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Chapter 17 Clearing the Air Respiratory, Cardiovascular, and Excretory Systems Copyright © 2010 Pearson Education, Inc. 17.1 Effects of Smoke on the Respiratory System ETS – Environmental Tobacco Smoke or “secondhand smoke” is inhaled by passive smokers - people who are in the same environment as active smokers Carbon monoxide = most abundant chemical in ETS ETS has a high concentration of particulates (tar) ETS damages lungs, but chemicals can also pass into bloodstream Copyright © 2010 Pearson Education, Inc. 17.1 Effects of Smoke on the Respiratory System On average, a resting human: Breathes once every 12 seconds Takes a breath with a volume of about 500 mililiters Sends about 6 liters of air per minute into the lungs Copyright © 2010 Pearson Education, Inc. 17.1 Effects of Smoke on the Respiratory System - Diaphragm Breathing is accomplished by the diaphragm and rib cage. Copyright © 2010 Pearson Education, Inc. 17.1 Effects of Smoke on the Respiratory System - Lungs Respiratory tree starts with the trachea Air enters the lungs through bronchi. Bronchi branch into bronchioles. Bronchioles finally end at alveoli small, vascularized sacs Site of gas exchange with blood Copyright © 2010 Pearson Education, Inc. 17.1 Effects of Smoke on the Respiratory System - Lungs On average, lungs contain about 300 million alveoli, and these contain the respiratory surface through which the body acquires oxygen and eliminates CO2 waste. The total area of the respiratory surface in a pair of lungs is about the same area as a tennis court. Copyright © 2010 Pearson Education, Inc. Figure 17.3 17.1 Effects of Smoke on the Respiratory System - Lungs Each alveolus is surrounded by a network of capillaries—tiny, thin-walled blood vessels (a) (b) Blood in: Low oxygen, high carbon dioxide Air Blood out: High oxygen, Low carbon dioxide Copyright © 2010 Pearson Education, Inc. Figure 17.4 17.1 Effects of Smoke on the Respiratory System - Gas Exchange Gas exchange is the primary function of the lungs: O2 from the environment is exchanged for CO2 from the body. Gas exchange occurs by simple diffusion between the alveoli and the capillaries. Copyright © 2010 Pearson Education, Inc. Alveolus: oxygen concentration high, carbon dioxide concentration low O2 Diffusion CO2 Capillary: oxygen concentration low, carbon dioxide concentration high Figure 17.5 17.1 Effects of Smoke on the Respiratory System - Gas Exchange Why is O2 needed and where does CO2 come from? Cells use ATP for energy. ATP is made during cellular respiration The molecular bonds in sugar molecules are broken to release energy, and the remaining carbons are given off as CO2 O2 from the environment serves as the final electron receptor in cellular respiration, allowing for the energy from electrons to be used to build ATP. For review, see chapter 4 Copyright © 2010 Pearson Education, Inc. Figure 17.5 17.1 Effects of Smoke on Respiratory System The Role of Hemoglobin in Gas Exchange CO2 easily diffuses from blood to air O2 requires help to enter the blood. Hemoglobin – respiratory pigment, a protein that binds to oxygen Hemoglobin turns bright red when it binds with oxygen A single hemoglobin is made up of 4 different protein chains, each with an iron atom A red blood cell contains about 250 million hemoglobin molecules; it can carry 1 billion oxygen molecules Protein chains Oxygen (O2) Iron (Fe+++) Heme group Copyright © 2010 Pearson Education, Inc. Figure 17.6 17.1 Effects of Smoke on Respiratory System The Role of Hemoglobin in Gas Exchange Hemoglobin is efficient at binding O2, but even more effective at binding carbon monoxide. Even small amounts of carbon monoxide can tie up a lot of hemoglobin. Carbon monoxide causes oxygen shortages in tissues. Carbon monoxide is especially damaging to fetuses and embryos. Lower than average birth weights associated with smoking mothers are due to oxygen deprivation. Copyright © 2010 Pearson Education, Inc. 17.1 Effects of Smoke on Respiratory System Smoke Particles and Lung Function The majority of the damage to lungs is caused by particulates (tar) in smoke, which damage the surfaces of the lungs. Children and infants particularly vulnerable Copyright © 2010 Pearson Education, Inc. 17.1 Effects of Smoke on Respiratory System Bronchitis and Asthma Particles can interfere with the lung’s defense systems Cough is first response to lung irritants Small particles don’t trigger cough; they become trapped in mucus lining the respiratory tract Cilia move trapped particles to nose and mouth – i.e. mucociliary escalator Particulates increase mucus production, but damage cilia => smokers cough or Bronchitis Copyright © 2010 Pearson Education, Inc. 