Healthy Human Body Systems
The skeletal system is the structure of the body, it consists of bones and other connective tissues. This systems helps protects/supports the internal organs and body tissues, it also allows you to move any way you want. The adult skeleton contains 206 bones, three of which are located in one ear, for the hearing function.
The bones that make up your body are very much alive, growing and changing all the time like the the other parts of your body. Almost every bone is made of the same materials.
Bones: The outer surface of a bone is called periosteum. It's a thin dense membrane that contains nerves and blood vessels that nourish the bone. The next layer is made up of compact bone. This part is smooth and very hard. It's the part you see when you look at a skeleton.
Within the compact bone are many layers of cancellous bone, which looks a bit like a sponge. Cancellous bone is not as hard as compact bone, but is still very strong. The cancellous bone protects the innermost part of the bone, the bone marrow. The bone marrow’s job is to make blood cells.
A baby’s body has about 300 bones at birth. These eventually fuse together until you have 206. Some of a baby's bone is made entirely of a special material called cartilage.
Spine: The spine lets you twist and bend, and holds your body upright. It also protects the spinal cord, which is a large bundle of nerves that sends information from the brain to the rest of the body. The spine is made of 26 bones in total. These bones are called vertebrae. There are different types of vertebrates in the spine, and each does a different kind of job. The first vertebrae is called cervical. They’re the the bones in the back of your neck, just below your brain, they support your head and neck.
Below the cervical vertebrae are the thoracic vertebrae, there are 12 in total. These bones help to keep your ribs in place. Below the thoracic vertebrae are 5 lumbar (spinal tap) vertebrates. Beneath that is the sacrum vertebrae, which is made up of 5 vertebrates that are fused together to form one single bone. The bottom of the spine, is the coccyx, which is a bone made of four fused vertebrae. The lower section of the spine is important in order for you to keep a posture for your weight, and for you keep a good center of gravity. When you pick up a heavy item the lumbar vertebrae, sacrum, and the coccyx give you the strength to do so. When you do anything physical these also help maintain your balance. In Between the vertebrae are small disks called cartilage. These disks help keep the vertebrae from rubbing against one another, and also acts as a the spines shock absorber. This means that when you jump, the vertebrae gives you the cushioning that you need.
The bones that make up your body are very much alive, growing and changing all the time like the the other parts of your body. Almost every bone is made of the same materials.
Bones: The outer surface of a bone is called periosteum. It's a thin dense membrane that contains nerves and blood vessels that nourish the bone. The next layer is made up of compact bone. This part is smooth and very hard. It's the part you see when you look at a skeleton.
Within the compact bone are many layers of cancellous bone, which looks a bit like a sponge. Cancellous bone is not as hard as compact bone, but is still very strong. The cancellous bone protects the innermost part of the bone, the bone marrow. The bone marrow’s job is to make blood cells.
A baby’s body has about 300 bones at birth. These eventually fuse together until you have 206. Some of a baby's bone is made entirely of a special material called cartilage.
Spine: The spine lets you twist and bend, and holds your body upright. It also protects the spinal cord, which is a large bundle of nerves that sends information from the brain to the rest of the body. The spine is made of 26 bones in total. These bones are called vertebrae. There are different types of vertebrates in the spine, and each does a different kind of job. The first vertebrae is called cervical. They’re the the bones in the back of your neck, just below your brain, they support your head and neck.
Below the cervical vertebrae are the thoracic vertebrae, there are 12 in total. These bones help to keep your ribs in place. Below the thoracic vertebrae are 5 lumbar (spinal tap) vertebrates. Beneath that is the sacrum vertebrae, which is made up of 5 vertebrates that are fused together to form one single bone. The bottom of the spine, is the coccyx, which is a bone made of four fused vertebrae. The lower section of the spine is important in order for you to keep a posture for your weight, and for you keep a good center of gravity. When you pick up a heavy item the lumbar vertebrae, sacrum, and the coccyx give you the strength to do so. When you do anything physical these also help maintain your balance. In Between the vertebrae are small disks called cartilage. These disks help keep the vertebrae from rubbing against one another, and also acts as a the spines shock absorber. This means that when you jump, the vertebrae gives you the cushioning that you need.
Ribs: The heart, lungs, and liver are all very important for your body, and luckily you have your ribs to protect them. Your ribs act as a cage around your chest. Ribs come with 2 pairs, the right and left. Most people have 12 pairs of ribs, but some people are born with one extra or less pairs. All 12 pairs of ribs are attached to the back of the spine, where they are held in place by the thoracic vertebrae. The first 7 pairs attach in the front to the sternum, a strong bone that holds these ribs in place. The next 3 ribs are attached to the ribs above them with cartilage. The very last 2 sets of ribs are called floating ribs because they’re not attached to the sternum or the ribs above it, they are securely attached to the back of the spine.
