Circulatory System

 The circulatory system moves blood, and similar fluids through our bodies.Without it, no oxygen or nutrients would be able to get to our cells. Also, it transports oxygen and waste away from our cells.

The earthworm.

worm hearts 

The worm has five hearts. Not because it has a lot of love, but because they need to transport hemolymph, or the white blood, throughout their bodies.

-Blood travels toward the posterior end, through ventral blood vessels, then returns to the anterior end, through a dorsal blood vessel.

-Between open and closed circulatory system, a worm has an closed one. This means blood is closed at all times. Also, blood is pumped to the heart using vessels, and when compared to a closed circulatory system, the blood doesn't usually fill body cavities.




The crayfish.
-The dorsal heart first pumps hemolymph into large vessels.
-The vessels then carry it to different regions of the body.
-Hemolymph returns to the dorsal side, and enters the heart.
-Once the hemolymph leaves the vessels, it enters nemocoel, or bathing tissues.
-Unlike the worm, the crayfish has an open circulatory system. An open circulatory system is when blood is pumped into the hemocoel, as blood diffuses back and forth between cells. Unlike the closed circulatory system, blood is inserted by the heart into body cavities.

The frog.

-The frog has two types of circulation. Systematic, and pulmonary.
-Systematic: carries oxygenated blood from heart to muscles and organs
-Pulmonary: Carries deoxygenated blood from heart to lungs, then back to blood.
-The frog has a closed circulatory system, like the worm.

-The frog's heart (pictured left) is made up of three chambers. Two atria, and one ventricle. The ventricle is in charge of not getting the oxygenated, and deoxygenated blood mixed. This is similar in humans, and rats.
-The only blood that is mixed is the one that passes through the aortic arches. It contains oxygen that is needed for the remainder of the body.


The rat and humans.

rat heart(opened)

-The heart pumps blood through an intricate network of blood vessels.
-A paricardiom surrounds the heart, almost like a sack.
- The heart is split into two sections: the right sends blood to the lungs, and the left sends blood everywhere else.
-It is also split into two chambers: upper and lower. The upper chamber is the atrium, and the lower is the ventricle.
-Arteries transport blood from the heart, whereas veins take blood to the heart.
-Capillaries allow rapid change of material, and allow blood into cells.
-The heart ensures blood flow of deoxygenated blood and oxygenated blood not to mix.
-The vessels make sure blood circulates through tubular vessels.
-Like the crayfish, and grass frog, both rat and human have a closed circulatory system.

There are 4 types of blood:
- Red Blood Cells; which transport oxygen, and carbon dioxide. Every living thing has these because we all need oxygen and carbon dioxide to perform cellular reparation.
-White Blood Cells; are in charge of fighting foreign molecules or cells.
-Plasma; fluid that carries water, and nutrients. Most every living creature contains this. This is because we all need nutrients to perform actions.
-Platelets; causes blood clotting.

Respiratory System

 The respiratory system is the system that controls gas. It brings oxygen, removes harmful gases(carbon dioxide), warms and filters air, and is needed for cellular respiration.

-What each of the organisms has in common is hemoglobin. It transports oxygen. Oxygen binds into hemoglobin. Also, each of the organisms have a pharynx. This is the passageway for air flow. As well as the trachea, which is a catilaginous tube or 'wind pipe'.

The earthworm's respiratory system evolved first because it is the most simplest.

-The earthworm has a permable skin, which was mentioned before. It allows gases to exchange. Specifically, oxygen. In many other things, we use lungs or gills.

-The oxygen that gets passed through is then mixed with slime.
-A disadvantage to breathing through your skin is that if you encounter water, you will suffocate.

-The worm has a lot of surface area for gas exchange. This is because it only uses its skin, not like the frog, which has a smaller surface area in its lungs because it can use its skin, too.



The crayfish's respiratory system evolved next.

-The crayfish has gills. This is an advantage because it can swim.
-As shown in the picture, the gills are located between the body wall, and carapce, and are attached to the legs to allow breathing as it walks.
-The crayfish has this pocket-like thing that holds water. This is needed to hold water as it comes on land.
-We can tell that the crayfish evolved after the worm because it can go on water, and land, and the crayfish has a more complex system of getting oxygen.
-As you can see, the gills have an arch structure. This is because this creates more surface area. A bigger suface area means more oxygen. Who wouldn't love that?
-An advantage to having both a water sack, and gills is that it allows you to be in water, and land. You can escape from prey easier.

The frog's respiratory system is next.
-A frog has both lungs, and permable skin.
-We can tell that a frog is more recently evolved than a crayfish because as a tadpole, it has gills. As it becomes a frog, it develops lungs, and permable skin.
-Respiration in the lungs is called pulmonary respiration.
-The reason the frog has both repiration through the skin, or cutaneous repiration, and pulmonary respiration is because its lung capacity is small.
-Some advantages to the frog's respiratory system is that it has small lungs, compared to ours because it can also use its back-up, its skin, to breathe.
-A disadvantage to this is that it needs to be picky about what can get into the skin, and what it can't. With lungs, you can hold you breath to not let anything in, but with skin, anything can get in.

Rat and human respiratory system are quite similar.

-We use our lungs to breathe.
-Air begins at the mouth, and nose. Once it makes it to the nasal cavity, mucous membranes help filter, and moisturize the air. This prevents damage to tissues.
-Then, the now moistured air moves to the pharynx, then to the trachea. The upper part of the pharynx is the larynx, and then the trachea branches off into two bronchi, which lead to the lung.
-Exchange of gases occurs in the alveoli. They have a thin skin which is mocousy and wet. This is similar to a worm's skin. There are lots of alveoli, because this allows more surface area. The more surface area, the more oxygen.
-The lungs full capacity is about 70 m squared. This is huge compared to the frog. This is because we don't use another form of breathing also, just lungs.
-The ribs and diaphgram allow movement in the lungs.
-In humans, blood is mixed with oxygen, and the blood sends carbon dioxide to our body.
-A disadvantage to having lungs would be its maintenence. Anything toxic can damage our lungs right away. This can cause death if we breathe in something bad.
-An advantage would be the lungs' large capacity of oxygen. Like I said before, who wouldn't want more oxygen? The more the better, because you get more energy from cellular respiration.

  Cellular repiration; its needed to breathe.

C₆H₁₂O₆ + O₂ ---> H₂O + CO₂ + 36ATP
-Needed is glucose, and oxygen, which turns into water, carbon dioxide, and energy. Every living thing performs this.
-Without cellular respiration, we would not have ATP (energy), which can help cells perform all of the things they do. It gives us the energy to do everything.
-When we breathe, we supply the oxygen which is needed for cellular respiration.