What is Bone
A live piece of connective tissue.
A sturcture which is always changing
What are the Five main functions of the bone
Support
Storage
Blood Cell Production /Haematopoiesis
Protection
Leverage
Explain Support as a bone function
The skeletal system provides structural support for the whole body with individual bones or groups of bones providing a framework for attachment of soft tissues and organs
Explain Storage as a function of the bone
- Areas filled with Yellow marrow stores energy reserves as lipids.
- Bones store an abundance of minerals and ions (most notably calcium) which can be released on the body’s demands under the influence of hormones and help to maintain normal levels.
Explain Blood cell Production as a function of the bone
- Production of blood cells only takes place in Red Bone Marrow in adults
- Red Blood Cells = Erthrocytes
- White Blood Cells = Leucocytes
- Platelets = Thrombocytes
Explain protection as a function of the Bone
- Protects soft tissues and organs
- Cranium = Brain
- Spinal column/Vertebrae = Spinal Cord
- Thoracic Cavity/ Sternum and Ribs = Heart and Lungs
- Pelvic Cavity = Bladder, Rectum, Anus and reproductive organs
There are 7
Name the main parts of the Long Bone
*Diaphysis
* Epiphyses
* Metaphysis
* Articular Cartilge
* Periosteum
* Medullar Cavuty
* Endosteum
What is the Diaphysis
The Shaft main portion of the bone, Long and cylindrical in shape
What is the Epiphyses
Two ends of the bone Proximal and Distal ends
What is the Metaphysis
- Wide portion of the bone located between the Diaphysis and the Epiphyses.
- It is where Diaphysis (grow in length) growth occurs at the growth plate.
- Each Meatphysis contains a growth plate made from hyaline Cartilage. When bone growth finishes 18-21 the hyaline Cartilage within the growth plate forms the Epiphyses Line.
What is the Articular Cartilage
- Thin layer of Hyaline Cartilage which covers the epiphyses of the bone where it meets another bone to form a joint (articular Surface)
- Reduces friction and is shock absorbing at freely movable joint.
- Articular Cartilage does not contain Perichondrium (connective tissue which covers most cartilage and contains blood vessels and nerves) hence damaged articular cartilage struggles to heal.
What is the Periosteum
- Tough connective tissue membrane which covers the outside of the bone (except the Epiphyses where articular cartilage is)
- Outer layer is dense irregular connective tissue
- Inner layer is a layer of Osteogenic cells that can develop bone width but not length.
Key functions of the Periosteum
Key functions of the Periosteum:
* Protect and nourish bone tissue
* Act as attachment for ligaments
* Assist in bone repair
What is the Medullar Cavity
- Cylindrical cavity within the Diaphysis containing blood vessels and bone marrow.
- Helps reduce weight of the bone and maintains strength through its shape
What is the Endosteum
- Membrane lining the inner cavity of long bones.
- Responsible for healing of fractures by creating new bone cells.
How does compact bone differ from spongy bone
- Bone contains small cavities which allow blood vessels pathways to exchange nutrients and waste products as well as providing a storage area for red bone marrow.
- The size of the cavity and the number of cavities within the bone determines what category of bone falls into either Spongy or Compact
Detail what Compact Bone is
- Strongest type of bone tissue and is dense and contains few spaces
- Offers a high degree of support and protection
- Can be found beneath the Periosteum (connective tissue which covers outside of the bone except the Epiphyses) and accounts for the majority of the Diaphysis (shaft) of long bones
Detail What Spongey Bone/Cancellous Bone is (4)
- Consists of Columns of bone known as Trabeculae
- Between the columns lie spaces filled with red and Yellow bone marrow and blood vessels
- Spongey bone is always found inside the bone and is protected by a layer of compact bone
- Is light in weight and tends to be found in bone which is under less stress.
Explain Levarage as a function of the bone (2)
- Bones function as levers that change the magnitude and directionnof forces
- This results in delicate motions to more powerful ones that move the entire body
What are Erythrocytes also known as
Red Blood Cells
What are Leucocytes also known as
White Blood Cells
What are Platelets also known as
Thrombocytes
Detail the structure of compact bone (5)
- Consists of closley packed Osteons/Haversian systems
- Each Osteon (single canal system) is surrounded by circles of lamelle
- The Spaces/cavity between the lamelle are known as Lacunae and contain Osteocytes (mature bone cells)
- Small channels known as Canuliculi spread from the lacunae to the haversian canal and allow osteocytes to be in contact with nearby cells
- The Haversion systems contain blood vessels that run paralell tot he long axis of the bone and interconnect by way of perforating canals with the blood vessels at the surface of the bone
What is the function of the Haversion canal System/ Osteons (1)
They house blood vessels and nerve fibres allowing the bone to get oxeygen and nutrients without being highly vascular
