Module 7 Intro

Module 7—The Digestive and Respiratory Systems

Module Summary

 

In this module you studied the digestive and respiratory systems. In the first lesson you explored the molecules of living systems: proteins, fats, and carbohydrates. Each molecule has specific characteristics that make them unique. Your body uses these nutrients and enzymes to sustain life.

 

These macromolecules are made up of smaller, chemically simpler subunits. Macromolecules are assembled by dehydration synthesis and are disassembled by hydrolysis. These reactions either add or remove a molecule of water. Each macromolecule has a corresponding enzyme that speeds up chemical reactions such as hydrolysis. Enzymes are designed to have an active site for a specific molecule, or substrate, on its surface.

 

The substrate will bind to the active site on the enzyme. Bonds in the substrate become less stable and are thus easier to break. This speeds up the process of breaking down substrates or creating new compounds. Enzymes work best under optimal conditions. Factors such as fluctuations in temperature or pH can affect the shape of an enzyme and, therefore, its ability to bind with a substrate molecule.

 

Inhibitor compounds can also bind to the active site of an enzyme to prevent substrate molecules from binding. A knowledge of these molecules was necessary for you to understand how the digestive system worked together from gums to bums to digest macromolecules. Lesson 2 explored each organ involved in digestion from the mouth to the colon. You also explored how the body exchanges matter and energy via the digestive system. Nutrient absorption, occurring primarily in the small intestine, provides cells with the necessary resources to maintain and repair cellular function. For example, mitochondrion depend on the digestion of carbohydrates to fuel ATP synthesis.

 

The respiratory system was introduced in Lesson 3. As with all body systems, there is energy and matter exchange occurring via the respiratory system. Primarily, your respiratory system serves to exchange carbon dioxide and oxygen. Oxygen is required for aerobic respiration, and carbon dioxide is a product of aerobic respiration. The act of respiration involving your lungs continuously exchanges oxygen and carbon dioxide in the alveoli.

 

Breathing is regulated by the need to remove carbon dioxide from your body. Chemoreceptors sense a buildup of carbon dioxide and stimulate the diaphragm to relax. This causes you to breathe out. The air pressure inside your lungs when the diaphragm is relaxed is higher than external air pressure. In order to maintain equilibrium, air will move from high pressure to low pressure. When you breathe in, the diaphragm is contracted to create more volume and less pressure inside your chest cavity. In an effort to maintain pressure equilibrium, you will inhale.

 

You looked at the pattern of respiration through interpreting a spirograph. By measuring the volumes of inhalation and exhalation, you can determine levels of fitness or help to diagnose several health conditions. The respiratory system is also a mechanism for body temperature control. Heat produced by cellular respiration is dissipated into the lungs and transferred to the external environment with each inhalation. Conversely, cold air is warmed along its journey to the alveoli in an effort to maintain body equilibrium.

 

In Lesson 4 you learned about the effects of lifestyle choice, germs, and genetics on the health of your digestive and respiratory system and about how technology may limit or benefit the treatment of any disorders. You were asked to compare traditional and Western medicine practices.

 

Traditional medicine incorporates the use of herbal and spiritual remedies to cure illness. In contrast, Western medicine often approaches the treatment of disease by drugs, invasive medical treatments, and surgery. By investigating a variety of diseases you discovered how disorders interrupt the body’s natural exchange of matter and flow of energy. Both traditional and Western medicines attempt to restore homeostatic balance to your body system. However, medicine cannot cure all diseases. Being healthy is a function of smart lifestyle choices and available technology that can help you maintain or restore homeostasis.

 

This module has allowed you to investigate two important systems. Each system—digestive and respiratory—plays an important role in maintaining homeostasis. In the final module of this course, you will explore the circulatory, immune, and excretory systems.

 

Module Assessment

 

Now that you have completed the lessons in this module, you will complete a module project. In the module project you will have the choice between two extended responses.

 

Module Project

 

The purpose of an extended response is to help you take a closer look at a specific area of study. In this case you will choose between investigating digestive enzymes through experimentation OR investigating the effects of smoking on the respiratory system.

 

You may choose one assignment because you feel you have a stronger grasp of the content, or you may choose an assignment because you feel you would benefit from further study of that particular body system. The extended response activities allow you to further explore each body system. In the Unit Assessment you will build upon these module projects by pursuing an in-depth inquiry into the interdependence of your body systems in maintaining homeostasis.

 

Choice 1. The Digestive System: Investigating Digestive Enzymes

 

In this investigation you will look at the materials a student has used to show that a pancreatic enzyme hydrolyzes fats into glycerol and fatty acids. Based on your knowledge of enzyme action, you will be asked to recreate the experiment that the student may have performed, based on the given materials, and predict results. You may wish to recreate this lab virtually, if required.

 

Use the following information to answer the next question.

 

 

1. Design an experiment demonstrating that lipase digests milk to produce an acid and that emulsification is important in the digestion of lipids. Write the steps of a procedure. Be sure to include a control test in the procedure. (10 marks)
   
   
2. Explain the purpose of the milk, the soap, the sodium bicarbonate, and the water bath in this investigation. (4 marks)
   
   
3. Use a data chart to predict what the student observed in each test tube during the investigation, and interpret the results in each test tube. (6 marks)
   
   
4. Identify the test tube that would show the fastest reaction, and explain why. (2 marks)

Choice 2. The Respiratory System

 

In this activity you will look at a technology doctors use to diagnose respiratory disorders. You will also examine the effects of smoking on the respiratory system.

 

Use the following information to answer the next question.

 

 

1. If the flexible fibre-optic instrument was inserted through the nose, list, in order, the parts of the respiratory system that the camera would pass. (8 marks)
   
   
2. A doctor suspects her patient may have lung cancer. What is lung cancer? Identify one reason why a doctor would order a bronchoscopy for this patient. (3 marks)

To answer questions 3, 4, and 5, look up the following terms on the Internet: "cough reflex," "smoker's cough," and "emphysema."

3. Describe how smoking interferes with the body’s ability to maintain gas exchange between internal and external environments. Explain how a smoker’s cough is the body’s attempt to maintain balance. (4 marks)
   
   
4. Identify the three symptoms that a person with emphysema would have, and explain why these symptoms would occur. (6 marks)
   
   
5. Most people with emphysema are or were smokers. Explain the role that smoking plays in developing this disorder. (3 marks)

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