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Skeletal System

Skeletal System. Skeletal Tissue. Skeletal Tissue. Osseous tissue Made up of inorganic compounds like calcium and phosphorous Give hardness and rigidity Made up of organic compounds like cartilage Give small amount of flexibility, to stop from easily breaking. Skeletal Tissue.

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Skeletal System

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  1. Skeletal System Skeletal Tissue

  2. Skeletal Tissue • Osseous tissue • Made up of inorganic compounds like calcium and phosphorous • Give hardness and rigidity • Made up of organic compounds like cartilage • Give small amount of flexibility, to stop from easily breaking

  3. Skeletal Tissue • Types of Bones • Long Bones • Femur, humerus • Short Bones • Carpals and tarsals • Flat bones • Scapulae, ribs, sternum • Irregular bones • Sphenoid • Sesamoid bones- irregular bones that appear singularly like the patella

  4. Parts Of A Long Bone • Diaphysis- main part of bone, compact bone • Epiphysis- ends of long bone, cancellous bone • At development epiphysis is separated from the diaphysis by a thick layer of cartilage called the epiphyseal plate (where mitosis occurs) • Articular Cartilage- hyaline cartilage that covers epiphysis • Periosteum- fibrous connective tissue that covers bone except at articulations • Medullary cavity- hollow tube in diaphysis, in adults it’s filled with yellow marrow • Endosteum- lines the medullary cavity of long bones

  5. Microscopic Anatomy • Compact Bone • Osteocytes are found in lacunae • Lacunae are arranged in circles called lamellae • Lamellae are formed around Haversian canal • Canaliculi radiate to all lacunae and act as a transportation system

  6. Microscopic Anatomy • Cancellous Bone • Doesn’t contain Haversian System • Instead has trabeculae where bone cells are found • Site of red marrow and hematopoesis

  7. Bone Cells • Osteoblasts • Build up bone • Osteoclasts • Erode bone (break it down) • Osteocytes • Mature osteoblasts that no longer have function

  8. Regulation of Blood Calcium Levels • Bones store 98% of body calcium • Calcium levels must be maintained for bone formation, blood clotting, nerve impulses and skeletal and cardiac muscle contraction • Controlled by two hormones: parathyroid hormone and caclitonin • Parathyroid hormone: When blood calcium is low, hormone is stimulated, activating osteoclasts. Bone will be broken down and calcium will enter blood. When blood calcium levels are too high, PTH will be supressed, reducing amount of calcium that enters blood stream • Calcitonin- activated by high levels of blood calcium, stimulates osteoblasts activity, decreases osteoclast activity • PTH is main hormone involved in calcium regulation

  9. Development of Bone • Ossification- bone formation • Skeleton begins as hyaline cartilage but then turns into bone (for all bones except flat bones) • Cartilage is covered by bones (osteoblasts) and then cartilage is eaten away, forming medullary cavity

  10. Repair of Bone Fracture • Blood at injury site forms a clot • Callus tissue forms, binding bones together • Bone remodeling then takes place

  11. Skeletal System Bone Markings

  12. Bone Markings • Angle-corner • Body-main part of bone • Condyle-rounded bump • Crest- raised ridge, usually a place for muscle attachment • Epicondyle- bump near condyl (muscle attachment) • Facet- flat surface that forms a joint w/ a flat bone • Fissure-long, thin hole for blood vessels and nerves • Foramen- round hole • Fossa-depression, receives articulating bone • Head-distinct epiphysis on long bone • Line- more faint than crest • Margin-edge of flat bone • Meatus-tubelike opening or channel • Neck-narrow portion, usually at end of head • Notch-V like margin at edge of flat area • Process- raised area of projection • Ramus-curved portion of bone • Sinus-cavity within a bone • Spine-raised more than a crest • Sulcus-elongated depression • Trochanter- large bump for muscle attachment (largest of the bumps) • Tuberosity-oblong raised bump for muscle attachment

  13. Functions of Skeletal System • Protection • Movement • Mineral Storage • Blood Cell Formation • Support

  14. Skeletal System Axial Skeleton

  15. Axial Skeleton • Forms longitudinal axis of body • Face and Skull • Vertebral Column • Bony Thorax (chest)

  16. Skull • Cranium- 8 bones • Face- 14 bones

  17. Cranium • Composed of eight flat bones • Except for two paired bones (parietal and temporal) the rest are single bones • Frontal, 2 Parietal, 2 Temporal, Occipital, Sphenoid, Ethmoid

