According to the Bohr model, the wavelength of the light emitted by a hydrogen atom when the electron falls from a high energy (n = 4) orbit into a lower energy (n = 2) orbit.
A network of arteries and veins also carry blood throughout the body: Arteries transport blood from the heart to the body tissues. Veins carry blood back to the heart.ow the heart works. The heart is a large, muscular organ that pumps blood filled with oxygen and nutrients through the blood vessels to the body tissues. It's made up of: Four chambers. The two upper chambers, the atria, receive and collect blood.
Blood Vessels There are five general classes of blood vessels in the cardio-vascular system: arteries, arterioles, capillaries, venules, and veins (see Figure 5â5). Arteries are elastic vessels that are very strong, able to carry blood away from the heart under high pressure.rteries: Elastic vessels able to carry blood away from the heart under high pressure. Arterioles: Subdivisions of arteries; they are thinner and have muscles that are innervated by the sympathetic nervous system. Atria: The upper chambers of the heart; they receive blood returning to the heart.