Life Processes long 6 Flashcards
Explain the process of blood in the heart?
Oxygen-rich blood from the lungs comes to the thin-walled upper chamber of the heart on the left, the left atrium. The left atrium relaxes collecting this blood then contracts, while the next chamber,
the left ventricle, relaxes, so that the blood is transferred to it. When the muscular left ventricle contracts in its turn, the blood is pumped out to
the body. De-oxygenated blood comes from the body to the upper chamber on the right, the right atrium, as it relaxes. As the right atrium contracts, the corresponding lower chamber, the right ventricle, dilates. This transfers blood to the right ventricle, which in turn pumps it to the lungs for oxygenation. Since ventricles have to pump blood into various organs, they have thicker muscular walls than the atria do. Valves ensure that blood does not flow backwards when the atria or ventricles contract.
Give a note when oxygen enters the blood in the lungs?
The separation of the right side and the left side of
the heart is useful to keep oxygenated and deoxygenated blood from mixing. Such separation
allows a highly efficient supply of oxygen. Animals, like amphibians or many reptiles have three-chambered hearts, and tolerate some mixing
of the oxygenated and de-oxygenated blood
streams. Fishes have only two chambers to their hearts, and the blood is pumped to the gills, is oxygenated there. Blood goes only once through the heart in the fish during one cycle of passage through the body.
Give a note on the tubes-blood vessels?
Arteries are the vessels which carry blood away from the heart to various organs of the body. The arteries have thick, elastic walls. Veins collect the blood from different organs and bring it back to the heart. They do not need thick walls because the blood is no longer under pressure, instead they
have valves that ensure that the blood flows only in one direction.
