Rou Wei Long
The prawn's skeletal system's main features are it's thin hard shell that covers the whole body and the 8 lims (first picture below shows its many lims). The skeletal system helps the prawn by allowing it to move (swim) by using it's legs and arms. It's hard shell protects the whole body, the shell is split into a couple of sections so the prawn can move without being restricted. Shrimps have a similar skeletal system to the prawn, it has a hard shell protecting the body (also seperated into sections) and many legs to help it's movement in the water. The prawn's skeletal system is different to a human's, while human's have bones in the inside that allow movement (plus protecting organs) and more fragile skin covering the body, the prawn's have a hard shell that protects the inside and it doesn't have bones like human's do inside. The benefits of having the skeletal system of a prawn is that the shell will protect the body from possible danger and it can still move freely. The disadvantage of this type of skeletal system is when the prawn's grow it sheds it's shell to grow a bigger one, during this time it becomes vulnerable without any protection (third picture below shows the prawn without it's shell). This skeletal system is call exo-skeleton.
The worm skeletal system is a hydroskeleton, this type of skeletal system is made of fluid, which makes the muscles move to allow the body to travel. Because it doesn't have anything hard in it's body this means the worm is very flexible and can move it all directions (pictures below show it's flexibility).
The cuttlebone (refer to pictures below) is a hard internal bone inside of the cuttlefish and it is very lightweighted. The main role of this is bone is to help the cuttlefish float in the water with the help of the gasses (calcium carbonate) that fills the bone. The cuttlefish has an internal skeleton.
The average human skeleton is made up of 206 bones. The axial skeleton (the green bones in the picture below) role is to protect organs, such as the rib cage protecting the heart, it consists of 80 bones. The appendicular skeleton (the yellow bones in the picture below) allows movement, without these 126 bones we would just be a bunch of organs laying on the ground. Our bones are made from ___, and bone marrow (this is where blood cells are produced). The skeletal system changes as we grow from a baby to an adult, we are born with 300 bones but end up with 206. This is because as the grow some of our bones fuse together to create one bone (like the skull). This type of skeleton is a endoskeleton as the bones are in the inside not the outside. Basically all mammals have endoskeletons, such as our average pets the dogs, and wild animals like lions, giraffes, tigers, pigs, horses and rabbits.
Chicken Wing Dissection
Remove skin from chicken wing. Identify the upper wing and the lower wing, along with the wing tip.
What structures do these correspond to in humans? The wing is similar to the human arm as it extends and contracts. The arm and the wing both have antagonist muscle, the biceps contract and the triceps extend when you bend your arm, and the opposite when you straighten.
Identify the muscles in the upper wing. Have a go at tugging on each of these muscles.
What happens when you tug on these muscles? The muscle pulls and straightens the bones, the muscles contracts and relax.
What muscles do they correspond to in humans? The muscles are similar to the human biceps and triceps.
Which muscle is an extensor? When pulling the wing, the biceps relax and extends.
Which muscle is a flexor? The triceps are the flexor as it contracts and tightens.
Indentify the muscles in the lower wing. Have a go at tugging on each of these muscles.
What happens when you tug on these muscles? The muscle is stuck close to the bone and is quite tuff and thick. It is hard but movable and slippery.
Cut away come of the muscle tissue. Find the tissue that connects the muscle to the bone.
What is this tissue called? The tissue is called tendons.
Decribe what it looks like. It's thin, white, soft and stretchable.
Observe the elbow joint.
What is the tissue that connects the bones at this joint called? Ligaments connect bones to bones.
What kind of joint is this? This type of joint is a ball and socket, (refer to the first picture below.)
What kind of joint connects the wing at the shoulder? A pivot joint connects the wing and the shoulder.
Describe the cartilage that lines the joint (appearence, texture, how much is there?) The carilage is white, hard and smooth, and it covers the top of the joint.
Continue to cut away all of the muscle, so as to expose just the bones. Name the bones found in the chicken wing. The radius, ulna, alula, phalanges and the humerus.
Describe the appearance of the heart. What does it look like? How does it feel? Are there any features you can describe? The heart is a dark red colour with a bit
of blue and it is slightly smaller than a clenched fist. It is triangular shape
and the coronary artery is very visible. It feels quite tough, especially the
fat surrounding the heart, which isn’t very smooth.
Find the blood vessels on the surface of the heart muscle. These are coronary arteries. They carry nutrients and oxygen to the heart muscle.
