The Muscular System Pictures

Epimysium Epimysium Bone Perimysium Tendon Endomysium Muscle fiber in middle of a fascicle (b) Blood vessel Fascicle (wrapped by perimysium) Endomysium (between individual muscle fibers) Perimysium Fascicle Muscle fiber (a)

Part of a skeletal muscle fiber (cell) I band A band I band Z line H zone Z line Myofibril M line Sarcolemma Triad: • T tubule • Terminal cisternae of the SR (2) Sarcolemma Tubules of the SR Myofibrils Mitochondria

Myofibrils Sarcolemma Nucleus Mitochondrion Myofibril Dark A band Light I band

Features of a Sarcomere Thin (actin) filament Z line H zone Z line Thick (myosin) filament I band A band Sarcomere I band M line Sarcomere Z line M line Z line Thin (actin) filament Elastic (titin) filaments Thick (myosin) filament

Longitudinal section of filaments within one sarcomere of a myofibril Thick filament Thin filament In the center of the sarcomere, the thick filaments lack myosin heads. Myosin heads are present only in areas of myosin-actin overlap. Thick filament Thin filament Each thick filament consists of many myosin molecules whose heads protrude at opposite ends of the filament. A thin filament consists of two strands of actin subunits twisted into a helix plus two types of regulatory proteins (troponin and tropomyosin). Portion of a thick filament Portion of a thin filament Myosin head Tropomyosin Troponin Actin Actin-binding sites Heads Tail Active sites for myosin attachment ATP- binding site Actin subunits Flexible hinge region Myosin molecule Actin subunits

1 2 Z H Z I A I Fully relaxed sarcomere of a muscle fiber Z Z I A I Fully contracted sarcomere of a muscle fiber

Cross bridge formation. Thin filament Actin Ca2+ Myosin cross bridge ADP Pi Thick filament Myosin 1 Cross bridge formation. ADP ADP Pi ATP hydrolysis Pi 4 Cocking of myosin head. 2 The power (working) stroke. ATP ATP 3 Cross bridge detachment.

Actin Ca2+ Thin filament ADP Myosin cross bridge Pi Thick filament Myosin 1 Cross bridge formation.

ADP Pi 2 The power (working) stroke.

ATP 3 Cross bridge detachment.

ADP ATP hydrolysis Pi 4 Cocking of myosin head.

Cross bridge formation. Thin filament Actin Ca2+ Myosin cross bridge ADP Pi Thick filament Myosin 1 Cross bridge formation. ADP ADP Pi ATP hydrolysis Pi 4 Cocking of myosin head. 2 The power (working) stroke. ATP ATP 3 Cross bridge detachment.

Latent period Single stimulus Period of contraction relaxation Myogram showing the three phases of an isometric twitch

Coupled reaction of creatine phosphate (CP) and ADP Energy source: CP Direct phosphorylation Oxygen use: None Products: 1 ATP per CP, creatine Duration of energy provision: 15 seconds Creatine kinase ADP CP ATP

Head Facial Temporalis Epicranius, frontal belly Orbicularis oculi Masseter Zygomaticus Shoulder Orbicularis oris Trapezius Neck Deltoid Sternohyoid Arm Platysma Triceps brachii Sternocleidomastoid Biceps brachii Brachialis Thorax Pectoralis minor Forearm Serratus anterior Pronator teres Pectoralis major Brachioradialis Intercostals Flexor carpi radialis Palmaris longus Abdomen Pelvis/thigh Rectus abdominis Iliopsoas Internal oblique Pectineus Transversus abdominis External oblique Thigh Rectus femoris Thigh Vastus lateralis Tensor fasciae latae Vastus medialis Sartorius Adductor longus Leg Gracilis Fibularis longus Extensor digitorum longus Leg Gastrocnemius Tibialis anterior Soleus

Neck Epicranius, occipital belly Sternocleidomastoid Arm Trapezius Triceps brachii Brachialis Shoulder Deltoid Forearm Infraspinatus Brachioradialis Teres major Extensor carpi radialis longus Rhomboid major Latissimus dorsi Flexor carpi ulnaris Extensor carpi ulnaris Hip Gluteus medius Gluteus maximus Extensor digitorum Iliotibial tract Thigh Adductor magnus Hamstrings: Biceps femoris Leg Gastrocnemius Semitendinosus Soleus Semimembranosus Fibularis longus Calcaneal (Achilles) tendon

Epicranius Galea aponeurotica Corrugator supercilii Frontal belly Orbicularis oculi Occipital belly Levator labii superioris Zygomaticus minor and major Temporalis Buccinator Masseter Risorius Sternocleidomastoid Orbicularis oris Trapezius Mentalis Splenius capitis Depressor labii inferioris Depressor anguli oris Platysma

