells are multinucleate.

25 Smooth Muscles Multiunit Smooth Muscle
Muscle fibers function as separate units Found in the irises of the eyes & walls of large blood vessels Contract after stimulation by neurons or certain hormones The muscle fibers are less well organized and function as separate units, independent of their neighboring cells. Typically contracts only after stimulation by neurons or certain hormones.

26 Smooth Muscles Visceral Smooth Muscle Fibers respond as a single unit
Found in the walls of hollow organs (intestines, stomach, bladder, uterus) Two features- conduction of impulses and rythmicity produce peristalsis Peristalsis- wavelike motion of contraction Peristalsis is what help your body move food from organ in the digestive system to the next Vascular smooth muscle Found in the walls of small blood vessels where it helps control blood pressure and blood flow Composed of sheets of spindle shaped cells held close together by gap junctions. Fibers respond as a single unit, when one fiber is stimulated, the impulse conducted over its surface may excite adjacent fibers that stimulate others. Peristalsis consists of alternate contractions and relaxations of the longitudinal and circular muscles. These movements help force the contents of a tube along its length. In the intestines, for example, peristaltic wves move masses of partially digested food and help to mix them with digestive fluids. Peristalsis in the ureters moves urine from the kidneys to the urinary bladder.

27 Cardiac Muscle Found only in the heart
Composed of striated cells joined end to end Opposite ends of cardiac cells are connected by intercalated discs Help join cells, transmit the force of contraction, & diffuse ions from cell to cell It is composed of striated cells joint end to end, forming fibers interconnected in branching, three-dimensional networks. Each cell contains a single nucleus and many filaments of actin and myosis similar to those in skeletal muscle. A cardiac muscle cell also has a well-developed sarcoplasmic reticulum, a system of transverse tubules, and many mitochondria.

28 Skeletal Muscle Actions
Skeletal action depends on Type of joint it is associated with The way the muscle is attached on either side of the joint

29 Skeletal Muscle Actions
Body Movement When a body part moves bones and muscles interact as a lever 3 types of levers 1st class- resistance-fulcrum, force (seesaw; when the arm straightens at the elbow) 2nd class- fulcrum- resistance- force (wheelbarrow; when you chew something up) 3rd class- resistance-force-fulcrum (tweezers- when the arm bends at the elbow) 4 basic components of a lever A rigid bar or rod A fulcrum or pivot on which the bar turns An object moved against resistance A force that supplies energy to move the bar

30 Skeletal Muscle Actions
Origin and Insertion Origin- less moveable end of the muscle Insertion- more moveable end of the muscle When a muscle contracts Insertion is pulled toward its origin Head of the muscle is the part closest to its origin One end of a skeletal muscle is usually fastened to a relatively immovable or fixed part on one side of a joint, and the other end is connected to a moveable part on the other side of the joint

31 Skeletal Muscle Action

32 Skeletal Muscle Actions
Interaction of Skeletal Muscles Agonist- muscle that causes an action Synergists- muscles that work together Prime mover- muscle that does most of the work during an action Antagonists- muscle that opposes action Most skeletal muscles function in groups. A muscle that causes an action is called an agonist for that action. While an agonist is acting, other nearby muscles may also contract and help with the action. Muscles that work together are called synergists. The agonist can also be the prime mover. The antagonist is a muscle that works to oppose an action. These muscles can cause movement that acts in the opposite direction.

33 Major Skeletal Muscles
Muscles of Facial Expression Innervated by the facial nerve (CN VII) Lack of symmetry in facial expression may indicate nerve damage

34 Muscles of Facial Expression
Orbicularis oculi orbicular= circular Oculi= eye Origin: orbital rim, frontal & maxillary bones Insertion: lateral region of eye, some encircle the eye Action: closing the eyelid Expression: form’s crows feet

35 Muscles of Facial Expression
Corrugator Origin: frontal bone Insertion: eyebrow Action: draws eyebrow medially & inferiorly Expression: frowning & suffering Runs from the bridge of the nose to eyebrows

36 Muscles of Facial Expression
Procerus Origin: fascia covering the lower nasal bone & upper lateral nasal cartilage Insertion: skin between and above the eyebrows Action: causes transverse wrinkles over the bridge of the nose Expression: squinting Runs from the bridge of the nose to the medial corner of the eyebrow

