Biology SAC 3
“The Transport systems play an essential role in the survival of flowering plants and mammals”
It is imperative that the organism’s cells have an ideal supply of the necessary materials to ensure its survival. At the same time, waste material must be removed to make room for the new material coming in and to avoid infection. Necessary substances and waste material merely move in and out of unicellular organisms by diffusion, osmosis or active transport due to direct contact with their surroundings. However, not all the cells in multi-cellular organisms are in contact with the external environment for rapid exchange of substances between the internal and external environment. Thus, specialized transport systems are utilized. The substances travel along vessels to where they are needed. However, osmosis, diffusion and active transport remain the key procedures employed by transport systems.
The cardiovascular system, a transport system in mammals, composes of the blood, heart, and blood vessels. Blood vessels consist primarily of arteries, veins and capillaries. Blood traveling in them comprise of water, mineral ions and proteins, white blood cells, platelets and red blood cells. Red blood cells carry oxygen and waste material (carbon dioxide) around the organism. Oxygen is bound loosely to haemoglobin, an iron-containing protein in the blood cell. In this form, it’s called oxy-haemoglobin. Oxygenated blood is mostly found in arteries. The blood in veins is usually deoxygenated and waste-material. Blood in capillaries gather food from the small intestine by diffusion as it passes. The food molecules mainly consist of glycerol and fatty acids, glucose, and amino acids. The capillaries also carry oxygenated blood before oxygen is delivered and deoxygenated blood after it is. Lymphatic vessels, part of a transport system called the lymphatic system, acquire lymph from leftover tissue fluid from capillaries. Lymph is not present in
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