Systems of the Body

Grace Mackay


The Skeletal System is an internal or external framework of bone, cartilage, or other rigid material supporting or containing the body of an animal or plant.

Skeletal System of a Prawn

A prawn has an external skeleton also known as an Exo Skeleton, made of chitin. It has a large shell protecting its whole body. Whilst dissecting the prawn a major part was defining the poo line and ensuring to take it out as well has taking its head off, which then you could see inside and try to identify the brain. The skeleton of the prawn gives protection but also works with the muscular system to allow movement. Grasshopper along with spiders also shares the same skeleton as the prawn but all humans have an internal skeleton, different to the external. The great thing about an external skeleton is the protection that it provides from the outside. When the prawn is shedding and growing its skeleton and itself can become quite vulnerable.

Skeletal System of a Worm, Cuttlefish and Human

Skeletal system of a Worm:

The skeleton of a worm is also known as a Hydro skeleton which stretches and retracts for movement.

Skeletal system of a cuttlefish:

The bone from a cuttlefish is very light and chalky but it is very good at providing protection, structure and buoyancy. The skeleton is made up from calcium carbonate and is an internal skeleton.

Skeletal system of Humans:

Our skeleton grows from the ends of our bones (extremities) and continues to grow until owner has reached full maturity, usually into the early twenties. The skeleton is made up of bone, cartilage, tendons, muscle and tissue which all assists in holding our bodies upright. Bone marrow is the soft tissue found in the cavities of our bones which is the source of all red blood cells, which provides us with strengths and supporting our bodies to stand upright. The human skeleton is also known as an EndoSkeleton, which mammals, and most fish and reptiles share too. from a young new born we have many more bones than we do once fully developed into adult hood. As we grow our bones become larger and join together.


The muscular system is a large organ that contains smooth as well as cardiac and skeletal muscles. It authorises movement in the body whilst also maintain posture and circulating blood.

Chicken wing dissection

In a chicken the upper and lower wing correspond very much to the shoulder and joints, forearm and the hands. When you tug on the muscles of the chicken the lower wing moves by contracting and extending, the muscles correspond to the tricep and bicep in the human body. The outer and upper wing of the chicken (between shoulder and elbow) is the extensor and the flexor is the inner and lower wing (between elbow and wrist) of the chicken. When these muscles are tugged the tip of the wing moves.

The skin of the chicken is a whitish cream colour, where the muscles are faded yellow and see through and the rest is a pale pink. In the elbow joint, which is a hinge joint the tendons and ligaments are the tissue that connects the bones. A ball and socket joint is what connects the wing to the shoulder as it provides a round movement. The cartilage that lines the joints of the chicken is very much a white, smooth texture and is around half a centre metre around the joints and bones. The bones found in the chicken are the Humerus, Radius and the Ulna.

Circulatory system

The circulatory system is a large network of organs and vessels that is in charge of the flow of blood, nutrients, oxygen and other gases and hormones to and from cells. Without the Circulatory system, the body wouldn’t be able to fight disease or maintain a constant internal atmosphere. The circulatory system is made up of the heart (cardiovascular), lungs (pulmonary) and arteries, veins and coronary.

heart dissection

The heart is in the shape of a cone, it is very tough with dark red and light pink coloured areas. Lining the top of the heart is white, tough fat, the coronary veins were visible from the surface of the heart and beneath was the dark red, plump muscle. The aorta wasn't clear in my particular heart to dissect, therefore it was a struggle to identify its hole.

The coronary arteries are red and thin, their job is to carry nutrients and oxygen to the heart. If an artery had a blood clot (build-up of blood) it wouldn't be able to escape since blood can’t flow backwards, therefore the effect would be a heart attack. The aorta is the place to identify the difference between the left and right side

The muscles at the top of the heart are thin, as the left and right atriums don’t pump blood out, but rather is lets it come in (this doesn’t use much force and muscle). There is around 3cm of fat surrounding the heart which acts as an insulator to this organ. The aorta, pulmonary artery and vein are the main vessels that are entering and exiting the heart.

Deoxygenated blood leaves the right ventricle in an artery and travels 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 pumps out blood and therefore needs more force, the power is sourced from the left ventricle which is around 2cm thick, and the blood is distributed to the rest of the body.

The vena cava is larger in comparison to the aorta, and it goes back into the right side of the heart. The water went into the vena cava and into the heart and came out of the pulmonary vein. When the water was flowing through the pulmonary vein, it came out the pulmonary artery.

in the left side of the heart there is the aorta, atrium and connecting vessels and tissue. their job is to prevent blood from flowing back out of the heart. The aorta is much thicker walls and extremely muscular.


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. The respiratory system does this 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

The rings of the cartilage are important as they prevent the trachea from bending or collapsing on itself. The lungs were soft, fragile and pink (when deflated), when alive the lungs would have been pale, cream colour and firm. The heart connects to the lungs via the pulmonary artery and vein. Deoxygenated red blood cells pass by the lungs alveoli to receive oxygen and transport it around the body. The diaphragm controls our breathing by contracting to allow the lungs to fill with air therefore expanding; when diaphragm relaxes it pushes the air out of the lungs. The liver produces bile and breaks down toxins, like alcohol and stores sugars such as glycogen.


The skeletal system is moved by the muscles which are connected and attached to the bones by tendons. The muscles work in antagonistic pairs to move the body at joints (eg, bicep and tricep bend at the elbow joint).

The circulatory and respiratory systems are linked by gas exchange between the red blood cells and the alveoli. Deoxygenated blood travels to the lungs via the pulmonary artery. When it reaches the alveoli, CO2-rich gas is exchanged for O2-rich gas. The now oxygenated blood travels back to the heart via the pulmonary vein.

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