The respiratory system is a series of organs responsible fordelivering oxygen to the body and expelling carbon dioxide. Red blood cellstransport air inhaled air from the lungs to the rest of the body, as well ascarry carbon dioxide from the body, back to the lungs. Inhalation andexhalation are the processes of breathing (Zimmermann, 2016). The respiratory is comprised of a upper andlower tract. The organs in the upper tract include the nose, the pharynx, andthe larynx; which are located outside the chest cavity. The lower tract,located in the chest cavity, contains the trachea, the lungs, and all segmentsof the bronchial tree.
Cellular respiration is the process in which moleculesare broken down by cells and used for their energy. Oxygen is used to fuelthese reactions, while carbon dioxide is a waste product generated from thework. Oxygen breathed in and glucose from food is turned into carbon dioxide,water and sweat, as well as energy in the form of ATP (‘What Is the ChemicalEquation for Cellular Respiration?’ n.d.). Cellular respiration is a crucialpart to life as without it cells would not have the energy required to sustainand perform necessary functions.The nasal cavity conditions air to be received by therespiratory system. Passing air is warmed or cooled to 1 degree within bodytemperature, as well as humidified.
A sticky mucous membrane lining the nasalcavity traps any debris and dust particles. Short thick hairs called vibrissaeaid in the filtration of air in conjunction with microscopic cilia (“Nasalcavity,” n.d.). Commonly referred to as the throat, the pharynx connects thenasal and oral cavities to the larynx and esophagus. It allows for the movementof air from the nose and mouth to the larynx as part of the respiratory journey(“Pharynx,” n.
d.). The epiglottis keeps the passage to the windpipe coveredwhen swallowing, to prevent food from entering the larynx and trachea. Thelarynx connects the pharynx to the trachea in the neck. It is more commonlyknown as the voice box as it has the folds necessary for the production ofsound. In the larynx sound is created as air moves through the vocal cords, apair of movable folds in the mucous membrane (“Larynx Anatomy and Physiology,”n.d.
). The trachea is a hollow tube thatconnects the larynx (voice box) to the bronchi of the lungs. It is 2.6cm indiameter and has a thin, membranous wall with C-shaped rings of cartilageembedded into it (“Trachea Windpipe,” n.d.).
There are four layers of tissue that make up the trachea;the mucosa (innermost layer), submucosa, hyaline cartilage and adventitia(outermost layer). Muscles in the wall of the trachea allow for it to expand orcontract depending on what action is being performed (coughing, breathing,swallowing). The lungs are one of the biggest and most important organs in thebody. The right and left lungs are not the same size and width, with the rightlung divided into 3 lobes versus 2 on the left lung. These lobes are made ofsponge-like tissue which is enveloped by a membrane called pleura; it separatesthe lungs from the chest wall.
Half of each lung has its own pleura sack. Whenthey expand lungs pull air and oxygen into the body. When they compress, carbon dioxide isexpelled.
The diaphragm and rib cage pump the lungs to allow for expansion andcompression (Bradford, 2015). The bronchi are the main passageway into thelungs. Air travels from the trachea intothe bronchi (first part of branching system) and then into smaller and smallerbranches. A bronchus (there are 2) is a sub division of the windpipe thatenters the lungs (“Bronchi Function, Parts and Location – A part of Lungs,”n.
d.). The mucous lining of the lumen inside a bronchus protects the lungsagainst dust, germs and dirt particles.
The bronchioles branch out from the twobronchi to disperse air throughout the lungs. At the very end of each bronchiole is the alveolus sac; where thetransfer of carbon dioxide and oxygen to the blood takes place. The bronchiolesare divides into three sections that progressively gets smaller: Lobularbronchioles, Terminal bronchioles and Respiratory bronchioles (Eldridge, n.d.
).The bronchioles are lined with smooth muscle tissue that allows for contractionand dilation to control the flow of air. There are hundreds of millions of microscopicalveoli at the end of the respiratory tree. The interactions between the wallsof the alveoli is when the respiratory system comes into direct contact withthe circulatory system to exchange gases (“What Are the Functions of Alveoli inthe Lungs?” n.
d.). Blood vessels around the alveolus sac quickly absorb air andcarry it through the blood stream. Oxygen and other gases such as carbondioxide are separated in the blood. Each alveolus sac is surrounded by a thinlayer of fluid that allows air to pass through to cells (McDougal, n.d.).