37 Muscles of Facial Expression
Nasalis Circles the opening of the nostrils Has 2 parts: Dilator naris Compressor naris Action: dilates & compresses nostrils Wiggles your nostrils

38 Muscles of Facial Expression
Epicranius Origin: occipital bone Insertion: skin around the eye & orbicularis oculi Action: elevates eyebrows, moves scalp forward & backward Expression: surprise 2 bellied muscle connected with an aponeurosis

39 Muscles of Facial Expression
Orbicularis Oris Oribicular= circle oris = mouth Origin: encircles mouth Insertion: angle of mouth Action: encloses & protrudes up; helps keep food on occlusal surfaces during chewing Expression: closing or pursing lips

40 Muscles of Facial Expression
Quadratus Labii Superioris 4 muscles of the upper lip Levator labii superioris alaeque nasi Levator labii superioris Zygomaticus minor Zygomaticus major Allow you to frown and smile

41 Muscles of Facial Expression
Quadratus Labii Superioris cont… Levator labii superioris alaeque nasi Origin: maxilla Insertion: nose Action: dilates nostrils & raises upper lip

42 Muscles of Facial Expression
Quadratus Labii Superioris Levator labii superioris Origin: maxilla Insertion: upper lip Action: raises upper lip Expression: scorn

43 Muscles of Facial Expresssion
Quadratus Labii Superioris Cont… Zygomaticus minor Origin: zygomatic bone Insertion: upper lip Action: raises upper lip Expression: scorn Zygomaticus major Insertion: angle of mouth Action: elevates the corner of the mouth Expression: smiling

44 Muscles of Facial Expression
Levator Anguli Oris Origin: canine fossa (on the maxilla) Insertion: orbicularis oris Action: elevates the angle of the mouth Expression: smiling (laughing)

45 Muscles of Facial Expression
Smiling Produced by the contraction of 2 facial muscles: Zygomaticus major Oribicularis oculi

46 Muscles of Facial Expression
Risorius Origin: fasica superficial to masseter muscle Insertion: angle of the mouth Action: pulls angle of the mouth laterally Expression: smiling widely; grinning

47 Muscles of Facial Expression
Depressor labii inferioris Origin: mandible Insertion: lower lip Action: depresses the angle of the mouth Expression: sadness; grief

48 Muscles of Facial Expression
Depressor Anguli Oris A.K.A triagularis Origin: mandible Insertion: angle of the mouth Action: depresses angle of the mouth Expression: frowning

49 Muscles of Facial Expression
Mentalis Origin: mandible near the incisive fossa Insertion: skin of the chin Action: pulls skin of chin upward; protrudes lower lip; raise lower lip Expression: doubt; disdain Also called the lip fighter muscle like at the dentist when they have to keep holding down your lip so that they can get at your lower teeth.

50 Muscles of Facial Expression
Buccinator 2 origins: Pterygomandibular raphe Alveolar process of the mandible & maxilla Insertion: orbicularis oris Action: draws the corners of the lips laterally, compresses cheek, helps keep food on occlusal surface during chewing Plays and important role in chewing Makes up the musculature of the cheek

51 Muscles of Facial Expresion
Laughter Muscle that form the core of the laughter of exhilartion: Zygomatic major Oribicularis oculi Muscles used to enhance laughter: Levator labii superioris Risorius Mentalis Depressor anguli oris Orbicularis oris

52 Muscles of Facial Expression
Auriculares 3 small muscles around the auricle of the ear Not well developed in man Allow you to wiggle your ears

53 Muscles of Facial Expression
Platysma Broad, thin, superficial muscle Origin: fascia below clavicle Insertion: lower border of mandible from canine to second molar Action: depresses angle of the mouth, wrinkles the skin of the neck & upper chest Expression: dejection, horror, grimacing

54 Muscles of Mastication
4 pairs of muscles attached to the mandible 3 pairs close the lower jaw 1 pair lowers the jaw & allows side to side movement

55 Muscles of Mastication
Masseter Origin: zygomatic arch Insertion: lateral surface of the mandible Action: elevates the mandible

