sliding filament theory and major muscles of the human body
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Sliding Filament Theory and Major Muscles of the Human Body. Lesson. Skeletal Muscle. Human body contains over 400 skeletal muscles 40-50% of total body weight Functions of skeletal muscle Force production for locomotion and breathing Force production for postural support - PowerPoint PPT PresentationTRANSCRIPT
Sliding Filament Theoryand
Major Muscles of the Human Body
Lesson
Skeletal Muscle
• Human body contains over 400 skeletal muscles– 40-50% of total body weight
• Functions of skeletal muscle– Force production for locomotion and breathing– Force production for postural support– Heat production during cold stress
Structure of Skeletal Muscle:Connective Tissue Covering
• Epimysium– Surrounds entire muscle
• Perimysium– Surrounds bundles of muscle fibers
• Fascicles
• Endomysium– Surrounds individual muscle fibers
Structure of Skeletal Muscle:Microstructure
• Sarcolemma– Muscle cell membrane
• Myofibrils– Threadlike strands within muscle fibers– Actin (thin filament)
• Troponin• Tropomyosin
– Myosin (thick filament)
Structure of Skeletal Muscle:The Sarcomere
• Further divisions of myofibrils– Z-line– A-band– I-band
• Within the sarcoplasm– Sarcoplasmic reticulum
• Storage sites for calcium
Muscular Contraction
• The sliding filament model– Muscle shortening occurs due to the
movement of the actin filament over the myosin filament
– Formation of cross-bridges between actin and myosin filaments
– Reduction in the distance between Z-lines of the sarcomere
The Sliding Filament Model of Muscle Contraction
Cross-Bridge Formation in Muscle Contraction
Sliding Filament Theory
• Rest – uncharged ATP cross-bridge complex
• Excitation-coupling – charged ATP cross-bridge complex, “turned on”
• Contraction – actomyosin – ATP > ADP & Pi + energy
• Recharging – reload cross-bridge with ATP
• Relaxation – cross-bridges “turned off”
http://www.youtube.com/watch?v=0kFmbrRJq4w&feature=related
Muscles Origins and Insertions
Muscles from pg. 46 in text
Muscle Name Function Describe movements
Origin Insertion
SternocleidomastoidBroad superficial muscle running up each side of the neck
Agonist Flexes and rotates the head
Sternum
Clavicle
Mastoid process
Muscle Name Function Describe movements
Origin Insertion
Splenius
Runs posterior joins skull and spine
Agonist Flexes and rotates the head
Cervical & thoracic vertebrae
Temporal &occipital lobes
Neck Muscles
Muscles of Vertebral Column
Muscle Name Function Describe movements
Origin Insertion
Longissimus
Lateral to spinalis
Agonist Laterally Flexes and extends the spine
Cervical,
Thoracic,
Lumbar vertebrae
Mastoid process & cervical vertebrae
Spinalis
Most medial attaches to vertebrae
Agonist Laterally Flexes and extends the spine
Cervical,
Thoracic,
Lumbar vertebrae
Mastoid process & cervical vertebrae
Illiocostalis
Most lateral
Agonist Laterally Flexes and extends the spine
Saccrum,Lumbar vertebrae, Ribs
Cervical vertebrae
&
Ribs
Back Muscles
SpinalisIliocostalisLongissiumus
Thoracic Cage Muscles
Muscle Name Function Describe movements
Origin Insertion
Diaphragm
Anatomical Divider
Agonist Decreases pressure in the thoracic cavity
Sternum,
Ribs,
Lumbar vertebrae
Central tendon
Intercostals
Muscles in between ribs
Agonist Elevates,
Depresses ribs
Inferior aspect of all ribs
Superior aspect of all ribs
Transverse
Thoracis
Triangle muscles under ab wall
Agonist Pulls abdominal wall invward
Sternum,
Xiphoid process
Cartilidge of ribs 2-6
Thoracic Cage
Abdominal Muscles
Muscle Name Function Describe movements
Origin Insertion
Rectus Abdominus
Wash board look
Agonist Flex trunk,
Aids in some expiration
Child birth
Symphysis pubis & pubic crest
Xiphoid Process
Inferior ribs
External Obliques
Agonist Flex and rotate the vertebral column
Lower eight ribs
Iliac Crest,
Pubis
Quadratus Lumborum
Deep muscle
Agonist Extend and laterally bends the vertebral column
Iliac Crest and Lumbar vertebra
12th Rib and upper lumbar vertebrae
Abdominals
Moving Upper Limb
Muscle Name Function Describe movements
Origin Insertion
Pectoralis
Major
Thick Muscles covering the chest
Prime Mover
Internal rotation, adduction and flexion of the arm
Clavicle,
Sternum,
Costal cartilage of first 6 ribs.
Intertubercular groove
Latissimus Dorsi
“Lats”
V shape
Prime Mover
Adductor, Extensor and internal rotator of the arm
Lower Thoracic and Lumber verts. Iliac Crest and sacrum
Humerus
Rotator CuffMuscle Name Function Describe
movementsOrigin Insertion
Supraspinatus Agonist Stabilize shoulder joint. Abducts shoulder
Above scapular spine
(supraspinous fossa)
Greater Tubercle of Humerus
Infraspinatus Agonist Stabilize shoulder joint. Lateral rotation
Below scapular spine
(infraspinous fossa)
Greater Tubercle of Humerus
Teres Minor Agonist Stabilize shoulder joint. Lateral rotation.
