By Charley Malligan
The skeletal System
The prawn has an exoskeleton which is strong, clear and thin. It is made of chitin (a type of sugar) and calcium carbonate (which gives it it's strength).
The prawns skeleton protects it and it's internal organs. It does this by providing a hard outer shell.
Some other animals that have this type of skeleton are lobsters, crabs and other crustaceans.
It is different to our skeleton because we have an endoskeleton (an inner skeleton) and we have bones, whereas the prawn has an outer shell.
The benefits of the skeleton are that it protects the whole body and the organs. Some disadvantages are that it limits the growth of the prawn and doesn't allow it to move very easily because it has no joints.
It grows by shedding the skeleton, then re-growing it.
The worm has a hydro skeleton this means that it has cavities filled with fluid that are controlled by muscles, when they contract, the worm is able to move. You can see the movement of the worm below.
The cuttlebone was light weight, white, chalky and flat. The main role of the cuttlebone was to help the cuttlefish with buoyancy. The cuttlebone is made of calcium carbonate. The cuttlefishes skeleton is an internal skeleton.
The human skeletal system is a supportive frame made of many bones. The role is for support, movement and protection of our organs.
Bone marrow is found inside bones, it produces red blood cells. Our bones are made of: collagen and calcium phosphate. As we grow our bones develop by fusing together. Our skeleton is an endoskeleton, some other animals that have this skeleton are: other mammals such as primates.
The muscular system
The chicken wing dissection
The bones in the chicken wing are very similar to the bones of the upper and lower arm in the human.
When you tug on the muscles in the upper part of the chicken wing, the wing flexes and extends as you can see in the diagram below. These muscles correspond to the bicep and the tricep in humans. The tricep is an extensor and the bicep is a flexor.
When you tug on the muscles in the lower part of the wing, the tip of the wing flexes and extends.
Once cutting away some of the muscle tissue from the chicken wing, we could identify the tissue that connects the muscle to the bone called the tendon. This was white soft and thin and tightly connected the muscle to the bone.
When observing the elbow joint, you can see the tissue that connects the bones to it, this tissue is called ligament. This joint is a hinge joint. Where the wing connects to the shoulder, the joint is a ball and socket joint which allows more movement than a hinge joint. Cartilage lines the ends of the bones to stop the bones from grinding. When we observed the cartilage, we found that it was white, hard and smooth.
The Circulatory system
The heart was fist sized, it was squishy, fatty and a reddy colour.
There are bloods vessels on the surface of of the heart, these are called coronary arteries. These carry nutrients and oxygen to the heart muscle. This artery is a thick, elastic tube. If this artery was blocked by a clot, it would stop blood flow to the heart and the heart would stop pumping.
You can tell which is the left and right side of the heart by seeing where the aorta leads to. The aorta leads to the left side the heart.
The heart muscle is thicker at the bottom, the top of the heart is very fatty. The bottom is very thick and not as fatty. The major vessels entering the the heart are thick elastic tubes.
Deoxygenated blood leaves the right ventricle in an artery and travels to to the lungs. Here, the blood collects oxygen, so it is now oxygenated. The blood travels back to the heart via a vein.
The aorta carries blood away from the left ventricle of the heart. This vessel is very thick because it to pump blow out of the heart at a high pressure. It taking blood to the major organs of the body other than the lungs.
The vena cava is the the vein that returns blood from the body. It is not as thick because the blood that the aorta pumps is at a higher pressure than the vena cava so it does need to be as muscly. The vena cava goes back into the right atrium. We poured water into the vena cava, we then observed that it came out in the pulmonary artery and when we poured it into the pulmonary artery, the water came out of the vena cava.
When we cut open the left side of the heart we could see valves, cords and muscle. The valves job is to stop back flow and to direct and allow the flow of blood. When we cut into the aorta, we found that it was muscly, tough, thick and elastic.
Walking the heart
In one lesson, we went to the basketball courts and with chalk, drew the box diagram of the heart in a larger scale. Below you can see my group and our diagram and also my group walking through it and showing when the blood is oxygenated and when it is de-oxygenated by using red and blue plastic plates.
The Respiratory System
For the respiratory system, we were given a bike pump and a tube to pump air into animal lungs. To start off our pluck station, we first observed the trachea (the long tube that once would have connected to the mouth). The trachea was provided its structure by strong rings of cartilage. These rings also kept it open so that gases could easily pass through. The cartilage was firm yet flexible.
The lungs were a light pink colour, while the animal was functioning, the lungs may have been a darker pink because of the blood that was being transferred into the veins on and around the lungs.
The heart connects to the lungs by the pulmonary artery which delivers deoxygenated blood to the lungs. The blood moves into the capillaries which collect oxygen from the lungs through air sacks. The capillaries then connect to the pulmonary vein which delivers the blood back to the left atrium.
The diaphragm is the muscle under the ribs. The contraction of the diaphragm causes pressure changes in the heart and the lungs. When the diaphragm contracts it causes an increase in pressure in the lungs which causes a person to exhale. When the diaphragm relaxes, air is drawn into the lungs due to a decrease in pressure.
The liver helps to filter all the blood in the body before it goes back into the heart and re-circulated.
Links Between Systems
The link between the skeletal and circulatory system is that the muscles connects bones at the joints and the muscles allow the joints to move. The bones provide stability while the muscles allow movement. Without each other, the body could not function.
There is also a link between the circulatory system and the respiratory system. When you breathe in oxygen it is transferred into the blood through the lungs, the blood transports it around the body, then the lungs removes the carbon dioxide. All systems in the body work together to create a working, living being.