56 Muscles of Mastication
Temporalis Origin: temporal fossa Insertion: coronoid fossa of the mandible Action: elevates the mandible; retraction

57 Muscles of Mastication
Lateral Pterygoid Origin: sphenoid bone Insertion: mandibular condyle Action: depresses & protracts mandible

58 Muscles of Mastication
Medial Pterygoid Origin: sphenoid, palatine, & maxilla Insertion: medial surface of the mandible Action: elevates mandible; moves it from side to side

59 Muscles That Move the Head and Vertebral Column
Sternocleidomastoid Origin:sternum & collar bone Insertion: temporal bone Action: pulls head to one side, flexes neck or elevates the sternum

60 Muscles That Move the Head & Vertebral Column
Splenis Capitis Origin: spinous process of lower cervical & upper thoracic vertebrae Insertion: occipital bone Action: rotates head, bends head to one side, or extends neck

61 Muscles That Move the Head & Vertebral Column
Semispinalis capitis Origin: processes of lower cervical & upper thoracic vertebrae Insertion: occipital bone Action: elevates head & rotates the head

62 Muscles that Move the Head & Vertebral Column
Quadratus lumborum Origin: iliac crest Insertion: upper lumbar vertebrae & twelfth rib Action: aids in breathing, extends lumbar region of vertebral column

63 Muscles That Move the Head & Vertebral Column
Erector Spinae Origin & Insertion at many locations on the axial skeleton Action: extend & rotate the head & maintain the erect position of the vertebral column

64 Muscles That Move the Pectoral Girdle
Work closely with the muscles that move the arm Connect the scapula to near by bones & help move the scapula up, down, forward, & backward

65 Muscles That Move the Pectoral Girdle
Trapezius Origin: occipital bone & spines of the cervical & thoracic vertebrae Insertion: clavicle, spine, & acromion process of scapula Action: rotates scapula; shrugs shoulders

66 Muscles That Move the Pectoral Girdle
Rhomboid Major Origin: spines of upper thoracic vertebrae Insertion: medial border of the scapula Action: retracts, elevates, & rotates the scapula

67 Muscles That Move the Pectoral Girdle
Rhomboid Minor Origin: spines of the lower cervical vertebrae Insertion: medial border of the scapula Action: retracts & elevates the scapula

68 Muscles That Move the Pectoral Girdle
Levator Scapulae Origin: transverse process of the cervical vertebrae Insertion: medial margin of the scapula Action: elevates scapula

69 Muscles That Move the Pectoral Girdle
Serratus Anterior Origin: outer surfaces of upper ribs Insertion: ventral surface of scapula Action: pulls scapula anteriorly & downward

70 Muscles That Move the Pectoral Girdle
Pectoralis Minor Origin: sternal ends of upper ribs Insertion: coracoid process of scapula Action: pulls scapula forward and downward to raise ribs

71 Muscles That Move the Forearm
Most forearm muscle movements are produced by muscles that connect the radius or ulna to the humerus or pectoral girdle. Muscles that move the forearm are grouped into three categories: Flexors- Extensors Rotators

72 Muscles That Move the Forearm
Flexor: Biceps Brachii Origin: above the glenoid cavity of the scapula Insertion: radius Action: flexes elbow & rotates the hand laterally (turning a doorknob or screw driver)

73 Muscles That Move the Forearm
Flexor Brachialis Origin: anterior shaft of the humerus Insertion: coronoid process of ulna Action: Flexes elbow Strongest flexor of the elbow

74 Muscles That Move the Forearm
Flexor: Brachioradialis Origin: distal lateral end of humerus Insertion: lateral surface of the radius above the styloid process Action: flexes elbow

75 Muscles That Move the Forearm
Extensor Triceps Brachii Origin: below glenoid cavity & lateral & medial surfaces of the humerus Insertion: olecranon process of the ulna Action: extends elbow This is the only muscle on the back of the arm.

