MUSCULOSKELETAL SYSTEM Flashcards
(25 cards)
Function
- Work together to support and move the body.
- The muscles contract to cause movement
- Bones produce blood cells
- Bones store ( and release) minerals and fats
Bone
- A bone is a form of connective tissue ( more extracellular matrix than cells).
- Matrix consists of large quantities of ca+, K+, Na +, in solid state
- If bones were solid, the skeleton would be too heavy, and we would be unable to move.
- There are 2 types of bones,
: Compact bone
: Spongy bone
Human skeleton
Consists of 206 bones
made from the axial and appendicular skeleton
Axial skeleton
- Head and trunk
- largely responsible for protecting vital organs - brain, lungs, heart, liver, spinal cord and kidneys
- essential for posture
- include the cranium bones, ribcage, sternum
Appendicular skeleton
- Forms the limbs.
- Largely responsible for position and movement.
- Includes: Pectoral and pelvic griddles
Griddles
How limbs are attached to your body.
Type of bones
- long bones
- short bones
- flat bones
- irregular bones
- sesamoid bones
Flat bones
- Bones that have 2 flat surfaces that are made of cortical bones with spongy bones ( Even thickness between them)
- Act as a shield in protecting internal organs
- Example - Sternum, ribs, cranial bones
Long bones
- Bones that have a shaft (diaphysis) like pipe made of cortical bone with a space in the middle, and ends (epiphyses) of trabecular bones
- Provide strength and length
- Examples - Humerus, Fermer, tibia
Long Bone STRUCTURE
- Diaphysis
- Epiphyses
- Periosteum
Articular cartilage
A smooth, white tissue, that covers the end of the bones where they join to form joints
Diaphysis
-Tube of compact one with marrow filled cavity (fat storage)
Epiphyses
Expanded ends of bones, thin outer cortical bone and inner trabecular bone. ( In L bones, marrow spaces contain red marrow)
Periosteum
A dense, fibrous covering of the bone that extends up to the articular cartilage tissue
Short bones
- Made from trabecular bones.
- Often fit together, limits movement, but provides some flexibility and ‘shock absorption’ with stability.
Examples - Carsals and Tarsals
Irregular bones
Found in vertebrates and consists of a combination of cortical and trabecular bone.
Examples - Found in the vertebral column
- Many facial bones
Sesamoid bones
Come in variety of shapes and sizes.
They form in tendons (tissue attach muscle to bones)
Example - Patella
Bone Developement
- Epiphyseal plates are sites of growth in developing bones.
- larger bones then to be more advanced than smaller bones.
Cells in Bones
3 Types of cells:
1. Osteoblasts
2. Osteoclasts
3. Osteocytes
Extracellular matrix consists of both organic (40%) and inorganic (60%)
Organic consists of a protein called collagen
Inorganic material is mostly solid material, hydroxyapatite
Osteoblasts
Secretes from the organic matrix, which binds material that forms a base
Form new bones and grow and heal existing bones
Osteoclasts
Large cells that reabsorb bone matrix, necessary for repair of damaged bones and remodelling of growth bones.
Osteocytes
Osteoblasts that got trapped in their own matrix layer.
They maintain bone health by sensing changes and regulating minerals.
Compact bones
Dense and strong tissues that form the outer layer of bone structure. They provide strength and support, allowing bones to withstand stress
Compact bones STRUCTURE
Organised into a unit called osteons containing:
The Haversian canal: located centrally of the osteon, containing blood vessels, nerves and lymphs.
Lamellae - concentric rigs of matrix
Between the Lamellae - Trapped osteocytes live in the lacunae. They are able to pass nutrients and signals to nearby cells through canalicile
Osteons rull parallel to the long axis of the bone.
Their strength is maximal in this direction
There are usually some circumferential lamellae lying between the osteons and the periosteum
There is also small amount of trabecular bone between the marrow cavity and the cortical bone.
