HS1 Skeletal System Overview

Next is the skeletal system. Babies are born with approximately 350 soft bones. Many of these fuse to gather throughout life. The average adult has 206 individual bonds, and they weigh approximately 20 pounds. Bones have their own system of blood vessels allowing for circulation, nutrients, oxygenation inside the bone. Functions of the skeletal system include framework or support, provides the shape and the posture to support the body's muscles, fat and skin. Another function is protection, bone surround, vital organs that are soft and delicate, such as your brain, the spinal cord, the heart and the lungs, the brain is protected by the cranium, the spinal cord by the vertebra, the heart and lungs by the ribs and the sternum. Additional functions include movement and flexibility. Skeletal muscles which we talked about in the body's structure in the tissue unit, the skeletal muscles move the bones which then in turn act as a lever. Bones are also the storage for minerals, especially calcium, when a nutrition is an adequate or if a nutrient is in, low level, then the bones will release the necessary amount of that nutrient to maintain a homeostasis. Hemolysis is the last major function of the bones of the skeletal system. Hemo AG, MO, which means blood and then poiesis which is production. Hematopoiesis the production of red blood cells, RBCs, or the correct name urethra sites, and outside there are some white blood cells or leukocytes that are produced here inside of the bone in the red marrow. Osteocytes, which are mature bone cells, osteo, which means bone sight, cyt means cell. They are composed of 35% of organic or a living material, and 65% inorganic are non living material. Organic materials include collagen, which we've spoke about previously with the type of connective tissue. And in a provides the bones, the excuse me, ability to be in provides them with some flexibility. If our bones did not have some flexibility and they were just entirely inorganic material when you jumped when you stepped down hard, then that bone would fracture or bright. So they need a little bit of flexibility to be able to allow you to jump and the bone not break. It needs to be able to begin. Inorganic materials are important because these minerals give bones their hardness. Osteocytes again bone sail. Now the process of bone growth is like building a brick wall from one side and then chipping or eroding it away from the other side. If binds were to just continue to deal with osteocytes throughout the lifetime, then the bones would become thicker and wider. Our bodies wouldn't have the ability to even carry our bones around. Osteoblasts, which the bee and blast if you'll remember builder is to create and deposit new bone. Osteoclast, the sea and class can stand for Carver, secretes an enzyme that dissolve and digest bone. When we're younger, zero to 20 years, bone grows because the osteoblasts the bee and the builder produces a new bone tissue faster than the osteoclast, the sea for the Carver, can dissolve the old bone tissue. As I said, if your buttons were to grow wider throughout your lifetime, they would become enormous. But I don't. In your 20s to 40s, bone growth, the ostia blast, and the bone destruction by the osteoclasts, occur at approximately the same right. After about age 40, the destruction by the osteoclasts occurs at a faster rate. Now, this can result in an osteopenia allow bone cell or osteoporosis where you actually end up with pores or open spots within the bones. So they write a 20 osteoblast at a greater rate, 20 to 40, osteoblasts, osteoclasts, basically the same rate after 40, destruction by the osteoclasts occurs at a faster rate. Bioinformation occurs by the hailing cartilage. Now we spoke of this in the embryo in utero in the body structure unit. And it begins to harden at 8th week of pregnancy. And this bone hardening continues throughout the lifespan. The process of bone hardening is ossification. There are four types of bones, and they're classified according to their form or structure in their shape, anatomy. The degree of the movement is determined by the shape of the bone. The first type is flat bones. Flat bones are two layers of bone divided by a narrow span. Examples are the skull, the sternum, which is attached to the ribs and the front of the chest. And the shoulder blades are the scapulas which are shown here in this diagram. Bone types, the second is irregular. These are just basically bones that don't fit in any other category, examples are the buns of the face, the spine which are the vertebra and they're shown here in this diagram. And the hips or the ilium. The third type are short binds, and the definition is basically they have the same length and the same width. And most of the time that's correct with your phalanges are the sections of your fingers. They are longer than they are wide, but they're still an extremely short bone. Examples are the wrist or the carvels, the hand, the metacarpals, the ankle, the tarsals, and the feet, the metatarsals. The fourth type is long bones, and long bones are longer than they are wide. This is what your project on a long bone, which you'll be completing in class is about. Examples of this are the humerus, which is the upper bone, and your arms, the radius, which is the lower bone in your arm on your thumb side, and the ulna, which is the other bone in your lower arm from your elbow to your wrist. The femur, which is the example shown here in this diagram, which is the thigh bone, is the largest bone in the body. The tibia, which comes down and forms your lower leg along with the fibula, they also form your ankles. Long bone structure consists of the diaphragm, which are the ends of the bone. Excuse me, the diaphus, which is the shaft of the bone, the long part, the apathy, which is the end of the bone, the medullary canal which is inside this shaft, though stem, the spongy bone, which you can locate here in the ends, the Paris stamp, and then the articular cartilage, which is also found on the ends. So the diaphus or the shaft is a hollow cylinder of hard compact bind. This allows the bones to be very strong, but yet lightweight. The apathy which you see here on the ends of the bone is located at the ends of the diaphragm and this is a soft spongy bone. This does act as a shock absorber. Now, the growth plate here will also be called the epiphyseal line. Articular cartilage covers the epithets, and you can see here it diagrammed as white. Now this absorbs shock from movement. So it is a shock absorber just like on the car, the same way this ends of the epithets, there's a soft spongy bone. If you've ever seen a chicken bun, you can see the white articular cartilage on the ends of those buns. Now this protects the apathy and the joints from the erosion if the bones were to rub against each other whenever we move, there would be such tremendous wear and tear that there would be an erosion of the bone. Now the epiphyseal line which we saw in the earlier diagram and it's a growth plight or it's there at that line. As bones, when you're born, there are certain length, but of course they grow and they become longer throughout life. So this a car is at the ends of the diaphragm before it reaches the epithets those ends. So that's where the epiphyseal line or that growth plate is where your growth takes place. As that line ossifies or hardens, then that's when your growth is complete and you've reached your full height. So spongy bound is located in the ends, it contains the red marrow and it is act as a shock absorber. The Paris stem, that you know the word peri means around. So this is a tough fibrous tissue. It's located on the outside of the bone. It contains the blood vessels which allows the bones to be living matter, the limp vessels, which is part of the immune system, and then the nerves. Compact hard bone is located in the diaphragm in the long shaft area. And that gives bonds their hardness. Now, it also contains the haversian canals, which carry and transport the osteocytes, which are the bone cells. The medullary canal, which is located in the center of long bone in the diaphus, contains the yellow. And any time in the body, when you see yellow globular structures, this indicates fat. So this is the yellow marrow of the bone, and it's surrounded by the hard compact bone. Now, the endosteum just surrounds the medullary canal keeping it intact and doesn't allow it to be part of the hard compact bone. So you have the medullary canal in the center, surrounded by the indo stem, and that's in the center of the diaphragm.