Muskulo-Skeletal System Flashcards
What does the musculoskeletal system do?
provides protection for the organs
essential in the survival response
stores important salts like calcium and phosphorus
involved in the production of red cells (haematopoisis)
keeps important organs such as the heart, blood vessels or the digestive system working: most key organs of the body are formed by muscles
What is the cortical bone?
It is the hard outer layer of the bone. This is also called the compact bone. It accounts for 80% of the total bone mass in the human skeleton. Each column bone is formed by multiple osteons.
What is an osteon?
This is the primary anatomical and functional unit of the cortical bone. Each column is formed by multiple layers of osteocytes that form a honeycomb like matrix that helps to give the bone rigidity. In the middle of each osteon the harversian canal contains blood vessels that feed the bone and allows for the exchange of calcium and phosphates for bone remodelation.
What is the trabecular bone?
Also known as cancellous or spongy bone. This is the internal part of the bone, formed by a porous network, which makes it more flexible than the cortical bone. It is typically found at the end of long bones, near joints and in the interior of vertebrae. It is highly vascular and contains bone marrow.
What is bone marrow?
It is a semisolid tissue composed by stem blood cells, that is in charge of new blood production (haematopoiesis)
What is an osteocyte?
These are mature bone cells that have become trapped in the bone remodelation process. their function is to monitor and maintain bone tissue.
What is periosteum?
It is the most outer layer of the bone, covering the surface of the bone and with the ability to transform into osteoblast to create more bone.
What is bone?
Bone is a dynamic, living tissue, constantly being remodelled and renewed. Just like skin, it is being replaced throughout life through the action of cells.
What are the 2 types of cells that help to renew and remodel bones?
Osteoblast and osteoclast
Describe an osteoblast.
These cells are the immature bone cells that, as the bone develops, become trapped within the newly formed bone, transforming into osteocytes (mature bone cells)
Describe an osteoclast
These cells break down the bone, releasing calcium and phosphate into the blood stream
What 2 hormones mediate the process remodelling bone?
Calcitonin
Parathyroid
What does calcitonin do?
It facilitates the absorption of calcium from the blood to osteoblast to form new bone
What does the parathyroid hormone do?
It facilitates the release of calcium from the bone back to the blood stream with the action of the osteoclasts
What is ossification?
The formation of bone