76 Muscles That Move the Forearm
Rotators: Supinator Origin: lateral epicondyle of humerus & ulna Insertion: lateral surface of radius Action: rotates forearm laterally and supinates the hand (palm facing upward)

77 Muscles That Move the Forearm
Rotators: Pronator teres Origin: medial epicondyle of humerus and the ulna Insertion: lateral surface of radius Action: rotates forearm medially and pronates the hand

78 Muscles That Move the Forearm
Rotator: Pronator Quadratus Origin: anterior distal end of ulna Insertion: anterior distal end of radius Action: rotates forearm medially and pronates hand

79 Muscles That Move the Hand
Movements of the hand include movements of the wrist and fingers. 2 major groups of muscles Flexors- on anterior side of the forearm Extensors- on the posterior side of the forearm

80 Muscles That Move the Hand
Flexors Flexor carpi radialis Origin: medial epicondyle of the humerus Insertion: base of the 2nd & 3rd metacarpals Action: flexes wrist & abducts hand

81 Muscles That Move the Hand
Flexor Flexor carpi ulnaris Origin: medial epicondyle of the humerus Insertion: carpals & metacarpals Action: flexes the wrist & adducts the hand

82 Muscles that Move the Hand
Flexors Palmaris longus Origin: medial epicondyle of humerus Insertion: fascia of the palm Action: flexes wrist; like you are telling someone to come here

83 Muscles That Move the Hand
Flexors Flexor Digitorum Profundus Origin: anterior surface of the ulna Insertion: bases of distal phalanges in fingers 2-5 Action: flexes distal joints of fingers

84 Muscles that Move the Hand
Flexor Flexor digitorum superficialis Origin: humerus Insertion: tendons of fingers Action: flexes the fingers and wrist

85 Muscles that Move the Hand
Extensor Extensor Carpi Radialis Longus Origin: distal end of the humerus Insertion: base of 2nd metacarpal Action: extends wrist and abducts the hand

86 Muscles that Move the Hand
Extensor Extensor carpi radialis brevis Origin: lateral epicondyle of the humerus Insertion: base of 2nd & 3rd metacarpals Action: extends wrist & abducts hand

87 Muscles that Move the Hand
Extensors Extensor carpi ulnaris Origin: lateral epicondyle of humerus Insertion: base of the 5th metacarpal Action: extends wrist & adducts hand

88 Muscles that Move the Hand
Extensor Extensor Digitorum Origin: lateral epicondyle of the humerus Insertion: posterior surface of phalanges in fingers 2-5 Action: extends fingers

89 Muscles that Move the Arm
Flexors Coracobrachialis Origin: coracoid process of the scapula Insertion: shaft of the humerus Action: flexes & adducts the arm

90 Muscles that Move the Arm
Flexor Pectoralis major Origin: clavicle, sternum, & costal cartilages of upper ribs Insertion: humerus Action: flexes, adducts, and rotates arm medially

91 Muscles that Move the Arm
Extensor Teres Major Origin: lateral border of scapula Insertion: humerus Action: extends, adducts, and rotates the arm medially

92 Muscles that Move the Arm
Extensor Latissimus Dorsi Origin: spines of scral, lumbar, & lower thoracic vertebrae, iliac crest, & lower ribs Insertion: humerus Action: extends, adducts, and rotates the arm medially, or pulls the should downward & back

93 Muscles that Move the Arm
Abductors Supraspinatus Origin: posterior surface of scapula above spine Insertion: humerus Action: abducts the arm

94 Muscles that Move the Arm
Abductors Deltoid Origin: acromion process, spine of the scapula, & clavicle Insertion: humerus Action: abducts, extends, & flexes the arm

95 Muscles that Move the Arm
Rotators Subscapularis Origin: Anterior surface of scapula Insertion: humerus Action: rotates arm medially

96 Muscles that Move the Arm
Rotators Infraspinatus Origin: posterior surface of scapula below spine Insertion: humerus Action: rotates arm laterally

97 Muscles that Move the Arm
Rotators Teres Minor Origin: lateral border of scapula Insertion: humerus Action: rotates arm laterally

98 Muscles of the Abdominal Wall
Muscles of the abdominal wall connect the rib cage & vertebral column to the pelvic girdle Linea alba- band of tough connective tissue that extends from the xiphoid process of the sternum to the pubic symphysis & provides attachment for some of the abdominal muscles Contraction of these muscles helps move air out of the lungs during forceful exhalation & other everyday functions of the body The walls of the chest and pelvic regions are supported directly by bone, but those of the abdomen are not. Instead, the anterior and lateral walls of the abdomen are composed of layers of broad, flattened muscles. These muscles connect the rib cage and vertebral column to the pelvic girdle

