{"id":575,"date":"2021-01-18T03:05:57","date_gmt":"2021-01-18T03:05:57","guid":{"rendered":"https:\/\/pressbooks.publishdot.com\/anatomyphysiology\/chapter\/10-1-the-functions-of-the-skeletal-system\/"},"modified":"2021-12-07T09:38:34","modified_gmt":"2021-12-07T09:38:34","slug":"10-1-the-functions-of-the-skeletal-system","status":"publish","type":"chapter","link":"https:\/\/pressbooks.publishdot.com\/anatomyphysiology\/chapter\/10-1-the-functions-of-the-skeletal-system\/","title":{"raw":"10.1 The Functions of the Skeletal System","rendered":"10.1 The Functions of the Skeletal System"},"content":{"raw":"
\n

Learning Objectives<\/strong><\/p>\n\n<\/header>\n

\n\nBy the end of this section, you will be able to:\n
    \n \t
  • Define bone, cartilage and the skeletal system<\/li>\n \t
  • List and describe the functions of the skeletal system<\/li>\n<\/ul>\n<\/div>\n<\/div>\nBone<\/strong>, or osseous tissue<\/strong>, is a hard, dense connective tissue that forms most of the adult skeleton, the support structure of the body. In the areas of the skeleton where bones move (for example, the ribcage and joints), cartilage<\/strong>, a semi-rigid form of connective tissue, provides flexibility and smooth surfaces for movement. The skeletal system<\/strong> is the body system composed of bones and cartilage and performs the following critical functions for the human body:\n
      \n \t
    • supports the body<\/li>\n \t
    • facilitates movement<\/li>\n \t
    • protects internal organs<\/li>\n \t
    • produces blood cells<\/li>\n \t
    • stores and releases minerals and fat<\/li>\n<\/ul>\n

      Support, Movement and Protection<\/h2>\n[caption id=\"attachment_574\" align=\"alignright\" width=\"202\"]\"Photo Figure 10.1.1. Bones support movement.<\/strong> Bones act as levers when muscles span a joint and contract. (credit: Benjamin J. DeLong).[\/caption]\n\nThe most apparent functions of the skeletal system are the gross functions\u2014those visible by observation. Simply by looking at a person, you can see how the bones support, facilitate movement, and protect the human body.\n\nJust as the steel beams of a building provide a scaffold to support its weight, the bones and cartilage of your skeletal system compose the scaffold that supports the rest of your body. Without the skeletal system, you would be a limp mass of organs, muscle, and skin.\n\nBones also facilitate movement by serving as points of attachment for your muscles. While some bones only serve as a support for the muscles, others also transmit the forces produced when your muscles contract. From a mechanical point of view, bones act as levers and joints serve as fulcrums (Figure 10.1.1). Unless a muscle spans a joint and contracts, a bone is not going to move.\n\nBones also protect internal organs from injury by covering or surrounding them. Your ribs protect your lungs and heart, the bones of your vertebral column (spine) protect your spinal cord, and the bones of your cranium (skull) protect your brain (Figure 10.1.2).\n\n[caption id=\"attachment_574\" align=\"aligncenter\" width=\"492\"]\"Skeleton Figure 10.1.2. Bones protect brain.<\/strong> The cranium surrounds and protects the brain from non-traumatic injury.[\/caption]\n\n
      \n

      Career Connection<\/h2>\nOrthopaedist<\/strong>\n\nAn orthopaedist is a doctor who specialises in diagnosing and treating disorders and injuries related to the musculoskeletal system. Some orthopaedic problems can be treated with medications, exercises, braces, and other devices, but others may be best treated with surgery (Figure 10.1.3).\n\nWhile the origin of the word \u201corthopaedics\u201d (ortho- = \u201cstraight\u201d; paed- = \u201cchild\u201d), literally means \u201cstraightening of the child,\u201d orthopaedists can have patients who range from paediatric to geriatric. In recent years, orthopaedists have even performed prenatal surgery to correct spina bifida, a congenital defect in which the neural canal in the spine of the foetus fails to close completely during embryologic development.\n\n[caption id=\"attachment_573\" align=\"alignleft\" width=\"300\"]\"Photo Figure 10.1.3. Arm brace.<\/strong> An orthopaedist will sometimes prescribe the use of a brace that reinforces the underlying bone structure it is being used to support. (credit: Juhan Sonin).[\/caption]\n\nOrthopaedists commonly treat bone and joint injuries but they also treat other bone conditions including curvature of the spine. Lateral curvatures (scoliosis) can be severe enough to slip under the shoulder blade (scapula) forcing it up as a hump. Spinal curvatures can also be excessive dorsoventrally (kyphosis) causing a hunch back and thoracic compression. These curvatures often appear in preteens as the result of poor posture, abnormal growth, or indeterminate causes. Mostly, they are readily treated by orthopaedists. As people age, accumulated spinal column injuries and diseases like osteoporosis can also lead to curvatures of the spine, hence the stooping you sometimes see in the elderly.\n\nSome orthopaedists sub-specialise in sports medicine, which addresses both simple injuries, such as a sprained ankle, and complex injuries, such as a torn rotator cuff in the shoulder. Treatment can range from exercise to surgery. The Australian Orthopaedic Association (AOA) is a not-for-profit organisation that provides specialist education and training, ensuring high standard of orthopaedic care, and is a leading authority body who actively supports scientific research and orthopaedic humanitarian initiatives in Australia and worldwide.\n\n \n\n<\/div>\n

