The picture above shows a representation of the general structure of the skeletal system.
The picture above shows some example of different joints. There are the joints previously mentioned called hinge and ball and socket. There is also saddle such as your wrist that glides up and down, plane such as your spine that can bend in most directions, ellipsoid such as your such as your wrist that allows extension, and pivot such as the vertebra in your neck that turns in most directions.
The skeletal system is made of bone, connective tissue, and minerals. There are two parts to your bone. They are called compact and spongy bone. Compact bone is hard and dense. This gives structure to the bone. Inside the compact bone is spongy bone. Spongy bone gives strength and support the bone and contains a lot of blood cells. It contains so many because the bone as a whole stores bone marrow. Bone marrow produces red and white blood cells. Red blood cells are crucial for your circulatory system and white for your immune system. The yellow bone marrow is used to store fat and produce a small amount of red and white blood cells. The bone contains minerals especially Calcium Phosphate. Your bones are constantly worn down overtime. To repair themselves osteoclasts take of worn calcium phosphate and puts down new healthy calcium phosphate. This process is essential for bone growth and development. Joint are anywhere where two or more bones meet. They are joined by connective tissue. There are many types of joints. The main types of joints are ball and socket and hinge. Ball and socket can move all around such as your shoulder. Hinge can only move up and uto cause you to move. The skeletal system helps you maintain homeostasis by producing movement so you can react and respond to the outside environment with the help of the nervous system.
Osteoporosis is a medical condition where bones become brittle and fragile from loss of tissue. As you grow older some bone cells dissolve away into matrix while new bone cells make osteoid. This process helps keep bones strong and helps them develop and grow. When osteoporosis takes place, the bone loss or dissolving of the bone cells is faster than the making of new bone. This is usually caused from change in hormones/aging or loss of calcium or Vitamin D. As a result of the loss or change, the density and quality of bones reduces which greatly increases the risk of fracture. An osteoporosis fracture is estimated to occur every three seconds around the world. This includes 1 out of 3 women and 1 out of 5 men. They mainly occur in the spine or hip and results are serious including: severe back pain, loss of height, and/or deformity. This disease can be genetically passed down. However, when it is passed down, the disease doesn't kick in until later, so you can reduce the risk by making healthy lifestyle choices.
The picture above shows on the left what healthy bone looks like and on the right what a bone looks like with osteoporosis.