Bones, Muscles & Joints
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The skeleton is more than just a support system.
Our video will take students on a tour of the skeletal system. We will learn about all kinds of bones in the body including: Compact vs Spongy Bone, Bone Marrow and its purpose, Long bones vs short bones and so much more.
What Are Bones and What Do They Do?
What Are Bones and What Do They Do?
Bones provide support for our bodies and help form our shape. Although they're very light, bones are strong enough to support our entire weight.
Bones also protect the body's organs.
The skull protects the brain and forms the shape of the face.
The spinal cord, a pathway for messages between the brain and the body, is protected by the backbone, or spinal column.
The ribs form a cage that shelters the heart and lungs.
The pelvis helps protect the bladder, part of the intestines, and in women, the reproductive organs.
Bones are made up of a framework of:
A protein called collagen,
with a mineral called calcium phosphate
Both makes the framework hard and strong.
Bones store calcium and release some into the bloodstream when it's needed by other parts of the body.
The amounts of some vitamins and minerals that you eat, especially vitamin D and calcium, directly affect how much calcium is stored in the bones.
What are the two types of bone tissues?
What are the two types of bone tissues?
Compact bone is the solid, hard outside part of the bone. It looks like ivory and is extremely strong. Holes and channels run through it, carrying blood vessels and nerves.
Cancellous (KAN-suh-lus) bone, which looks like a sponge, is inside compact bone. It is made up of a mesh-like network of tiny pieces of bone called trabeculae (truh-BEH-kyoo-lee). This is where bone marrow is found.
In this soft bone is where most of the body's blood cells are made. The bone marrow contains stem cells, which produce the body's red blood cells and platelets, and some types of white blood cells. Red blood cells carry oxygen to the body's tissues, and platelets help with blood clotting when someone has a cut or wound. White blood cells help the body fight infection.
Bones are fastened to other bones by long, fibrous straps called ligaments (LIG-uh-mentz). Cartilage (KAR-tul-ij), a flexible, rubbery substance in our joints, supports bones and protects them where they rub against each other.
How Do Bones Grow?
How Do Bones Grow?
The bones of kids and young teens are smaller than those of adults and contain "growing zones" called growth plates. These plates consist of multiplying cartilage cells that grow in length, and then change into hard, mineralized bone.
These growth plates are easy to spot on an X-ray. Because girls mature at an earlier age than boys, their growth plates change into hard bone at an earlier age.
Bone-building continues throughout life, as a body constantly renews and reshapes the bones' living tissue. the human skeleton is replaced every 7-10 years.
Bone contains three types of cells:
Osteoblasts, which make new bone and help repair damage
Osteocytes, mature bone cells which help continue new born formation
Osteoclasts, which break down bone and help to sculpt and shape it
IN OTHER WORDS
Early in the development of a human fetus, the skeleton is made entirely of cartilage. The relatively soft cartilage gradually turns into hard bone through ossification. This is a process in which mineral deposits replace cartilage. As shown in Figure below, ossification of long bones, which are found in the arms and legs, begins at the center of the bones and continues toward the ends. By birth, several areas of cartilage remain in the skeleton, including growth plates at the ends of the long bones. This cartilage grows as the long bones grow, so the bones can keep increasing in length during childhood.
Long bones ossify and get longer as they grow and develop. These bones grow from their ends, known as the epiphysis, and the presence of a growth plate, or epiphyseal line, signifies that the bone is still growing.
In the late teens or early twenties, a person reaches skeletal maturity. By then, all of the cartilage has been replaced by bone, so no further growth in bone length is possible. However, bones can still increase in thickness. This may occur in response to increased muscle activity, such as weight training.
The Bone Shapes
The Bone Shapes
The bones of the human skeleton are classified by their shape.
Long Bones Sutural Bones
Short Bones Sesamoid Bones
Flat Bones Irregular Bones
Long bones, are longer than they are wide and have a shaft and two ends. The diaphysis, or central shaft, contains bone marrow in a marrow cavity. The rounded ends, the epiphyses, are covered with articular cartilage and are filled with red bone marrow, which produces blood cells. Most of the limb bones are long bones—for example, the femur, tibia, ulna, and radius. Exceptions to this include the patella and the bones of the wrist and ankle.
Sesamoid bones are small, flat bones and are shaped similarly to a sesame seed. The patellae are sesamoid bones. Sesamoid bones develop inside tendons and may be found near joints at the knees, hands, and feet.
Flat bones are thin and relatively broad bones that are found where extensive protection of organs is required or where broad surfaces of muscle attachment are required. Examples of flat bones are the sternum (breast bone), ribs, scapulae (shoulder blades), and the roof of the skull.
Short bones, or cuboidal bones, are bones that are the same width and length, giving them a cube-like shape. For example, the bones of the wrist (carpals) and ankle (tarsals) are short bones.
Irregular bones are bones with complex shapes. These bones may have short, flat, notched, or ridged surfaces. Examples of irregular bones are the vertebrae, hip bones, and several skull bones.
Sutural bones are small, flat, irregularly shaped bones. They may be found between the flat bones of the skull. They vary in number, shape, size, and position.
Bones Anatomy
Bones Anatomy
Bones
Anatomy
Periosteum
This thin, dense membrane on the surface of the bone contains nerves and blood vessels that help nourish bone tissue.
Compact (Hard) Bone
This type of bone is strong, solid, and whitish in color. It makes up the hard outside portion of a bone.
Cancellous (Spongy) Bone
This type of bone is located inside the compact bone. It looks like a sponge, with bone marrow filling its spaces.
Bone Marrow
The soft bone marrow, which is found inside many bones, makes most of the body's red blood cells, white blood cells, and platelets.
3 Ways to Build Strong Bones
3 Ways to Build Strong Bones
It's easy to take our bones for granted. After all, they do all their work behind the scenes. But when a bone breaks, it's a big deal. Bones take time to heal, even for kids.
Having strong bones in childhood is a good start for bone health throughout life. We build almost all our bone density as kids and teens. People are mostly finished building bone around age 20. As adults, we still replace old bone with new bone, but more slowly. As older adults, our bones get weaker over time.
Kids with strong bones have a better chance of avoiding bone weakness later in life.
The 3 key ingredients for healthy bones: calcium, vitamin D, and exercise.
1.High-Calcium Foods for Strong Bones
Calcium is a mineral that's known for building healthy bones. It's found in dairy products, beans, some nuts and seeds, and leafy green vegetables. It's also often added to foods like orange juice or cereal.
2. Get Enough of Vitamin D
Vitamin D (sometimes labeled as vitamin D3) helps the body absorb calcium. We get vitamin D from foods like fatty fish, mushrooms, liver, and eggs, and from exposure to sunlight. Most people don't eat many foods that naturally contain vitamin D, and they're often inside and not exposed to the sun during cold weather.
To help people get enough vitamin D, many foods have vitamin D added, like cereals, orange juice, and yogurt. Milk also has added vitamin D, including some soy, almond, and oat milks. Because vitamin D is so important, health care providers recommend kids take a vitamin D supplement if they don't get enough in their diet.
3. Encourage Physical Activity
Our muscles get stronger the more we use them. The same is true for bones.
Activities like walking, running, jumping, and climbing are especially good for building bone. They are called weight-bearing activities because they use the force of our muscles and gravity to put pressure on our bones. The pressure makes the body build up stronger bone.
Activities like riding a bike and swimming don't create this weight-bearing pressure. They are great for overall body health, but kids also need to do some weight-bearing exercises.
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