Biology-Organisation

• If someone has a faulty valve, blood could flow backwards and mix the de-oxygenated blood with the oxygenated blood. This would cause you to have slurred speech and an unability to move.
• The heart is made up of four chambers - two atria (top) and two ventricles (bottom).
• Blood flows from the right side of the heart into the lungs where it picks up oxygen and releases carbon dioxide. It then returns back to the left side of the heart which pumps it out around the body again.
• Arteries are thick-walled, elastic, and carry blood away from the heart. Veins are thin-walled, muscular, and carry blood back to the heart.
• Capillaries are tiny vessels that connect arterioles to venules. They allow diffusion between cells and capillary walls.
• The lungs are made up from the : trachea, bronchus, bronchioles, alvioli, ribs and diaphram
• Alvioli are good diffusers because they have a large surface area for a higher diffusion rate, a wet surface for faster diffusion, a small diffusion distance and a constant flow of blood to keep the high concentration.
• The alveoli are surrounded by a network of capillaries. Oxygen diffuses across the wall of the alveolus and into the capillaries. Carbon dioxide diffuses in the opposite direction.