Body Systems: Practical Actvity Portfolio
Skeletal System of a Prawn
The prawn has an exoskeleton - a rigid, external casing that protects the softer body of the crustacean. Upon observation, the exoskeleton of the prawn appeared relatively hard, and was visibly protecting the more vulnerable flesh underneath. It resembled a shell, and appeared to be broken into sections or chambers. It was flecked orange in colour, and the shell although hard did in fact bend with the body - it was malleable.
This skeletal system would provide primarily support and structure for the prawn, as well as protection of the flesh underneath from immediate danger or impact. Other animals that have this kind of skeletal system include crustaceans, shellfish and numerable insects.
Whilst the prawns have an exoskeleton, humans have an endoskeleton - a hard, internal skeleton embedded in deep tissue below a protective layer of skin on the surface. The main difference between the prawn's exoskeleton and the human's endoskeleton is that that the human skeleton is much stronger.
Some benefits of this kind of skeletal system are that it provides a layer of protection for the fragile body underneath. This layer, unlike humans, also protects its tissue lying underneath. Some disadvantages to this kind of skeletal system are that although strong in relation to the size of the prawn, it is thin and not as strong as other's skeletons, therefore the prawn is still vulnerable. Another disadvantage is that when the prawn sheds its exoskeleton once it has become too small, it spends a period of time completely exposed and with no protection, making it extremely vulnerable.
The prawn sheds its skeleton as it grows, and produces a new one relative to the body size of the crustacean. The skeleton is made of chitin: a tough, protective, semitransparent compound substance, and is the primary component of exoskeletons.
^A prawn, with its peachy exoskeleton visible.
^The clear exoskeleton of the prawn
Skeletal System of a Worm
The worm has a hydroskeleton, a skeleton system that consists of a fluid filled cavity surrounded by muscle and is found in most soft and cold bodied animals. A combination of muscle movement and the pressure of the fluid can help the creature change shape or cause movement: this type of skeleton is extremely flexible. Earthworms, which are completely boneless, use their skeletons to burrow through the ground.
^The small worm, with chambers faintly visible
Skeletal System of a Cuttlefish
The cuttlebone of the cuttlefish could be described as off-white and solid. it is relatively large, as well as lightweight and porous: it also had a dried appearance. The main role of the cuttlebone would be to assist with the structure of the cuttlefish. This porous bone would be buoyant when in water, and would help the fish to float. It is made from calcium carbonate, and is an internal/endoskeleton.
^The creamy, porous cuttlebone
Skeletal System of Humans
The structure of the skeletal system of humans is internal, and both lightweight and strong. The axial skeleton provides protection, and is found encasing most vital organs such as the brain, lungs and heat. The appendicular skeleton, which involves the bones in the leg, arm and shoulders, helps us move. Our skeletal system is made from bone - principally made from collagen and calcium phosphate, along with bone marrow. Our skeletal system also involves cartilage, ligaments and tendons, of which assist in connecting bones to other areas of our body such as muscle.
The role of our skeletal system is to support, protect, and allow movement. Our skeletal system supports our soft tissues, provides protection for our organs (axial skeleton) and enables us to move around (appendicular skeleton).
The role of bone marrow, a soft, spongy tissue, is to produce new platelets, as well as both red and white blood cells. On average, the bone marrow creates 500 billion new cells per day, and these use the blood vessels, found within the marrow, to transfer into the circulatory system. Bone marrow is found in the hollow spaces in the interior of our bones.
Our bones are made from primarily collagen and calcium phosphate. The outer surface of bone is a thin, dense membrane that contains nerves and blood vessels that nourish the bone. The next layer is made up of compact bone, and is both smooth and extremely hard. Within the compact bone are many layers of cancellous or spongy bone, and this protects the bone marrow.
Our skeletal system changes dramatically from birth to an adult. When an infant, our bones are significantly smaller than what they will grow to be once an adult. A baby has approximately 300 bones at birth, and these eventually fuse together to form the 206 bones adults have. As a baby, some bones are also made from soft, flexible cartilage, and throughout time this grows and is replaced by bone.
