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The Respiratory System continued. The Process of Gas Exchange The exchange of oxygen gas and carbon dioxide gas occurs at the alveoli. This area has a.

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Presentation on theme: "The Respiratory System continued. The Process of Gas Exchange The exchange of oxygen gas and carbon dioxide gas occurs at the alveoli. This area has a."— Presentation transcript:

1 The Respiratory System continued

2 The Process of Gas Exchange The exchange of oxygen gas and carbon dioxide gas occurs at the alveoli. This area has a rich supply of capillaries that allow for the exchange of oxygen and carbon dioxide between the circulatory system and the respiratory system. Air that enters the bronchial tubes is rich in oxygen and therefore is needed by the cells of the body. The oxygen diffuses from the alveoli into the capillary. The capillaries contain red blood cells that contain the iron rich protein hemoglobin.

3 Hemoglobin transports oxygen to the cells of the body via the blood vessels. Oxygenated blood appears red and deoxygenated blood appears blue. Carbon dioxide, produced in the cells as a waste product, also binds to hemoglobin and is transported to the alveoli for removal. Carbon dioxide diffuses out of the blood and into the alveoli. From there, the carbon dioxide is expelled from the body through exhalation.

4 The diagram above summarizes the human respiratory system and the process of internal gas exchange.

5 Breathing Breathing is an involuntary process. The medulla oblongata, which is located in the brain, ultimately controls the breathing rate. You can alter your breathing rate by temporarily holding your breath or breathing faster. However, your brain will ultimately take over the process if the body becomes stressed.

6 Breathing is a physical process of inhaling air that will move from an area of high pressure to an area of low pressure. There are two main muscles that are involved in breathing, the intercostal muscles of the rib cage and the diaphragm. The diaphragm is a thin layer that separates the lungs from the stomach.

7 The next diagram illustrates the physical process of inhalation and exhalation. In inhalation, the intercostal muscles contract and force the chest cavity to move out and up. At the same time the diaphragm contracts and moves downward. This movement increases the volume of the chest cavity. As a result, the internal pressure of the lungs decreases and air moves into the lungs. In exhalation, the intercostal muscles relax and the chest cavity moves down and inwards. The diaphragm relaxes and moves upwards. The volume of the chest cavity decreases. The internal pressure of the lungs increases and air moves out.


9 Try this at home! eo/hse2_5_frame.html?module eo/hse2_5_frame.html?module

10 Many factors can influence the breathing rate. These include air quality, altitude, pulmonary diseases and medications. When the breathing rate is altered, the level of oxygen and carbon dioxide within the body may fluctuate from normal levels. The flow chart (next slide) illustrates the negative feedback loop that is used to regulate the concentration of oxygen and carbon dioxide gas. You may be surprised to learn that carbon dioxide plays a bigger role in regulating the breathing rate than oxygen.


12 When oxygen levels are lowered, the body will immediately increase the breathing rate to increase the amount of oxygen available to the cells. In addition, the body will also increase the production of red blood cells. Remember, it is hemoglobin found within red blood cells that transports both oxygen and carbon dioxide throughout the body.

13 Breathing Animation /hlw/hlw_when.html /hlw/hlw_when.html

14 Questions 1.How does exercise affect the breathing rate? 2.The XIX Olympic Games were held in Mexico City amongst much opposition because of its high altitude. The air in Mexico City contains 30% less oxygen than at sea level. (a) What effects may an athlete feel when arriving in Mexico City? (b) What advice would you give to an athlete who is competing at a higher altitude? (c) Is there any benefit to training at a higher altitude prior to a competition at sea level?

15 Answers 1.When a person exercises, they require energy in the form of ATP. ATP is generated through the process of cellular respiration. Cellular respiration involves the breakdown of glucose in the presence of oxygen. One of the products produced is carbon dioxide. An increase in cellular respiration increases the amount of ATP available and also increases the concentration of carbon dioxide in the blood. Therefore, an increase in carbon dioxide will trigger the body to increase the breathing rate.

16 2. (a) An athlete may feel tired, light headed, nausea, and shortness of breath. (b) An athlete who will perform at high altitudes should arrive a couple of weeks prior to their competition. This will allow the body to adjust to the low levels of oxygen and produce more red blood cells. A diet rich in protein or an iron supplement will help the body construct the protein hemoglobin needed to transport oxygen gas. (c) Being at high altitudes causes your body to produce more red blood cells. More red blood cells will increase the delivery of oxygen to the cells. This will increase the rate of cellular respiration and therefore provide the cells of the body with more energy (ATP). However, once the athlete returns to sea level, the body will adjust and the red blood cells production will decrease.

17 Task All living things must be able to acquire oxygen from their external environment and eliminate carbon dioxide waste produced during cellular respiration. However, the respiratory systems of animals vary greatly. Some animals use diffusion while others require a system that is composed of specialized organs, tissues and cells. Research the respiratory systems of the following organisms. Describe and explain how each respiratory system meets the needs for the specific organism. You may include illustrations or images in your explanations. Bacteria Grasshopper Earthworm Fish

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