bones structure and function. skeletal system organization system = skeletal organs = bones each...
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BonesStructure and Function
Skeletal System Organization System = Skeletal
Organs = Bones Each bone is an
individual organ Work together as joints
(considered later)
Tissues = Connective Compact Bone Spongy (cancellous)
Bone Hyaline Cartilage
Skeletal System – Macroscopic Anatomy
Axial Skeleton Head Vertebrae Ribs Pelvic Girdle
Appendicular Skeleton Arms Legs
Bone Types
We will use long bones as our example.
Long Bone – Macroscopic AnatomyEpiphysis (end)
• covered with hyaline cartilage
• compact bone forms exterior
• spongy bone forms interior
• contains epiphyseal line/plate
Diaphysis (middle)• compact bone forms exterior
• center composed of the medullary cavity containing yellow or red marrow
Fig 7.1
Long Bone – Macroscopic Anatomy
Fig 7.2
Long Bone – Microscopic Anatomy Osteon =
circular structure organized around blood vessels
Osteocyte = bone cells
Bone matrix = hard calcium-based material between cells
Fig 7.3
Bone – Tissue Types Bones and joints are composed primarily of
connective tissue Connective tissue is organized by type of
extracellular matrix
Connective Tissue
Specialized
Connective Tissue
Bone
Spongy Bone
Compact bone
Blood Cartilage
Hyaline Elastic Fibro
Connective Tissue Proper
Loose
Reticular Adipose Areolar
Dense
Tissue Types – Compact BoneFunctions
Hard and provides stability, framework, protection
Structure Matrix has hard mineral structure, based on calcium
Cells and matrix are arranged in regular, concentric pattern
Compact Bone
Tissue Types – Spongy BoneFunctions
Lightens total bone weight and provides space for bone marrow
Structure Matrix is softer mineral, less organized and less of it
Empty spaces between matrix structure are filled with bone marrow
Spongy (cancellous) Bone
Tissue Types – Hyaline CartilageFunctions
Provides soft and smooth covering to end of bone (articular surface)
Helps provide smooth and easy movement between bones (at joints)
Provides the starting material for new bone growth
Structure Matrix is spongy (like jello)
and evenly distributed between the cells
Cells (chrondocytes) are found in pairs within capsules called lacunae Hyaline Cartilage
Bone PhysiologyLiving bones perform the following processes:
Formation Starts as an embryo, continues through fetal
development and after birth
Growth Occurs from before birth through maturity
Remodel Old matrix is removed and replaced with new matrix
Repair Damaged bones will heal and return to normal
structure
Bone Physiology – Formation Fetal bones are made of hyaline cartilage As cartilage cells die, they are replaced with spongy bone in
diaphysis After birth, spongy bone invades diaphysis Compact bone replaces spongy bone in diaphysis Hyaline cartilage remains on epiphyseal surface and in growth plate
Fig 7.5
Bone Physiology – Growth Bones grow in length at the
epiphyseal plate – hyaline cartilage in the epiphysis
Cartilage cells divide causing the epiphyseal plate (and bone) to grow
Cartilage cells die and are replaced by spongy bone
As adolescence ends, the growth plate decreases in size and eventually is replaced by bone
bone growth video
Bone Physiology – Growth
Epiphyseal (Growth) Plate
Bone Physiology – Growth
Bone Anatomy and Physiology Lab – 2A
Cow = more compact bone; less hyaline cartilage; no active growth plate (bone not cartilage); yellow marrow
Calf = less compact bone; more hyaline cartilage; active growth plate (cartilage, not bone); red marrow
Bone Anatomy and Physiology Lab – 2A
Bone Physiology - Repair Hemotoma, a mass of
clotted blood, forms at the fracture site.
A fibrous callus forms, and cartilage matrix is secreted.
Spongy bone forms to replace cartilage.
Bone remodeling occurs to remove excess material and replace compact bone.
Bone Physiology - Remodeling Bone matrix is inorganic and
breaks down over time
Specific bone cells (osteoclasts) remove old, broken matrix
Other bone cells (osteoblasts) re-make/deposit new matrix
The entire skeleton is re-modeled every 7-10 years
Remodeling slows with age, elderly people have thinner bones and are more susceptible to broken bones as a result