Our skeleton is an endoskeleton, and other animals that share this skeletal system include mammals, birds and reptiles such as dogs, cats, horses, pigeons and snakes.
^A diagram of the human skeleton, axial and appendicular skeletons not shown
Chicken Wing Dissection Response Questions
Remove the skin from the chicken wing. Be careful no to cut into any muscle tissue. The best way to remove the skin is to cut along the length of the bone. Identify the upper wing and the lower wing, along with the wing tip.
1. What structures do they correspond to in humans?
These structures correspond to the upper arm, lower arm and hand/fingers. Specifically, the bones and joints that correspond are the humerus, ulna, radius, elbow and wrist, and the muscles that correspond are the biceps, triceps, ulnaris and radius longus.
Identify the muscles in the upper wing. Have a go at tugging on each of these muscles.
2. What happens when you tug on these muscles?
The lower wing as well as the wing tip move upwards and downwards, corresponding to which muscle was being tugged at. These actions work in the same fashion as our muscles would when we move. For example, if you tugged on the bicep of the upper arm, the lower arm and wing tip would raise.
3. What muscles to they correspond to in humans?
The muscles in the upper wing correspond to the bicep and tricep, and in the lower wing the ulnaris and radius longus.
4. Which muscle is an extensor (causes the limb to extend when it contracts)?
As the chicken wing's natural position is slightly bent (upwards), when straightened flat the bicep is the extensor.
5. Which muscle is a flexor (causes the limb to flex when it contracts)?
As the chicken wing's natural position is slightly bent (upwards), when straightened flat the tricep is the flexor.
Identify the muscles in the lower wing. Have a go at tugging on each of these muscles.
6. What happens when you tug on these muscles?
Very similar to response 2, the wing tip itself moves upwards and downwards, corresponding to which muscle was being tugged at. These actions work in the same fashion as our muscles would when we move. For example, if you tugged on the ulnaris of the lower arm, the wing tip itself would move upwards.
Identify the muscles on the diagram below. Use two different colours to identify the extensor muscle and flexor muscle. Next to each muscle, explain what happens when the muscle contracts. (See diagram below)
Cut away some of the muscle tissue. Find the tissue that connects the muscle to the bone.
7. What is this tissue called?
The tissue is called tendon.
8. Describe what it looks like.
The tendons seen look like a a thin, white, band, and appear to be an extension of the muscle connecting to the bone.
Observe the elbow joint.
9. What is the tissue that connects the bones at this joint called?
The tissue is called ligament.
10. What kind of joint is this?
This joint is a hinge joint.
11. What kind of joint connects the wing at the shoulder?
This joint is a ball and socket joint.
12. Describe the cartilage that lines the joint (appearance, texture, how much is there).
The cartilage that lines the joint appears as white, with a hint of light purple, and is very smooth and slippery when a finger is run across it, which would have assisted with the reduction of friction. There was only a very thin layer covering the joint.
Continue to cut away all of the muscle, so as to expose just the bones.
13. Name the bones found in the chicken wing.
The bones found in the chicken wing are the humerus, radius and ulna.
Label the diagram below with the bones and joints you can identify. (See diagram below)
Photographs of the Chicken Wing Dissection
^A whole chicken wing, lying in its natural position
^Chicken wing with its skin off and muscles exposed
^A tendon appearing as a thin, white extension of the muscle
^A ligament appearing as a thin band connecting the bone
^Both ligaments and tendons, shown as white bands
^Cartilage covering the bone surface, appearing as white-purple
^Diagram showing the extensor and flexor muscles when straightening the wing
^Diagram showing the muscles and joints found in a chicken wing
Heart Dissection - Prac Write Up
1. Describe the appearance of the heart. What does it look like? How does it feel? Are there any features on it that you can describe?
