1. Human Anatomy
Skeletal System
Page 121 in book

2. Functions Support: body structure and shape
Protection for vital organs (brain, heart, etc.)
Movement for attached skeletal muscles
Tendons: attach muscle to bone
Ligaments: attach bone to bone
Mineral storage: calcium and phosphorus
Blood cell formation - hematopoiesis
Muscles contract and extend to move bones
If blood levels of Calcium get high goes into bone and visa versa
Blood cell –hema means blood ppy-ee sis means to make in the red bone marrow

3. Types of Bone

4. Compact Bone Very dense, stress bearing Haversian systems –basic unit
of compact bone
Lamellae: concentric cylinder
shaped calcified structure
Lacunae: small spaces containing tissue fluid
Osteocytes: facilitate exchange of calcium between blood and bone
Canaliculi: canals connecting the lacunae together and to the haversian canal which carries nutrients and wastes to and from the osteocytes
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5. Cancellous Bone Light, spongy
Found at ends of long bones, ribs, sternum, hips, vertebrae, cranium
No haversian systems
Web-like arrangement
Highly vascular

6. Classification of Bones

7. Long bones Found in the extremities Act as levers Includes:
Epiphysis
End of long bones
Covered with hyaline cartilage for articulation
Filled with cancellous bone
Diaphysis
Shaft
Covered with periosteum
Medullary canal
Compact bone
Examples: femur, tibia, fibula, humerus,
radius, clavicle, metacarpals, phalanges
Epiphysis –red bone marrow fills in the spongy bone
Diaphysis – hollow tube made of hard compact bone – rigid , but light weight shaft covered with periosteum – a strong fibrous covering the long bone except at joints which then is covered by articular cartilage
Medullary cavity – holoow area inside the diaphysis of the bone contains the soft yellow bonemarrow (inactive fatty substance in adults

8. Short Bones Cube shaped Allows flexible movement
Cancellous bone covered by compact bone
Examples:
Carpals
Tarsals

9. Flat Bones
Protect vital organs and provide broad surface area for muscle attachment
Examples:
Cranial bones
Scapula
Sternum
Ribs

10. Irregular Bones
Peculiarly shaped to provide support and protection, yet allow flexibility
Examples:
Vertebrae
Ear
Hyoid
Mandible

11. Sesamoid Bones Extra bones found in certain tendons Example: Patella
Round

12. Composition Collagen: chief organic constituent (protein)
Inorganic calcium salts (Vitamin D essential for absorption of minerals i.e. calcium)
Deposition favored by
a. Estrogen, testosterone
b. Alkaline phosphatase
c. Thyrocalcitonin
d. Mechanical stress i.e. traction
Withdrawal favored by
a. Alkaline phosphatase
b. Parathormone
c. Inactivity
If you use bones they get strong – lack use makes them weak - Astronauts in space

13. Composition
Cells
Osteoblasts: bone building, bone repairing cells in the periosteum
Osteocytes: mature bone cells within the bone matrix
Osteoclast: causes reabsorption of bone
Periosteum
1. Dense, fibrous membrane covering bone
2. Contains blood vessels
3. Essential for bone cell survival and bone formation

14. Cells that Aid in Bone Formation
Osteoblast
Builds new bone
Mature bone cell
Osteocyte
OsteoblastsOsteoblasts are responsible for building new bone and lie at the centre of bone physiology. Their functions include the synthesis of collagen and the control of mineralisation.
OsteoclastsOsteoclasts are specialised cells that resorb bone. They work by sealing off an area of bone surface then, when activated, they pump out hydrogen ions to produce a very acid environment, which dissolves the hydroxyapatite.
OsteocytesBone adapts to applied forces by growing stronger in order to withstand them; it is known that exercise can help to improve bone strength. Osteocytes are thought to be part of the cellular feed-back mechanism which directs bone to form in the places where it is most needed. They lie within mineralised bone and it is thought that they may detect mechanical deformation and mediate the response of the osteoblasts.
Osteoclast
Eats bone 14

15. Bone Formation Initially collagen fibers secreted by fibroblasts
Cartilage deposited between fibers
Skeleton fully formed by 2nd month of fetal development (all cartilage)
After 8th week of fetal development ossification (mineral matter deposited and replaces cartilage) begins
Childhood and adolescence:
ossification exceeds bone loss
Early adulthood thru middle age:
ossification equals bone loss
After age 35:
bone loss exceed ossification

16. 275 bones 12 weeks (6-9 inches long)
Fetal Skeleton
275 bones 12 weeks (6-9 inches long)
How many bones do we have?
206 total
80 bones in the axial and 126 in the appendicular 16

17. Anatomy of Long Bone Diaphysis Epiphysis Periosteum Endosteum Arteries
Shaft
Composed of compact bone
Epiphysis
Ends of bone composed mostly
of spongy bone
Periosteum
outside covering of diaphysis
Endosteum
Lines medullary cavity
Arteries
Articular cartilage
Medullary cavity
Cavity inside the shaft
Contains yellow marrow (mostly fat) in adults
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18. Bone Marrow Red bone marrow Yellow bone marrow
Found in vertebrae, ribs, sternum, cranium, ends of humerus and femur
Produces:
Erythrocytes – red blood cells
Plateletes - thrombocytes – clotting cells
Some leukocytes – white blood cells
Yellow bone marrow
Found in medullary cavity of long bones
Fat storage

19. Bone Marrow Yellow marrow Medullary cavity of long bones Fat storage
Red marrow
Hematopoietic tissue
In all cancellous bone in children
In adults: cancellous bone of vertebrae, hips, sternum, ribs, cranial bones, proximal ends of femur and humerus
Forms RBCs, platelets, some WBCs, and destroys old RBCs and some foreign materials

20. Divisions of the Skeletal System

21. Axial Skeleton Forms the longitudinal axis of the body
Divided into three parts: then subdivided
Skull
Cranium
Ear bones
Face
Vertebral Column
Thorax
Ribs
Sternum
Hyoid bone

22. Ribs: Fixed, False and Floating

23. Appendicular Skeleton
Composed of 126 bones
Includes bones of the:
Limbs (appendages)
Pectoral (shoulder) girdle
Pelvic (hip) girdle

24. Man VS Woman Difference:
Men bigger and pelvic inlet shaped like a funnel
Woman smaller and pelvic inlet shaped like a basin to cradle the baby and the outlet is much wider
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25. Joints

26. Classification Synarthrotic: immovable - cranium
Amphiarthrotic: limited movement i.e. pubic symphysis, vertebral joints, sacroiliac joint
Diarthrotic: freely movable
Gliding: bones of the wrist
Pivot: between radius and ulna
Ball and socket: hip
Hinge: elbow

27. Immovable Joints Synarthrosis

28. Slightly Movable Joint Ampharthrosis28

29. Freely Movable Diarthrosis

30. Synovial Joint Movement
Extension
Rotation
Flexion
Adduction
Abduction 30

31. Diseases / Disorders Arthritis Bunions Bursitis Dislocation Simple
Compound
Greenstick
Comminunted