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Chapter 10 The Digestive System Overview Animals use energy released from, carbohydrates, lipids, proteins, and nucleic acids – known as macromolecules- to perform metabolic functions. These macromolecules are broken down during the process of digestions. Water, vitamins, and minerals are also essential for metabolic function. The alimentary canal varies among animals. In general, herbivores have longer intestines than carnivores to accommodate their different diets. As food moves through the human alimentary canal, it is processed in four stages. 1. Ingestion: takes place in the mouth. 2. Digestion: begins in the mouth and continues through the small intestine. 3. Absorption: takes place in the small and large intestines. 4. Elimination: takes place at the anus. Physical digestion breaks food down into smaller pieces. In chemical digestion, enzymes and acids break macromolecules down into smaller molecules that can be absorbed through the cells that line the small intestine. Several disorders such as peptic ulcers, hepatitis, and diabetes can affect the functioning of the digestive system. We have developed diagnoses and treatments for many of these diseases and research is ongoing. Chapter 11 The Respiratory System Overview Body cells need a constant supply of oxygen to carry out metabolic functions. The respiratory system is responsible for bringing oxygen into the body, delivering it to cells in all parts of the body, and carrying carbon dioxide away from the cells and out of the body. Animals in different environments have a variety of types of respiratory systems. Fish obtain oxygen by passing water over gills, earthworms obtain oxygen through their skin, and insects have a network of branching tracheae that bring air close to tall their body cells, where diffusion can occur. In many animals, including humans, inhaling brings air into the lungs. Air travels through the nasal passages, pharynx, and larynx; into the bronchus; and through two bronchioles into two lungs protected by the ribs. In the alveoli of the lungs, oxygen diffuses from the air into tiny capillaries. Oxygen-rich blood is then transported by the circulatory system to cells around the body. Carbon dioxide-rich blood is transported to the lungs, where the carbon dioxide diffuses from the capillaries into the air. The air is then released from the body by exhaling. Some disorders of the respiratory system, such as pneumonia and bronchitis, can often be treated with antibiotics. For other disorders – including asthma, cystic fibrosis, and emphysema – treatments are used to relieve symptoms. Gene therapy is being explored as a cure for cystic fibrosis. Chapter 12 The Circulatory System In multi-celled animals, the circulatory system transports gases, nutrients, wastes and other chemical substances from one part of the body to another. It also regulates body temperature and protects against blood loss and disease. Vertebrates and other large complex animals have closed circulatory systems. A heart pumps blood into thick, elastic arteries, which carry the blood to small, thin capillaries. Materials diffuse from the capillaries into body cells and from body cells into the capillaries. Veins carry blood back to the heart. Humans have a double circulatory system – the circulation of blood around the body (systemic circulation) is separate from the circulation of blood to the lungs (pulmonary circulation). Separate chambers in the heart pump blood in each part of the system. To pump the blood, the SA node and the AV node (two areas of specializes tissue in the heart) emit electric signals that cause the heart muscle to contract and relax rhythmically. We experience this rhythmic pumping as a heart beat. Valves in the heart and in the veins prevent blood from flowing backward. Many factors can be measured to help monitor the health of the circulatory system, including electrical activity in the heart, blood pressure, stroke volume, and cardiac output. Disorders of the circulatory system include arteriosclerosis, arrhythmias, congenital heart defects, stroke, hemophilia, and leukemia. Many common disorders can be prevented and controlled by lifestyle choices. Some, however, have other causes. Hemophilia is caused by a genetic sex-linked trait. Most causes of congenital heart defects are unknown. Medical technology has brought some creative solutions to the treatment of circulatory system disorders, including angioplasty, bypass surgery, pacemakers, and xenotransplants. Review Practice Questions 1. List 6 Vitamins or minerals and state the function for each Vitamin or Mineral Function in the Human Body Calcium Iron Magnesium forms bone, conducts nerve signals, contracts muscle, clots blood produces hemoglobin to transport oxygen in the blood supports enzyme function and is needed to produce protein Vitamin A promotes good vision, and healthy skin and bones Vitamin D helps absorb calcium and form bone Vitamin E strengthens red blood cell membranes 2. List three macromolecule nutrients, a key function each one performs in the body, and a food that each one can be found in. Answers may vary but sample: Carbohydrates provide the cell with quick energy; rice. Lipids insulate and cushion internal organs; butter. Protein helps muscles move; salmon. 3. Name the parts of the alimentary canal where each part of the digestive process occurs (ingestion, digestion, absorption). Refer to page 408 in your textbook for help. Ingestion: mouth, throat, esophagus Digestion: gizzard, stomach, small intestine Absorption: intestines (large and small) 4. Name two organs that help break up food physically. How do they help? The tongue and teeth. They work together to chew the food, forming a bolus that will then travel down the esophagus. 