Title : Study of lung capacity of an individual by using spirometerIntroduction :RespirationThe primary function of the respiratory system is to supply the blood with oxygen in order for the blood to deliver oxygen to all parts of the body. The respiratory system does this through breathing. When we breathe, we inhale oxygen and exhale carbon dioxide. This exchange of gases is the respiratory system's means of getting oxygen to the blood.Respiration is achieved through the mouth, nose, trachea, lungs, and diaphragm. Oxygen enters the respiratory system through the mouth and the nose. The oxygen then passes through the larynx (where speech sounds are produced) and the trachea which is a tube that enters the chest cavity. In the chest cavity, the trachea splits into two smaller tubes called the bronchi. Each bronchus then divides again forming the bronchial tubes. The bronchial tubes lead directly into the lungs where they divide into many smaller tubes which connect to tiny sacs called alveoli. The average adult's lungs contain about 600 million of these spongy, air-filled sacs that are surrounded by capillaries. The inhaled oxygen passes into the alveoli and then diffuses through the capillaries into the arterial blood. Meanwhile, the waste-rich blood from the veins releases its carbon dioxide into the alveoli. The carbon dioxide follows the same path out of the lungs when you exhale.The diaphragm's job is to help pump the carbon dioxide out of the lungs and pull the oxygen into the lungs. The diaphragm is a sheet of muscles that lies across the bottom of the chest cavity. As the diaphragm contracts and relaxes, breathing takes place. When the diaphragm contracts, oxygen is pulled into the lungs. When the diaphragm relaxes, carbon dioxide is pumped out of the lungs.SpirometerA spirometer is the standard equipment used to investigate and detect the changes in lung volume during breathing and measure the capacity of the human lungs. There are several versions of this laboratory apparatus available with most of all consist of a chamber (of capacity approximately 6 dm3) suspended freely over water and counterbalanced so that gas passed in or drawn out makes the chamber rise or fall. You can make a permanent record of the movements of the chamber either by attaching a pen to it and allowing it to write on a drum revolving slowly (kymograph) or by attaching a motion sensor which will convert movement into electronic signals that are then interpreted by your data logging software.This typical type of spirometer consists of a Perspex lid enclosing the spirometer chamber, hinged over a tank of water. This chamber is connected to the person taking part in the experiment via an interchangeable mouthpiece and flexible tubing. As breathing proceeds, the lid rises and falls as the chamber volume changes. With the spirometer chamber filled with air, the capacity of the lungs when breathing at different rates can be investigated. Incidentally, if the spirometer chamber is filled with oxygen, and a carbon dioxide-absorbing chemical such as soda lime is added to a compartment on the air return circuit, this apparatus can be used to measure oxygen consumption by the body as well.Nevertheless, due to the fact that the aforementioned spirometer is too bulky that it is hardly possible to be carried around efficiently, there are some hand-held versions of spirometers available - small devices that measure air flow and calculate volume electronically. For instance, there is a newly-introduced product, spiropet spirometer which is going to be used in this experiment. In addition, Philip Harris offers a 'pocket spirometer' which can be used outside the laboratory for collecting data in the field, and PASCO produce a data-logging spirometer (Pasport Spirometer) for which you would need the Data Studio software, but it produces instant traces on screen.Spiropet spirometer is a completely new product. It can measure vital capacity (forced vital capacity, forced lung capacity), without using water. It has a number of advantages over conventional tank-type spirometer, which make it easier to handle: handiness (lightweight and small size). It has a broad measurement range of 1000 ml- 7000 ml. Exhale through the device to measure vital capacity. Spiropet spirometer gives a very accurate measurement of lung volume (forced lung volume). Spiropet spirometer includes 50 disposable plastic mouthpieces. It can be used for many purposes, including sports tests and health care.Vital Capacity (VC )Vital capacity is the maximum amount of air a person can expel from the