Describe what this artery looks like. It is thin and long, starts at the top of the heart and crosses down to the bottom. What do you think would happen if this artery was blocked by a clot? The coronary artery wouldn't be able to deliver oxygen and nutrients to the heart muscle, this can result in medical problems such as a heart attack. Without the nutrients and oxygen the heart doesn't have the power to continue it's job and also keep itself healthy.
How do you know which is the left and right ride of the heart? The left side of the heart is more tuff as it has more muscle, so it can pump blood to the rest of the body. (Refer to the picture below, the left side has more muscles compared to the right side.)
Have a feel of the thickness of the heart muscle at the top and bottom of the heart. Describe the features. The thickness of the muscles at the top of
the heart is very strong but has less muscle, and the thickness of the muscles
at the bottom of the heart is more spongy and has more muscles. The amount of fat surrounding the heart is just a thin layer that covers most of the heart. The fat isn’t in clumps instead it fades away as it gets to a section of the heart. The vena cava and the aorta were the clearest to see entering and exiting the heart.
Choose the correct answer.
Oxygenated/Deoxygenated blood leaves the right ventricle/ right atrium in an artery and travels to the lungs/rest of the body. Here, the blood collects oxygen/drops off oxygen, so it is now oxygenated/deoxgenated. The blood travels back to the heart via an artery/vein.
Fin the aorta that carries the blood away from the left ventricle of the heart. Decribe the thickness of this vessel. Why do you think it needs to be so thick? The aorta needs to be thinker so it can pump the blood to the body, this way it won’t be weak. The blood pressure is high in this vessel, it will travel faster and will not break because of the pressure. Where is it taking blood to? It is taking the blood to the brain and the
rest of the body.
Find the vena cava. This is the vein that returns blood from the body. Compare the thickness of the vena cava to the aorta. Why do you think it is different? The aorta is thicker to be able to send the blood around the body in high blood pressure without the artery breaking. The vena cava has low blood pressure and is returning blood back after it has giving it’s oxygen to an organ. What part of the heart does the vena cava go back in to? The vena cava goes back in to the right atrium, which the blood will then travel down to the right ventricle. Remember what you observed when you observed the water flowing throught the heart. The water went into the vena cava and into the heart. Which blood vessels did the water come out of the heart from? The water came out of the heart from the pulmonary artery after it came out of the vena cava.
When the water was flowing into the pulmonary vein, which vessel did it come out of? The water came out of the aorta, this is where it will then travel to the body and brain.
Internal Examination of the Heart
Firstly cut open the left ventricle. Decribe what you see inside the left side of the heart. There is a lot of vessels, inside is really red compared to the outide and is quite layered. The muscle is really thick.
Observe any valves you see. What do you think their job would be? The are stretchy, strong and goes across the artery. It is to stop the blood from traveling the wrong direction, as it might then end up traveling to the brain with no oxygen to give.
Cut the aorta. Describe how it appears and how it feels and any other features. It has a lot of valves and vessels going across it. It feels bumpy too.
Cut open the right ventricle, observe this side of the heart.
When the air is pumped into the lungs, it enlarges and turns a lighter pink (as you can see on the photo above.) There were leaks in the lungs so the air didn't spread to the whole of the lung. As the pump (used to pump air in) was moved around other parts of the lungs also turned light pink and enlarged (second picture below has a clear picture of the oxygenated lung.) When we breathe, we suck in oxygen through our mouths, it travels down our our esophagus and into our lungs. The oxygen spilts evenly into alveoli where the blood will come and collect the oxygen. When the blood comes it also delivers carbon dioxide, when we breathe out the carbon dioxide is released into the air.
Skeletal & Muscular System
The skeletal system and muscular system both work together to move the body physically. When muscles contract it moves the bones to create movement throughout the body. The skeletal system structures the body and protect organs within the body. The muscles can work in pairs (biceps and triceps) to allow the body to walk and hold a glass of water up. They both contribute to the body's movement.
Circulatory & Respiratory System
The circulatory and respiratory system keep us alive, and sends blood around our body. The respiratory system sends oxygen around the body by first collecting the oxygen from the lungs. The circulatory system lets us breathe and take in oxygen into our mouthes and through to our lungs where the blood (pumped by the heart) collects it and travels back around to the heart. Here the respiratory system delivers it. Together they take oxygen in, deliver it to the brain and body to keep our organs healthy and us alive.