Chicken Bone Lab A lab report will be written for this lab. Blue or black ink must be used; no first person or contractions can be used; and neatness and spelling are a must! Be sure to include the following in your lab write up: 1. A descriptive title 2. An introduction with information about the structures (gross and microscopic anatomy) and functions of bones. Use the “background information” to help you, but do not copy it word for word. 3. A procedure should be written so that anyone could repeat the lab that we have completed. 4. A results section should include a written description of your data, as well as data tables to indicate your qualitative and quantitative results. 5. A discussion should explain the structural roles of muscles, tendons, bones, and joints in the movement (function) of the chicken wing. Also, explain how different chemical solutions affect the bone’s chemical make-up (microscopic structure) and its ability to function normally. Lastly, make connections between the observations you make in this lab and occurrences in human bones (i.e. disease, homeostasis, functioning). Background Information Bone is a dynamic, living tissue - not the hard, dry, lifeless frame seen in scary movie or desert scenes or even on a pirate flag. About 30% of bone is living tissue, cells, and blood vessels - the tissues that make your bones grow. The blood vessels go in and out of the bone carrying oxygen and nutrients, and taking away wastes. Bones contain marrow which produces red blood cells and white blood cells. Bones have nerves that can feel pressure and pain. Bones even help us hear! About 45% of bone is mineral (primarily calcium and phosphorus), giving bone its hardness and rigidity and storing these minerals for future use. Bone releases some of this mineral when other body parts, such as nerves, may need them. Bone also contains the proteins, collagen and elastin. Finally, about 25% of bone is made up of water. Bone is built of two very important chemical groups: (a) mineral, calcium phosphate (calcium and phosphorus), and (b) the proteins (elastin and collagen). These chemicals are obtained from the foods we eat and are responsible for the firmness and durability of bone. Normally, the minerals in our bones do not dissolve completely away, but they do become less able to maintain their density in bone structure as we age. If we have provided our bodies with enough calcium in our diets as we are growing up (in childhood and early adulthood), we hope to have enough stored in our bones to keep them in good shape as we age. Bone tissue consists of compact bone (cortical or solid bone) and spongy bone (trabecular or cancellous bone). Compact bone is made up of structural units called Haversian systems. The system is composed of concentrically arranged layers of hard inorganic matrix surrounding a microscopic central Haversian canal. Blood vessels and nerves pass through the canal. Spongy bone is like a network of hardened bars with spaces between them filled with marrow. Bone tissue is made and maintained by several types of cells: osteoblasts, osteocytes, and osteoclasts. Osteoblasts make new bone by hardening the protein, collagen, with minerals. Osteocyctes maintain bone, passing nutrients and wastes back and forth between the blood and bone tissues. Osteoclasts destroy bone, releasing minerals into the blood. All through life, bone is continually being reconstructed and reshaped. A baby has very soft bones made up of cartilage. As the infant grows, the cartilage is replaced by calcium (ossification). When a person reaches the age of 20 or so, the bones stop getting longer or bigger, but there is still a lot of growing going on. Old bone cells dissolve and are replaced by new bone cells. Because bone keeps growing, your body is able to repair any breaks that may occur. Bone is made up of a hard outer "shell" consisting of compact bone. Tendons, ligaments, and other parts attach to this shell by way of the bone's covering, the periosteum. Inside the compact bone is a looser network of spongy bone containing marrow. There are 206 bones in the human body, making up our skeletal systems. Over half of them are in the wrists, ankles, hands, and feet! The skeletal system provides a strong framework for the body giving our body its shape, and permits us to stand upright. It supports and protects vital internal organs such as the brain and heart. It provides a point of attachment for muscles and connective tissue (ligaments, tendons, cartilage) and certain bones, connected at flexible joints, form a combination of levers that allow coordinated movement. Bones may be classified into four groups: long bones, flat bones, short bones, or irregular bones. Long bones are strong shafts made of compact bone tissue with the ends consisting of spongy tissue covered with com-pact tissue. Their slightly curved shafts enable them to absorb shock. Flat bones provide broad surfaces to protect other structures and for anchoring muscles. They are broad flat plates of spongy tissue sandwiched between two layers of compact tissue. Short bones are strong, irregular cubes, made of spongy bone covered with compact tissue. Irregular bones are shaped differently enough that they cannot be grouped with the other three types of bones. Their proportion of spongy to compact tissue varies from bone to bone. Special Safety Considerations Put on goggles, gloves, and an apron for working with acetic acid and to protect against possible salmonella contamination from handling raw chicken. Be careful handling bones; if they break, they can splinter and puncture your skin. Materials Chicken wing, dissecting kit, dissecting pan, glass containers, bleach, vinegar, alcohol, electronic balance, ruler, gloves, safety goggles, apron Part I – Gross Anatomy and Function of Chicken Wing Procedures: 1. Study the diagram of a chicken wing. Use the diagram to help you locate certain muscular and skeletal structures. 