Outline

1. Locomotion and Support Systems

2. Outline • Diversity of Skeletons • Hydrostatic Skeleton • Exoskeletons • Endoskeletons • Human Skeletal System • Axial Skeleton • Appendicular Skeleton • Human Muscular System • The Muscles • Muscle Contraction

3. Hydrostatic Skeleton • Functions • Supports body form • Provides resistance for the contraction of muscles to act against • Source • Some organisms use their fluid-filled gastrovascular cavity • Others use their fluid-filled coelom

4. Locomotion in an Earthworm

5. Exoskeletons and Endoskeletons • Exoskeleton - External Skeleton • Molluscs - composed of calcium carbonate • Arthropods - composed of chitin • Endoskeleton - Internal Skeleton • Echinoderms and vertebrates • Mineralized bone and cartilage • Grows as the animal grows • Does not limit space for internal organs • Supports greater weight

6. Exoskeleton

7. The Vertebrate Endoskeleton

8. Human Skeletal System • Functions • Supports and protects the body • Permits movement • Provides resistive foundation for muscles to act against • Bones store calcium and phosphate ions • Certain bones produce red blood cells

9. Bone Growth and Renewal • Cartilage structures in early development act as models for future bones • Calcium salts deposited in matrix by cartilage cells and later by osteoblasts • Endochondral ossification • Osteoclasts • Break down bone • Remove worn cells • Deposit calcium in the blood • Work with osteoblasts to heal broken bones

10. Anatomy of a Long Bone • Gross • Main shank • Thick outer cylinder of compact bone • Medullary cavity in center • Spongy bone at ends • Details • Compact bone • Unit of structure called osteon • Concentric lamellae arranged around central canal • Osteocytes lie in lacunae at lamellar boundaries • Spongy bone • Numerous bars and plates separated by irregular spaces • Spaces filled with red bone marrow

11. Anatomy of a Long Bone

12. The Human Skeleton

13. The Axial Skeleton • Lies in the midline of the body • Consists of • The skull • The vertebral column • The sternum, and • The ribs

14. The Skull • Formed by cranium and facial bones • Major bones are named after • The lobes of the brain, and • The facial bones • Foramen magnum • Opening at base of skull • Where spinal cord connects to brain • Bones of cranium surround sinuses

15. The Skull

16. Vertebral Column • Vertebral column • Supports the head and trunk • Protects the spinal cord and roots of spinal nerves • Segments (from superior to inferior) • Cervical - Neck • Thoracic - Thorax • Lumbar - Small of back • Sacral - Sacrum • Coccyx - Tailbone • Intervertebral disks of fibrocartilage act as padding

17. Rib Cage • Protects the heart and lungs, and assists breathing • Support by the thoracic vertebrae • Twelve pairs of ribs • True ribs • Connect directly to sternum • Seven pairs • “False” ribs • Do not connect directly to sternum • Five pairs

18. The Rib Cage

19. The Appendicular Skeleton • Consists of • The bones within the pectoral and pelvic girdles • The attached limbs • Pectoral girdle – Bones of the shoulder • Anterior • Supports the arms and hands • Pelvic girdle - Bones of the pelvis • Posterior • Supports the legs and feet

20. Bones of the Pectoral Girdle,the Arm, and the Hand

21. Bones of the Pelvic Girdle,the leg, and the Foot

22. Classification of Joints • Fibrous Joints • Immovable • Between cranial bones • Cartilaginous Joints • Slightly Movable • Between vertebrae • Synovial Joints • Freely Movable • Bones separated by a cavity • Ligaments bind bones together at joint

23. The Knee Joint

24. Human Muscular System • Skeletal muscles • Attached to the skeleton by cable-like fibrous connective tissue called tendons • Arranged in antagonistic pairs • Can only contract, cannot push • When one muscle contracts, it stretches its antagonistic partner • A muscle at “rest” exhibits tone (minimal contraction) • A muscle in tetany is at maximum sustained contraction

25. Human Musculature

26. Antagonistic Muscles

27. Microscopic Anatomy and Physiology • Sarcolemma • Plasma membrane • Sarcoplasmic Reticulum • Modified endoplasmic reticulum • Myofibrils • Contractile structures in sarcoplasm • Sarcomeres • Units of contraction • Consist primarily of proteins • Myosin • Actin

28. Skeletal Muscle FiberStructure and Function

29. Sliding Filament Model • Actin filaments at both ends of sarcomere • One end of each filament attached to a Z-plate at one end of the sarcomere • Other end suspended in sarcoplasm • Myosin filaments suspended in between Z-plates • Myosin filaments contain cross-bridges which pull the actin filaments inward • Causes Z-plates to move toward each other • Shortens sarcomere • Sarcomeres stacked together in series and cause myofiber to shorten • Working muscles require ATP • Myosin breaks down ATP • Sustained exercise • Requires cellular respiration • Regenerates ATP

30. Muscle Innervation • Neuromuscular junction • The synaptic contact between a nerve fiber and a muscle fiber • Nerve impulses bring about the release of a neurotransmitter that cross the synaptic cleft • Signals the muscle fiber to contract

31. Neuromuscular Junction

32. The Role of Calcium and Myosin inMuscle Contraction

33. Review • Diversity of Skeletons • Hydrostatic Skeleton • Exoskeletons • Endoskeletons • Human Skeletal System • Axial Skeleton • Appendicular Skeleton • Human Muscular System • The Muscles • Muscle Contraction

34. Locomotion and Support Systems