Tongue Styloid process Styloglossus Genioglossus Hyoglossus Mandibular symphysis Stylohyoid Hyoid bone Geniohyoid Thyrohyoid Thyroid cartilage

Median raphe Anterior belly Mylohyoid Digastric Stylohyoid Posterior belly Hyoid bone Omohyoid (superior belly) Stylohyoid (cut) Thyrohyoid Sternohyoid Thyroid cartilage of the larynx Sternocleido- mastoid Thyroid gland Omohyoid (inferior belly) Sternothyroid

Ligamentum nuchae Mastoid process of temporal bone Semispinalis capitis Longissimus capitis Semispinalis cervicis Iliocostalis cervicis Longissimus cervicis Semispinalis thoracis Iliocostalis thoracis Longissimus thoracis Spinalis thoracis Iliocostalis Erector spinae Longissimus Spinalis Multifidus Iliocostalis lumborum Quadratus lumborum External oblique

External intercostal Internal intercostal

Xiphoid process of sternum Foramen for inferior vena cava Foramen for esophagus Costal cartilage Central tendon of diaphragm Diaphragm Foramen for aorta Lumbar vertebra 12th rib Quadratus lumborum Psoas major

Pectoralis major Serratus anterior Linea alba Tendinous intersection Transversus abdominis Internal oblique Rectus abdominis External oblique Aponeurosis of the external oblique Inguinal ligament (formed by free inferior border of the external oblique aponeurosis)

Rectus abdominis External oblique Internal oblique Lumbar fascia IIiac crest Pubic tubercle Lumbar fascia Transversus abdominis Inguinal ligament

Sternocleido- mastoid Subclavius Clavicle Subscapularis Deltoid Pectoralis minor Pectoralis major Coracobrachialis Sternum Serratus anterior Biceps brachii Humerus

Levator scapulae Trapezius Supraspinatus Clavicle Deltoid Spine of scapula Rhomboid minor Infraspinatus Teres minor Rhomboid major Teres major Humerus Latissimus dorsi

Superficial transverse ligament of palm Palmar aponeurosis Flexor retinaculum Pronator quadratus Flexor digitorum superficialis Flexor pollicis longus Flexor carpi ulnaris Palmaris longus Extensor carpi radialis longus Flexor carpi radialis Brachioradialis Medial epicondyle of humerus Pronator teres Tendon of biceps brachii Medial head of triceps brachii Biceps brachii

Tendon of flexor digitorum superficialis (cut) Tendon of flexor digitorum profundus Lumbricals Tendon of flexor pollicis longus Thenar muscles of thumb Tendon of flexor carpi ulnaris (cut) Pronator quadratus Flexor pollicis longus Flexor digitorum profundus Supinator

Extensor expansion Tendons of extensor digitorum Tendons of extensor carpi radialis brevis and longus Extensor pollicis longus Extensor indicis Extensor pollicis brevis Extensor digiti minimi Abductor pollicis longus Extensor carpi ulnaris Extensor digitorum Flexor carpi ulnaris Extensor carpi radialis brevis Anconeus Extensor carpi radialis longus Insertion of triceps brachii Brachioradialis

12th rib 12th thoracic vertebra Quadratus lumborum Psoas minor Iliac crest Psoas major Iliopsoas Iliacus 5th lumbar vertebra Anterior superior iliac spine Tensor fasciae latae Pectineus Adductor longus Sartorius Gracilis Quadriceps femoris Adductor magnus • Rectus femoris • Vastus lateralis • Vastus medialis Tendon of quadriceps femoris Patella Patellar ligament

Gluteus medius Gluteus maximus Adductor magnus Gracilis Iliotibial tract Long head Biceps femoris Short head Hamstrings Semitendinosus Semimembranosus

Patella Head of fibula Gastrocnemius Soleus Fibularis longus Extensor digitorum longus Tibialis anterior Extensor hallucis longus Fibularis tertius Fibularis brevis Superior and inferior extensor retinacula Flexor hallucis longus Extensor hallucis brevis Fibular retinaculum Extensor digitorum brevis Lateral malleolus 5th metatarsal

Plantaris (cut) Gastrocnemius lateral head (cut) Gastrocnemius medial head (cut) Popliteus Soleus (cut) Tibialis posterior Fibula Fibularis longus Flexor digitorum longus Flexor hallucis longus Tendon of tibialis posterior Fibularis brevis Medial malleolus Calcaneal tendon (cut) Calcaneus