skeletal system Flashcards
(8 cards)
what is skeletal system
The skeletal system consists of bones, joints, and ligaments. These parts are located inside the body and serve several important functions. One of their main roles is to protect our internal organs—for example, the skull protects the brain, and the rib cage protects the heart and lungs.
In addition to protection, the skeletal system also supports movement. Bones are connected by joints, and they work together with muscles to allow us to move. Skeletal muscles are attached to bones, and when these muscles contract, they pull on the bones to produce movement.
Another important function of the skeletal system is the production and storage of red blood cells. This happens in the bone marrow, which is found inside certain bones.
they also store minerals
why bones arent just dried bodies
Although the word skeleton comes from the Greek word meaning “dried-up body,” our internal framework is beautifully formed and proportioned. Strong yet light, it is perfectly adapted for its functions of protecting the body and allowing motion. No other animal has such long legs (compared to the arms or forelimbs) or such a strange foot, and few have grasping hands with opposable thumbs.
longitudual vs appendicular
The bones of the skeleton are part of the skeletal system, which also includes joints, cartilages, and ligaments (fibrous cords that bind the bones together at joints). The skeleton is divided into two parts: the axial skeleton, the bones that form the longitudinal axis of the body, and the appendicular skeleton, the bones of the limbs and girdles that attach them to the axial skeleton. Joints give these parts of the skeleton flexibility and allow movement to occur.
support
Bones, the “steel frame” of the body, form the internal framework that supports the body and cradles its soft organs. The bones of the legs act as pillars to support the body trunk when we stand, and the rib cage reinforces the thoracic wall.
protection
Bones protect soft body organs. For example, the fused bones of the skull provide a snug enclosure for the brain, allowing someone to juggle a soccer ball with their head without worrying about injuring the brain. The vertebrae surround the spinal cord, and the rib cage helps protect the vital organs in the thorax.
Allow movement.
Allow movement. Skeletal muscles, attached to bones by tendons, use the bones as levers to move the body and its parts. As a result, we can breathe, walk, swim, and throw a ball. Before continuing, take a moment to imagine that your bones have turned to putty. What if you were running when this change took place? Now imagine your bones forming a rigid metal framework inside your body (without joints). What problems could you envision with this arrangement? These images should help you understand how well our skeletal system provides support and protection while allowing movement.
storage
Storage. Fat is stored in the internal (marrow) cavities of bones. Bone itself serves as a storehouse for minerals, the most important of which are calcium and phosphorus. Most of the body’s calcium is deposited in the bones as calcium salts, but a small amount of calcium in its ionic form must be present in the blood at all times for the nervous system to transmit messages, for muscles to contract, and for blood to clot. Problems occur not only when there is too little calcium in the blood, but also when there is too much. Hormones control the movement of calcium to and from the bones and blood according to the needs of the body. Indeed, “deposits” and “withdrawals” of calcium (and other minerals) to and from bones go on almost all the time
Blood cell formation.
Blood cell formation. Blood cell formation, or hematopoiesis (hem”ah-to-poi-e’sis), occurs within the marrow cavities of certain bones.
