The Mechanism of Carbon Dioxide and Oxygen Exchange in the Respiratory of Human Essay

Title: the mechanism of carbon dioxide and oxygen exchange in the respiratory of human Abstract The purpose of the experiment is to determine gas exchange activity in the respiratory system of human. The first lab for comparing the room and breathe temperature was to understand the function of the nasal cavity where the gas passed after an inhalation. The second lab for changing of chest circumference and abdomen circumference between inspiration and expiration was to know how the air moved in and out.

The third lab of level of time of bromothymol blue colour change between normal and exercise was to discover the change level of carbon dioxide in the blood between relaxed and exercise. The forth lab of change time of holding breath after deep breath and quick breath was to show level of carbon dioxide change in the blood after deep breath and quick breath. The fifth lab of measuring diameters of the balloon which was blew by normal and force exhalation was to get the vital volume and the vital capacity form the graph of lung volume vs. balloon diameter. Introduction

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The major function of the respiratory system is gas exchange between the external environment and an organism’s circulatory system. In humans, this exchange facilitates oxygenation of the blood with a concomitant removal of carbon dioxide and other gaseous metabolic wastes from the circulation. As gas exchange occurs, the acid-base balance of the body is maintained as part of homeostasis. If proper ventilation is not maintained, two opposing conditions could occur: respiratory acidosis, a life threatening condition, and respiratory alkalosis (West, John B. 1993).

That is why people need to understand their mechanism of gas exchange in their respiratory system. Materials and methods In the experiment, materials required were a stop watch, a measuring tape, a thermometer, two straws, 25mL of bromthymol blue, two beakers, a balloon, a meter stick, two metric rulers and a bathroom scale. In lab A, the first step was to use thermometer to record the room temperature. And then, the thermometer was held between the lips of the subject which the subject exhaled. At that moment, through the thermometer, the breath temperature could be read and recorded.

The last step was to exhale onto a cooled window and to record what happened. In lab B, while the subject was relaxed, to use a tape measured the chest circumference at the fifth rib and the abdomen circumference at the level of the umbilicus as the initial circumference and also recorded those measurements. Next, while the subject had a full inhalation and a full exhalation, results measured and recorded were regarded as the final circumference. After several calculations, changes in circumference were taken.

In lab C, there were 25mL of bromthymol blue poured into both two beakers and to record the beginning colour in each beaker was beneficial to compare with the ending colour and observe changes in colour. While the volunteer was relaxed, the volunteer blew into the first beaker through one straw and then observers recorded the ending colour and the time to change colour from the stop watch. After the volunteer did thirty jumping jacks and blew into the second beaker, the ending colour and the time to change colour were recorded. In lab D, sitting down and breathing normally were the condition.

After a deep breath, the partner needed to hold it while being timed and another recorded the result. While the partner normalized the breathing’s rate, the job was to record the breath-holding time after twenty-to-thirty-minute quick breath. Finally, the partner returned the breathing normal again. The final result was the breath holding time after a deep breath as before. In lab E, the first job was to stretch a round balloon several times. Then, when the subject inhaled normally and exhaled normally into a balloon, the subject recorded the diameter of the balloon what the two rulers measured.

The subject gained another measurement by repeating the trail and the average result by calculation. According to the graph of balloon diameter vs. lung volume, the tidal volume was taken. The vital capacity was taken by repeating the procedure. The only change was to breathe forcefully. Results Table A: temperature change between room and breathe and its product Subject| Room temp. (? )| Breathe temp. (? )| Effect on slide| Serena| 17| 21| The glass is foggy and has some tiny water droplets. |

Table B: chest and abdomen circumference between inspiration and expiration Subject| Chest Circumference (cm)| Abdomen Circumference (cm)| Initial Circumference| 77. 5| 75| Final Circumference| Inhalation| Exhalation| Inhalation| Exhalation| | 79| 76| 72| 81| Change in Circumference| +1. 5| -1. 5| -3| +6| Table C: level of carbon dioxide change between normal and exercise Beaker| Beginning Colour| Ending Colour| Time to change colour| 1| Light blue| Light yellow | 7. 34s| 2| Light blue| Light yellow | 3. 75s| Table D: level of carbon dioxide change between deep breath and quick breath Procedure| Time|

Deep breath| 1min 16. 03s| Quick breath| 44. 47s| Deep breath| 54. 44s| Table E: tidal volume and vital capacity Subject| Balloon Diameter| | Tidal Volume (cm)| Vital Capacity (cm)| | Trail 1: 5| Trail 2: 15| | Trail 2: 5. 7| Trail 2: 15. 6| Average| 5. 35| 15. 3| Volume from Graph| 100| 2000| Discussion In part A, air entered the nose and then passed through the nasal cavity. Mucous membranes that moistened the air and blood vessels that warmed the air lined the nasal cavity. The nasal cavity increased the surface area for moistening and warming air during inhalation and for trapping water droplets during exhalation.