The heart is a combination of multiple colours: the fat around it is off-white, and the muscle tissue ranges from a red-brown to almost purple. Blood vessels (coronary arteries) are visible around the heart, and these appear as irregular, diagonal thin red lines. The vena cava, aorta, pulmonary vein, and pulmonary artery are just visible at the top of the heart.
2. Provide a sketch of the front exterior of the heart.
My sketch of the heart is included in the pictures below.
3. Find the blood vessels on the surface of the heart muscle. These are coronary arteries. They carry nutrients and oxygen to the heart muscle.
a. Describe what this artery looks like.
The coronary arteries appear as thin, multi-directional (but primarily diagonal) red lines, and seem well protected by fat and heart tissue.
b. What do you think would happen if this artery was blocked by a clot?
If a coronary artery became blocked, the heart would not be able to obtain oxygen and blood. This can cause severe chest pain, also referred to as an angina attack.
4. How do you know which is the left and right side of the heart?
The right and left sides of the heart can be distinguished by the thickness of the muscle. The left ventricle has thicker muscle than the right because it has to pump out masses of blood to the rest of the body, through the aorta.
5. Have a feel of the thickness of the heart muscle at the top and the bottom of the heart. Describe the following features:
a. The thickness of the muscles at the top of the heart.
The muscle at the top of the heart is thick, firm and very tough; the layer of fat at the top of the heart contributes to this thickness.
b. The thickness of the muscles at the bottom of the heart.
At the bottom of the heart, the muscle is even thicker, especially around where the septum would be located. Notably, the left side is considerably thicker than the right, as the left ventricle wall is bigger than the right. This is because the left ventricle pumps out large amounts of blood to the body through the aorta, and needs a thick wall to complete this job.
c. The amount of fat surrounding the heart.
There is a reasonable amount of fat surrounding the heart, especially at the top. The fat on the upper half of the heart is 1-2cm thick, and surrounding the lower areas it is approximately 50 millimetres thick.
d. Any major vessels entering and exiting the heart.
The major vessels entering/exiting the heart are the aorta, the vena cava, the pulmonary vein, and the pulmonary artery. These have been chopped very finely, so although difficult to initially locate they are present. All major vessels appear as hollow holes that lead into the body of the heart.
6. Find the pulmonary artery that leaves the right ventricle. Find the pulmonary vein that enters the left atrium. Circle the correct answer:
Deoxygenated/Oxygenated blood leaves the right ventricle/Left atrium in an artery/vein and travels to the lungs/rest of the body. Here, the blood collects
oxygen/drops off oxygen so it is now oxygenated/deoxygenated. The blood travels back to the heart via an artery/vein.
7. Find the aorta, which carries blood away from the left ventricle of the heart.
a. Describe the thickness of this vessel. Why do you think it needs to be so thick?
The aorta is circular, wide and thick; approximately 1-2cm wideness in diameter. It needs to be this thick to withstand the high pressure of the heartbeat and strong blood flow.
b. Where is it taking blood to?
The aorta takes blood to the brain and other internal organs such as the stomach, liver and kidneys.
8. Find the vena cava. This is the vein that returns blood from the body.
a. Compare the thickness of the vena cava to the aorta. Why do you think it is different?
The vena cava is marginally thinner than the aorta and less elastic. It is different to the aorta because it doesn't need to with stand as much pressure from the flow of oxygenated blood.
b. What part of the heart does the vena cava go back into?
The vena cava goes back into the right ventricle.
c. Remember what you observed when you saw the water flowing through the heart. The water went into the vena cava and into the heart. Which blood vessel did the water come out of the heart from?
From the vena cava, water would have come out of the pulmonary artery.
9. When water was flowing into the pulmonary vein, which vessel did it come out of?
From the pulmonary vein, water would have come out of the aorta.
1. Describe what you see in the left side of the heart.
In the left side of the heart there is a narrow cavity with a very thick muscle wall. The muscle wall is a continuous deep red, and many valves inside the heart are visible. The valves appear as almost slimy, and are small and cylindrical. These attach the vessel wall to the muscle wall of the heart.
