Bone StructureBone Structure

All bones are similar in their All bones are similar in their structure, the way they structure, the way they

develop, and the functions develop, and the functions they performthey perform

GeneralityGenerality

Human skeleton consists of 206 Human skeleton consists of 206 bonesbones

We are actually born with about 300 We are actually born with about 300 bones, but some fuse togetherbones, but some fuse together

These bones support your body and These bones support your body and allow you to moveallow you to move

Functions of BonesFunctions of Bones

Even though our bones provide body Even though our bones provide body shape, they also perform important shape, they also perform important body functionsbody functions

1.1.SupportSupport

2.2.ProtectionProtection

3.3.MovementMovement

4.4.StorageStorage

5.5.Blood cell formationBlood cell formation

1. Support1. Support

Form the internal frameworkForm the internal framework

Cradles soft organsCradles soft organs

Bones of legs act as pillars to Bones of legs act as pillars to support trunksupport trunk

Rib cage supports thoracic wallRib cage supports thoracic wall

2. Protection2. Protection Protect soft body organsProtect soft body organs

Example: Fused bones of skull Example: Fused bones of skull provide enclosure for brainprovide enclosure for brain

Example: Vertebrae surrounds Example: Vertebrae surrounds spinal cordspinal cord

What is another example?What is another example?

3. Movement3. Movement

Skeletal muscles attach to bones by Skeletal muscles attach to bones by tendonstendons

Bones are used as levers to move Bones are used as levers to move the bodythe body

As a result we can walk, swim, As a result we can walk, swim, throw, and breathethrow, and breathe

4. Storage4. Storage

Bones store many important minerals Bones store many important minerals including calcium and phosphorus including calcium and phosphorus

Most of body’s calcium is deposited in Most of body’s calcium is deposited in bone as calcium saltsbone as calcium salts

- “Deposits” and “withdrawls” of calcium - “Deposits” and “withdrawls” of calcium go on all the timego on all the time

Bones store fat within the internal Bones store fat within the internal cavitiescavities

5. Blood Cell Formation5. Blood Cell Formation

Blood cell formation occurs within Blood cell formation occurs within the marrow cavities of certain bonesthe marrow cavities of certain bones

HematopoiesesHematopoieses

Makes red and white blood cellsMakes red and white blood cells

Skeletal structureSkeletal structure Bone is composed Bone is composed

of a variety of of a variety of tissuestissues

Bone tissue, Bone tissue, cartilage, fibrous cartilage, fibrous connective tissue, connective tissue, blood, nerve tissueblood, nerve tissue

Bone contains very Bone contains very active, living tissuesactive, living tissues

Parts of a Long BoneParts of a Long Bone

Epiphysis- at each end Epiphysis- at each end of the bone, forms a of the bone, forms a joint with another bonejoint with another bone

Articular cartilage- Articular cartilage- hyaline cartilage on hyaline cartilage on the outer surface of the outer surface of the epiphysisthe epiphysis

Diaphysis- shaft of the Diaphysis- shaft of the bonebone

Parts of a Long BoneParts of a Long Bone Periosteum- tough, Periosteum- tough,

vascular covering of vascular covering of fibrous tissue fibrous tissue

Fibers are Fibers are continuous with continuous with ligaments and ligaments and tendonstendons

Formation and Formation and repair of bone tissuerepair of bone tissue

Parts of a Long BoneParts of a Long Bone

Compact bone- Compact bone- tightly packed tightly packed tissue forming the tissue forming the wall of the wall of the diaphysisdiaphysis

Solid, strong, Solid, strong, resistant to resistant to bendingbending

Parts of a Long BoneParts of a Long Bone Spongy bone- Spongy bone-

epiphyses composed epiphyses composed mainly of spongy bonemainly of spongy bone

Consists of many Consists of many branching bony platesbranching bony plates

Irregular spaces occur Irregular spaces occur between these plates, between these plates, help reduce weighthelp reduce weight

Provides bone Provides bone strength, highly strength, highly developed where it is developed where it is subject to forces of subject to forces of compressioncompression

Medullary cavityMedullary cavity Hollow chamber Hollow chamber

within diaphysis that within diaphysis that connects to spaces connects to spaces of spongy boneof spongy bone

Filled with Filled with specialized soft specialized soft connective tissue, connective tissue, marrowmarrow

Red marrow- Red marrow- produces red blood produces red blood cellscells

Yellow marrow- fat Yellow marrow- fat storagestorage

Bone MarrowBone Marrow

2 kinds2 kinds1. Red marrow- formation of red blood 1. Red marrow- formation of red blood cells, white blood cells, plateletscells, white blood cells, platelets

- hemoglobin within red blood cells- hemoglobin within red blood cells

2. Yellow marrow- replaces red marrow 2. Yellow marrow- replaces red marrow with increasing agewith increasing age

- fat storage tissue, inactive in blood - fat storage tissue, inactive in blood cell cell productionproduction