17.1 Effects of Smoke on the Respiratory System - Smoke Particles and Lung Function Bronchitis Copyright © 2010 Pearson Education, Inc. Figure 17.7 17.1 Effects of Smoke on the Respiratory System - Bronchitis and Asthma Asthma = an allergic reaction where bronchioles constrict and mucus production increases. Particulates are known to exacerbate asthma. The EPA estimates that environmental tobacco smoke, or ETS, will cause 26,000 additional cases of asthma per year. Copyright © 2010 Pearson Education, Inc. 17.1 Effects of Smoke on the Respiratory System - Bronchitis and Asthma Tiniest particles of smoke can even reach alveoli where gas exchange occurs. Without cilia, these particles can remain in the alveoli for long periods Causes irritation or even permanent damage to alveoli called Emphysema Copyright © 2010 Pearson Education, Inc. 17.1 Effects of Smoke on Respiratory System Emphysema As alveoli are damaged, scar tissue forms and alveoli merge into fewer and larger sacs. This drastically reduces surface area for gas exchange. The damage is permanent; lung tissue is not regenerated. Copyright © 2010 Pearson Education, Inc. Figure 17.8 17.1 Effects of Smoke on Respiratory System Lung Cancer Cancerous tumor Many of the particulates in cigarette smoke contain chemicals known to be carcinogens Particulates can stay on lung surfaces for long periods of time Risk of mutation remains long after cigarette has been smoked Copyright © 2010 Pearson Education, Inc. Figure 17.9 17.1 Effects of Smoke on the Respiratory System - Lung Cancer PLAY Animation—Gas Exchange in the Lung Copyright © 2010 Pearson Education, Inc. 17.2 Spreading the Effects of Smoke: The Cardiovascular System Spreads components of tobacco smoke through body, leading to: 1. Throat, bladder and pancreatic cancer 2. high blood pressure, heart attack, stroke 3. Premature aging of skin Copyright © 2010 Pearson Education, Inc. 17.2 Spreading the Effects of Smoke: The Cardiovascular System Three main components 1. Circulating fluid (blood) 2. Pump (heart) 3. Vascular system (blood vessels and capillaries) Copyright © 2010 Pearson Education, Inc. 17.2 Spreading the Effects of Smoke: The Cardiovascular System - Blood The average adult human has 5 liters (11 pints) of blood Consists of cellular and liquid components Cellular portion = red blood cells, white blood cells, platelets Liquid portion = plasma Copyright © 2010 Pearson Education, Inc. Figure 17.10 17.2 Spreading the Effects of Smoke: The Cardiovascular System - Blood Cellular components of blood are produced by stem cells in the bone marrow. Blood stem cell Blood stem cell Platelet-producing cell Red Platelets blood cells Copyright © 2010 Pearson Education, Inc. White blood cells Figure 17.11 17.2 Spreading the Effects of Smoke: The Cardiovascular System - Blood Red blood cells White blood cell Red blood cell carry oxygen; shape provides large surface area to volume ratio White blood cells several varieties; components of immune system Platelets produce blood clots, prevent blood loss Fibrin Copyright © 2010 Pearson Education, Inc. Platelet Figure 17.12 17.2 Spreading the Effects of Smoke: The Cardiovascular System - Blood Tobacco on Blood Clots Tobacco smoke increases stickiness of platelets and promotes production of fibrinogen (precursor of fibrin) Thrombosis = when a blood clot blocks a blood vessel Embolism = when a clot breaks free and then blocks a distant vessel Copyright © 2010 Pearson Education, Inc. White blood cell Fibrin Red blood cell Platelet Figure 17.12 17.2 Spreading the Effects of Smoke: The Cardiovascular System - Heart From body Heart Structure The heart consists of four chambers 1. Two atria 2. Two ventricles Semilunar valves To lungs SA node Right atrium Pumps blood through two parallel systems 1. Pulmonary 2. Systemic Copyright © 2010 Pearson Education, Inc. To body Left atrium From lungs AV valve Left ventricle AV valve Right ventricle Figure 17.13 17.2 Spreading the Effects of Smoke: The Cardiovascular System - Heart The sino-atrial node (SA node) is the pacemaker and stimulates the heart to beat. Valves prevent backflow of blood during and between contractions Copyright © 2010 Pearson Education, Inc. From body To body Semilunar valves To lungs SA node Right atrium Left atrium From lungs AV valve Left ventricle AV valve Right ventricle Figure 17.13 17.2 Spreading the Effects of Smoke: The Cardiovascular System - Blood Vessels The SA node stimulates both atria to contract Pumps blood into ventricles 0.1 sec later, both ventricles contract Cardiac Cycle Systoli = ventricular contraction Diastole = ventricular relaxation Copyright © 2010 Pearson Education, Inc. Figure 17.14 17.2 Spreading the Effects of Smoke: The Cardiovascular