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Chicken Leg Dissection


Background information: A bone is a kind of body tissue which is made of both living and nonliving material. Each human body contains 206 different bones. All of the bones in the body, together with the tissues the bind them and protect them form the skeletal system. Each bone is made up of several different parts. A typical long bone is enlarged at both ends with a shaft in between. A membrane called the periosteum covers the bone. Under that layer is compact bone. Beneath the compact bone is a material called spongy bone. Spongy bone is softer than compact bone and contains many hollow spaces. These spaces help prevent the bone from breaking, because they act as shock absorbers when the bone is hit or banged. It is most of the material at the ends of long bones. Inside the shaft is a soft tissue called marrow, where the body's blood cells are produced. There are two types of marrow: yellow marrow and red marrow. It is the red marrow that produced red blood cells, white blood cells and platelets. Just like other living tissues in the body, the bones must be supplied with blood or they will die.

The skeletal system has five very important jobs. Support, protection, movement, storage, and production of blood cells. Just think, if we did not have a skeletal system we would be just like a blob of Jell-O. The bones also protect many organs, and also the brain. Our skull protects the brain and our ribs protect our internal organs.

The place where bones are connected is called a joint. Joints give you the freedom to move your body. A skeleton without joints would be like a statue. There are several different types of joints in our body. The hinge joint (knee, elbow, fingers) works like a door's hinge. It only allows movement only in one plane. The ball and socket joint (hip, shoulder) allows a great range of movement in all directions. The pivot joint (neck) moves around in a back and forth motion. A globe rotating is a good example of this. The gliding joint (wrist, ankle) allows a great range of motion. This joint is connected by one bone sliding over another bone. Finally, fixed joints (skull, pelvis) do not move at all. All of these joints are crucial to the proper functioning of the body.

Vocabulary: ligament, tendon, skeletal muscle, periosteum, solid bone, spongy bone, cartilage, femur, tibia, fibula, patella, hinge joint, ball and socket joint, connective tissue, epithelial tissue, muscle tissue

Lab Goals:
1. To observe scientifically the shape, color, and properties of Muscle, Skin, Ligament, (Tendons) and Cartilage Tissue.
2. To record how the tissues are attached together to make a moveable joint, like the knee joint


Dissection Drawing:


Procedure:
1. Place the chicken leg quarter on a dissecting tray

2. The following parts are present in the specimen:
• The lower leg of the chicken is called the drumstick. It is the equivalent of the lower leg of the human and includes the tibia and fibula.
• The upper leg of the chicken is called the thigh, just as it is in humans. Its bone is the femur.
• The bones above the thigh are part of the hip and backbone of the chicken.

3. Look at the skin and record its properties in the results table below. Examine the skin (epithelial tissue). Note any dimples (goose bumps) which show where feathers were
attached to the skin. Are there any present?

4. Look closely at the hip bone. What type of joint does it make? ______________

5. Gently move the knee joint. What type of joint is it? _________________

6. Can it move sideways? ___________________

7. Remove the skin by pulling it down and off the end of the lower leg. It may be cut off if it is too difficult to remove. The yellow-white material is fat that lies under the skin.
Look at the muscle tissue below the skin. Record your findings in the table.

8. Examine the meat. The meat is muscle, and muscles work in bundles. Separate the bundles of muscles by separating them out with your fingers. Begin by inserting your thumb into the muscle of the lower leg.You will need to push forcefully through the shiny lining (called fascia) over the muscle, but it will give way at the natural separations between the muscle bundles. Continue separating the muscle into bundles by forcing your thumb and fingers through the
muscle until you are able to distinguish several separate bundles.

9. The strong, white cords, called tendons, hold the muscle to the bones. Some of these tendons will pull away from the bone as you separate the muscle bundles. Gently pull away the muscle from the bone and look for the tendon which connects the muscle to the bone. Write down what it looks like in the table. How many different insertions did you find?_____________

10. What is the physical difference in the tendon of the insertion when compared to the origin? ____________________________________________________________
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11. Arteries are generally more muscular (thicker) than veins. Follow the artery superiorly as
far as you can and locate as many branches as possible. How many do you find?___

12. Nerves are generally thin, threadlike white strands found between the muscle and the
nearest bone. Look for the nerve in your specimen. Did you find them? ____

13. Using the dissection scissors, cut across the tendons at Line A (see diagram). Observe the numerous tendons and pull the freed muscles down and away from the bone, as if you were peeling a banana. Careful you don't cut any ligaments that attach bone to bone. Look closely at the ligaments. Write down what they look like in the table. Examine the two bones in the lower leg. The large bone (Bone A) is the tibia. The small, toothpick-like bone(Bone B) is the fibula.

14. Bend the specimen at Joint A and observe that it is a hinge joint like our knee.Carefully cut away the muscle over Joint A. Make the cuts parallel to the bones, so you do not cut into the capsule over the joint. Remove as much of the pink muscle tissue as possible so that you can see the shiny white of the ligaments and cartilage around the joint. Locate one white
band of ligament on each side of the joint. These exterior ligaments hold the bones together.

15. Bend the specimen at Joint B and rotate the femur in all directions. Observe that this joint is a ball and socket joint like our hip. Remove the muscle that covers Joint B by cutting parallel to the femur, upward toward the backbone. Remove pink muscle tissue until you see a shiny white sheet of ligament that covers the joint. Present is an exterior ligament that holds the femur in the hip socket.

16. Cut the exterior ligament over the joint by cutting all around the head of the femur. As you cut this sheet of ligament, you will notice the joint becoming very loose. When it is completely loosened, pull out and downward on the femur, so the bone comes partly out of the socket in the hip. Look into the socket and see the ligament that holds the femur in the center of the socket.

17. Cut onto the hinge joint by cutting into the top of the covering of the joint from the femur side. It will become apparent that you must remove the knee cap area to expose the menisci and ligaments within. Pull up on the knee cap area and cut through it with the scissors. You will have cut through the bursa, a sac that acts as a shock absorber for the knee joint. These are found in every joint. Pull the covering back and look into the inside of the joint. You will see more white bands of ligaments holding the bones together. Observe the shiny, white layer covering the ends of the bones is cartilage. It helps the bones slide smoothly when the leg bends. Describe it in the table below.

18. Finally look at the bone. Draw a diagram to show the shapes of the ends of the bones and how they fit together. Explain how it is allowed to move in one direction but not in any other like a door on a door hinge. This is a hinge joint. Using your hands, break Bone A in half. Be careful not to contact the broken edges of bone. Inside is the soft red marrow. This is where blood cells are made. Observe how hard the bone is.

19. Explore and examine all the parts before cleaning the area.

20. Make sure to wash your hands with plenty of soap and water .


Results

Tissue Color Stretchiness Hardness Are Fibres Visible? Thickness (mm)

Skin

 

Muscle

 

Tendon

 

Ligament

 

Cartilage

 


Other observations.
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Drawing of Bones at the hinge joint in the knee.