Allie = omnipotent

Section assessments:
1. The human circulatory system consists of the heart, a series of blood vessels, and the blood that flows through them.
2.  As blood flows through the circulatory system, it moves through the three types of blood vessels – arteries, capillaries, and veins.
Capillaries:
–most numerous vessels
–connect arteries to veins
–microscopic, one cell thick walls
–site of much exchange between the blood and the intracellular fluid (lymph) by diffusion
Arteries
                        –carry blood away from the heart
–usually spurt blood when cut
–all except the pulmonary artery carry oxygenated blood
–thick walled and elastic
H. Veins
–carry blood toward the heart
–contain valves
–closer to the body surface than the arteries
–all except the pulmonary vein carry deoxygenated blood
–thinner, less muscular and elastic than arteries
–depend upon muscle and diaphragm movements for blood flow
3. The flow of blood occurs, coincidentally, in the heart. It consists of two muscular fibers, (one in the atria, and the other in the ventricles.) When the network in the atria contracts, blood flows into the ventricles, and when the ventricles contract, blood flows OUT of the heart! The oxygen-rich blood, leaving the heart, then flows into a large blood vessel, known as the aorta. It then moves through the rest of the arteries which carry blood from the heart to the tissues of the body.  Next, the blood moves through the capillaries to move nutrients and oxygen to the tissues and absorbing carbon dioxide and other waste products, and finally the blood moves into the veins from which the blood flows back into the heart and repeats the process.
4. The heart beat is controlled by two muscular fibers, (one in the atria, and the other in the ventricles. When the network in the atria contracts, blood flows into the ventricles, and when the ventricles contract, blood flows OUT of the heart!
5.  Exercise promotes good circulation because it increases your respiratory system’s efficiency, controls your weight, reduces body fat, and reduces stress. It also strengthens your muscles, including your heart.
Section 2
1. The main functions of the red blood cells is to transport oxygen, the white blood cells are meant to attack foreign substances or organisms, and blood clotting is made possible by plasma and platelets.
2. The lymphatic system collects the fluid that is lost by the blood and returns it to the circulatory system. The fluid is known as lymph.]
3.  Plasma dissolves gases, salts, nutrients, enzymes, hormones, waste products, and proteins called plasma proteins.
4. First the blood vessel is injured, platelets clump at the site and release thromboplastin; this converts prothrombin into thrombin. And lastly, thrombin converts fibrinogen into fibrin, which causes a clot. The clot prevents further loss of blood. YAAAAY! Poor hemophiliacs. :’(
5. The reason why tissues swell due to infections is because the lymph nodes harbor all the bacteria and microorganisms that cause disease. When they trap so many they become inflamed.
Section 3
1. Air moves from the nose to the pharynx, to the larynx, to the trachea, to the bronchi, and finally to the lungs.
2. Smoking causes chronic bronchitis, emphysema, and lung cancer. In bronchitis the bronchi become swollen and clogged with mucus.  Emphysema is the loss of elasticity in the tissues of the lungs, making breathing quite difficult.
3.  Oxygen dissolves in the moisture on the inner surface of the alveoli and then diffuses in the opposite direction in the bloodstream diffuse in the opposite direction, across the membrane of an alveolus and into the air within it. The air we inhale usually has 21 percent oxygen and 0.04 percent carbon dioxide. Exhaled air usually contains less than 15% oxygen and percent C02. The lungs remove about 1/3 of the oxygen in the air that you inhale and increase the carbon dioxide content of the air by a factor of 100.
4. The nervous system controls your breathing in a place in your brain called the medulla oblongata. Cells in its breathing monitor the amount of carbon dioxide in the blood. As its level rises, nerve impulses from the breathing center cause the diaphragm to contract, bringing air into the lungs.
 5.  People at high altitudes, such as when you are in a plane, do not need masks because the plane is pressurized. Although, in case of an emergency and their bodies are infact starving for oxygen the body doesn’t sense a problem. This is because they have no more carbon dioxide in their blood