System - Blood Vessels Cardiac Cycle Systoli = ventricular contraction AV (atrioventricular) valves close Diastole = ventricular relaxation Semilunar valves close Copyright © 2010 Pearson Education, Inc. Figure 17.14 17.2 Spreading the Effects of Smoke: The Cardiovascular System - Blood Vessels Vascular system includes Arteries Capillaries Veins Capillaries Lung Heart Vein Kidney Artery Copyright © 2010 Pearson Education, Inc. Figure 17.14 17.2 Spreading the Effects of Smoke: The Cardiovascular System - Blood Vessels Arteries carry blood away from heart have thick elastic walls that expand with the contraction of ventricles Capillaries Lung Heart Vein Kidney Artery Copyright © 2010 Pearson Education, Inc. Figure 17.14 17.2 Spreading the Effects of Smoke: The Cardiovascular System - Blood Vessels Capillaries thin, porous walls where the exchange of gasses occurs Some plasma is forced out of the capillaries by blood pressure Copyright © 2010 Pearson Education, Inc. Capillaries Lung Heart Vein Kidney Artery Figure 17.14 17.2 Spreading the Effects of Smoke: The Cardiovascular System - Blood Vessels From arteries To veins High blood pressure forces material out. Muscles that can cut off blood flow through capillary bed Capillaries Copyright © 2010 Pearson Education, Inc. Materials are absorbed into the bloodstream down their concentration gradient. Figure 17.15 17.2 Spreading the Effects of Smoke: The Cardiovascular System - Blood Vessels Veins carry blood to heart thinner walls than arteries Have valves skeletal muscles aids the movement of blood Copyright © 2010 Pearson Education, Inc. Capillaries Lung Heart Vein Kidney Artery Figure 17.14 17.2 Spreading the Effects of Smoke: The Cardiovascular System - Blood Vessels Veins are only vessels with Valves •Veins have very low blood pressure •Valves keep blood moving in one direction •Skeletal muscles act as ‘secondary pumps’ Copyright © 2010 Pearson Education, Inc. Figure 17.16 17.2 Spreading the Effects of Smoke: The Cardiovascular System Two parallel systems 1. Pulmonary 2. Systemic Copyright © 2010 Pearson Education, Inc. Figure 17.17 17.2 Spreading the Effects of Smoke – Smoke and Cardiovascular Disease Most cardiovascular damage from smoking is caused by nicotine. In high doses, nicotine is toxic to mammals. Nicotine increases production of LDL and decreases production of HDL, which can lead to atherosclerosis. Nicotine stimulates blood clot formation, which can result in stroke or heart attack. Copyright © 2010 Pearson Education, Inc. 17.2 Spreading the Effects of Smoke - Smoke and Cardiovascular Disease PLAY Animation—The Cardiovascular System Copyright © 2010 Pearson Education, Inc. 17.3 Removing Toxins From the Body The Excretory System Major organs Kidneys Ureters Bladder Urethra Kidney Ureters Bladder Urethra Copyright © 2010 Pearson Education, Inc. Figure 17.19 17.3 Removing Toxins From the Body Kidney Structure and Function Nephron = functional unit of the kidneys, where filtration of wastes occurs Each kidney contains about 1,250,000 nephrons. Each kidney filters about 1000 liters of blood every day. Capillaries surround nephrons; wastes diffuse out of blood. Collecting ducts = collect fluids from nephrons and concentrate waste by absorboing fluids Copyright © 2010 Pearson Education, Inc. 17.3 Removing Toxins From the Body – Kidney Structure and Function 4 phases of urine production 1. Filtration 2. Reabsorption 3. Secretion 4. Osmotic concentration Copyright © 2010 Pearson Education, Inc. Blood 1 Filtration: Blood pressure forces plasma into the nephron through tiny holes in the adjacent capillaries. 2 Reabsorption: Sugars, amino acids, and water are reabsorbed into the kidney tissue across the nephron loop. Salt actively removed from the filtrate on the ascending limb of the nephron loop becomes concentrated in Water the interior of the kidney, causing water to flow out passively. Toxins Salts 3 Secretion: Wastes that are in low concentration in the blood are actively secreted into the far end of the nephron. 4 Excretion: After the filtrate is further concentrated as the tube extends into the salty tissue of the kidney, urine is excreted into the bladder. Figure 17.20 17.3 Removing Toxins From the Body Smoking and the Excretory System Smoking has a severe impact on the excretory system Probably related to increased blood pressure, which strains nephrons Increased particulate load also stresses kidneys with increased waste removal Smokers have 38% higher incidence of kidney cancer Bladder cancer 3 times more common in smokers Copyright © 2010 Pearson Education, Inc. 17.3 Removing Toxins From the Body Smoking and the Excretory System PLAY Animation—The Mammalian Kidney Copyright © 2010 Pearson Education, Inc.