Essay On Mammal Circulatory System

reduces the surface tension of the water lining the alveoli. Mammals have a circulatory system as their gas exchange system. It operates by the oxygen that is diffused being delivered to respiring body cells and returning with carbon dioxide to the lungs due to the blood vessels lining the alveoli transporting these gases. As diffusion would take much longer to reach the cells in a much larger organism, the blood flow through the capillaries guarantees that the oxygen reaches the distant cells more efficiently. This is why mammals require a transport system due to their large size as otherwise oxygen would take too long to diffuse from the gas exchange surface to the body tissues. The circulatory system in a mammal works by the blood circulating

through the body and the lungs soon obtaining the returning oxygen poor blood. This blood flow helps to sustain the concentration gradient that is required for gas exchange to occur by making certain that the lungs has a lower concentration of oxygen and a higher concentration of carbon dioxide. As mammals breathe in air they are often taking in unwanted particles into the gas exchange system, in order to keep the gas exchange system moist and clean, mammals have the ability to produce mucus in the trachea and bronchi. By the mammal’s lungs being located deep inside the body it keeps the lungs moist and harder for the moisture to evaporate. The lungs work by the mammal taking in air through its nose and mouth and to the warm the air before it enters the lungs, it passes through the capillaries that line the nose and mouth of the organism. The capillaries humidify the air the mammal breathes in and makes it warm, therefore moist, this ensures that the drying out of the lining of the lungs and bronchial tubes is prevented. (http://www.entnet.org/content/your-nose-guardian-your-lungs, 25.08.15).

To prevent your lungs taking in debris and dust, the mammal has small hairs and produces mucus that catches it. A mammal’s airways are lined with tiny hairs which have the purpose of sweeping debris that the mucus has caught in a wave like motion to the top of the throat and this is then swallowed and further destroyed in the stomach. It is these features and adaptations which help to maintain a large surface area for gas exchange to occur as it prevents these bacterial products from sticking and gathering on the gas exchange surface. A mammal’s lungs are surrounded and protected by a muscle structure called the rib cage which allows the lungs to move in and out as the rib cage provides a canopy for them. The diaphragm contracts to draw in the air and then relaxes pushing out, this ventilates the lungs. Tidal ventilation occurs as the air goes in and out the same way but this is similar to insects in the way that it isn’t the most efficient process as not all the air that is taken in with each breath is breathed out again as some of the oxygen has already been lost to the blood flow and not all the air taken in with each breath actually makes it to the gas exchange surface in the

alveoli.