Muscles Joints Ch 8 Movements of the body

Muscles & Joints Ch. 8

Movements of the body • Flexion: >in angle of a jt. By bending it. • Extension: < in angle of jt. By straightening it. • Hyperextension: extension beyond the anatomical position • Abduction: moving away from midline • Adduction: moving toward midline

movements • Dorsi flexion: bending ankle so foot moves toward the shin. • Plantar flexion: bending ankle so foot points downward • Inversion: moving foot so sole move inward( medially) • Eversion: moving sole of foot outward( laterally)

movements • Circumduction: circular movement along the length of body part. • Rotation: twisting around the axis of limb internal rotation: moves medially external rotation: moves laterally • Elevation: raising body part • Depression: lowering body part

movements • Supination: turning hand palm up • Pronation: turning hand palm down • Protraction: moving part forward • Retraction: moving part backward

joints 1. Form where bones meet – Joints are functional junctions between bones 2. Related terms articulation: junction of 2 or more bones arthro: joint arthology: study of joints arthritis: inflammation of the joint Arthroscopic: joint scope surgery

Joints 3. Functional vs. structural Functional classification is based on: Available movement Structural classification is based on: Materials that make up the joint

Joints 4. Functional classification Synarthroidal= immovable examples: sutures, coccyx-sacrum Amphiarthroidal= slightly moveable examples: pubic symphysis, ribs, vetebral disks, intervertebral jts. Diarthroidal= freely moveable examples: all synovial jts.

joints 5. Structural classification – Fibrous – Cartilagenous – synovial

Joints of the body 6. Fibrous Joints – Syndesmoses (amphiarthroidal) • Bones held together by connective tissue(interoseous membrane) • Tibia-fibula/Radius-Ulna – Suture (synarthroidal) • Between flat bones – Gomphosis ( synarthroidal) • Teeth to jaw

joints 7. Cartilagenous – Temporary: Synchondrosis (synarthroidal) • (bone-cartilage-bone) • Slightly movable: compression • Example – Epiphyseal plates – 1 st rib/manubrium – Permanent: Symphasis ( amphiarthroidal) • Example – Pubis symphasis – Intervertebral jts

Joints 8. Synovial – Freely moveable – All are diarthroidal – Synovial membrane- secretes synovial fluid • Lubricates joint – Joint capsule( fibrous tissueligament) – Articular ( Hyaline) cartilage ( meniscus/menisci) – Bursae: fluid filled sacs • Reduce friction

Joints 8. Types of synovial joints ball & socket condyloid gliding hinge pivot saddle

joints 10. Ball & Socket • allows for greatest Range of Motion( ROM) • • shoulder & hip triaxial movement flexion-extension-add/abduction- rotation

joints • Condyloid ( ellipsoidal) – Egg in spoon – Flexion/extensionadd/abduction – Wrist- MCP, MTP, IP, PIP, DIP • Gliding joint (plane) – Articular ends nearly flat or slightly curved. – Inter (carpal/tarsal), vertebrae, SI joint

Joints – Hinge • spool & cap • Flexion/extension – elbow, Knee, ankle (talus-tib/fib) – Pivot – Cylinder within a ring – Rotation » Radio-humeral, atlas-axis Radius Ulna

Joints • Saddle – Saddle on a horse • Flexion/ext, abd/adduction • Carpometacarpal of thumb

muscles • 3 types – Skeletal (striated, voluntary) – Cardiac (striated, involuntary) – Smooth ( involuntary) • Characteristics – – Irritability: ability to respond to stimuli Contractility: ability to change length Extensibility: ability to be stretched Elasticity: ability to return to original shape

Muscle facts • • • Most common type of tissue in the body (over 600) Makes up 35 -45% of body weight Muscles produce action only by pulling, they cannot push Tendons connect bones to muscle One muscle may attach to another through an aponeurosis (tendon) Each muscle is made up of many bundles of fibers Each fiber is an individual cell Cells are multinucleated They are thin, elongated cylinders Each cell may run the entire length of a muscle

Features of a muscle • • • Epimysium; muscle facia; outer covering of muscle Perimysium: sheath that separates muscle cells into fascicles Fasicle: bundle of muscle fibers Endomysium: thin covering around each muscle fiber Sarcolemma: membrane of the muscle cell Sarcoplasm: cytoplasm of muscle cell Muscle fiber: muscle cell composed of many myofibrils Myofibril: threadlike structures within sarcoplasm essential for contraction, made of myofilaments. Myofilaments: protein strands actin (thin) and myosin (thick). Give striped appearance to muscle. Sarcomere: functional unit of muscle contraction between Z-lines of each myofibril. Myosin filament: Thick dark filament, make up A bands of sarcomere, contains cross-bridges that connect them to the thin filaments. Actin Filaments: Thin, light colored filaments, make up I bands connected together at Z lines, move with a muscle contraction.

