The epiphysis is a thin shell of compact bone filled with a lattice or sponge-like structure that is surrounded by red marrow which makes red blood cells. Obtain and cook enough chicken pieces to provide one or more different bones any size or shape to each group of students.
You also may have students bring leftover cooked chicken bones from home. OR use the long bones prepared for the activity, "The Skeleton. It always is a good idea to have students wash hands before and after any lab activity. Point to your arm or leg and ask students to think about characteristics that might be important for large arm or leg bones. Tell students they will be conducting an investigation that will provide clues about the structure of long bones in humans and other vertebrates.
Specifically, they will be comparing the relative abilities of solid and hollow cylinders to support external weights. Ask, Is a hollow cylinder or a solid cylinder able to support more weight, relative to its own weight? Each group should conclude its explorations by calculating the ratio of weight supported to cylinder weight for each kind of cylinder.
Did either cylinder hold more weight than you expected? Which cylinder had a higher ratio of weight supported? Did you expect this result? Ask students to think about which type of cylinder hollow or solid might make a better bone. Have students record their predictions about the structure of long bones hollow or solid. Have the Materials Managers pick up one or more bones for their groups. Joints are where two bones meet. They make the skeleton flexible — without them, movement would be impossible.
Joints allow our bodies to move in many ways. Some joints open and close like a hinge such as knees and elbows , whereas others allow for more complicated movement — a shoulder or hip joint, for example, allows for backward, forward, sideways, and rotating movement.
Reviewed by: Larissa Hirsch, MD. Larger text size Large text size Regular text size. Bones are made up of 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. How Do Bones Grow? Bone contains three types of cells: osteoblasts AHS-tee-uh-blastz , which make new bone and help repair damage osteocytes AHS-tee-o-sites , mature bone cells which help continue new born formation osteoclasts AHS-tee-o-klasts , which break down bone and help to sculpt and shape it What Are Muscles and What Do They Do? Humans have three different kinds of muscle: Skeletal muscle is attached by cord-like tendons to bone, such as in the legs, arms, and face.
Skeletal muscles are called striated STRY-ay-ted because they are made up of fibers that have horizontal stripes when viewed under a microscope. These muscles help hold the skeleton together, give the body shape, and help it with everyday movements known as voluntary muscles because you can control them. They can contract shorten or tighten quickly and powerfully, but they tire easily. Smooth, or involuntary, muscle is also made of fibers, but this type of muscle looks smooth, not striated.
We can't consciously control our smooth muscles; rather, they're controlled by the nervous system automatically which is why they're also called involuntary. Examples of smooth muscles are the walls of the stomach and intestines, which help break up food and move it through the digestive system.
If you suffered from arthritis of the knee, you would be unable to straighten or bend your knee fully and moving it would be very painful.
Sadly there is no cure for this condition, but joints may be replaced with steel or plastic to make artificial bone and cartilage. What are bones made of? If you looked at a cross section of your arm, you would be able to see that the bone is actually a hollow structure; in the middle is a cylinder. So, bones are actually hollow tubes, a bit like bamboo which is a type of plant.
A hollow structure means that the weight of the bone is a lot less than it would be if it were solid. Have a look at the Extreme Limits and see what happens when different forces are applied to bones. What do these clips have in common apart from being gory!
The Haversian canals also surround nerve cells throughout the bone and communicate with osteocytes in lacunae spaces within the dense bone matrix that contain the living bone cells through canaliculi. This unique arrangement is conducive to the storage of mineral salt deposits that give bone tissue its strength.
Haversian canal : The Haversian canals surround blood vessels and nerve cells throughout the bone. The vascular supply of long bones depends on several points of inflow, which feed complex sinusoidal networks within the bone. These in turn drain to various channels through all surfaces of the bone except that covered by articular cartilage. Epiphyseal plate : Image shows the location of the epiphyseal plates or lines and the articular surfaces of long bones.
One or two main diaphyseal nutrient arteries enter the shaft obliquely through one or two nutrient foramina leading to nutrient canals. Their sites of entry and angulation are almost constant and characteristically directed away from the growing epiphysis.
The nutrient arteries divide into ascending and descending branches in the medullary cavity. These approach the epiphysis dividing into smaller rami. Near the epiphysis, they anastomose with the metaphyseal and epiphyseal arteries. The blood supply of the immature bones is similar, but the epiphysis is a discrete vascular zone separated from the metaphysis by the growth plate.
Epiphyseal and metaphyseal arteries enter on both sides of the growth cartilage, with anastamoses between them being few or absent. Growth cartilage receives its blood supply from both sources and also from an anastamotic collar in the adjoining perichondrium.
Young periosteum is more vascular, has more metaphyseal branches, and its vessels communicate more freely with those of the shaft than adult periosteum. The basic microscopic unit of bone is an osteon, which can be arranged into woven bone or lamellar bone.
Bones are composed of bone matrix, which has both organic and inorganic components. Bone matrix is laid down by osteoblasts as collagen, also known as osteoid. Osteoid is hardened with inorganic salts, such as calcium and phosphate, and by the chemicals released from the osteoblasts through a process known as mineralization.
The basic microscopic unit of bone is an osteon or Haversian system. Osteons are roughly cylindrical structures that can measure several millimeters long and around 0. Each osteon consists of a lamellae of compact bone tissue that surround a central canal Haversian canal. The boundary of an osteon is called the cement line. Osteons can be arranged into woven bone or lamellar bone. Osteon : A photo taken through a microscope that shows the anatomy of compact bone with a detailed view of an osteon.
Woven bone : Woven bone is characterized by the irregular organization of collagen fibers and is mechanically weak. Woven bone is found on the growing ends of an immature skeleton or, in adults, at the site of a healing fracture. Woven bone is characterized by the irregular organization of collagen fibers and is mechanically weak, but forms quickly. The criss-cross appearance of the fibrous matrix is why it is referred to as woven.
It has a high proportion of osteocytes to hard inorganic salts that leads to its mechanical weakness. Woven bone is replaced by lamellar bone during development. In contrast to woven bone, lamellar bone is highly organized in concentric sheets with a much lower proportion of osteocytes to surrounding tissue.
The regular parallel alignment of collagen into sheets, or, lamellae, causes lamellar bone to be mechanically strong. Femur head showing trabecular bone : A cross-section of the head of the femur showing lamellar bone on the borders and trabecular bone in the center.
Lamellar bone makes up the compact or cortical bone in the skeleton, such as the long bones of the legs and arms. When the same lamellar bone is loosely arranged, it is referred to as trabecular bone. Trabecular bone gets its name because of the spongy pattern it displays in an x-ray. The spaces within trabecular bone are filled with active bone marrow. After a fracture, woven bone forms initially, but it is gradually replaced by lamellar bone during a process known as bony substitution.
Acid-base imbalances, including metabolic acidosis and alkalosis, can produce severe, even life-threatening medical conditions. Traveling to a high altitude can cause an acid-base imbalance due to reduced levels of oxygen in the atmosphere, and, therefore, in the blood.
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