99 Muscles of the Abdominal Wall
External oblique Origin- outer surfaces of the lower ribs Insertion- Outer lip of iliac crest & linea alba Action- Tenses abdominal wall & compresses abdominal contents

100 Muscles of the Abdominal Wall
Internal Oblique Origin- crest of ilium & inguinal ligament Insertion- cartilages of the lower ribs, linea alba, & crest of the pubis Action- Tenses abdominal wall & compresses abdominal contents

101 Muscles of the Abdominal Wall
Transversus abdominis Origin- costal cartilages of the lower ribs, processes of the lumbar vertebrae, lip of iliac crest, & inguinal ligament Insertion- linea alba & crest of pubis Action- tenses abdominal wall & compresses abdominal contents

102 Muscles of the Abdominal Wall
Rectus Abdominis Origin- Crest of the pubis & pubic symphysis Insertion- xiphoid process of sternum & costal cartilage Action- tenses the abdominal wall & compresses abdominal contents & also flexes the vertebral column

103 Muscles that Move the Thigh
Muscles that move the thigh are attached to the femur & to part of the pelvic girdle Important exceptions: sartorius & rectus femoris Muscles can be separated into 2 groups: Anterior- primarily flexes the thigh; advance the lower limb when walking Posterior- primarily extends, abducts, or rotates the thigh

104 Muscles that Move the Thigh: Anterior Group
Psoas major Origin: lumbar intervertebral discs; bodies and transverse processes of lumbar vertebrae Insertion: lesser trochanter of the femur Action: flexes the thigh

105 Muscles that Move the Thigh: Anterior Group
Iliacus Origin: Illiac fossa of ilium Insertion: lesser trochanter of the femur Action: Flexes thigh

106 Muscles that Move the Thigh: Posterior Group
Gluteus maximus Origin: sacrum, coccyx, & posterior surface of the ilium Insertion: posterior surface of the femur & fascia of the thigh Action: extends hip; helps straighten the lower limb at the hip when you walk, run, or climb

107 Muscles that Move the Thigh: Posterior Group
Gluteus minimus Origin: lateral surface of the ilium Insertion: greater trochanter of the femur Action: abducts & rotates the thigh medially

108 Muscles that Move the Thigh: Posterior Group
Gluteus medius Origin: lateral surface of the ilium Insertion: greater trochanter of the femur Action: abducts & rotates thigh medially

109 Muscles that Move the Thigh: Posterior Group
Piriformis Origin: anterior surface of the sacrum Insertion: greater trochanter of the femur Action: abducts & rotates the thigh medially ; stabilizes the hip

110 Muscles that Move the Thigh: Posterior Group
Tensor fasciae latae Origin: anterior iliac crest Insertion: greater trochanter of the femur Action: abducts, flexes, & rotates thigh medially

111 Muscles that Move the Thigh: Adductors
Pectineus Origin: spine of the pubis Insertion: femur distal to lesser trochanter Action: Flexes & adducts thigh

112 Muscles that Move the Thigh: Adductors
Adductor brevis Origin: pubic bone Insertion: posterior surface of femur Action: adducts & flexes thigh

113 Muscles that Move the Thigh: Adductors
Adductor longus Origin: pubic bone near the pubic symphysis Insertion: posterior surface of the femur Action: adducts & flexes the thigh

114 Muscles that Move the Thigh: Adductors
Adductor magnus Origin: Ischial tuberosity Insertion: posterior surface of the femur Action: adducts thigh, posterior portion extends & anterior portion flexes thigh

115 Muscles that Move the Thigh: Adductors
Gracilis Origin: Lower edge of pubic symphysis Insertion: medial surface of the tibia Action: adducts thigh & flexes knee

116 Muscles that Move the Leg
Connect the tibia or fibula to the femur or pelvic girdle. Two major groups: Flexors Extensors