Lateral border of scapula
Greater Tubercle of Humerus
Subscapularis Stabilizer Rotates medially and stabilizes shoulder
Iliac Crest and Lumbar vertebra
Lesser Tubercle of Humerus
Scapular MusclesMuscle Name Function Describe
movementsOrigin Insertion
Trapezius Agonist Scapular elevation, adduction, retraction, upward rotation & extends neck
Occipital bone,
Cervical & thoracic vertebrae
Spine of Scapula, acromion process &clavicle
Rhomboids
Major & Minor
Agonist Assist Traps in downward rotation of scapular &adduction of scapula
Maj. T2-T5
Min. C1-T1
Medial border of the scapula
Levator Scapulae
Agonist Elevates scapula Base of skull & upper cervical vertebrae
Upper medial border of scapula
Serratus anterior
Stabilizer Upward rotation & abduction of the scapula
Ribs 1-8 Medial border of the scapula
Scapular Muscles cont.
Muscle Name Function Describe movements
Origin Insertion
Pectoralis
Minor
Agonist Elevates ribs & Depresses Scapula
Ribs 3,4,5 Coracoid process
Muscles that move Humerus
Muscle Name Function Describe movements
Origin Insertion
Deltoids
Three heads
Anterior, lateral, posterior
Agonist Laterally abducts arms,
Medial and lateral rotation
From the clavicle to the acromion to scapular spine
Humerus
(Deltoid tuberosity)
Coracobrachialis Agonist Flexor and arm adductor
Coracoid Process
Humerus
Teres
Major
Agonist Medial rotator and adductor
Lateral Border of the scapula
Humerus
Elbow Flexors & ExtensorsMuscle Name Function Describe
movementsOrigin Insertion
Bicep
Brachii
Agonist Supinator and flexor of the arm
2 places
Short head on corracoid
Long Head superior glenoid fossa
Radius
Radial
Tuberosity
Brachialis Agonist Pronator and arm flexor
Anterior surface of humerus
Coronoid process
Tricep Brachii Agonist Arm Extensor 1)Lateral head – posterior humerus
2)Long Head – infragleniod fossa
3)Medial head posterior humerus
Olecranon
Brachioradialis Agonist Elbow flexor, very powerful when arm is pronated
Lateral epicondyle of humerus
Olecranon
Supination and Pronation of the Forearm
Muscle Name Function Describe movements
Origin Insertion
Pronator Quadratus
Agonist Pronates forearm
Anterior surface of distal ulna
Distal surface of radius
Pronator teres Agonist Pronates forearm
Medial epicondyle of the humerus and the coronoid porcess
Lateral mid shaft of radius
Supinator Agonist Supinates forearm
Lateral epicondyle of humerus
Lateral aspect of radius
Extrinsic Hand MusclesMuscle Name Function Describe
movementsOrigin Insertion
Flexor – Pronator
Group
Agonist Pronator and flexor of the wrist and digits
Medial epicondyle of the humerus
Meta carpals
Phalanges
Extensor –
Supinator
Group
Agonist Supinator and flexor of wrist ad digits
Lateral epicondyle of humerus
Meta Carpals
Phalanges
Pelvic Muscles
Muscle Name Function Describe movements
Origin Insertion
Gluteus
Maximus
Agonist Hip extension and external rotation
Illiac crest saccrum and coccyx
Greater trochanter
Gluteus
Medius
Agonist Abduction and internal rotation
Anterior surface of the illiac crest
Posterior surface of greater trochanter
Sartorius Agonist Hip Flexion
Outward rotation
Medial surface of the tibia
Medial surface of the tibia
Gluteus Max, Med, Min
Hip Adductors
Muscle Name Function Describe movements
Origin Insertion
Illiopsoas Agonist Hip and trunk felxion
Ilium and lumbar vertebrae
Lesser Trochanter of the Femur
Adductor
longus
Agonist Hip Adduction Pubis Femur
Adductor
magnus
Agonist Hip adduction and extension
Pubis and ischium
Femur
QuadricepsMuscle Name Function Describe
movementsOrigin Insertion
Rectus Femoris
Agonist Knee Extension and Hip Flexion
Iliac crest Patellar
Tendon
Vastus Lateralis
Agonist Knee Extension Femur Patellar
Tendon
Vastus intermedius
Agonist Knee Extension Femur Patellar
Tendon
Vastus Medialis
Agonist Knee Extension Femur Patellar
Tendon
Quadriceps
HamstringsMuscle Name Function Describe
movementsOrigin Insertion
Bicep Femoris Agonist Flexes knee, Rotates knee externally, extends hip
Ischium Head of Fibula
Semi-membranosus
Agonist Flexes knee, Rotates knee internally, extends hip
Ischium Medial tibial condyle
Semi-tendinosus
Agonist Flexes knee, Rotates knee internally
Ischium Medial tibial condyle
Hamstrings
Lower LegMuscle Name Function Describe
movementsOrigin Insertion
Tibialis Anterior
Agonist Dorsi Flexes ankle and inverts foot
Anterior shaft of tibia
Metatarsals
Gastrocnemius Agonist Plantar Flexes ankle and felxes knee
Medial and Lateral Condyles
Calcaneous
Soleus Agonist Plantar Flexes ankle Fibula Calcaneous
Lower Leg Muscles