  18. Frontal • Forehead bone • Supraorbital margin • Supraorbital foramen • Glabella

  19. Parietal • Form top sides of cranial cavity

  20. Temporal • Form lower sides of cranium • Mastoid process • External auditory meatus • Styloid process

  21. Occipital • Posterior part of cranium • Foramen magnum

  22. Sphenoid • Butterfly shaped bone • Spans width of skull and forms floor of cranial cavity • Sellaturcica/Turk’s saddle- holds pituitary gland in place

  23. Ethmoid • Lies anterior to sphenoid • Forms roof of nasal cavity and medial walls of orbits • Cristagalli- process

  24. Fontanels • Skeleton is unfinished at birth • Fontanels are areas where hyaline cartilage hasn’t ossified in skull • Called soft spots • Anterior fontanel (largest) • Closes at 18 months • Posterior fontanel (2nd largest) • 2months • Mastoid fontanel • Begins to close 1 month after birth, not complete until 1yr • Sphenoid fontanel • Closes by 3 months

  25. Sutures • Interlocking, immovable joints that hold all but one of facial bones together • Saggital suture • Seperates parietal bones • Lamboidal suture • Occipital and parietal • Squamous • Seperates temporal and parietal • Coronal • Seperates parietal and frontal

  26. Bones of the face • Composed of 14 bones • All are paired but 2 • Nasal (2), Maxillary (2), Zygomatic (2), Mandible (1), Lacrimal (2), Palatine (2), Inferior nasal conchae (2), Vomer (1)

  27. Inferior Nasal Conchae • Bone that forms shelf along inner surface of sidewall of nasal cavity • Serves to filter air and bring it to body temp

  28. Palantine • L shaped • Forms posterior part of hard palate

  29. Nasal • Small bones that form bridge of nose

  30. Maxilla • Articulates with every bone of face except mandible • If palantine process and maxilla bones don’t unite before birth, a cleft palate will result

  31. Zygomatic • Cheek bone

  32. Mandible • Largest and strongest of facial bones • Only moveable bone in face • Mental foramen- site of anesthetics administered by dentist

  33. Lacrimal • Smallest bone of the face • Resembles shape and size of fingernail, helps form sidewall of nasal cavity

  34. Vomer • Triangular bone forms the inferior and posterior parts of the nasal septum

  35. Bones of the ear • Two sets of 3 bones (one set/ear) • Malleus (hammer) • Incus (anvil) • Stapes (stirrup)

  36. In Summary • Total # of bones of skull 28 • 8 Cranial bones • 14 Facial boens • 6 Ear bones • Bones that make up the orbit • Ethmoid • Lacrimal • Maxillary • Frontal • Sphenoid • Zygomatic • Palentine

  37. Hyoid • Single bone of neck • U shaped • Above larynx but below mandible • Does not form a joint with any other bone in body

  38. Vertebral Column • 24 vertebrae + sacrum + coccyx • 70cm (28 in) • Cervical vertebrae=7 • Thoracic vertebrae=12 • Lumbar vertebrae=5

  39. Typical Vertebrae • All are similar but have slight differences in size, shape and detail • Body • Vertebral Arch • Pedicles, laminae, vertebral foramen, intervertebral foramina • Processes • 7 arise from the vertebral arch • Transverse will extend laterally, spinous projects posterior, remaining four will join with other vertebrae (2 superior, 2 inferior)

  40. Cervical Vertebrae • C1-C7 • C1=Atlas • No body or spinous process • Supports head • C2=Axis • Allows head to rotate from side to side

  41. Thoracic Vertebrae • T1-T12 • Larger body • No transverse foramen

  42. Lumbar Vertebrae • L1-L5

  43. Coccyx Sacrum • 4-5 separate vertebrae in a child, fuse into one as an adult • Tail bone • Five separate vertebrae until age 25, when they fuse into a wedge shaped bone Sacrum and Coccyx

  44. Curvature of Vertebral Column • Increases carrying strength • Makes balance possible

  45. Sternum • Breast bone • Dagger shaped • 3 parts • Manubrium • Body • Xiphoid process

  46. Ribs • True Ribs • Upper 7 • Directly attached to sternum by costal cartilage • False Ribs • Do not attach to sternum • Upper 3 attach to last true rib • Bottom 2 do not attach to anything • Called floating ribs

  47. Skeletal System Appendicular Skeleton

  48. Appendicular Skeleton • Consists of upper and lower extremities

  49. Upper Extremities • Bones of shoulder girdle • Upper arm • Lower arm • Carpals • Metacarpals • Phalanges

  50. Bones of the shoulder girdle • Clavicle • Only articulation With skeleton is formed by sternoclavicular joint (clavicle and sternum) • Scapula • Doesn’t form a joint with axial skeleton • Acromion process • Glenoid cavity

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