2. Observe any valves you see. What do you think their job would be?
The role of valves is to make sure that blood doesn't flow back the wrong way, or back in the direction it came from.
3. Cut the aorta. Describe how it appears, how it feels and any other features.
The aorta is a large hole with a thick, tough muscle wall. It appeared as a light red colour, and was slippery. Our heart's aorta was cut off very finely at the top, so not much else was visible.
4. Fill out the table below.
5. In the table below, indicate the location and role of the following structures.
6. In the diagram below, label the parts of the heart. Indicate the direction of the blood flow around the body. Use red and blue pencils to indicate oxygenated and deoxygenated blood. Indicate where the blood has come from and where the blood leaving the heart is going to.
Photographs of the Heart Dissection
^The heart orientated correctly (left and right sides)
^ Arial view of the heart, showing the vena cava, aorta and cavities leading to the atria
^Making an incision into the heart tissue
^The left ventricle, with valves visible
^The septum, found between the two chambers
^The right ventricle
^Sketch of the front exterior of the heart
Heart Box Diagram Activity
As part of assessment of the circulatory system, we (Kira, Ella, Rou Wei, Louise and I) created an adaption of the heart box diagram, as shown below. Using sport equipment from the shed, we successfully managed to represent the chambers of the heart, major blood vessels and blood flow.
Explanation of our re-created heart box diagram:
1. Oxygenated blood enters the left ventricle through the pulmonary vein, which is represented by a green and yellow sector of dots as the chamber, and red lacrosse sticks (symbolising oxygenated blood) as the vein.
2. It is then pushed up through the aorta, represented by red lacrosse sticks, and is pumped through the body, represented by red dots leading to purple bibs.
3. The organs in the body use this blood, and it leaves deoxygenated, represented by blue dots (symbolising deoxygenated blood) leaving the purple bibs.
4. The deoxygenated blood returns to the heart's right ventricle via the vena cava, represented by blue dots as the path taken, blue lacrosse sticks as the vena cava and a sector of green and yellow dots as the ventricle.
5. Here the blood is pumped up the pulmonary artery, represented by blue lacrosse sticks, and flows to the lungs, represented by blue dots leading to orange bibs.
6. In the lungs, blood becomes oxygenated again and travels back to the left ventricle through the pulmonary vein again, represented by a path of red dots, and the original set of red lacrosse sticks.
The numbers (1,2,3 etc.) used above to describe processes of the heart are incorporated into the annotated photograph, for further clarification.
Photographs of the Heart box Diagram Walk Through
^ The original heart box diagram
^A photograph showing our reconstructed heart box diagram, using equipment from the sports shed.
^An annotated explanation of our heart box recreation
Pluck Demo and Dissection
The primary function of the respiratory system is to supply the blood with oxygen in order for the blood to deliver oxygen to all parts of the body – done through breathing. When we breathe, we inhale oxygen and exhale carbon dioxide. This exchange of gases is the respiratory system's means of getting oxygen to the blood. The pluck demo clearly showed this process, where air enters the lungs through a pump, and the lungs expand and contract as they would function when breathing. expanding and contracting – this representing how the lungs would function when breathing.
When breathing, the air enters body through the mouth and/or nostrils and travels down the trachea. Down the trachea, the oxygen then passes through the larynx (where speech sounds a reproduced) and the trachea (a small tube that enters the chest cavity). In the chest cavity, the trachea splits into two smaller tubes called
the bronchi. Each bronchus then divides again forming the bronchial tubes. The
bronchial tubes lead directly into the lungs where they divide into many smaller tubes which connect to tiny sacs called alveoli which are surrounded by capillaries. The inhaled oxygen passes into the alveoli and then transfers through the capillaries into the bloodstream via the semi-permeable capillaries. Meanwhile, the waste-rich blood from the veins releases its carbon dioxide into the alveoli. The carbon dioxide then follows the same path out of the lungs when you exhale. The diaphragm assists in this process, helping to pump the carbon dioxide out of the lungs and pull oxygen into the lungs. When the diaphragm contracts oxygen is pulled into the lungs, and when it relaxes carbon dioxide is pumped out of the lungs.
