3. Definition of BONE...
“Bone is the substance that forms the skeleton of the body. It is
composed chiefly of calcium phosphate and calcium carbonate”
FUNCTIONS OF BONE…
The human skeleton serves six major functions
Support
Movement
Protection
Production of blood cells
Storage of iron
Endocrine regulation
4. (1) What are the Bone Regions?
Axial
Down the center of body
Skull, vertebral column, rib cage, center pelvis
Appendicular
Off the sides of body
Upper and lower limbs, shoulder and hip bones
5.
6. Axial Skeleton (Head + Neck +Trunk)
SKULL 22 Bones
Ear Ossicle (3+3) 6 Bones
Hyoid 1 Bone
Vertebral coloumn 33 Bones
Ribs (12+12) 24 Bones
Sternum 1 bones
Total = 80 Bones
Appendicular Skeleton (upper lim+lower limb)
Upper limb (Right 32+ Left 32) 64 Bones
Lower limb (Right 31+ Left 31) 62 Bones
Total = 126 Bones
GRAND TOTAL 80+126=206 BONES
7. Developmental Classification
MEMBraNE BONES…
Bone formed directly in connective tissue, i.e. by intramembranous
ossification, rather than by replacing cartilage (compare cartilage bone). Small
areas of membrane become jelly-like and attract calcium salts
Examples = Some face bones, skull bones, and part of the clavicle
are membrane bones.
Cartilagenous bobes…
Intracartilaginous ossification • In intra cartilaginous ossification →
cartilaginous model is formed which is closely resemble the bone to be formed.
•This cartilage is subsequently replaced by (not converted into) bone. eg.
Almost all of the long bones.
Membranocartilagenous BONES…
These bones develop partly in membranes and partly in cartilage.
Example=Occipital,Temporal,sphenoid bones of the skull, mandible, clavicle
8. (2) What are the types of Bones?
Long
Short
Flat
Irregular
9.
10. (3) Long Bones
Longer than they are wide
Has a shaft and 2 ends
Weight bearing bones (like steel beams)
Provide the greatest structure and support
Examples:
All limb bones
Except…. Kneecap,Wrist andAnkle bones
11.
12. (4) Short Bones
Nearly same length,width,thickness but shape irregularly
Allow for wider range of movement
Examples:
Wrist (carpals)
Ankle (tarsals)
16. (6) Irregular Bones
Complicated, unusual shapes
Muscles, tendons, ligaments usually attach to these
Examples:
Vertebrae
Hip bones
17.
18. (8) Bone Structure
Unique based on location + bone type.
Compact Bone (Outer Layer):
Dense
Smooth and Solid to naked eye
Spongy Bone (Inner Layer):
Hole-y (like a honeycomb)
Made of small needle-like, flat pieces called “trabeculae”
Open spaces between trabeculae are filled with red or yellow bone marrow
19.
20. (9) Structure of a Long Bone
Diaphysis:
Center, main shaft
Long part of bone
Made of very thick compact bone surrounding a central marrow cavity
Epiphysis:
Ends of bone
Wider than diaphysis
Made of compact bone which surrounds spongy bone.
Joint surface of each epiphysis is covered with hyaline cartilage
21. Epiphyseal Line:
Remnant of Epiphyseal Plate
Found in adult bones
Shows amount of cartilage growth during adolescence
Membranes:
Periosteum =Around the outside
Richly supplied with nerve fibers, lymphatic vessels and blood vessels
Provides anchoring points for tendons and ligaments
Endosteum =Around the inside
Surrounds the spongy bone
22.
23. (12) Chemical Composition of Bone
Contains organic & inorganic components
Organic:
Cells (osteoblasts, osteocytes, osteoclasts)
Osteoid
Made of glycoproteins and collagen fibers
Secreted by osteoblasts
“filler matrix” around cells
Contribute to flexibility and tensile strength
Inorganic:
Mineral Salts (calcium phosphates)
Contribute to hardness of bone (allowing for compression resistance)