The skeleton has 206 bones in an adult Babies have 270 which fuse for this result The skeleton is divided into two main zones: axial skeleton (bones) topped by the skull appendicular bones Your brain is in the cranium acts as a hull The mandible or jawbone able to expand useful for talking The ossicles are small bones found inside your ear Bones that help you hear: Maleus Incus Stapes Sound waves are amplified by these three bones then move to the cochlea discerns the tones The ribcage helps to protect: lungs heart Ribs 12 ribs on each side the sternum in the front Your vertebral column made up of vertebrae Are stacked up very neatly in a vertical array

consists of: (encephalon - brain) The cervical vertebrae make up your neck 7 The ribs are supported by thoracic vertebrae 12 The spinal cord keeps your reflexes on deck goes through the cervical, thoracic, and a bit of the lumbar vertebrae Lumbar vertebrae at the end of the spinal cord pathway 5 Five sacral vertebrae are fused to form your sacrum includes: cauda equina filum terminale Which holds your upper body and is found in your bum 5, fused Below it is the coccyx (the tailbone) 4, fused In humans the coccyx has not really grown The appendicular skeleton has 126 bones In shoulders, arms and legs Your scapula (shoulder blade) Next to the clavicle (collarbone) is laid You have three arm bones one above and two below Here they come together to meet at the elbow The bones of the forearm: the ulna on top the radius on bottom The humerus the upper arm You have 54 bones in one hand and one wrist consist of: carpals metacarpals phalanges consist of: proximal intermediate distal Make up your fingers which you can move with ease hands where you find the carpals/metacarpals feet where you will find all your tarsals/metatarsals The hip bone can be divided into three ilium ischium pubis The bones in your leg there are four: The patella kneecap The tibia and fibula found below the knee the femur found above it There are 52 (26 x 2) bones in your ankles and your feet the feet bones: Tarsals metatarsals Phalanges Proximal intermediate Distal

Introduction to the Skeletal and Muscular Systems

Skeletal System

The skeletal system includes all of the bones and joints in the body. Each bone is a complex living organ that is made up of many cells, protein fibers, and minerals (phosphorus, magnesium). The skeleton acts as a scaffold by providing support and protection for the soft tissues that make up the rest of the body. The skeletal system also provides attachment points for muscles to allow movements at the joints. New blood cells are produced by the red bone marrow inside of our bones. Bones act as the body’s warehouse for calcium, iron, and energy in the form of fat. Finally, the skeleton grows throughout childhood and provides a framework for the rest of the body to grow along with it.

The skeletal system of the human body consists of 206 bones. The skeleton makes up about 30-40% of an adult’s body mass. The skeleton’s mass is made up of a non living bone matrix and many tiny bone cells. Roughly half of the bone matrix’s mass is water while the other half is collagen protein and solid crystals of calcium carbonate and calcium phosphate.

Bone is covered with a living membrane called the periosteum, which contains bone forming cells called osteoblasts. During embryonic development (in the womb), the skeletal framework is composed of cartilage and membranes. The osteoblasts replace the cartilage and membranes with bony tissue. These bones are arranged into two major divisions: the axial skeleton and the appendicular skeleton. The axial skeleton runs along the body’s midline axis and is made up of 80 bones in the following regions: Skull Hyoid Auditory ossicles Ribs Sternum Vertebral column The appendicular skeleton is made up of 126 bones in the following regions: Upper limbs Lower limbs Pelvic girdle Pectoral (shoulder) girdle 26 vertebrae form the vertebral column of the human body. They are named by region: 1- Cervical (neck) - 7 vertebrae 2- Thoracic (chest) - 12 vertebrae 3- Lumbar (lower back) - 5 vertebrae 4- Sacrum - 1 vertebra 5- Coccyx (tailbone) - 1 vertebra With the exception of the singular sacrum and coccyx, each vertebra is named for the first letter of its region and its position along the superior-inferior axis. For example, the most superior thoracic vertebra is called T1 and the most inferior is called T12. Living bone cells are found on the edges of bones and in small cavities inside of the bone matrix. Although these cells make up very little of the total bone mass, they have several very important roles in the functions of the skeletal system. The bone cells allow bones to: Grow and develop Be repaired following an injury or daily wear Be broken down to release their stored minerals. calcium eaten regurarly to provide help for bones and heart The skeletal system’s main function is to provide support for the body. For example, the spinal column provides support for the head and torso. The legs, on the other hand, support and bear the weight of the upper body while a person stands. But the skeletal system has several additional functions, including:

Ex. ribcage protects soft organs Protecting internal organs from injury. For example, the skull protects the brain, while the thoracic cage protects the heart and lungs. Allowing for movement. Muscles attach to bones through tendons. This connection allows the body to move in many different ways. Producing blood cells. The soft, red, bone marrow inside of many bones produces red blood cells, white blood cells, and platelets. Storing minerals and nutrients. Bones can store and release minerals, including calcium and phosphorus, which are important for many bodily functions. Additionally, soft, yellow bone marrow also known as adipose (fat) tissue that can be used as energy can be found in this part of the bone marrow.

these bones give your body structure protect your internal organs let you move and much more the adult human body has 206 bones and an infant has 300 bones this has become some smaller bones combined together and thus form bigger bones skull it carries our brain and also supports our face it protects the brain from knocks and bumps we have a very small bone in our ears stirrup it is a smallest bone of our body about 2.5 to 3.3 millimeters only these are called the clavicle are shoulder bones or collarbone there are two clavicles one on the right and one on the left it is the only long bone in the body that lies horizontally it's a sternum a long flat bone oh did you notice it's shaped like a necktie it's located in the center of our chest and this cage-like thing is our rib cage our heart and lungs are behind these bones so you can say rib cage is the curved wall of ribs that surrounds and protects our heart and lungs this bone in the hand is called the humerus the long bone of the upper arm extending from the shoulder to the Elbow there are two more long bones in our hands radius and ulna they form the lower arm and these bones in the Palms ah these over here are called the carpels metacarpals and phalanges now let's see the back of this look it's not a single bone it is built of 33 small bones called vertebrates and this whole structure is known as the spine the spine helps you twist and bend also it holds our body upright now look at this see this is the pelvic girdle it protects the bladder and uterus the longest and strongest bone in our body is the femur and these two bones in the lower leg are fibula and tibia a broken femur is life-threatening these over here are the tarsals, metatarsals and phalanges human bone is made of collagen mostly it is a protein that is woven into a flexible framework it also contains Calcium Carbonate calcium phosphate and minerals that add strength and Harden the frame the combination of collagen and calcium gives the bone its flexibility and strength we should do exercise running dancing jumping and we should play Outdoor Sports it makes our bones strong you know if your body doesn't have enough calcium it will take it from your bones making your bones weaker good reason to drink milk protect those skull bones by wearing a good helmet for bike riding skating and other sports