Bio Ch.36 - CHAPTER 36 SKELETAL MUSCULAR AND INTEGUMENTARY...

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CHAPTER 36 – SKELETAL, MUSCULAR, AND INTEGUMENTARY SYSTEMS
36-1 The Skeletal System
The SkeletonThe skeleton supports the body, protects internal organs, provides for movement, stores internal reserves, and provides a site for blood cell formation.The human body would collapse without its skeleton.
Bones protect the internal organs of the body.Bones provide a system of levers on which muscles act to produce movementBones contain reserves of minerals, mainly calcium salts, that are important to many body processes.Bones are the site of blood cell formation. Blood cells are produced in the soft marrow tissue that fills the internal cavities in some bones.
There are 206 bones in the adult human skeleton. Bones can be divided into two parts – axial skeleton and the appendicular skeleton.Axial skeleton – supports the central axis of the body. It is made up of the skull, the vertebral column, and the rib cage.Appendicular skeleton – made up of the bones of the arms and legs, pelvis and shoulder area
Structure of BonesBones are a solid network of living cells and protein fibers that are surrounded by deposits of calcium salts.Periosteum– a tough layer of connective tissue that surrounds the bone. Blood vessels that pass through the periosteum carry oxygen and nutrients to the boneHaversian canals– a network of tubes that run through bone that contain blood vessels.Spongy bone is a less dense tissue that is found inside the outer layer of compact bone. It is not actually soft and spongy. It is very strong.
Bone marrow– soft tissue in the cavities of bones. There is yellow and red bone marrow. Yellow marrow is made up of mostly fat cells. Red marrow produces red blood cells, some white blood cells, and cell fragments called platelets.Development of BonesThe skeleton of an embryo is made up almost entirely of cartilage, which is connective tissue.Cartilage doesn’t contain blood vessels.Cartilage is found in flexible parts of the body, like the tip of the nose and the external ears.Ossification– the process of bone formation (when cartilage is replaced by bone)Ossification takes place up to seven months before birth.
Types of JointsJoint– a place where one bone attaches to another boneJoints permit bones to move without damaging each otherDepending on its type of movement, a joint is classified as immovable, slightly movable, or freely moveable.
Immovable joints

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