Circulation

Group 1: Luis, Sofia, Giovanna The cardiovascular system has three main functions:
 * __The Cardiovascular System__**
 * Delivers needed materials- most substances that need to get from one part of the body to another are carried in blood (nutrients/hormones, oxygen)
 * Removing waste products- the cardiovascular system picks wastes up from the cells (carbon dioxide)
 * Fighting disease- the cardiovascular system also transports cells that attack disease, causing microorganisms. (white blood cells/antibodies)

Each time the heart beats, it pushes blood through through the vessels of the cardiovascular system.
 * __The Heart__**

The right and the left side of the heart are separated by a wall called septum.
 * __Heart's Structure__**

There are 4 chambers- 2 upper ones are called ATRIA (singular = atrium) 2 lower ones are called VENTRICLES (singular = ventricle) Valve - flaps of tissue that prevent the blood from flowing backwards

The pump has two phases: 1st- Heart muscle relaxes so it can be filled with blood, 2nd- Heart contracts and blood pumps up.
 * __How the Heart Works__**

When the muscle cells in the ventricle contract, they exert a force on the blood. The contraction of left ventricle is much stronger than the right one because the left one pumps blood throughout the body.
 * __The Force of the Ventricles__**


 * Group 2: Felipe, Caio, Emyr**
 * Regulation of the Heartbeat**

The heartbeat is regulated by a group of cells called the pacemaker. The pacemaker sends signals that make the muscles in the heart contract. When you exercise your heart cells need more oxygen so the pacemaker makes the heart beat faster.

The two loops: - the first loop takes the blood from the heart, to the lungs, and back to the heart. This is done to release the carbon dioxide from the blood and to make it rich in oxygen. So the goal of this first loop is to help the gas exchange between lungs/blood. - the second loop takes the blood from the heart, to the whole body, and back to the heart. This is done to distribute the oxygen in the blood to the cells in our body and to collect waste products like carbon dioxide.

[|heart_loops.jpg] Group 3: Girlany, Pedro, Nicolas

**Blood Pressure** blood pressure is caused by the force with wich the ventricles contracts then, when the blood moves further away from the heart, the pressure decreases, "this charge happens because the farther away from the ventricle the blood moves, the lower its force is." The blood flowing out of the heart through the arteries has the hieghest blood pressure, that is why the arteris are thicker, so that they wont break or rupture. To measure blood pressure, you need to use an instrument called a sphygmomanometer, which you wrap around your arm. this stops the blood flow through the artery is stopped. as the pressure is let out, the sphygmomanometer measures your pulse. Group 5: Bea, Guilherme, Steven
 * Group 4: Lucas, Mary, Courtney**

=BLOOD=

Plasma

 * The liquid part of blood.
 * 90% of plasma is water, the other 10% is dissolved materials.
 * Carries nutrients, wastes, hormones, salts, gases.

**Blood Cells**
 * Take oxygen from the lungs and deliver it to cells in our body.
 * They are produced in bone marrow.
 * They are flexible, which enables them to squeeze through capillaries.
 * Made mostly of **__hemoglobin__**, an iron-containing protein.
 * Hemoglobin picks up oxygen in the lungs and releases it as blood goes through the capillaries.

White Blood Cells

 * Fight disease.
 * Many types of white blood cells:
 * 1) Alert the body it has been invaded
 * 2) Create chemicals to destroy organisms
 * 3) Surround and kill organisms

Platelets

 * Cell fragments that play an important part in blood clotting.
 * They collect by forming fibers and stick to the wound.

Photo of Blood


Group 6: Rafael, Giovanni, Debora

__**The lymphatic system**__ //lymphatic system//: it is a network of vein-like vessels that returns the fluid to the bloodstream.

//lymph//: once the fluid is inside the lymphatic system it is called a lymph

//lymph nodes//: when lymph passes through the lymphatic system it passes through small knobs of tissue, called lymph nodes. The lymph nodes filter the lymph trapping bacteria in the fluid. Group 7: Gabriel, Rich, Victor We cannot perform at our peaks if our cardiovascular system isn't in a good shape. Some diseases that affect the cardiovascular system are atherosclerosis and hypertension.
 * __Cardiovascular diseases__**
 * Atherosclerosis**: It is a condition in which an arterys' walls are filled with fatty materials. This increases the blood pressure in the artery because there is less space for the blood to pass.
 * Hypertention**: Is a disorder that a persons blood pressure is consistenly higher than normal. Hypertension makes the heart work harder to pump the blood and this can damage the heart and the arteries severely over time.

__**How to stay HEALTHY**__ To stay healthy, you just need to adapt yourself to a balanced law saturated fat/ trans fat diet, exercise, and avoid smoking. Some other things to avoid are: cholesterol and sodium.