When observing and dissecting the pluck, the trachea appeared as a large, vertical, pale tube connecting to the lungs. The rings of cartilage were clearly visible, and girls that held the detached trachea described the trachea as “… a spring inside a
thin plastic water bottle.” The lungs were both similar sized, and appeared as dark, skewed oval-shaped sacs. The diaphragm, which was visible when the lungs were turned over, appeared a thin sheet of muscle similar in colour to the lungs. The heart, liver and gall bladder were also visible – and these were all connected to the lungs through both muscle and arteries (such as the pulmonary for the heart.) The heart appeared as it did in the dissection, although the arteries and veins were far more prominent, especially the pulmonary artery. The liver was very large, relatively flat and an off brown colour – the gall bladder a small sack protruding from this.
When the lungs were actually filled with the air from the pump, which was placed inside the lung sac, they expanded rapidly to almost twice their original size, and turned a lot lighter in colour. As soon as the air left the lungs, they deflated/relaxed to their original position and size, and returned in colour as well. When the pump was pushed down again, this process repeated itself.
Photographs Showing the Pluck Demo
^An annotated diagram of the pluck
^ The pluck showing an inflated lung (left lung)
^A detached lung from the pluck
^The heart form the pluck, with aorta and other vessels clearly visible
In conclusion, after completing numerous dissections, activities and experiments all relative to the skeletal, muscular, circulatory and respiratory system, it is clear that links can be drawn between multiple systems.
There are links between the skeletal and muscular system of which help us to move our bodies - both these systems depend on each other, and without them we wouldn't able to move. When extensor and flexor muscles (muscular system) contract and relax, they pull on the bones (skeletal system) which are attached by connective tissue such as ligaments and tendons. There are also specific attachment points for where muscle meets bone to ensure smooth movement. Without bones, the muscles wouldn't be attached to anything and couldn't function, and without bone the muscles alone wouldn't be able to move our bodies.
This connection was best demonstrated in the chicken wing dissection, where muscles, tendons, ligaments and bones were clearly visible. When the muscles were tugged, the bones moved in synchronisation, and the specific points where bone meets muscle were defined by bands of connective tissue.
There are also links between the circulatory and respiratory system of which together provides our body with oxygen and blood to use - both of these systems depend on each other, and without them we wouldn't be able to survive. Specifically, they are connected through a process called gas exchange. Oxygen, which is an essential to all of our bodily functions, is gathered through the respiratory. In humans, the path of oxygen through the circulatory system and respiratory system begins with inhalation. When a person inhales, the diaphragm contracts, pulling air into the lungs. The air moves through a series of tubes that lead from the nose and mouth into the lungs. Once air has reached the lungs, it moves into small structures called alveoli which are surrounded by capillaries. The alveoli and capillaries in the
lungs are the point at which the circulatory and respiratory system meet. When
air comes into contact with capillaries, the oxygen in the air transfers through
the capillary walls, which are semi-permeable. At the same time, carbon dioxide from the waste-rich blood enters the lungs through the same semi-permeable wall. Once oxygen molecules have moved into the blood, they bind to sites on the red blood cells and are carried through the body. The carbon dioxide is breathed out in the same way oxygen was inhaled. Oxygenated blood is then pumped from the lungs
to the heart. Once it reaches the heart, it is pumped into the rest of the body
and moves through a series of vessels, where the oxygen is used and replaced with carbon dioxide, or deoxygenated blood. The deoxygenated blood returns to the heart and is pumped to the heart where the process is repeated.
This connection was best demonstrated in the heart dissection, as well as the pluck demo. With the heart dissection, the vessels that connected to the lungs were identified, and in the pluck the actual process of breathing was simulated.