5. Where do most of the enzyme reactions related to digestion occur? Mouth, stomach, small intestine 6. Why is protein breakdown mostly in the stomach? The stomach has a pH of 2 and pepsin, which breaks down protein, works best at a low pH 7. Complete the table below Carbohydrates Organs in which chemical digestion takes place Enzymes involved End Products Function(s) in the body Proteins Lipids mouth, small intestine stomach, small intestine small intestine salivary amylase, pancreatic amylase, sucrase, maltase, lactase pepsin, proteases (trypsin and chymotrypsin), peptidases bile, lipases monosaccharides amino acids glycerol, fatty acids energy energy, enzymes, protein energy, cushioning 8. Some components of the human digestive system play a role in the respiratory system as well. What are the components, and what additional role does each one serve? Answers may vary. For example: both air and food can enter through the mouth and pass through the pharynx 9. Describe and give the cause and treatment for the following respiratory system disorders. Pneumonia, bronchitis, asthma, emphysema, cystic fibrosis, lung cancer Disorder Description Cause Treatment Pneumonia - alveoli fill with thick fluid, - bacterial infection making gas exchange difficult (including - can affect one or both lungs Streptococcus pneumoniae) - viral infection - antibiotics or anti-viral medications - a vaccine is available for bacterial pneumonia Bronchitis - bronchi become red and - bacterial infection inflamed - prolonged exposure to - couching brings up mucus dust, chemicals, or - in chronic bronchitis, cilia cigarette smoke can lining the bronchi may be cause chronic destroyed, which limits the bronchitis lung’s ability to clear mucus - chronic bronchitis is a chronic obstructive lung disease (COPD) - antibiotics (short-term bronchitis) - chronic bronchitis cannot be cured, but can be treated by quitting smoking, taking medications, and exercising Asthma - airways become inflamed and - inhaled irritants, such as - can be managed by using bronchioles constrict, making pollen, dust, and smoke an inhaler to inhale it difficult for air to pass can cause an asthma medication in mist or - wheezing, coughing, and attack in some people powder form. shortness of breath occur - the medication relaxes the muscles around the airways Emphysema - alveoli lose elasticity, burst and- smoking is the main cause- no known cure fuse into enlarged spaces, - symptoms can be relieved reducing surface area for gas by using an inhaler to exchange, and making it open airways and a difficult to get enough slow-flow oxygen tank oxygen to boost the supply of - a chronic obstructive lung oxygen to the body disease Cystic Fibrosis - thick mucus in the lungs results- a gene mutation causes - gene therapy is being in inflammation, infection, cells lining the airways explored infection due to trapped to release thick mucus - symptoms can be treated bacteria, and damage to lung- also causes ducts in the with medicine that thins tissue pancreas to be blocked the mucus and with antibiotics Lung Cancer - uncontrolled cell growth and - smoking is the main cause- radiation and division causes cells to form- other causes include chemotherapy to destroy a carcinoma pollutants, radon gas, the cancerous cells - cancerous cells can break away and asbestos - surgery or laser surgery to and spread cancer to other remove tumours organs 10. How is the process of inhalation accomplished? A decrease in pressure of the thoracic cavity 11. Diffusion of carbon dioxide between the blood and the body’s tissue cells is part of what process? Internal respiration 12. What is the additional volume of air that can be forced out of the lungs beyond a tidal exhalation? Expiratory reserve volume 13. Create and label a typical spirograph See notes 14. Describe oxygen’s path in the circulatory system Oxygen diffuses from the alveoli to capillaries, to the pulmonary vein and the left atrium, to the left ventricle, to the aorta, through arteries to capillaries, then diffuses to body cells 15. Where do nutrients enter the human circulatory system? In the villi of the small intestine 16. How does the SA node cause the heart to beat? It emits an electric signal that is transmitted to cardiac muscle cells in the atria causing the muscles to contract. This signal is also transmitted to the AV node, which emits an electric signal causing the heart muscle in the ventricles to contract. 17. What technology can a doctor use to monitor the beating of a heart? Stethoscope, electrocardiogram (ECG) 18. Define systolic and diastolic blood pressure Systolic: the pressure inan artery during a ventricular contraction Diastolic: the pressure in an artery between ventricle contractions 19. List the steps you would take to take someone’s blood pressure See notes 20. When the average person is running, will their cardiac output be higher or lower than 4900 mL/min? Why? Higher. They will require more oxygen while running so the heart pumps blood faster, causing increased pressure 21. A person has a resting cardiac output of 4900 mL/min abnd a heart rate of 90 bpm. What is the person’s stroke volume? 54 mL 22. An athlete has a normal cardiac output, but a very low heart rate. Why might this be? The athlete’s heart muscle is strong and the heart can pump more blood with each beat - a higher stroke volume 23. Which disorders primarily affect each part of the circulatory system? a. the heart b. the blood vessels c. the blood a. heart valve disorders, arrythmia, congential heart defects b. stroke, aneurysm, arteriosclerosis c. hemophilia, leukemia 24. Create a table to compare the treatments on pages 500 and 501 of your textbook (xenotransplants, artificial hearts, and targeted drug delivery). Include a description of each treatment, advantages, and potential problems or issues. Xenotransplants: living cells, tissues, or organs are transplanted from other species into humans. Still experimental. Advantages - animal tissue and organs can be more readily available than human tissue and organs. Potential problems or issues include organ rejection, introduction of diseases, and the fact that animals must be killed to obtain the organs Artificial Hearts: transplanting a mechanical pump with batteries and a controller to function (temporarily) as a heart. Advantages - can keep a person alive until a suitable human heart becomes available. Potential problems or issues - an external battery pack must be worn most of the time, risk of mechanical or battery failure. Targeted drug delivery: drugs are released only when they come into contact with specific enzymes or pH range (indicating cancerous or diseased tissue). Advantages - chemicals used to kill pathogens or cancerous cells will not harm healthy body cells. Potential problems or issues - unknown.