Skeletal System Flashcards
How many bones are there in the human body?
206
What are the 2 main groups of bones?
- Axial - forms the long axis of the body and includes bones of the skull, vertebral column and rib cage
- Appendicular - bones of the limbs and the pectoral and pelvic girdles
What are the 2 types of bone tissue?
- Compact bone - dense, smooth, homogenous
2. Spongy bone - needle-like pieces of bone called trabeculae and lots of open space
What is the function of trabeculae?
To allow the bone to resist stress
What are the 4 types of bone?
- Long bone
- Short bone
- Flat bone
- Irregular bone
Give 2 characteristics of long bones
- Longer than they are wide
- Very strong - good for support and movement
What are the 3 parts of a long bone?
- Epiphysis - wide area on each end filled with spongy bone that produces RBC
- Diaphysis - long cylindrical middle filled with compact bone that takes the brunt of the force that the bone supports
- Metaphysis - between epiphysis and diaphysis, transfers load and stress from joints and is important in bone growth
Give 2 examples of long bones
- Femur
2. Humerus
Give 3 characteristics of short bones
- Usually cube shaped
- Contain spongy bone with an outer layer of compact bone
- Provide support and stability
Give 2 examples of short bones
- Talus
2. Trapezium
Give 4 characteristics of flat bones
- Thin bone with a high SA
- Usually curved
- Protect organs and are an attachment site for muscle
- Made up of compact bone on the surface and spongy bone in the middle
Give 2 examples of flat bones
- Sternum
2. Parietal
Give 2 characteristics of irregular bones
- Contain spongy bone with an outer layer of compact bone
- Shape of the bone is specific to its function
Give 2 examples of irregular bones
- Vertebrae
2. Pubis
What is the function of ligaments?
To connect bones to each other
What is the function of tendons?
- To connect muscle to bone
- To provide durability and conserve space
What are the 3 types of bone cells?
- Osteoblasts
- Osteocytes
- Osteoclasts
What are the 3 main functions of osteoblasts?
- Form bones
- Create collagen fibres
- Create an extracellular matrix to absorb minerals from the blood and deposit them in the matrix
What is the function of osteocytes?
- Mature osteoblasts
- Exchange nutrients and waste products with the blood stream to keep bone tissue alive
What is the main functions of osteoclasts?
- Break down bone cells by breaking down the extracellular matrix and releasing the products into the bloodstream
- This maintains homeostasis and defines the shape of the bone
What are the individual units of bone called?
Osteons
Describe the structure of osteons
- Rings called lamellae (concentric layers)
- Spaces called lacunae (contain osteocytes)
- Central (Haversian) canal (contains blood vessels, lymph vessels and neurones)
- Aligned in the same way as the force applied to the bone
Describe the structure of the Haversian canal
- Each canal is connected by a Volkmann’s canal
- The central canal connects osteons to each other
What are the bones formed from?
- Long, short and irregular bones are formed from hyaline cartilage
- Flat bones are formed from fibrous tissue
What is the name of the process in which bones develop and grow?
Osteogenesis
When does Osteogenesis begin and when is it complete?
- Begins before birth
- Completed in 21st year of life
What is ossification?
The formation of bone using hyaline cartilage as a model
Describe the process of ossification
- Formation of the bone collar around a hyaline cartilage model
- Cavitation of hyaline cartilage (the cartilage matrix deteriorates)
- Invasion of internal cavities by the periosteal bud (blood vessel) and spongy bone formation occurs
- Formation of the medullary cavity, appearance of secondary ossification centres in the epiphyses
- Ossification of the epiphyses; when completed, the hyaline cartilage remains only in the epiphyseal plates and articular cartilages
Name 3 factors that affect bone growth
- Hormones
- Diet
- Exercise
How do hormones affect bone growth?
- Responsible for regulation of bone growth
- Deficiency/ excess results in abnormal bones (e.g. gigantism)