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.