Science Practical Activity Portfolio

THE SKELETAL SYSTEM

Labelled diagram of the human skeletal system

Prawn

The skeletal system of the prawn was very thin, but strong and flexible. It consisted of three main sections; the head, the body, and the tail. The role of the prawn's skeleton is to protect it's vital internal organs, and it is flexible to allow movement. Other animals which have this type of skeletal system are animals like crustaceans and insects. Advantages of this type of skeleton are that it acts as protection for soft or fragile body parts. Our skeletons leave our muscles open and vulnerable, whereas the prawn's covers them well. However, their skeletons may break easily, and the prawn might grow out of it. When the prawn does this and sheds its shell, it is very vulnerable when trying to grow a new one. The growing of a new shell also uses a lot of energy. The prawn's skeleton doesn't grow, but it sheds and a new one is created. This type of skeleton is called an exoskeleton. The prawn's exoskeleton is made of chitin.

Worm

Worms have what is called a hydro skeleton. This consists of a fluid filled cavity which supports its body, instead of bones, or some similar substance like chitin.

Cuttlefish

The cuttlefish's skeletal system consists of a single large bone. This cuttlebone is large, light, firm, and porous. The main role of the cuttlebone would be to help the cuttlefish float, because it is so light, buoyant and porous. It is made from calcium carbonate, and is an internal skeleton.

Human

Humans have an internal skeletal system which protects organs, allows us to move, and provides our body with support. Our skeletal system consists of the vertebrae, the skull, the pelvis, and many other different bones in the body. The role of the skeletal system is to support, protect, and assist movement. Bone marrow is found in the centre of bones, and it creates red blood cells, white blood cells, and platelets. Our bones are made from many different complex materials, although mainly calcium phosphate and collagen. Our skeletal system changes from baby to adult; bones fuse together. This is why babies have 300 bones, but adults have 206. Humans have what is called an endoskeleton. Other animals such as sheep, cows, giraffes, and most other mammals have endoskeletons.

THE MUSCULAR SYSTEM

Chicken Wing Dissection

The structures in the chicken wing (upper wing, lower wing and wing tip) correspond to the upper arm, forearm and hand respectively in a human. When I tugged on the muscles in the upper wing, the lower wing moved up and down. The muscles in the upper wing correspond to the bicep and tricep in humans. In the movement of extending the wing, the bicep is the extensor, and the tricep is the flexor. When I tugged on the muscles in the lower wing, the wing tip moved up and down, as demonstrated in the two photos below.

After cutting away some of the muscle tissue, a tissue was displayed which connected the muscle to the bone. This tissue is called a tendon, and it was white, thin and strong, pictured in the first image below. When examining the elbow joint, I saw another tissue which connected the bones, and this is called a ligament. The elbow joint is a hinge joint, and the joint which connects the wing at the shoulder is a ball and socket joint. The cartilage at the elbow joint was white, smooth and slippery, firm, and there was a lot around the edges of the bones. The bones found in the chicken wing are the humerus, the radius and the ulna.

THE CIRCULATORY SYSTEM

Heart Dissection Prac

EXTERNAL EXAMINATION

1. The heart is a mixture of colours; the fat around it is an off-white, and the muscle tissue is a red-brown. Blood vessels are visible around the heart. The vena cava, aorta, pulmonary vein, and pulmonary artery are visible at the top of the heart.

2.

3. The coronary arteries look thin, red and well protected by fat and heart tissue. 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. 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 blood to the rest of the body.

5. a) The muscle at the top of the heart is thick firm and tough.

b) At the bottom of the heart, the muscle is very thick; the left side being considerably thicker than the right.

c) There is a large amount of fat surrounding the heart; 1-2cm around the top.

d) The major vessels entering the heart are the aorta, the vena cava, the pulmonary vein, and the pulmonary artery.

6. Deoxygenated blood leaves the right ventricle in an artery and travels to the lungs. Here, the blood collects oxygen so it is now oxygenated.

