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Overview of Muscle Tissue

Overview of Muscle Tissue. Skeletal -Muscle fibers are the longest of muscle types;striations; voluntary;somatic movement;adaptable. Cardiac -Constitutes bulk of heart walls; striated;involuntary;pacemaker sets contractions.

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Overview of Muscle Tissue

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  1. Overview of Muscle Tissue • Skeletal-Muscle fibers are the longest of muscle types;striations; voluntary;somatic movement;adaptable. • Cardiac-Constitutes bulk of heart walls; striated;involuntary;pacemaker sets contractions. • Smooth muscle-Found in walls of visceral organs, forces fluids/substances through internal body channels; nonstriated; involuntary.

  2. Muscle Functions • Producing movement-Skeletal muscle is responsible for all somatic movements & manipulation;cardiac muscle courses blood through vessels;smooth muscle-peristaltic actions • Maintaining posture-Continuously defying gravity via constant adjustments • Stabilizing/strengthen joints • Generation of heat-Skeletal muscle contractions responsible for heat production.

  3. Skeletal muscle functions • Produce somatic movements • Maintain body posture/position • Reinforce soft tissue-anterior/posterior walls/pelvic floor • Guard entrances/exits-orifices of alimentary/urinary tracts • Regulation of body temperature-heat loss by muscle contractions

  4. Gross Anatomy of Skeletal Muscles • Epimysium-dense CT surrounds entire muscle;blends with deep fascia. • Perimysium and fascicles-fibrous CT surrounding bundles of fibers. • Endomysium-sheath of CT surrounding muscle fiber. • CT coverings contributes to muscle tissue elasticity

  5. Nerve and Blood Supply • Normal activity of skeletal muscle dependant on nerve/blood supply;each muscle is served by one nerve,artery & vein;nerves penetrate CT septa; each fiber supplied with nerve ending(myoneural junction). • Muscle requires large amount of energy;extensive blood supply delivers O2 & nutrients for ATP production.

  6. Attachments • Movable insertion moves towards immovable origin. • Direct attachment-epimysium fused to periosteum/perichondrium. • Indirect attachment-epimysium extends beyond muscles as sheet like aponeurosis; anchors muscle to bone, cartilage or fasciae of other muscles.

  7. Microscopic Anatomy of Skeletal Muscle • Muscle fiber is long, cylindrical, oval multinuclear myocyte; sarcolemma • Sarcoplasm contains glycosomes. • Myoglobin-red pigment • Myofibril-account for 80% of cellular volume.

  8. Microscopic Anatomy of Skeletal Muscle (cont’d) • Sarcoplasmic reticulum-membrane complex similar to SER; essential in contraction of myofibrils;t-tubule /terminal cisternae (triad) • Myofilaments-actin (thin filaments)/myosin (thick filaments); sarcomeres. • Sarcomere organization-M-line, Z-line, A-band (thick,thin), H band (thick), I-band (thin)

  9. Tendons and Aponeuroses • Tendon-fusion point of collagen fibers of endo-, peri-, and epimysium that attach muscle to bone, skin, or another muscle; resemble thick cords or cables • Aponeuroses-Formation of thick, flattened sheets.

  10. Microscopic Anatomy of Skeletal Muscle (cont’d) • Thin filaments-F-actin strand (G actin/tropomyosin, troponin. • Thick filaments-Myosin molecule (tail, head);elastic(titin)core

  11. Naming Skeletal Muscles • Location-temporalis, intercostals • Shape-deltoid, trapezius • Relative size-maximus, minimus, longus, brevis • Direction-rectus, oblique • Number of origins-biceps, triceps • Location of attachments-origin first/sternocleidomastoid • Action-flexor, extensor,adductor.

  12. Arrangement of Skeletal Muscle Fibers • Circular-orbicularis oris • Convergent-pectoralis major • Parallel-sartorius • Unipennate-extensor digitorum longus • Multipennate-deltoid • Fusiform-biceps • Bipennate-rectus femoris

  13. The Axial Musculature • The axial musculature is involved in moving the head and spinal column. • Categorized into five groups: (1) muscles of the head; (2) muscles of neck & vertebral column; (3)muscles of the thorax; (4) muscles of the abdominal wall;(5) muscles of the pelvic floor/perineum

  14. Cephalic muscles • Scalp Epicranius-frontalis/occipitalis • Facial Orbicularis oculi Zygomaticus Risorius Orbicularis oris Buccinator Platysma

  15. Cephalic Muscles (cont’d) • Mastication Temporalis Medial/lateral pterygoids Buccinator • Tongue movements Genioglossus

  16. Neck & Vertebral Column • Neck Sternocleidomastoid Scalenes • Vertebral Column Erector Spinae-spinalis,longissimus, Iliocostalis Semispinalis Quadratus lumborum

  17. Muscles of the Thorax • External intercostals • Internal intercostals • Diaphragm

  18. Muscles of the Abdominal Wall • Rectus abdominis • External oblique • Internal oblique • Transversus abdominis

  19. Muscles of the Pelvic Floor • Levator ani- pubo-,iliococcygeus • Sphincter urethrae • Ischiocavernosus • Bulbospongiosus

  20. Appendicular Skeletal Muscles • Involved in stabilization of pectoral & pelvic limbs. • Accounts for 40% of skeletal muscle mass.

  21. Pectoral Girdle Muscles/Upper Limbs • 4 divisions 1. Pectoral girdle positioning 2. Brachium movement 3. Antebrachium movement 4. Hand/finger movement

  22. Pectoral Girdle Positioning • Anterior Thorax Pectoralis minor Serratus anterior • Posterior thorax Trapezius

  23. Brachium movement • Pectoralis major • Latissimus dorsi • Deltoid • Subscapularis • Supra-,infraspinatus • Teres major, minor • Coracobrachialis

  24. Antebrachium Movement • Posterior aspect: extensors Triceps Anconeus • Anterior aspect: flexors Biceps brachii Brachialis Brachioradialis

  25. Hand/Finger Movement • Anterior aspect Pronator quadratus, teres Flexor carpi radialis, ulnaris Palmaris longus • Posterior aspect Supinator Extensor carpi radialis, ulnaris Extensor digitorum

  26. Intrinsic hand muscles • Thenar (ball of thumb) • Hypothenar (ball of little finger) • Midpalm (lumbricals, interossei)

  27. Pelvic Girdle Muscles and Lower Limbs • Larger, stronger than pectoral limb muscles • 3 groups: (1) Thigh movement; (2) Leg movement; (3) Foot & toe movement.

  28. Thigh Movement • Anterior compartment Iliopsoas Sartorius • Medial compartment Adductor magnus, longus, brevis Pectineus Gracilis

  29. Thigh Movement (cont’d) • Posterior compartment Gluteus maximus, medius, minimus Piriformis Obturator internus Gemellus Quadratus femoris

  30. Leg Movement • Anterior thigh compartment Rectus femoris Vastus lateralis, medialis, intermedius • Posterior thigh compartment Biceps femoris Semitendinosus Semimembranosus

  31. Foot & Toe Movement • Anterior compartment Tibialis anterior Extensor digitorum longus Extensor hallucis • Lateral compartment Peroneus longus, brevis

  32. Foot & Toe Movement (cont’d) • Posterior compartment Gastrocnemius Soleus Flexor digitorum longus Tibialis posterior Flexor hallucis longus

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