Respiration and Diffusion - Essay Example

 Respiration and diffusion Respiration is the series of actions that result in the exchange of oxygen and carbon dioxide between the atmosphere and cells of the body. (science.yourdictionary.com) Types of respiration Aerobic respiration –this is respiration that needs oxygen. It occurs in cells when glucose reacts with oxygen. The equation is as follows: glucose + oxygen    →    carbon dioxide + water (+ energy) C6H12O6 + 6O2    →    6CO2 + 6H2O (+ energy) Anaerobic respiration- this does not require oxygen and occurs when there is insufficient oxygen for aerobic respiration. The word equation is as follows: glucose    →    lactic acid (+ energy) A smaller amount of energy is liberated by anaerobic respiration compared to aerobic respiration. NB: Energy is indicated in brackets in each equation since it is not a chemical substance. Diffusion on the other hand is the movement of molecules of a particular substance from a region of reasonably high concentration to that of lesser concentration(wiki.answers.com ) The aspects that control the speed of diffusion consist of surface area, concentration gradient, and diffusion distance. Animals have developed to increase the diffusion speed across respiratory membranes by increase of the respiratory surface area, concentration gradient, or reducing the distance of diffusion. They are illustrated by Fick’s Law as follows: Fick’s Law of Diffusion: It states that: The speed of transmission of a gas through an area of tissue is proportional to the tissue area and the variation in gas partial pressure between the 2 sides and inversely proportional to the tissue thickness.(source) Volume of gas (per unit time)=Area/Thickness x Diffusion constant x (Partial Pressure 1 - Partial Pressure 2) dV/dt = A/T * D * (P1 - P2) Fick's Law of Diffusion looks at the rate of transfer of gases through tissues. For instance in respiration, the law governs the rate of transfer of Oxygen that comes from alveoli to the blood through the thin blood gas obstacle, and Carbon Dioxide in the reverse direction. (Karp, 2010). The outcome of this correlation is that the Carbon Dioxide will diffuse about 20 times more quickly compared to Oxygen through the tissue areas. This variation is as a result of the solubility of Carbon Dioxide being elevated and therefore raising the diffusion constant. The diffusion constant is relative to the solubility divided by the molecular weight square root. The Fick’s law equation can be practical to different localities and elements of a tissue. Diffusion of gas across thicker parts of tissue will reduce gas diffusion time contrasting to thinner tissue. In addition, bigger area influences the speed of diffusion, by presenting a raise in the volume of gas diffused (Sherwood, 2007). Respiratory system organs Respiration is attained through one’s mouth, nose, trachea, lungs and diaphragm. Oxygen gets into the respiratory system through the mouth and the nose. The oxygen then goes to the larynx and the trachea. In the chest opening, the trachea divides into two lesser tubes known as the bronchi. Every then splits again to form the bronchial tubes which go to the lungs where they split into several lesser tubes which attach to alveoli. The oxygen that is taken in pass through the alveoli then diffuses through the capillaries into the blood in the artery. Temporarily, the polluted blood from the veins liberates its carbon dioxide into the alveoli. Carbon dioxide takes the same course out of the lungs when one breathes out. A diaphragm assists in pumping carbon dioxide outside the lungs and draws oxygen into the lungs. As it relaxes and contracts, respiration occurs. It is by this means that one breathes in and out. Circulatory system The system includes the heart and the blood vessels and circulates blood all through the body. An individual’s body has approximately 5 liters of blood constantly circulating through the circulatory system. Circulatory organs team up, to form a proficient pipe system for ones body. The human body has three parts namely, the pulmonary circulation, coronary circulation and systemic circulation. Whereby the pulmonary circulation is the transfer of blood from the heart, to the lungs, and reverses it to the heart again. Coronary circulation on the contrary is the transfer of blood through the heart tissues. Systemic circulation provides sustenance to all human body tissues. Every circulatory system operates separately. There are there types of blood vessels and they include: the arteries, veins and capillaries. The arteries carry oxygen rich blood away from the heart, veins carry blood back towards the heart and capillaries are the thin blood vessels through which nutrients and waste products pass into and out of the blood. The human lungs are used to provide oxygen from air taken in to the capillaries and release the carbon dioxide they get. The Circulatory system not only moves different substances between body cells but also sustains the human body temperature. The digestive system Food gets into the digestive system through the mouth. The food is first bitten and chewed by use of the teeth and processed chemically by the saliva. It is then swallowed by organs like the tongue, oesophagus and the throat. The initial phase of swallowing can be able to be controlled; however, the moment food is inside our throat, the nervous system controls its movements. It is then taken to the oesophagus. The food then gets into the stomach where the swallowed food is stored, it also mixes the food, liquid and the digestive juice the stomach produces. The food is then emptied into the small intestine. The food that is digested is then absorbed through the walls of the intestines. The waste products move to the large intestines, where they stay for a few days until they are removed from one’s body in the form of feaces. In conclusion, we find that oxygen and carbon dioxide get into and out of the body tissues by the mode of diffusion. Because there is tiny microscopic organisms for instance the amoeba inside the pond, it can only rely only on diffusion to carry oxygen and to get rid of carbon dioxide from its single cell. Conversely, multi-cellular organisms are too large to rely exclusively on diffusion: the distances gases have to diffuse are so long, and the gas movement hence too slow support life. Even though in human beings the similar passive system of diffusion exclusively provides and gets rid of the gases from the human body. The trend of diffusion is increased by complex respiratory and circulatory systems which achieve what the water in the pond does for the amoeba in provide the sink for the gases. The lungs help diffusion since they have a large surface area that is thin which makes diffusion easier to occur. The circulation of blood forms the link of transport between the sites of diffusion of the capillaries inside the tissues. In a nut shell, diffusion is an important aspect in the process of respiration. References Sherwood, L. (2007). Human physiology: From cells to systems. Australia: Thomson/Brooks/Cole. Karp, G. (2010). Cell and molecular biology: Concepts and experiments. Hoboken, NJ: John Wiley. Respiration - Science Definition. (n.d.). Science. Retrieved December 6, 2012, from http://science.yourdictionary.com/respiration What is the definition of diffusion. (n.d.). The Q&A wiki. Retrieved December 6, 2012, from http://wiki.answers.com/Q/What_is_the_definition_of_diffusion Read More