7. a) The aorta is wide and thick; maybe 1-2cm wideness in diameter. It needs to be like this to withstand the high pressure of the heartbeat and strong blood flow.

b) The aorta takes blood to the brain and other internal organs such as the stomach, liver and kidneys.

8. a) The vena cava is a bit 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) The vena cava goes back into the right ventricle.

c) From the vena cava, water would have come out of the pulmonary artery.

9. From the pulmonary vein, water would have come out of the aorta.

INTERNAL EXAMINATION

1. In the left side of the heart there is a narrow cavity with a very thick muscle wall. The valves inside the heart are visible.

2. The job of valves is to make sure that blood doesn't flow back the wrong way.

3. The aorta is large, thick and tough. Our heart's aorta was cut off at the top, so not much else was visible.

4. The ventricles had thicker muscle wall than the atria. This is because the ventricles need stronger muscle to pump out blood. The left ventricle had thicker muscle than the right ventricle because it has to pump blood throughout the whole body, whereas the right ventricle only needs to pump blood to the lungs. The muscle separating the right and left sides of the heart is called the septum. The septum is thick and strong because it needs to separate the oxygenated and deoxygenated blood. The chambers of the heart are different sizes. The ventricles are larger than the atria because they are required to hold larger amounts of blood to pump out. The right ventricle appeared more spacious than the left ventricle, because it doesn't need as thick a wall.

5.

  • Left Ventricle- the chamber on the lower left side of the heart- it pumps out oxygenated blood to the body
  • Right Ventricle- the chamber on the lower right side of the heart- it pumps out deoxygenated blood to the lungs
  • Left Atrium- the chamber on the upper left side of the heart- oxygenated blood travels through it to reach the left ventricle
  • Right Atrium- the chamber on the upper right side of the heart- deoxygenated blood travels through it to reach the right ventricle
  • Aorta- largest artery in the body, begins at the left ventricle and travels through the rest of the body- blood travels through it to the rest of the body
  • Pulmonary Vein- this vein connects to the left atrium and the lungs. It carries oxygenated blood back to the heart
  • Pulmonary Artery- connects to the right atrium and the lungs. It carries deoxygenated blood to the lungs.
  • Vena Cava- the vena cava connects to the right atrium. It carries deoxygenated blood back to the heart
  • Valves- located inside the heart. They make sure that blood doesn't flow back the wrong way.
  • Coronary Artery- found on the outside of the heart. They carry blood to the heart.
  • Septum- found in between the two sides of the heart. Divides the left and right sides of the heart and stops oxygenated and deoxygenated blood from mixing.

6.

Box Heart Diagram

Walking the Heart Activity

Blood is pumped out of the left ventricle in to the aorta, where it travels throughout the body. The oxygen in the blood is used up by the body, and deoxygenated blood travels through the vena cava back to the heart- into the right ventricle. It is pumped out again from the right ventricle into the pulmonary artery which carries it to the lungs to collect oxygen. The newly oxygenated blood travels back to the heart via the pulmonary vein into the left ventricle, where the cycle starts again.

RESPIRATORY SYSTEM

Air travels down the trachea and into the bronchi. The bronchi then branch off into bronchioles, which have air sacs called alveoli at their ends. When the air reaches the alveoli, the oxygen would have transferred into the capillaries surrounding the alveoli and into the bloodstream. During the process of inhalation, the diaphragm contracts, moving downwards and flattening, to allow the lungs as much room as possible to expand and fill with air. As the air entered the lungs, they became more red in colour, as there was oxygen circulating through them.

CONCLUSION

The Skeletal system and the Muscular system are linked closely together in allowing movement. When the muscles contract and relax, they pull on the bones, causing the limbs to move. The muscles and bones are connected to each other by tendons.

The Circulatory system is also linked very closely with the Respiratory system. The oxygen we breathe in is transferred to the bloodstream and carbon dioxide from the bloodstream is transferred back into the lungs to be exhaled. These processes are called gas exchange. Both systems are linked very closely with giving oxygen to the body and retrieving waste products like carbon dioxide to be disposed of via exhalation.

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