Human Physiology

• Amylase is involved in carbohydrate digestion and is secreted by the salivary glands and pancreas.
• Lipase aids in fat digestion and is secreted by the pancreas into the small intestine.
• Trypsin is another protein-digesting enzyme, but it is secreted by the pancreas and acts in the small intestine, not the stomach.

To determine which blood vessel carries oxygenated blood from the lungs to the heart, we must understand the role of each of the given blood vessels:

• Pulmonary artery: This blood vessel carries deoxygenated blood from the right ventricle of the heart to the lungs for oxygenation.
• Aorta: The largest artery in the body that carries oxygenated blood from the left ventricle of the heart to the rest of the body. It does not carry blood from the lungs to the heart.
• Pulmonary vein: This vessel carries oxygenated blood from the lungs back to the left atrium of the heart. It is the only vein that carries oxygenated blood in the body.
• Vena cava: Comprised of the superior and inferior vena cava, these veins carry deoxygenated blood from the body back to the right atrium of the heart.

From the above information, the only vessel responsible for carrying oxygenated blood from the lungs to the heart is the pulmonary vein.

• RBCs: Transport oxygen
• WBCs: Fight infections
• Plasma: Carries nutrients, hormones, and waste
• Platelets: Help in blood clotting