The alveoli physically expand when deep breaths are taken,and relax when we exhale. Through diffusion, gas exchange occurs at the site ofthe alveoli. The alveoli wall is lined with epithelial cells, an extracellularmatrix and small blood vessels known as capillaries.
Blood arriving at thealveoli deposit the waste product of cellular respiration (CO2) and pick up O2to carry throughout the body. Theconcentration gradient between the alveoli air and the blood in thecapillaries, allows carbon dioxide to diffuse out of the blood while oxygendiffuses into the blood (“GCSE Bitesize Science – Gaseous exchange in thelungs,” n.d.
). Oxygen makes up 20.95% of the atmosphere that we breathe, withthe other 78.09% being nitrogen gas (“Atmosphere of the Earth,” n.d.
). It isessential for cellular respiration. Oxygen is a covalent, non-polar molecule. O2only has London dispersion forces as it is not a polar molecule (cannot haveLondon dispersion forces) and it does not have hydrogen bonding. CO2 onlyaccounts for 0.04% of Earths atmospheric gases. Carbon dioxide has is anonpolar, covalent molecule, therefore the only intermolecular force it has isLondon dispersion forces.
It is a waste product that is manufactured in thebody and expelled through the process of breathing. The primary muscle used topump the lungs for inhalation or exhalation. It is a dome shaped sheet that islocated behind the lower ribs. It is a thin skeletal muscle that contractsvoluntarily. During inhalation, the muscles in the diaphragm contract, and pullthe central tendon inferiorly into the abdominal cavity. This action enlargesthe thorax and allows air to fill the lungs (“Diaphragm Function, Definition& Definition | Body Maps,” 2015).
During exhalation, the diaphragm relaxesand elevates to a dome-shaped position in the thorax while the rib cage dropsto resting position. Air in the lungs is forced out as the thoracic cavitydecreases in size. Kinetic Molecular Theory (KMT) – The idea that allsubstances are composed of entities that are in constant, random motion. Thereare five parts to the KMT of gases: 1) Gas particles are in constant randommotion. They have translational, vibrational and rotational kinetic energy. 2)Gas particles are considered point masses. They have no volume.
3) Gasparticles do no exert attractive or repulsive forces on each other. 4)Collisions of gas particles with themselves or the container walls are elastic 5)The average kinetic energy of gap particles is directly related to temperature.Kinetic molecular theory describes the behavior of ideal gases – a hypotheticalgas made of particles that have mass, but no volume and no attractive forcesbetween them. These properties are true for all gases as long as they are atnormal temperatures: all gases behave the same, gases are compressible, theyexpand as temperature increases so long as pressure is constant, gases have lowviscosity, less dense than solids or liquids, all gases are miscible. Theproperties that all gases display is crucial to how we breathe and take inoxygen. With low density and viscosity, gases are easy to inhale and as aresult our respiratory systems have evolved to adapt to such properties. Sincethere is so much space between gas particles they can be easilycompressed.
This is beneficial whenoxygen needs to be compressed and stored in a tank for usage later on. Pressure– the force that is exerted on an object per unit of surface area. It isdirectly related to the force applied and inversely related to area. Pressureinside close containers is due to the frequency of gas molecule collisions withthe walls. Factors like volume and temperature affect pressure.
During diaphragm contraction, the chest cavityexpands to hold larger volumes of air. This expansion results in a lowerconcentration of gas molecules as the volume increases but the number ofmolecules remains the same. The pressure during inhalation is also lower sincethere are fewer molecular collisions (gas particles colliding with the walls).The pressure outside of the lungs (external pressure) is constant, meaning thatit is now at a higher pressure than the air within the lungs. Since gas movesfrom higher areas of pressure to lower areas of pressure, gaseous molecules rushinto the lungs to equalize the pressure. Kinetic molecular theory is applicableto all gases including oxygen. It describes the behavior of such gas whenpressure increases or decreases (collisions with same particles or containerwalls), they are in constant random motion and display no attractive orrepulsive forces on itself.