      Mineral Storage, Energy Storage and Haematopoiesis<\/h2>\nOn a metabolic level, bone tissue performs several critical functions. For one, the bone matrix acts as a reservoir for several minerals important to the functioning of the body, especially calcium and phosphorus. These minerals, incorporated into bone tissue, can be released back into the bloodstream to maintain levels needed to support physiological processes. Calcium ions, for example, are essential for muscle contractions and controlling the flow of other ions involved in the transmission of nerve impulses.\n\nBone also serves as a site for fat storage and blood cell production. The softer connective tissue that fills the interior of most bone is referred to as bone marrow (Figure 10.1.4). There are two types of bone marrow: yellow marrow<\/strong> and red marrow<\/strong>. Yellow marrow contains adipose tissue; the triglycerides stored in the adipocytes of the tissue can serve as a source of energy. Red marrow is where haematopoiesis<\/strong>\u2014the production of blood cells\u2014takes place. Red blood cells, white blood cells, and platelets are all produced in the red marrow.\n\n[caption id=\"attachment_574\" align=\"aligncenter\" width=\"543\"]\"Head Figure 10.1.4. Head of femur showing red and yellow marrow.<\/strong> The head of the femur contains both yellow and red marrow. Yellow marrow stores fat. Red marrow is responsible for haematopoiesis. (credit: modification of work by \u201cstevenfruitsmaak\u201d\/Wikimedia Commons).[\/caption]\n\n
      \n

      Section Review<\/strong><\/p>\n\n<\/header>\n

      \n\nThe major functions of the bones are body support, facilitation of movement, protection of internal organs, storage of minerals and fat and haematopoiesis. Together, the muscular system and skeletal system are known as the musculoskeletal system.\n\n<\/div>\n<\/div>\n
      \n

      Review Questions<\/strong><\/p>\n\n<\/header>\n

      \n\n[h5p id=\"281\"]\n\n<\/div>\n<\/div>\n
      \n

      Critical Thinking Question<\/strong><\/p>\n\n<\/header>\n

      \n\n[h5p id=\"282\"]\n\n<\/div>\n<\/div>\nClick the drop down below to review the terms learned from this chapter.\n\n[h5p id=\"283\"]","rendered":"
      \n
      \n

      Learning Objectives<\/strong><\/p>\n<\/header>\n

      \n

      By the end of this section, you will be able to:<\/p>\n

        \n
      • Define bone, cartilage and the skeletal system<\/li>\n
      • List and describe the functions of the skeletal system<\/li>\n<\/ul>\n<\/div>\n<\/div>\n

        Bone<\/strong>, or osseous tissue<\/strong>, is a hard, dense connective tissue that forms most of the adult skeleton, the support structure of the body. In the areas of the skeleton where bones move (for example, the ribcage and joints), cartilage<\/strong>, a semi-rigid form of connective tissue, provides flexibility and smooth surfaces for movement. The skeletal system<\/strong> is the body system composed of bones and cartilage and performs the following critical functions for the human body:<\/p>\n

          \n
        • supports the body<\/li>\n
        • facilitates movement<\/li>\n
        • protects internal organs<\/li>\n
        • produces blood cells<\/li>\n
        • stores and releases minerals and fat<\/li>\n<\/ul>\n

          Support, Movement and Protection<\/h2>\n
          \"Photo
          Figure 10.1.1. Bones support movement.<\/strong> Bones act as levers when muscles span a joint and contract. (credit: Benjamin J. DeLong).<\/figcaption><\/figure>\n

          The most apparent functions of the skeletal system are the gross functions\u2014those visible by observation. Simply by looking at a person, you can see how the bones support, facilitate movement, and protect the human body.<\/p>\n

          Just as the steel beams of a building provide a scaffold to support its weight, the bones and cartilage of your skeletal system compose the scaffold that supports the rest of your body. Without the skeletal system, you would be a limp mass of organs, muscle, and skin.<\/p>\n

