The Skeletal System

1. The Skeletal System

2. Skeletal System • Bony tissues that form the body’s framework comprise the Skeletal System. • In domesticated animals, the skeletal system is internal, called an endoskeleton, and are basically alike in most species.

3. Skeletal System • The number of bones in a horse’s neck are the same as those in a rabbit’s, but the size and length vary.

4. Skeletal System • The outer layers of bones are composed of hard mineral deposits. About 26% of total bone mass is composed of mineral matter. • The remainder of the composition of bones includes 20% protein, 4% fat, and 50% water.

5. Skeletal System • About 85% of the mineral matter is calcium phosphate. • The remaining 15% is calcium carbonate.

6. Skeletal System • The inner core of bones is soft tissue called bone marrow. • Some of the bone marrow consists of yellow fat, called yellow marrow. • The other portion is made of red tissue called red marrow, that is responsible for red blood cell formation.

7. Skeletal System • As an animal grows, bones increase in size and length in the region of cartilage between the end and shaft of bones. • As the animal matures, this cartilage ossifies (becomes bony material).

8. Skeletal System • In mature animals, bone is continually being reabsorbed and replaced, but no new bone growth occurs. • Osteoporosis occurs when the bone that is reabsorbed is not replaced.

9. Skeletal System • As long bones grow in length, they also increase in diameter. • This is caused by the production of new bony tissue in the periosteum that surrounds the outside of the bone.

10. Skeletal System • Bone growth is affected by hormones, vitamins, and other nutrients. • Therefore, bones can become fragile or distorted due to nutritional deficiencies. • Breaks in bones repair when the ends fill with a fibrin clot, that becomes bony tissue.

11. Skeletal System • The skeletal system provides body support and leverage for muscle movement, which is made possible by several types of joints.

12. Skeletal System • Ball-and-socket joints can move in all directions (shoulder). • Hinge joints move in only two directions (knee). • Pivot joints allow for movement in several directions (neck)

13. Skeletal System • Gliding joints allow for flexibility to move forward, backward, or sideways (vertebrae)

14. Skeletal System • Joints are held together by ligaments and are enclosed by a capsule which contains synovial fluid to lubricate the joint and allow friction-free movement.

15. Skeletal System • The skeletal system of animals of the phylum Chordata can be divided into three parts: • the axial (spine, ribs, sternum, skull) • the pectoral limb (foreleg) • the pelvic limb (pelvic girdle and hindlegs)

16. Skeletal System Axial - Pelvic - Pectoral -

17. Skeletal System • The vertebral column (spine) is divided into five regions: • Cervical (7 vertebrae) • Thoracic (13 vertebrae) • Lumbar (6 vertebrae) • Sacral (5 vertebrae) • Coccygeal (18-20 vertebrae)

18. Skeletal System - Axial Skull Thoracic Vertebrae Lumbar Vertebrae Sacral Vertebrae Coccygeal Vertebrae Ribs Cervical Vertebrae Xyphoid Sternum

19. Skeletal System - Pectoral Scapula Humerus Ulna Radius Metacarpal Bones Carpus Phalanges

20. Skeletal System - Pelvic Ilium Pelvis Ischium Femur Patella Tibia and Fibula Tarsus Metatarus Phalanges

21. Skeletal System

22. Maxillar Mandible Clavicle Scapula Sternum Humerus Ribs Lumbar Vertebrae Radius Pelvis Coccyx Ulna Carpus Metacarpus Phalanges Femur Patella Tibia Fibula Metatarsals Tarsus Phalanges

23. Skeletal System • Bones are divided into four classes based on their shape and function: • Long bones (support) • Flat bones (muscle attachment and organ protection) • Short bones (help in movement and change the direction of tendons) • Irregular bones (vertebrae)

24. Skeletal System • Parts of the skeletal system protect vital organs. • Skull (protects the brain) • Rib cage (protects the heart, lungs, and certain abdominal organs) • Vertebrae (protect the spinal column)