lungs after a maximum inspiration. It is equal to the inspiratory reserve volume plus the tidal volume plus the expiratory reserve volume.A person's vital capacity can be measured by a spirometer which can be a wet or regular spirometer. In combination with other physiologicalmeasurements, the vital capacity can help make a diagnosis of underlying lung disease. The unit that is used to determine this vital capacity is millilitres (ml).A normal adult has a vital capacity between 3 and 5 litres. After the age of 20 the vitalcapacity decreases approximatley 250 cc per ten yearsTidal Volume (TV)The volume of air that a human breathes into and out of their lungs while at rest or during normal, relaxed and rhythmical breathing is called the tidal volume. This is a relatively small volume of air (around 500 cm3) and provides enough oxygen for a human's resting needs.Expiratory Reserve Volume (ERV)The maximum amount of air that can be breathed outfrom the lungs by exhaling forcefully after the end of a normal tidal expiration is called the expiratory reserve volume. The typical adult value is 0.75 dm3 to 1 dm3.Residual Volume (RV)Even in dead mammals, the lungs are never completely empty of air. The air that we cannot expel from the lungs, even with the hardest effort of expiration, is called the residual volume. (The typical adult value is around 1.2 dm3) It cannot be measured by spirometry.Inspiratory Reserve Volume (IRV)the maximum amount of air that may be inspired in excess of normal inspiration during quiet breathing is called the inspiratory reserve volume. The typical adult value is 2 to 3.2 dm3. The IRV is calculated by adding the average values for TV and ERV and substracting the total from the evarage VC.Inspiratory CapacityInspiratory capacity is the maximum amount of air that can be inhaled from the normal end-expiratory level. The IC can be calculated by substracting ERV from VC.Total Lung CapacityTotal lung capacity is the maximum volume of air that the lung can hold when distended to the greatest possible extent.Problem Statement :Will lung capacity of a person increase after exercise?Objective :To determine the lung capacity of a normal person.Aim :To determine the lung capacity of a normal person before and after exercise.Hypothesis :Exercise will increase the lung capacity of a person.Apparatus and Materials :Spiropet spirometerTissue paperMouth pieceProcedures :The end of mouthpiece is set to nozzle (1) .(Figure 1 )The Spiropet is hold by one hand and indicator is confirmed to be pointing at zero.If indicator does not point at zero, it is adjusted to zero by moving upper outer ring (2) to right or left. (Figure 2)Next the subject inhales deeply stretching body upward.When lungs are full, the mouthpiece is set between lips. The subject breathes out strongly in one motion, without leaking. It is a knack to breathe out as completely as possible, within 5 or 6 seconds. For fixed measurement, it is necessary to keep the same way of breathing out.After breathing out, measurement on indicator is read.The breathing is repeated three times. The maximum value of the three measurements is the subject's vital capacityThe subject breathes in and out normally for five times and the maximum value of the measurement is divided by five to get tidal volume.To obtain expiratory reserve volume, the subject exhales normally (tidal expiration) and then breathes out the rest of the air to his maximum ability into the spirometer.Step 9 is repeated three times and the average value of the three measurements is the subject's expiratory reserve volume.The inspiratory reserve volume, inspiratory capacity and the total lung capacity is calculated by using the formula provided in the table below.The lower body of the spiropet spirometer is twisted clockwise direction. Water droplets and saliva are removed by using tissue paper.Step 1 till step 8 is repeated for the subjects who has conducted exercise.Results :
Vital Capacity (VC)
Trial 1
Trial 2
Trial 3
VC Highest Value
3800
3700
3900
3900
Tidal Volume (TV)
Total for five breathes
Average
2000
400
Expiratory Reserve Volume (ERV)
Trial 1
Trial 2
Trial 3
Average
1800
1800
1800
1800
Inspiratory Reserve Volume (IRV)
VC-(TV+ERV)
1700
Inspiratory Capacity (IC)
VC-ERV
2100
Residual Volume (RV)
1200
Total Lung Capacity (TLC)
VC+RV
5100
Table 1 : Various respiratory volumes and capacities of a normal personTable 2 : Various respiratory volumes and capacities of a normal person
Vital Capacity (VC)
Trial 1
Trial 2
Trial 3
VC Highest Value
4200
4200
4100
4200
Tidal Volume (TV)
Total for five breathes
Average