Skull: Your skull protects the most important part of all, the brain. The skull is made up of different bones. Some protect your brain, and some make up your face structure. The smallest bone is in your head called the stirrup bone, which is behind your eardrum. Your lower jawbone is the only bone in your head that can move. It opens and closes for you to talk and chew. As you grow up, the spaces between the bones in your skull (from when you were a baby), starts to close up and disappear. The special joints that connect the bones are called sutures.
Hands: When you use your hand for anything, you’re using the bones in your fingers, hand, wrist, and arm. Each arm is attached to a shoulder blade or scapula, a large triangular bone on the upper back corner of each side of the ribcage. The arm is made out of three bones: the humerus, which is above your elbow, and the radius and ulna, which are below the elbow. Each of these bones are wide at the end and skinner in the middle, to help give it strength when it meets another bone. At the end of the radius and ulna are smaller bones that make up the wrist. The center part of your hand is made up of five separate bones. Each finger has three bones excluding your thumb, which has two. Between your wrist, hands and fingers you have a total of 54 bones.
Skull: Your skull protects the most important part of all, the brain. The skull is made up of different bones. Some protect your brain, and some make up your face structure. The smallest bone is in your head called the stirrup bone, which is behind your eardrum. Your lower jawbone is the only bone in your head that can move. It opens and closes for you to talk and chew. As you grow up, the spaces between the bones in your skull (from when you were a baby), starts to close up and disappear. The special joints that connect the bones are called sutures.
Hands: When you use your hand for anything, you’re using the bones in your fingers, hand, wrist, and arm. Each arm is attached to a shoulder blade or scapula, a large triangular bone on the upper back corner of each side of the ribcage. The arm is made out of three bones: the humerus, which is above your elbow, and the radius and ulna, which are below the elbow. Each of these bones are wide at the end and skinner in the middle, to help give it strength when it meets another bone. At the end of the radius and ulna are smaller bones that make up the wrist. The center part of your hand is made up of five separate bones. Each finger has three bones excluding your thumb, which has two. Between your wrist, hands and fingers you have a total of 54 bones.
Your legs: Your legs are attached to a circular group of bones called your pelvis. The pelvis is a bowl-shaped structure that supports your spine. It is made up of the two large hip bones in front, and behind the sacrum and coccyx. The pelvis acts as a tough ring around parts of the digestive system. The bones in your legs are very large and strong to hold the weight of your body. The bone that goes from your pelvis to your knee is called the femur (longest bone in your body). At the knee there is a triangular-shaped bone called the patella, or kneecap, that protects the knee joints. Below the knee are two other leg bones called the tibia and the fibula. The ankle is where the lower leg bones connect to a large bone in the bone called the talus. Next to the talus are six other bones. Each toe has three tiny bones, except for your big toe, which only has two. There is a total of 52 bones in both of the feet and ankles. Without all your bones in your foot working together, it would be impossible to balance properly. The bones in your feet are arranged so the foot is almost flat and a bit wide, to help you stay upright.
Your joints: The place where two bones meet is called a joint. Some joints move and some don't. Fixed joints are fixed in place so they don't move. Your skull has some of these joints called the sutures. One of these joints are called the parleto-temporal. The moving joints allow you to twist, bend, and move different parts of your body. Some moving joints, like the ones on your spine, move only a little. Other joints move a lot. One of the main types of moving joints is called a hinge joint. Your elbows and knees each have hinge joints, which let you bend and then straighten your arms and legs. You also have many smaller hinge joints in your fingers and toes. Another important type of moving joint is the ball and socket joint. You can find these joints at your shoulders and hips. They are made up of the round end of one bone fitting into a small cup-like area of another bone. Ball and socket joints allow for lots of movement in every direction. Your joints come with their own special fluid called synovial fluid that helps them move freely. Bones are held together at the joints by the ligaments, which are like very strong rubber bands.
Your joints: The place where two bones meet is called a joint. Some joints move and some don't. Fixed joints are fixed in place so they don't move. Your skull has some of these joints called the sutures. One of these joints are called the parleto-temporal. The moving joints allow you to twist, bend, and move different parts of your body. Some moving joints, like the ones on your spine, move only a little. Other joints move a lot. One of the main types of moving joints is called a hinge joint. Your elbows and knees each have hinge joints, which let you bend and then straighten your arms and legs. You also have many smaller hinge joints in your fingers and toes. Another important type of moving joint is the ball and socket joint. You can find these joints at your shoulders and hips. They are made up of the round end of one bone fitting into a small cup-like area of another bone. Ball and socket joints allow for lots of movement in every direction. Your joints come with their own special fluid called synovial fluid that helps them move freely. Bones are held together at the joints by the ligaments, which are like very strong rubber bands.