          Bones also facilitate movement by serving as points of attachment for your muscles. While some bones only serve as a support for the muscles, others also transmit the forces produced when your muscles contract. From a mechanical point of view, bones act as levers and joints serve as fulcrums (Figure 10.1.1). Unless a muscle spans a joint and contracts, a bone is not going to move.<\/p>\n

          Bones also protect internal organs from injury by covering or surrounding them. Your ribs protect your lungs and heart, the bones of your vertebral column (spine) protect your spinal cord, and the bones of your cranium (skull) protect your brain (Figure 10.1.2).<\/p>\n

          \"Skeleton
          Figure 10.1.2. Bones protect brain.<\/strong> The cranium surrounds and protects the brain from non-traumatic injury.<\/figcaption><\/figure>\n
          \n

          Career Connection<\/h2>\n

          Orthopaedist<\/strong><\/p>\n

          An orthopaedist is a doctor who specialises in diagnosing and treating disorders and injuries related to the musculoskeletal system. Some orthopaedic problems can be treated with medications, exercises, braces, and other devices, but others may be best treated with surgery (Figure 10.1.3).<\/p>\n

          While the origin of the word \u201corthopaedics\u201d (ortho- = \u201cstraight\u201d; paed- = \u201cchild\u201d), literally means \u201cstraightening of the child,\u201d orthopaedists can have patients who range from paediatric to geriatric. In recent years, orthopaedists have even performed prenatal surgery to correct spina bifida, a congenital defect in which the neural canal in the spine of the foetus fails to close completely during embryologic development.<\/p>\n

          \"Photo
          Figure 10.1.3. Arm brace.<\/strong> An orthopaedist will sometimes prescribe the use of a brace that reinforces the underlying bone structure it is being used to support. (credit: Juhan Sonin).<\/figcaption><\/figure>\n

          Orthopaedists commonly treat bone and joint injuries but they also treat other bone conditions including curvature of the spine. Lateral curvatures (scoliosis) can be severe enough to slip under the shoulder blade (scapula) forcing it up as a hump. Spinal curvatures can also be excessive dorsoventrally (kyphosis) causing a hunch back and thoracic compression. These curvatures often appear in preteens as the result of poor posture, abnormal growth, or indeterminate causes. Mostly, they are readily treated by orthopaedists. As people age, accumulated spinal column injuries and diseases like osteoporosis can also lead to curvatures of the spine, hence the stooping you sometimes see in the elderly.<\/p>\n

          Some orthopaedists sub-specialise in sports medicine, which addresses both simple injuries, such as a sprained ankle, and complex injuries, such as a torn rotator cuff in the shoulder. Treatment can range from exercise to surgery. The Australian Orthopaedic Association (AOA) is a not-for-profit organisation that provides specialist education and training, ensuring high standard of orthopaedic care, and is a leading authority body who actively supports scientific research and orthopaedic humanitarian initiatives in Australia and worldwide.<\/p>\n

           <\/p>\n<\/div>\n

          Mineral Storage, Energy Storage and Haematopoiesis<\/h2>\n

          On a metabolic level, bone tissue performs several critical functions. For one, the bone matrix acts as a reservoir for several minerals important to the functioning of the body, especially calcium and phosphorus. These minerals, incorporated into bone tissue, can be released back into the bloodstream to maintain levels needed to support physiological processes. Calcium ions, for example, are essential for muscle contractions and controlling the flow of other ions involved in the transmission of nerve impulses.<\/p>\n

          Bone also serves as a site for fat storage and blood cell production. The softer connective tissue that fills the interior of most bone is referred to as bone marrow (Figure 10.1.4). There are two types of bone marrow: yellow marrow<\/strong> and red marrow<\/strong>. Yellow marrow contains adipose tissue; the triglycerides stored in the adipocytes of the tissue can serve as a source of energy. Red marrow is where haematopoiesis<\/strong>\u2014the production of blood cells\u2014takes place. Red blood cells, white blood cells, and platelets are all produced in the red marrow.<\/p>\n

          \"Head
          Figure 10.1.4. Head of femur showing red and yellow marrow.<\/strong> The head of the femur contains both yellow and red marrow. Yellow marrow stores fat. Red marrow is responsible for haematopoiesis. (credit: modification of work by \u201cstevenfruitsmaak\u201d\/Wikimedia Commons).<\/figcaption><\/figure>\n
          \n
          \n

          Section Review<\/strong><\/p>\n<\/header>\n

          \n

          The major functions of the bones are body support, facilitation of movement, protection of internal organs, storage of minerals and fat and haematopoiesis. Together, the muscular system and skeletal system are known as the musculoskeletal system.<\/p>\n<\/div>\n<\/div>\n

          \n
          \n

          Review Questions<\/strong><\/p>\n<\/header>\n

          \n
          \n