Thomas

Lab: Investigation of a Chicken Wing

Part A – The Skin

1.A. Observe the skin with a hand lens. Notice the small bumps on the surface of the

skin. What do you think these small bumps were for?

These bumps are the origins for where the feathers would be on the chicken.

B. These bumps are similar to what structure on human skin?

These bumps are similar to the origins of our hair follicles because they are somewhat of an equivalent to the feathers of a chicken.

2. As you removed the skin, you will notice how greasy it is. What tissue is responsible for this greasiness?

The tissue responsible for this greasiness is the fat.

Part B - Muscle

1. Which type of muscle do you find in the chicken wing?

The muscle found in the chicken wing is called striated muscle.

2. Using your probe to separate them, how many individual muscles can you identify in the chicken wing?

15 individual muscles were identified.

3. Describe the appearance and texture of the tendons.

The tendons of the chicken wing were white and had the texture and appearance of a plant stem or a chord.

4. Pull on the various muscles of the forelimb and observe the resulting movements.

N/A

5. Find an opposing pair in the wing. Describe how these muscles work together to produce movement in the wing. (Hint: Can they both contract at the same time?)

Opposing muscles (antagonistic muscles), as in humans, work together to perform opposite movements of the same joint. One of the muscles is usually responsible for extending the joint

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while the other is responsible for flexing the joint. Because they have opposite functions, they cannot both contract at the same time. For example, while one muscle is contracting to flex the joint, the muscle responsible for extending would be relaxing. When chickens flap their wings, there would be a few muscles responsible for adducting while their antagonistic muscles would be responsible for abducting the wing.

Part C – The Bones and Joints

1. How many joints are there between the upper limb and forelimb?

Between the upper limb and the forelimb, there are three joints; one between the upper limb and each of the bones in the lower limb (humeroulnar, humeroradial), and one between the two bones in the lower limb (radioulnar).

2. Explain how you determined this number (i.e what defines a joint?).

This number was determined by observing points of attachment of the bones in each limb. At these joints, there is a lot of cartilage, there are muscles crossing over, and there are ligaments.

3. Describe the connective tissue at the joints (ligaments). What does it look like? What is the texture?

The ligaments are shiny, white and have a slippery texture. They are very similar to the tendons because they have a plant stem or chord-like structure.

4. Ligaments are located at the joint capsule. Are you able to observe/separate each ligament surrounding a joint from one another? Why or why not?

You are able to separate each of the ligaments, but there is a lot of cartilage and connective tissue that keeps them together. In order to separate them, this cartilage has to be cut. These ligaments can be separated because they are located on different sides of the joint and connect the bones in different areas. They all have the same function (attachment of the articulating bones) but can be differentiated because of their slight difference in location.

5. Cut the bone apart at the joints (Figure 4.). Compare the texture of the articulating cartilage tissue to the texture and appearance of the bone. How does it differ?

The articulating cartilage tissue is white and shiny, flexible, slippery, and slightly elastic/stretchy and represents a cap (on the end of the bones), whereas the bone is inflexible, not very slippery, and has more of a rough surface. Bones are an off-white colour and have cartilage caps at the joints. These caps reduce friction and without them, there would be pain during articulation.

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6. Separate each individual bone from one another. How many bones are found in one chicken wing?

In the chicken wing that we were given, there are 3 bones (not including carpals, metacarpals, shoulder bones, etc) – the humerus, ulna, and radius.

7. Are there any bones/bone markings on the chicken wing that are similar to our own?

The chicken wing bones had condyles, tuberosities, epiphyses, and more marks that are similar to what humans have. They generally have the same structure and marks.

8. If bone marrow is present, describe the appearance/texture of this substance.

Bone marrow is red and clumpy. It is generally pretty soft and can be scooped out of the bone.

9. Is cancellous bone present at the epiphyseal region as it is in human bones?

Yes, the cancellous bone is present at the epiphyseal region.

Discussion:

1. Complete the following table.

Tissue Description Function

1. Skin: Epidermal Layer Soft, stretchy, easily cut, lays just on top of muscles, outermost layer

Protection of muscles, bones, etc

2. Skin: Subcutaneous Fat

Greasy, white, thin layer under skin

Protection, long term energy storage

3. Bone Marrow Red, can be taken out of bone in clumps

Creates red blood cells, some white blood cells

4. Ligament White, shiny, chord-like, connects bones

Connects bones, keeps them articulating

5. Tendon White, shiny, plant stem-like, connects muscles to bones

Connects muscles to bones, allows movement of joints

6. Cartilage White, shiny, between bones Prevents friction of bones during articulation, protection

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2. Compare the number of bones in a chicken wing to the number of bones found in the human arm – which has more and why?