Muscle fiber fasicle Actin & myosin filaments

Muscle cell diagram I-band A-Band I-band actin myosin Cross bridge Sarcomere Z line –Z line Z-line H- band sarcomere

• • Sarcomere contractile unit of muscle Actin: thin myofilament, troponin & tropomyosin Myosin: thick myofilament, has crossbridges. Z-line: connects ends of actin together, move toward each other during contraction A band: full length of myosin fiber within a sarcomere, between I bands I band: end of myosin in one sarcomere to the myosin in the next sarcomere. H- band: in the middle of the sarcomere between ends of actin gets smaller with contractions. Crossbridge: functional unit of myosin that attach to troponin/tropomyosin heads on actin filament to cause contraction

Muscle contraction 8. 3 -8. 4

Muscle contraction

Lets watch a sarcomere shortening • http: //highered. mcgrawhill. com/sites/0072437316/student_view 0/ chapter 42/animations. html# • Now let’s discover how this process occurs

Muscle contraction (sliding filament theory) 1. Nerve impulse travels down a motor neuron to muscle unit. 2. The motor neuron terminal releases neurotransmitter acetylcholine ( ACh) 3. ACh binds to ACh receptors (nicotinic receptor) on muscle Motor end unit http: //glencoe. mcgrawhill. com/sites/0015081981/student_view 0/chapter 8/function_of_the_neuromuscular_j unction_. html

Muscle contraction (sliding filament theory) 4. The sarcolemma is stimulated and the muscle impulse travels over the surface of the muscle fiber into the transverse tubules. 5. The impulse reaches the sarcoplasmic reticulum and Ca+ channels open 6. Ca+ ions diffuse from the sarcoplamic reticulum into the sarcoplasm and bind to troponin molecules. 4. 5 6.

Ca+ and it’s role in muscle contraction • http: //www. blackwellpublishing. com/matth ews/myosin. html

Muscle contraction (sliding filament theory) • Thin filaments slide past the thick filaments and the sarcomere shortens. • Myosin molecule has a head and a tail – Tail is a hinge allowing head to attach to actin – Head has a power stroke to pull actin molecule.

• Myosin uses ATP to contract ( head has binding site for actin & ATP) • Actin molecule has 2 proteins: troponin & tropomyosin – Tropomyosin covers binding site so myosin cannot bind ( prevents contraction) – Troponin exposed binding sites

7. Ca+ ions released by action potential of nerve causes tropomyosin to move off of binding site. 8. Cross-bridge flexes and binds to actin molecule. 9. Head flexes (power stroke) and pulls the actin, thus shortening the sarcomere ( muscle contraction)

Sliding filament in action http: //glencoe. mcgrawhill. com/sites/0015081981/student_view 0/chapter 8/myofi lament_contraction. html

Sarcomere shortening • http: //glencoe. mcgrawhill. com/sites/0015081981/student_view 0/ chapter 8/action_potentials_and_muscle_c ontraction. html

Muscle relaxation 1. Acetylcholinesterase( enzyme) decomposes Ach, and the muscle fiber membrane is no longer stimulated( no AP) 2. CA+ ions are actively transported back into sarcoplasmic reticulum. 3. ATP breaks linkages between actin & myosin filaments 4. Tropomyosin slides back over troponin binding sites 5. Muscle is relaxed and ready for next contraction Break down of ATP http: //glencoe. mcgraw-hill. com/sites/0015081981/student_view 0/chapter 8/breakdown_of_atp_and_crossbridge_movement_during_muscle_contraction. html

Energy source is ATP - We use creatine phosphate to re charge the ATP molecule - Has High energy phosphate bonds - 4 -6 x more abundant in muscle than ATP - Active muscle uses Creatine Phosphate rapidly. uses cellular respiration after creatine is gone. - Krebs cycle in aerobic environments - lactic acid fermentation in anaerobic

Figure 08. 10

Figure 08. 11

Oxygen supply - Myoglobin ( like hemoglobin) helps provide muscle with extra oxygen during respiration. - Oxygen Debt - During strenuous muscle use, anaerobic path ways are used to obtain energy(1 -2 mins) - the amount of Oxygen the liver needs to covert lactic acid to glucose + the amount of oxygen required to restore ATP/creatine phosphate back to original concentrations) VERY SLOW process - Can train to increase aerobic capacity - Fatigue is usually caused from a build up of lactic acid. - Lowers p. H so muscle cells no longer respond to stimuli

Table 08. 02 Copied in Homework

Muscle control • All-or-nothing response – Threshold: weakest stimuli to elicit a response - muscle fibers have different thresholds. must have threshold for muscle to contract (twitch) - Frequency fibers are stimulated & how many are stimulated determine contractile force - Recruitment of fibers occurs with larger stimuli

Muscle parts • 3 main parts – Origin= proximal; usually immovable belly • 2 origins= bi ceps • 3 origins= triceps • 4 origins= quadriceps – Insertion= distal attachment, usually movable – Belly= “body” of muscle, between O&I

