Presentation on theme: "Donya Razinoubakht 6 th block. Your Skeletal system is all of the bones in the body and the tissues such as tendons, ligaments and cartilage that connect."— Presentation transcript:
Donya Razinoubakht 6 th block
Your Skeletal system is all of the bones in the body and the tissues such as tendons, ligaments and cartilage that connect them. The teeth are also considered part of your skeletal system but they are not counted as bones.
Support: The main job of the skeleton is to provide support for the body. Without your skeleton your body would collapse into a heap. Protection: The skeletal system works closely with all the systems in the body to protect them. The brain, eyes, lungs, and spinal cord are all protected by the skeletal system. For example, the cranium protects the brain and eyes and the vertebrae protect the spinal cord.
Movement The bones of the skeletal system act as attachment points for the skeletal muscles of the body. Almost every skeletal muscle works by pulling two or more bones either closer together or further apart. Joints act as pivot points for the movement of the bones. To help the body move freely, the skeletal system works very closely with the muscular system. Without the skeletal system, the human body would not be able to support itself, but without muscles, the skeletal system wouldn't be able to move.
Storage: Bones have their own nerves and blood vessels. The skeletal system’s cell matrix acts as our calcium bank by storing and releasing calcium ions into the blood as needed. Proper levels of calcium ions in the blood are essential to the proper function of the nervous and muscular systems, and bones help regulate blood calcium levels to maintain homeostasis. The yellow bone marrow inside of our hollow long bones is used to store energy in the form of lipids. Hematopoiesis: Red bone marrow produces red and white blood cells in a process known as hematopoiesis. Red bone marrow is found in the hollow space inside of bones known as the medullary cavity. The calcified bones of the skeleton work closely with the circulatory system and immune system. Red and white blood cells are necessary for the body to function properly, and these cells couldn't be circulated through the body unless the bones of the skeletal system first created marrow
Endocrine Regulation Bone cells release osteocalcin, a hormone that helps regulate blood sugar and fat deposition
The skeleton begins to form early in fetal development as a flexible skeleton made of hyaline cartilage and dense irregular fibrous connective tissue. These tissues act as a soft, growing framework and placeholder for the bony skeleton that will replace them. At birth, the skeleton of a newborn has more than 300 bones; as a person ages, these bones grow together and fuse into larger bones, leaving adults with only 206 bones.
A typical bone has an outer layer of hard or compact bone, which is very strong and dense. Inside this is a layer of spongy bone, which is lighter and slightly flexible. In the middle of some bones is jelly-like bone marrow, where new cells are constantly being produced for the blood.
Cartilage is a connective tissue that supports the structure of many body parts and functions like the bones, ribs, ears and nose. A tendon is a is a tough band of fibrous connective tissue that connects muscle to bones. Tendons withstand pressure and tension; they work with muscles to enable rigorous movement. Ligaments are fibrous tissues that provide stability to joints throughout the body during rest and active movement An articulation, or joint, is a point of contact between bones, between a bone and cartilage, or between a bone and a tooth. Types of joints are: synovial joints, fibrous joints, and cartilaginous joints The teeth help with digesting.
All of the bones of the body can be broken down into five types: Long Short Flat Irregular Sesamoid.
The oldest human skeleton ever found is the Ardipithecus ramidus or “Ardi” fossils discovered in Ethiopia. Ardi lived 4.4 million ears ago. The biggest surprise about Ardipithecus's biology is its bizarre means of moving about. Hominids after Ardi all walked upright as we do, but Ardi’s feet, pelvis, legs and hands suggest she was a biped on the ground but a quadruped when moving about the trees. All previously known hominids—members of our ancestral lineage—walked upright on two legs, like us. But Ardi's feet, pelvis, legs, and hands suggest she was a biped on the ground but a quadruped when moving about in the trees. Later hominids could more efficiently walk on two legs due to losing some bones that Ardi had.
Bipedal adaptation There are few features to do with the spine which allow the human skeleton to be bipedal. The modern human spine has dual curvature, which allows us to stand erect. This also means that we can conserve energy as it will require less to remain upright due to the fact that the spine naturally curves that way anyway. Also, the foramen magnum is positioned in the centre of the basicranium (the bottom of the skull). This is a change from the foramen magnum being further back as it is in normal quadrupeds. It helps keep the head right and in optimum visual poison. The structure of the human foot is also significantly different in comparison to other modern mammals. Humans have evolved platform feet with enlarged big toes and large arches which act as propulsive levers and allow us to spring forward when walking. Again, this conserves more energy than if we had ape- like flat feet like the other great apes. Other adaptations of the human skeleton to accommodate bipedalism include a shorter, broader, pelvis, longer legs, and lock knees.