Human arms and chicken wings have the same number of bones because they share the same evolutionary origin. The limbs perform similar functions and move in similar ways which is why the structure is almost identical.

3. What type of joints can be found in the chicken wing? Be as specific as possible and you may include the joint that attaches the chicken wing to the body of the chicken.

Between the humerus and the ulna, there is a hinge joint. Between the ulna and the radius, there is a pivot joint. Between the radius and the humerus, there is a hinge joint. Between the humerus and the glenoid fossa is a ball in socket joint.

4. Which are easier to observe/identify at the joints of the chicken wing – individual ligaments or individual tendons? Why is that?

Tendons are more easily observed because they are usually more superficial than ligaments. To see the ligaments, you must cut through all the muscles and tendons.

5. Explain in detail (with the assistance of reference material) the structure of tendon and ligament as it relates to their function. What makes them so strong yet flexible? Which is more likely to heal after injury? Why?

Though tendons and ligaments are both fibrous connective tissues, they have very different functions. Both tendons and ligaments are made up of collagen fibrils but are constructed differently in each. In tendons, the fibrils run parallel which allows there to be more elasticity whereas in ligaments, the fibrils are perpendicular to provide a stronger structure and better support. Tendons are more likely to heal after an injury because once the fibres tear in a ligament, there might not be enough of a blood supply to heal it causing it to never actually return to its original state. Since tendons are part of muscles, and muscles have many blood vessels in the proximity, they have a better chance of being healed.

6. Differentiate between cartilage and bone. Focus on the structure and function of each.

Bone is the solid material that forms the structure for our body. Inside the bone, there is bone marrow which is where red blood cells are being made. Cartilage forms the attachment between bones and allows them to have motion and articulate. Some cartilage is protective, some is to prevent friction during articulation. Bones are made up of calcium and other minerals whereas cartilage is made up of proteins and fibres that allow for the flexibility.

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7. Research the names of the muscles/bones of the chicken wing. Are the names similar or different to human muscle names (e.g. Biceps brachii etc.)?

The names of the muscles and bones are extremely similar to those of humans. This is probably because they perform almost identical functions and because the two structures are very similar as well.

8. Briefly explain how the bones, muscles and joints work together to produce movement.

Bones provide the main structure for a body, the joints are what attach all the bones, and the muscles are what make everything move. Joints require special cartilage that allows for flexibility, while maintaining strength so that they are not constantly tearing. Muscles cross over joints and the contraction of these muscles is what allows the joint to flex and extend.

Conclusion:

1. When eating chicken wings, what component/tissue is often consumed as “meat”?

The component that is often consumed as meat is the muscle tissue.

2. How does the structure of the bones of a chicken wing allow for the overall function of the appendage – i.e. how do the bones allow for strength and stability while still allowing for movement/flight?

Over time, chickens have evolved wings that enhance the efficiency of their function. Their bones and joints have strategic placement and size relative to their bodies which allow them to fly. Chickens have similar bones to ours, except their bones are hollow and filled with air which helps them fly while maintaining a strong structure.

3. Describe the various similarities and differences between the chicken wing and the human arm.

Chicken wings and human arms have a very similar bone structure. They both have one larger bone – the humerus – in the upper arm and two smaller bones – the radius and the ulna – in the forearm. They both muscles that generally have the same function and have very similar antagonistic muscles. The main difference between a chicken wing and the human arm other than the size, is the structure after the carpals. The metacarpals and phalanges are much different on chickens because they require more surface area of the wing to allow for better flight.

4. Was this an effective dissection? Why or why not?

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This dissection was effective because it allowed us to see a structure that was very similar to that of our own arm. It provided an excellent visual and feel for the components of the arm including the bones, joints, muscles, tendons, ligaments, etc.

5. Are there any other organisms that would provide a better model of a human joint/limb than a chicken wing? Explain.

There are many other organisms that have a similar structure to ours because we have the same evolutionary origin as so many animals, but some animals that we are very similar to are apes, monkeys, and other mammals. This is because they have similar limbs to ours because of how the transport themselves. They walk and run with their lower limbs mostly, have the same number of joints, around the same number of bones, and have more recent ancestors with us than we have with almost every other organism on the planet.