Muscle names • Named for their – Action ( flexor, extensor) – Location (carpi, tibialis) – Shape and size ( deltoid, maximus, longus) – Number of attachments ( bi, tri. . ) – Point of attachment ( sternocleidomastoid) – Direction of their fibers ( transverse, oblique)

Muscle work in groups • Prime mover ( agonist) Muscle primarily responsible for movement – Ex. Deltoid-abducting arm/biceps-arm flexion biceps • Synergist assist prime mover – Make movements more smooth and efficient – Ex. Rotator cuff deltoid in arm Abduction • Antagonist performs opposite of agonist – Ex. Triceps/biceps; quad/hamstrings Brachialis (under biceps) triceps

Muscles of the face • Muscles of facial expression(6) – – – Epicranius: Orbicularis oris Orbicularis oculi Buccinator Zygomaticus platysma • Muscles of mastication(2) – Masseter – temporalis

1. epicranius: lifts eye brows 2. “flirting: 3. frontalis+ occiptalis 2. Obicularis oculi: closes eye 5. “winking” 3. Obicularis oris: close mouth “kissing” 4. zygomaticus: raises corner of mouth “smile” 5. Buccinator: compress cheeks in “whistle” 6.

6. platysma: draws angle of mouth downward “pout” 7. Sternocleidomastoid: Turns head to side, pulls head to chest, rasises sternum 7. 8.

8. masseter: elevates madible “chew” 9. Temporalis: elevates mandible “chew”

Muscles of pectoral girdle 1. Trapezius: A. upper: rotate/raise scapula B. Middle: adduct scapula C. Lower: depress scapula/shoulder 2. Deltoid A. anterior: flex shoulder B. Lateral: abduct shoulder C. Posterior: extend shoulder

3. Rhomboid: major& minor a. raise & Adduct shoulder 4. Levator scapulae: a. elevate & adduct shoulder b. flex head to side

Muscle that move shoulder girdle 5. Serratus Anterior a. Abducts scapula & rotates Serratus anterior a. 6. Pectoralis Minor a. Draws scapula forward & downward b. elevates ribs Pectoralis minor

Muscles that move Arm 7. Pectoralis Major a. flex, adduct & medially rotate arm 8. Latissimus Dorsi( Lats) a. extend arm b. adduct medially rotate arm c. pulls shoulder down & back

“Rotator Cuff” 9. Teres Major: extends, adducts & medially rotates arm 10. Teres Minor: Rotates arm laterally w/ infraspinatus 11. Infra spinatus: rotates arm laterally 12. Supraspinatus: abducts arm 13. Subscapularis: medially rotates arm

Muscles that move forearm 1. Biceps brachii: a. Flexes forearm b. Supinates hand 2. Brachialis a. flex forearm 3. Brachioradialis a. flex forearm

Muscles that move forearm 4. Triceps brachii – A. extend forearm supinator 5. Supinator a. supinates hand 6. Pronator teres a. pronates hand 7. Pronator quardratus a. pronates hand

Superficial muscles that move hand/wrist 1. Flexor carpi radialis 1. a. Flex abduct wrist 2. Flexor carpi ulnaris 1. a. Flex adduct wrist 3. Palmeris longus 1. a. Flex wrist

Superficial muscle that move wrist/hand 4. Extensor carpi radialis longus & brevis a. extend wrist, abduct hand 5. Extensor carpi ulnaris a. extend adduct wrist 6. Extensor digitorum a. extends fingers

Muscles of Abdominal Wall 1. Rectus abdominus 2. a. flex trunk 3. b. compress abdomen 4. 2. External oblique 5. a. both sides together= compress abdomen 6. b. one side, aids in trunk rotation & flexion 7. 3. Internal oblique 8. a. same as external 9. 4. Transverse abdominis 10. a. compress abdomen & rotation

Muscles that move thigh 1. Psoas Major 2. Iliacus 3. Together make Iliopsoas muscle 4. Flex hip

Muscles that move the Thigh 3. Gluteus maximus: extends thigh 4. Gluteus medius: abduct hip/ rotates medially 5. Tensor fasciae latae : abduct, flex, lateral rotation of thigh attached to IT band ( fascia)

Muscle that move thigh 6. Adductor longus adducts, flex, lateral rotation 7. Adductor magnus adducts, extends, lateral rotation 8. Gracilis adducts, flex & rotate lower leg medially

Muscles that move hip/leg 1. Sartorius( basket weaver) 2. flex leg & thigh, abducts& laterally rotates thigh, rotates leg medially 3. Quadriceps group 4. Rectus femoris: extends knee& flex hip 5. Vastus lateralis: extend knee 6. Vastus medialis: extend knee 7. Vastus intermedius: extend knee IT band

Muslces that move the leg Hamstring group 1. Biceps femoris: flex leg, extend thigh 2. Semitendonosis: flex leg, extend thigh 3. more superficial w/ long tendon 4. 3. Semimenbranosis: flex leg, extend thigh 5. 6. deep to semitendonosis, broad tendon