Therefore, the breath temperature was higher than the room temperature and some tiny water droplets appeared on the glass. In part B, during inspiration, the diaphragm contracted and lowered. Also, the external intercostals muscles contracted, and the rib cage moved upward and outward. Following this contraction, the volume of the thoracic cavity was larger than it was before. As the thoracic volume increased, the lungs expanded. Therefore, the chest circumference at the fifth rib increased and the abdomen circumference at the level of the umbilicus decreased.

During expiration, the elastic properties of the thoracic wall and lungs caused them to recoil. The abdominal organs pressed up against diaphragm, and contraction of the internal intercostals muscle forced the rib cage to move down and inward. Therefore, the chest circumference decreased and the abdomen circumference increased. In part C, bromthymol blue was an acid-base indicator which appeared yellow at the pH;lt;6. 0 (acid) and blue at pH;gt;7. 6 (base). When breathing normally, air entered the lungs and the external respiration happened.

At pulmonary capillaries, O2 (oxygen) entered red blood cells where it combined with Hb (hemoglobin) to form HbO2 (oxyhemoglobin). Then, at systemic capillaries, the internal respiration occurred. HbO2 inside red blood cells became Hb and O2. O2 left red blood cells and capillaries into the tissues. Next, CO2 from the tissues entered red blood cells. Some combined with Hb to form HbCO2 (carbominohemoglobin). Since H2O+CO2; H2CO3;HCO3- +H+, most was converted to HCO3- (bicarbonate ions), which was carried in the plasma. Hb now combined with H+ to form HHb (reduced hemoglobin). Finally, the blood backed to the lungs.

HCO3- was converted inside red blood cells to H2O and CO2. CO2 from plasma moved into the alveoli. By exhalation, CO2 were pushed out of the lungs and reacted with water in the mouth to form the H2CO3. H2CO3 was an acid, so when it from the mouth entered the bromothymol solution, the solution changed its colour into yellow. In addition, after exercising, demand for oxygen increased because the tissues required more ATP. In turn, more carbon dioxide was produced by tissues and diffused to the blood. The rise in the level of carbon dioxide caused more H2CO3 releasing into the solution, therefore, the solution changed colour faster.

In part D, gas exchange activity converted O2 into CO2. When the level CO2 increased, the brain commanded people to breathe. The time of holding breath after deep breath were longer than the time of holding breath after quick breath since deep breath brought more air to the body and the level of oxygen was higher in the blood. The gas exchange activity took a longer time. Meanwhile, the quick breath caused lower level of oxygen but higher level of carbon dioxide because there was no enough time for oxygen to move in and for carbon oxygen to move out. The equation for finding the surface area: SA= (height (cm)? eight (kg)/ 3600)1/2 The SA of Serena’s lungs= (158 cm? 56kg/ 3600)1/2 = 1. 567730136 The equation for finding the vital capacity: Males: SA? 2500 Females: SA? 2000 The vital capacity of Serena’ s lungs = 1. 567730136? 2000=3135. 460271 In part E, the tidal volume was the normal amount of air moves in and out with each breath. Therefore, when the subject was relaxed, only a small amount of air that moved out and made the balloon bigger, was the tidal volume. According to the graph of lung volume vs. balloon diameter, the average balloon diameter was converted into lung volume.

Moreover, the vital capacity was the maximum volume of air that can be moved out one breath. Thus, after a deep breath, the maximum amount of air that pushed out with a forceful exhalation was the vital capacity. According to the graph of lung volume vs. balloon diameter, the average balloon diameter was converted into lung volume. Nonetheless, as a result of some errors of the part E, the result of the vital capacity from the experiment was smaller than the result of the vital capacity from the calculation. Firstly, the balloon was filled with air and its shape was not a real ball.

The balloon had different diameters from different side, so the result of vital capacity depended on the way to measure the diameter of the balloon. The measurement of the diameter of the balloon was not accurate. In turn, the vital capacity of the lungs was inaccurate. Secondly, it was impossible to ensure the air not flew out. Some air moved out if people not hold the balloon tightly, so the result was not correct. Related to these errors, there were some improvements for the part E. First, people were able to put the balloon into a square box and measure the length of the box.

Second, to use some metal to hold the balloon tightly was the only way to prevent the gas to run out. Conclusion In the respiratory system, the gas exchange activity was controlled by the brain. The breathe temperature was higher than the room temperature and some water were produced. The circumference of the chest increased and the abdomen circumference decreased in the inhalation. However, the cheat circumference decreased and the circumference increased in the exhalation. The bromothymol blue changed colour more quickly after exercising than normal.

Also, the breath holding time after deep breath was longer than the time of holding breath. The actual vital volume was 100ml and the actual vital capacity was 2000ml. however, the theoretic vital capacity was 3135ml. Therefore, the mechanism of carbon dioxide and oxygen exchange increased the temperature of air and regulate the level of O2, CO2 and pH in the blood in different situations. Reference ;amp; literature cited 1. West, John B. (1993). Respiratory physiology– the essentials. Baltimore: Williams & Wilkins. pp. 1–10. ISBN 0-683-08937-4.


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