2. Rinse the chicken wing under cool, running water. Dry it thoroughly with a paper towel. 3. Examine the wing at the point where it was removed from the body. Depending on the way the wing is cut, you might see cartilage and bone marrow. 4. Using the scissors, cut down the middle of the skin, starting at the top end of the upper wing. Try not to cut through the muscles below the skin. Do this by piercing the skin and then slipping the scissors between the skin layer and the muscle. Cut until you reach the shoulder joint. (See Figure 1, Cut 1.) 5. Cut down the sides of the skin to make a T-shaped cut. Start at the first cut and cut away from it in both directions. Peel the skin and cut to loosen it. (Note: the chicken skin can be very difficult to remove. Take your time peeling it back so as not to damage the tissues underlying it. (See Figure 2, Cut 2.) Fat 6. Look for yellowish tissue clumped together beneath the skin. This is fat tissue, made of fat cells. Muscles 7. Observe the muscles in the wing. They look like bundles of pale pink tissue. 8. Find two muscles in the wing that bend and straighten the elbow joint. Each muscle pulls on the lower wing bones in one direction (the flexor bends the joint). Since the flexor cannot lengthen by itself to push the bone back to straighten the joint, another muscle pulls the bone in the opposite direction (extensor). 9. Hold the wing down at the shoulder and alternately pull on each muscle. Observe what happens. Tendons 10. Tendons are shiny white tissues at the ends of the muscles that attach muscles to bones. Find as many tendons as you can on the chicken wing. 11. Pull on a tendon to see how it helps the chicken move its wing. Joints and Ligaments 12. Two bones come together at a joint. Bend and straighten the elbow joint and observe how the bones fit together. 13. Ligaments connect bones to other bones at joints. They look like a shiny white covering of the joint surfaces. 14. Closely examine the elbow joint between the upper wing and the lower wing and identify the ligaments. Cartilage 15. Between the bones is another shiny white material that is slippery. This is cartilage, which helps the bones move without grinding against one another, or without causing trauma. Wing 16. Move the wing again. Explore how the muscles, tendons, ligaments, and cartilage play roles in the wing’s movement. 17. Complete the Observation Table. When you have finished observing the wing and writing your notes, properly dispose of the external chicken tissues. Keep the three wing bones for Part II. 18. Wash all equipment in hot, soapy water. Wash your hands with hot water and soap. Observations: Complete the Observation Table and questions. 1. Do you think this wing is from the left side or the right side of the chicken’s body? Explain your answer. 2. Which joint in the human body is similar to the joint you studied? 3. Describe any interesting observations you made about the chicken wing. Include names of bones and tissues in your description when possible. Discussion: 1. What type of tissue actually moves the chicken wing? 2. Why are tendons important to a muscle’s ability to make the body move? 3. What tissue of the chicken wing is commonly referred to as the “meat”? 4. Based on your observations, explain the roles of muscles, tendons, bones, and joints in the back-and-forth movement of the lower chicken wing. Part II – Microscopic Anatomy and Function of Chicken Wing Procedures: 1. Using the chicken bones from Part I, dry off any excess moisture, remove any extra “meat” and “gristle,” weigh and measure the length of each specimen. 2. Record data on a chart in your Results section. 3. Tie fishing line on each end of three bones. Then, place one chicken bone in a container of household vinegar. Provide enough vinegar to cover the bone. 4. Place the second chicken bone in a container of bleach. 5. Set up a control group by placing the third bone in a container of alcohol. 6. Each day, at the same time, remove the bones from their containers; dry off any excess moisture, and weigh and measure each bone. Record the findings onto the chart. Notice any changes in color, texture, or appearance of the bone. Write down your observations. Continue this for three days. 7. At the end of the third day, handle the bones and notice the difference between them. 8. Tap the bones on the table. Be careful with the brittle bone as it is likely to shatter. Observations: 1. Compare and contrast the three bones placed in the various liquids. 2. Generally, distilled water is used as a control when comparing the effects of liquids on types of tissues. However, in this experiment we used alcohol. Why? 3. Why do you think the liquids had the effect they did on the bones? Discussion: 1. In rickets, the bones are not properly calcified due to a lack of calcium and/or vitamin D which aids in the deposition of calcium in the bone. Which of above specimens more closely resembles the bones of a child with rickets? Explain. 2. What is the cause of osteoporosis? What are its symptoms? What age group does it normally affect? What preventive measures can be taken to prevent osteoporosis? Which of the above specimens more closely resembles the bones of an adult with osteoporosis? Explain.
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