Boyles law describes the relationship betweeninhalation; expansion of thoracic cavity to lower pressure and increase volume,with the following equation, where P is pressure and V is volume. The processof exhalation is the opposite of inhalation. As the muscles in the diaphragm relax, lung volume decreases andtherefore increases pressure within the lungs (less volume with same quantityof gas molecules = more collisions with the wall = higher pressure). Since theexternal pressure is lower than the pressure in the lungs, air is pulled out ofthe lungs in order to travel from high to low pressure. Again, Boyles law is ineffect during the process of exhalation, in which volume decreases causingpressure to increase as long as temperature remains constant. Respiration isthe cyclic process of creating pressure differences to pull air into or out ofthe lungs.
Atmospheric pressure (air pressure): the force exerted on a surfaceby the air above it a gravity pulls it towards Earth. It decreases as altitudeincreases since there are less entities that make up air. Atmospheric pressure increases when altitudedecreases as it there are more layers of atmospheric to exert a force on it. Airparticles are also more densely packed closer to the Earth. The summit of MountEverest is 8850m (29,000 feet) above sea with about 33% of the oxygen contentfound at sea level. With about 2/3 less oxygen than what we’re used to, thebody has to breathe more to get the same amount of oxygen into the bloodstream(“Valerio Massimo Everest Expedition 2009,” n.d.
). At high altitudes, theexternal air pressure is lower than it is inside the lungs, making air want toleave the lungs rather than flow into it (air travels from high to lowpressure). The body needs to work harder to pull in thinner air and plump bloodthroughout the body. This overworking can lead to high blood pressure, heartrate, dizziness and altitude sickness.
Decompression Sickness (DCS) is causedby the formation of bubbles of gas (mainly nitrogen) in the blood when the bodyundergoes changes in pressure during scuba diving. While diving, body tissuesabsorb nitrogen from breathing gas in proportion to the surrounding pressure.Nitrogen gas in the body is not used by the body and builds up in tissuesovertime. As long as a diver remains at the same pressure, there is no risk ofinjury (“The Bends: Symptoms, Treatment & Prevention,” n.d.). However, if adiver surfaces too fast, excess nitrogen comes out rapidly as gas bubbles inthe blood stream. DCS can occur in mild cases yet it can also cause severecomplications if not treated properly.
When high levels of bubbles occurreactions might take place in the spinal cord or brain. Numbness, paralysisand disorders of higher cerebral function may result. Signs of DCS include: blotchy rash paralysis, muscleweakness, confusion, amnesia, staggering, coughing up bloody, frothy sputum,collapse or unconsciousness and more (“Decompression Illness: What Is It and WhatIs The Treatment?” n.d.
). The only treatment for decompression sickness isrecompression; isolation in a compression chamber in which pressure is slowlybrought back to surface level. A few gas laws include Boyles law (P1V1 = P2V2),Charles law (V1/T1 = V2/T2) and Gay Lussac’s Law (P1/T1 = P2/T2). The combinedgas law, as its name suggests, combines these three gas laws into one equation:P1V1/T1 = P2V2/T2. When performing calculations to solve for pressure, volumeor temperature it is crucial to take into account proper units. Pressure isoften expressed in KPa (kilo-pascals) while temperature must be expressed inKelvin.
SATP (Standard ambient temperature and pressure) – a condition in whichpressure is at 101.325KPa and temperature is 298K STP (standard temperature andpressure) – a condition in which pressure is at 101.325KPa with temperaturebeing 273.15K. Pulmonologist – someone who specializes in diagnosing andtreating patients with lung problems. This includes conditions such as asthma,lung cancer, tuberculosis, COPD, sleep disorder, pulmonary vascular disease andmany others. These specialists may work in surgery, medical clinics andemergency rooms (“Medical professions,” n.
d.). Respiratory Therapist – These people diagnose breathing problems andsuggest treatments to patients. Respiratory therapists usually work intensivecare units, general hospitals or rehabilitation centers. They perform chestexams, talk with patients and analyze tissue. They also manage any breathingdevices that the patient might use such as ventilators, in order to ensure thatthe equipment it working properly and that the patient is safe (“Medicalprofessions,” n.d.