2400
480
Discussion :In the experiment, the vital capacity and tidal volume of a person before and after experiment is investigated. The highest capacity of the subject at rest is 3900 cc whereas after exercise the highest capacity of the subject is 4200cc which is higher compared to the person who is at rest. This is because, when a person exercise the demand of oxygen for the body cells increases and carbon dioxide output rise and as a result, both the tidal volume and ventilation rate increase and so maintain an adequate gas concentration in the lung for rapid gaseous exchange. However, the pattern of change is quite complex and it varies with the level of exercise, too. Thus, contraction of the diaphragm and intercostal muscle become more forceful. As a result, the lung capacity of a person after exercise is larger. Moreover, the tidal volume of a subject at rest is 400 cc which is obtain from five breathes because the value of measurement for one breath is too small to be measured. However, the tidal capacity of the subject after exercise is 480cc which is greater than that of a person who is at rest. Besides the expiratory reserve volume is 1800cc whereas inspiratory reserve volume is 1700 for the subject at rest. Inspiratory capacity of the subject is 2100cc. In the experiment, the subject is a male so residual volume of a male is 1200cc which is given for the experiment purpose.However, the lung capacity is different for different people. There are some factors affect the lung capacity of a person which is gender, age, fitness level of a person, height weight and so on. Thus, some factors have to fixed in order to study the lung capacity of a person. For instance, the lung capacity of a male is always higher than that of a female.There is some precaution and safety measures in the experiment. First and foremost, the spiropet must be kept horizontal during measurement. If it is not kept still, the vanes cannot revolve evenly and measurements result will not be correct. Moreover, when using, it is important that the small holes which are at the side of the upper are not cover up with your hands. When used frequently, water drops and saliva will condense inside. Accuracy is lost. Thus, once every ten measurements, the lower body is removed and inside is cleaned with a cloth. It is easily removed by turning it clockwise. Another thing to point out is that spiropet is a precision instrument like a watch and hence it must be handled carefully. Similarly, 3 replicate readings are taken the average reading are calculated to increase the reliability and validity of the results. It is also made sure that there is no leaking when the subject breathes air into the spiropet. After the experiment, the mouthpiece should be cleaned and further disinfected to prevent any infections among the students. In addition, the experimental subject should not inhale the air from the Spiropet because there is a possibility of infection especially if it is used for a number of times by many people. Moreover, the experiment should not be conducted on individuals who has recent heart attack. Lastly, if the subject feels light headed, faint, short of breath, or experiences chest pain, the experiment should be stopped at once.Conclusion :Hypothesis is accepted. Exercise will increase the lung capacity of a normal person.Limitation :Everyone has his own unique gene, although both person are same gender, age, fitness level, height and weight, lung capacity will still be different for both of them. This will lead to inaccuracy of the results.Although both person have same fitness level, the amount of physical activity have been done in order to get values of various respiratory volumes and capacities is difficult to determine. We cannot control both person run at the same speed. As a result, different amount of physical activity will result in different value of lung capacities. This is definitely leading to inaccuracy in result.Further Study :The lung capacity of the subjects with different gender.The lung capacity of the subjects with different weight.The lung capacity of the subjects with different physical fitness level.Bibliography :http://www.fi.edu/learn/heart/systems/respiration.htmlhttp://science.jrank.org/pages/6398/Spirometer.htmlhttp://www.duke.edu/~ajs9/framesite/BME154.pdfhttp://www.practicalbiology.org/areas/advanced/cells-to-systems/ventilation-systems/using-a-spirometer-to-investigate-human-lung-function,94,EXP.htmlC J Clegg, Edexcel Biology for AS, Hodder Education, 2008, pg123-126Edexcel AS Biology, A Pearson Company, 2008, pg158-160
