Skeletal System PDF

Skeletal System Objectives: Types and functions of skeletal system Bone tissue Calcium storage and homeostasis Disease related to calcium storage Accessory structures of the skeletal system Types and diseases of the joint Introduction and main functions of skeletal system: The Skele...

Skeletal System Objectives: Types and functions of skeletal system Bone tissue Calcium storage and homeostasis Disease related to calcium storage Accessory structures of the skeletal system Types and diseases of the joint Introduction and main functions of skeletal system: The Skeletal system is composed of 206 bones that, along with cartilage, tendons, and ligaments, make up the framework or skeleton of the body. Two types: 1. Axial 2. Appendicular Functions: 1.Protection: Protects some internal organs from mechanical injury; (e.g.: the rib cage protects the heart and lungs). 2.Structure and support: they give our bodies structure, support, and shape. 3.Movement: with the help of muscles, the muscles contract, and the bones will change positions allowing for specific movements.  3. Movement: with the help of muscles, the muscles contract, and the bones will change positions allowing for specific movements. 4. Production of blood cells: from red bone marrow. (yellow bone marrow stores fat) 5. Storage: your bones are a storage site for excess minerals and fat. Bone tissue: Bone is a type of connective tissue, which must have cells called osteocytes embedded in a hard substance called matrix for these cells. the matrix is a hard substance made of calcium salts which gives strength and collagen that gives flexibility. Storage of calcium and fat  Homeostasis of calcium this is done with the help of two hormones. 1)calcitonin: made in the thyroid gland, it is released when extra calcium is found in the blood. - When it is secreted, it will cause the extra Ca to be taken into the bone matrix, where it will be stored. 2) Parathyroid hormone (PTH): it is made in the parathyroid gland which is found behind the thyroid gland. - It is secreted when there is low Ca in the blood, where it will cause the bones to release Ca from the matrix into the blood.  Disease due to storage of calcium in the bones one disease that is related to the amount of calcium in the bone matrix is Osteoporosis. It happens when the amount of Ca is low which will lead to weak bones (less strong). Usually happens in older people. Accessory structures of the skeletal system: These are the “extra” parts of the skeletal system; they relate to bones and provide the overall function of the system: - Cartilage - Ligaments. - Tendons. - Joints.  Cartilage ❖Cartilage is a connective tissue that has the function of support. ❖It is made of cells, collagen, and a matrix. ❖It is more flexible than bones and is found where two or more bones connect. ❖It is also found in parts that need support and flexibility for movement such as the nose/ ears.  Ligaments ❑ Ligaments are connective tissues (fibrous) that connect two or more bones together. ❑ This tissue contains a large amount of collagen, which give strength, and elastin, which gives flexibility. ❑ they are found in the outer covering of the bones and connect with the outer covering of the other bones.  Tendons ❖ These are connective tissues (fibrous) that connect the bones with muscles. ❖ They are important since bones cannot move with the control of muscles. ❖ Like ligaments they are also made of collagen and elastin.  Joints ❑ Joints (articulation) are where two or more bones connect. ❑ Joints are very important since they connect different bones together and they provide flexibility to the skeletal system, which allows the movement of different body parts. ❑ There are several types of joints, and they could be classified by the amount of movement they provide at their location: 1. Sutures: ❑ these are the joints that provide very little, or no movement. ❑ Examples: sutures, which are the joints in the skull  2. Slightly moveable joints: joints that are found between bones that need slight movement Example: joints at the spine  3. Synovial joint: The most common type of joints that provide a wide range of movements between the bones. Examples: joints at the elbow, ankle, shoulder, etc. ❑ They can provide this wide range of movements due to a special space known as the synovial cavity. ❑ Inside this space there is a fluid (synovial fluid), which gives the bones cushion for the bones. ❑ Cartilage is found to make movement smoother. Cont.: Synovial joint:  Diseases of the Joints Osteoarthritis: ❖ This disease happens when the synovial joints become worn out (damaged), usually the cartilage becomes less strong. ❖ This makes movement very painful since there will not be a cushion or smooth surface between the bones. ❖ It usually happens to people of older age.  Rheumatoid arthritis: This disease happens when too much fluid is built up in the synovial cavity. It is a type of autoimmune disorder, where the body will release chemicals that recognize the tissue within the joints as “foreign” or harmful. It will later destroy the tissue causing an increase in the fluid inside the cavity. (inflammation). It can happen to people of any age and has no cure.