Introduction
Until 1895, we could only imagine what our bones looked like, either by feeling under our skin, or looking at bones of dead people who were dead for a long time. With the invention of the x-ray all that changed. We didn't have to wait until a corpse was discovered to examine the bones!
What happens underneath our skin is no longer a mystery. Scientists, Doctors, and teachers have given us the opportunity to "see" inside ourselves with the aid of x-rays, MRI (magnetic resonance imaging, CT scans (computer tomography) and ultrasounds. We no longer have to guess how long our femur is or where the fracture might have occurred. We can see clearly all 206 bones.
The 206 bone we have make up the wonderful skeletal system you will learn about in this unit. The skeletal system has five important functions. In this unit you will learn that
the bones support you and give you your shape, allow you to move, protect important organs, store materials, and produce blood cells.
Support/Shape and Movement
What would you do if you were just a pile of skin? Would you be able to walk? No! Would you be able to even stand up? No! Your bones allow you to say up right, walk and even dance. Bones are very strong because they need to hold up out body. Our leg bones allow us to stay upright. Even our toes keep us balanced! Our spinal column also keeps our bodies straight and balanced. The top sections of the vertebrae in the neck area supports out head. We would droop and swivel around if did not have the proper support. The curves in the vertebrae make it easier to keep your balance. Each vertebrae by it's self will allow you to twist and bend just a slight amount, but together you are able to move more.
Together with the muscular system we have tremendous amount of support to keep us upright, moving and balanced. When one muscle contracts and the other muscle relaxes, our bones move. This occurs with the help of ligaments, cartilage, tendons and muscles. Ligaments are strong tissue holding two bones together at a joint. Between two bones is a layer of cartilage. This soft material between bones like in your vertebrae prevents the bones for rubbing and therefore disintegrating. We have over 600 muscles attached to our bones that allow us to move. At the end of our muscles, connecting to the bones, are tendons.
To help your skeletal system move, your bones are connected at joints. This allows you to move freely. The joints are; ball and socket/shoulder, hinge/elbow, pivot/neck, saddle/base of your thumb, gliding/wrist, ellipsoid/ base of finger, sutures/skull. Joints are where bones are connected and held together by ligaments and tendons. We have over 230 moveable joints in our body.
There are two sections of the skeletal system. The center section called the axial; include the skull, ribs, breastbone, and vertebrae. This runs down the center of your body. The appendicular includes your arms, legs, hands, feet, hips, and shoulders. The word appendix means "to hang", so these parts hang off the axial sections of your skeletal system.
Protection
What would you do if you fell and hit your head but did not have a hard protection like a skull? Well, probably you would have a severe brain injury. The skeleton system protects vital organs. The skull protects your brain. It is like you are wearing a special helmet! The skull is made of 29 bones, even though it does not feel like separate bones. They are fused together. When you were born the bones were all separate and grew together as you age. There are bones that form the cranium which is the top part of your skull. The face part of the skull has 14 bones that gives you face it's beautiful shape! Part of the face bones includes the mandible which is your jaw. This allows your mouth to open and close.
Our ribs protect many organs. Our heart and our lungs are protected because without them we could not live. Because our lung expand and contract when we breathe, our ribs can not look like our skull. Instead our rib cage is perfect for protection, yet is flexible. We have 12 pair of ribs or 24 all together. The space between them is important for breathing. The top ribs are connected to a special cartilage which is connected to the sternum. Small children may know the sternum as their breastbone. The cartilage acts as a shock absorber, so we you fall or are hit in the chest, the ribs give slightly and absorb the pressure so not to injure the heart or lungs.
The pelvis or hips have two important functions; protection and a place there your legs are attached. The pelvis protects organs such as your bladder and large intestines. When forensic scientists or paleontologists discover the remains of a human they can distinguish between a male and a female by the size of the pelvic. A woman's pelvic is wider and has a larger opening for childbirth.
The spine is also multitasked! We learned that the spine gives you balance, yet it also protects your spinal column or spinal cord. Your vertebrae are on top of one another with the spinal cord running through. There are 31 pairs of nerves that extend off the spinal cord to the rest of your body. Your brain communicates and sends messages to all parts of your body and if it is damaged, the message will not go to the part of the body the brain wants it to. Therefore your vertebrae column has a very important job.
Around the outer layer end section of our bones we have a protective rubbery material called cartilage. This protects the bones from rubbing together and wearing thin. This protection allows you to move more freely without causing damage to your bones.
Between your bones in the point, is a sac filled with fluid. This is the synovial fluid. This fluid also protects the area between your bones by keeping it moist making movement easy. Older people have less synovial fluid between the bones causing movement more difficult. If you crack your knuckles, you can hear the air bubbles popping in the fluid.
Stores Material
Bones are not dried out as once was thought many years ago. They are living tissue storing important cells and minerals. The inside of bones stores both yellow and red marrow. Yellow marrow stores fat and releases it to needed parts of the body, and red marrow makes red and white blood cells along with platelets. The red blood cells carry oxygen through out the body, the white blood cells fight infection, and platelets help the blood to clot. Our bones also store minerals. The minerals are stored until a certain part of the body needs it and then it is released into your blood. Calcium is stored in your bones. Calcium is used to keep our bones strong and also to help blood clot. Calcium is also utilizes by the nervous system. Without it our muscles would not function properly. Phosphorus is also stored in our bones. Phosphorus is a chemical that is a building block of DNA.
Taking Care of Your Bones
Since bones are so important, we need to keep them healthy. Sometimes fractures do occur, but some could have been avoided. A fracture is the breaking of a bone. Sometimes sprains occur. This is when there is over stretching of the muscle or tendon. To keep your muscles from injury, stretch before and after exercise or when you are involved in a strenuous activity. Wearing important equipment during sporting events is very crucial. Strengthening your bone through proper exercise and diet will enable you to live longer and stay healthier. Sleep and proper rest is very important. When you sleep, your muscles relax and therefore allow them to get rid of the waste material they have stored throughout the day.
Conclusion
Today we are able to view the anatomy of our body thanks to modern technology. Children and adults are still curious about how we function, move, live and breathe. Science, especially the anatomy of the human body can be grotesque to some, but this unit will enlighten them. "Art and Anatomy: The Human Body Inside and Out" takes a hands on approach, making the lessons fun and engaging.