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Flashcards in Muskulo Skeletal System Deck (55)
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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?



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


At the fetal stage what are bones formed of?



How is the cartilage transformed into bone?

Through the action of osteoblasts. This process will take approx 25 years


What are the 2 types of bones?



what is an axial bone?

The bones forming the main, central axis of the body, while appendicular are the bones in the extremities


What is a sesamoid bone?

These are bones that are not in contact with any other bone, but instead they are embedded in a tendon or muscle to protect tendons from stress and wear: there are often in the hands and feel, or the kneecap


What is the structure of a long bone?

Contains both epiphysis and diaphysis


what is the epiphysis?

the rounded end of the bone, usually forming a joint with another bone. This part is mainly formed by trabecular or spongy bone. The head is in contact with the joint is covered by articular cartilage.


what is the diaphysis?

this is the shaft of the bone. Formed mainly be compact bone, with the medulla cavity that contains bone marrow


what is the transition from the epiphysis and diaphysis called?

the part of the bone that grows during childhood, as it formed mainly by cartilage tissue. Once bones have reached the adult size this part will ossify


What do muscles do?

provide strength, balance, posture, movement and heat for the body to keep warm


what are the 3 types of muscles?

Skeletal muscles, smooth muscles and cardiac muscles


Describe skeletal muscles.

these are muscles attached to the bones by ligaments. they are also known as voluntary muscles: when they contract they are responsible for movement. the cells of this type of muscles are long, single cylindrical and with multiple nuclei like strips


Describe smooth muscles.

These type of muscle tissue form the internal hollow organs, such as the digestive system, the lungs, the uterus or blood vessels. these are also known as involuntary muscles: they are controlled by the nervous system, but you cannot choose to control or relax this tissue. the smooth muscle cells are small, have one single nucleus and are spindle shaped


Describe cardiac muscle.

This is the only type of muscle that can contract without external nerve stimulus, just by the action of the cardiac pacemaker. This is a highly coordinated tissue


How are skeletal muscles formed?

By bundles of muscular cells called fibres. These are rope like structures, all contained inside a bag called fascia, that terminates in a cord like structure called tendon. Tendons attach muscles to bones.