(6)	Respiratory+system+-+efficiency+&+cleaning

__**Respiratory System**__
The respiratory system is the anatomical system of an organism that introduces respiratory gases to the interior and performs gas exchange. In humans and other mammals, the anatomical features of the respiratory system include airways, lungs, and the respiratory muscles. Molecules of oxygen and carbon dioxide are passively exchanged, by diffusion, between the gaseous external environment and the blood. This exchange process occurs in the alveolar region of the lungs. =**Moist**= Alveoli are tiny, multi-lobed air sacs. The alveoli must always stay moist to function more efficiently. Therefore, alveoli contains a type of cells that produce a substance called surfactant which reduces the surface tension of water. Surfactant avoids alveoli sticking together when exhaled. If the surface tension of water remains the same, the alveoli will stick together, which can cause damage when the alveolar cells tear away from each other during the inhale process. The tissues that form from this site will result permanent damage to the lung's elasticity and its ability to expand fully. Carter, Stein J. "Respiratory System." Biology at Clermont College - University of Cincinnati. 3 Nov. 2004. Web. 08 Feb. 2012. <[]>

The distance between air and the blood is very short because the walls of the alveoli and capillaries are extremely thin. The oxygen and carbon dioxide concentration gradiesnts are very steep.
 * __ Distance __**

The dense network of alveolar capillaries has a //very large // surface area (about 125 sq ft)

**__Diseases that affect the respiratory system__** Bronchitis is caused by the inflammation of the lining of the bronchioles. This may be due to infection by bacteria or viruses, or chemicals such as those found in tobacco smoke. Lung cancer is caused by a change in the cells inside the lungs, so that they divide out of control, and produce lumps of cells (tumours) which interfere with the normal functions of lungs. A major cause of this is tobacco smoke, but other substances, including the "natural " radioactive radon gas, which may build up in some areas, may also have an effect. Emphysema is a condition in which the structure of the alveoli is broken down (by smoke and coughing), reducing the surface area for gaseous exchange, as well as altering the elasticity of the lungs.

= SA = SA stands for Sleep Apnea, a sleep disorder when a person has pauses in breathing or shallow breaths. Normally, the airway, consisting of mouth, nose, windpipe and throat, remains open to allow air to enter and exit.



Obstructive Sleep Apnea can be dangerous. The airway will be partly blocked or completely blocked. When the airway is partly block, it is harder for air to enter the lungs. This lowers the efficiency of respiration and any air that tries to squeeze through the blockage will cause snoring.



Sometimes, the airway may be completely blocked, where there is no airflow. This is called apnea. With little or no air in the lung, apnea can be very dangerous, by reducing the blood oxygen level. The brain then give signals to disrupt the sleep which helps to reopen the airway. Apnea can also end when there is a gasp.

National Heart Lung and Blood Institute. "What Is Sleep Apnea? - NHLBI, NIH." NIH Heart, Lung and Blood Institute. 1 Aug. 2010. Web. 12 Feb. 2012. <[]>.

= Passive = The passive feature during breathing helps improve the efficiency of the respiration process. The passive feature only occurs during the expiration process, meaning exhaling air, out from the lungs as the respiratory muscles are relaxed. The elastic lung and chest wall will return passively to their resting volume.

Hopkins, Johns. "Muscles of Respiration." Untitled Document. 1995. Web. 12 Feb. 2012. <[]>.

=Thin= Thin is a feature used in in bronchiole and alveolus. Bronchiole and Alveolus both have very thin walls. The bronchi extend into the lungs spreading in branches by bronchial tubes. The respiratory bronchiole's wall becomes thin to permit gas exchange. Respiratory bronchioles communicate with alveolar ducts, alveolar sacs, and alveoli. The delicate structure of the alveoli helps improve the efficiency of respiration. Alveoli have thin walls, which form the respiratory surface. The exchange of gases between the blood and the air takes place through these walls. The interalveolar Septum is the ultra-thin wall of tissue made of epithelial cells separates air from blood. There is a large amount of surface area putting air and the blood stream in close to each other. This trait is needed for gas exchange to easily occur.

Oak, Manali. "Structure of the Human Respiratory System." Buzzle Web Portal: Intelligent Life on the Web. 2000-2011. Web. 12 Feb. 2012. <[]>.

John Carroll University. "Gas Exchange - ENotes.com." ENotes - Literature Study Guides, Lesson Plans, and More. 2012. Web. 12 Feb. 2012. <[]>.

Visual Histology. "Visual Histology - Histology Text Atlas Book - 303-485-9110." Histology Teaching Series on DVD and Video: Lecture Course With Lab Material - Complete Integrated Histology Course. Web. 12 Feb. 2012. <[]>.

=**Keeping the Respiratory System Clean**=

10,000 litres of air move in and out of the lungs every day. Each breath taken carries germs and other foreign including oxygen and carbon dioxide. As a result the lungs provide a complex physical and chemical defence system against unwanted materials getting into the body. The nose always have to be filtered and moist when air travels down the lungs because the air contains dust, bacteria, and other unwanted materials.



Mucus produced in the walls of the airways helps keep the throat, windpipe well cleaned. Along the nose, the respiratory track is lined by the cilliated cells which helps clean the nasal passages and filtering the air. The respiratory track includes goblet cell and cilia. These two parts help trap bacteria and dust, avoiding them traveling down to the lungs. Cells in the lungs contain enzymes that produce chemical changes in the blood. This helps adjust the pH level according to the effects when the body is taking part in a physical activity, to get rid of CO2. However, when the lungs are damaged by smoking or pollution, they can lead to breathlessness.

Fray, Regina, and Rachel Casiday. "PH Buffers in the Blood." Department of Chemistry | Washington University in St. Louis. 9 May 2008. Web. 12 Feb. 2012. <[]>. Foundation, British Lung. "British Lung Foundation | About Your Lungs | The Way Your Lungs Work." British Lung Foundation | Home Page. Mar. 2011. Web. 12 Feb. 2012. <[]>.

Functions of Cilia and Goblet Cells - CSTSGLOBAL - YouTube. Dir. CSTSGLOBAL. YouTube - Broadcast Yourself. 4 Feb. 2008. Web. 13 Feb. 2012. <[]>.

Haton Anthea. "Respiratory System." //Wikipedia//. Wikimedia Foundation, 03 Jan. 2012. Web. 02 Mar. 2012. [].