117 Muscles that Move the Leg
Hamstring Group Biceps femoris Origin: ischial tuberosity & linea aspera Insertion: head of fibula & lateral condyle of tibia Action: flexes knee, rotates leg laterally & extends thigh

118 Muscles that Move the Leg
Hamstring Group Semitendinosus Origin: ischial tuberosity Insertion: medial surface of the tibia Action: flexes knee, rotates leg medially & extends thigh

119 Muscles that Move the Leg
Hamstring Group Semimembranosus Origin: ischial tuberosity Insertion: medial condyle of tibia Action: Flexes the knee, rotates the leg medially & extends the thigh

120 Muscles that Move the Leg
Sartorius Origin: anterior superior iliac spine Insertion: medial surface of tibia Action: flexes knee & hip, abducts & rotates thigh laterally

121 Muscles that Move the Leg
Quadriceps Group Rectus Femoris Origin: spine of the illium & margin of the acetabulum Insertion: patella by tendon, which continues as the patellar ligament to the tibia Action: extends knee, flexes thigh

122 Muscles that Move the Leg
Quadriceps Group Vastus Lateralis Origin: greater trochanter & posterior surface of the femur Insertion: patella by tendon, which continues as patellar ligament to the tibia Action: extends knee

123 Muscles that Move the Leg
Quadriceps Group Vastus medialis Origin: medial surface of the femur Insertion: patella by tendon, which continues as patellar ligament to the tibia Action: extends knee

124 Muscles that Move the Leg
Quadriceps Group Vastus intermedius Origin: anterior & lateral surfaces of femur Insertion: patella by tendon, which continues as patellar ligament to the tibia Action: extends knee

125 Muscles that Move the Foot
Movements of the foot include movements of the ankle & toes Attach to the femur, tibia, & fibula to bones of the foot Move the foot upward (dorsiflexion) or downward (plantar flexion) and turn the foot so the plantar surface faces medially (inversion) or laterally (eversion) 4 types: dorsal flexors, plantar flexors, invertor, evertor

126 Muscles that Move the Foot
Dorsal Flexor Tibialis Anterior Origin: lateral condyle & lateral surface of the tibia Insertion: tarsal bone & first metatarsal Action: dorsiflexion & inversion of foot

127 Muscles that Move the Foot
Dorsal Flexor Fibularis Tertius Origin: anterior surface of the tibia Insertion: dorsal surface of the 5th metatarsal Action: dorsiflexion & eversion of the foot

128 Muscles that Move the Foot
Dorsal Flexor Extensor Digitorum Longus Origin: lateral condyle of tibia & anterior surface of the fibula Insertion: dorsal surfaces of 2nd & 3rd phalanges of the 4 lateral toes Action: dorsiflexion & eversion of the foot, extends toes

129 Muscles that Move the Foot
Dorsal Flexor Extensor Hallucis Longus Origin: anterior surface of the fibula Insertion: distal phalanx of the big toe Action: extends big toe, dorsiflexion & inversion of foot

130 Muscle that Move the Foot
Plantar Flexor Gastrocnemius Origin: lateral & medial condyles of femur Insertion: posterior surface of calcaneus Action: plantar flexion of foot, flexes knee

131 Muscles that Move the Foot
Plantar Flexor Soleus Origin: head & shaft of fibula & posterior surface of the tibia Insertion: posterior surface of the calcaneus Action: plantar flexion of the foot

132 Muscles that Move the Foot
Plantar Flexion Plantaris Origin: femur Insertion: calcaneus Action: plantar flexion of foot, flexes knee

133 Muscles that Move the Foot
Plantar Flexor Flexor Digitorum Longus Origin: posterior surface of the tibia Insertion: distal phalanges of four lateral toes Action: plantar flexion & inversion of foot, flexes four lateral toes

134 Muscles that Move the Foot
Invertor Tibialis Posterior Origin: lateral condyle & posterior surface of tibia & posterior surface of fibula Insertion: tarsal & metatarsal bones Action: plantar flexion & inversion of foot

135 Muscles that Move the Foot
Evertor Fibularis Longus Origin: lateral condyle of tibia & head & shaft of the fibula Insertion: Tarsal & metatarsal bones Action: plantar flexion & eversion of foot, supports arch


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