2-12-10 The Circulatory System-color

2-12-10 The Circulatory System-color - Clicker Question...

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Unformatted text preview: Clicker Question Should animals be used and even killed for medical and biological studies? A) Never, it is unethical to use or kill animals B) B) C) C) D) E) without their consent for the good of humans. Leaning toward A. Occasionally, using strict guidelines that respect the reverence of all life: human and animal. Leaning toward E. Yes, it is more ethical to kill animals than to let humans live with pain and illness. Where are we? Last time… I talked about the intestines, the pancreas, the liver, the absorption of nutrients, the discovery of hormones, and th the passage of gas. This time… I will talk about the circulatory system and the exchange of gas (CO2 and O2)—which, which, incidentally, allows for more classy music. The Fermi Solution and Dimensional Analysis The Fermi Solution and Dimensional Analysis (60 minutes/hour)(24 hours/day)(365 days/year) = 525,600 minutes/year (60 minutes/hour)(24 hours/day)(365 days/year) = 525,600 minutes/year 1 • Photosynthesis: • Eating and Digestion: • Absorption: • Circulation: www.rainn.org/get-information/statistics – Making organic matter from carbon dioxide and water as well as nitrogen, phosphorous and sulfur using the Sun’s energy. – Breaking down the ingested food mechanically, chemically and enzymatically into small molecules and atoms. – Transport of the small molecules and atoms across the Transport of the small molecules and atoms across the mucosa mucosa “into” the body. – Transport of small molecules and atoms from the intestines to the cells in the rest of the body. – Transport of oxygen from the lungs to the cells in the rest of the body. – Transport of carbon dioxide from the cells to the lungs where it is expired. www.ovw.usdoj.gov/sexassault.htm • Cellular Respiration and Biosynthesis (Monday) Function of a Circulatory System Picture the original singlesingle-celled eukaryotic organism, with a large surface ith to volume ratio, surrounded by flowing water that water can bring oxygen oxygen and food to the cell food to and carry away waste waste. Function of a Circulatory System • The cells in our multicellular body are remote remote from the sources sources of oxygen and food and oxygen food removed removed from the sites of waste elimination. li • The circulatory system circulatory functions to keep each cell in our body connected to connected a source of food and source oxygen oxygen as well as a sewerage system to remove remove wastes. Convection: Convection: Long Distance Mass Movement of Substances Driven by a Force Circulating Components of the Blood and their Functions • When diffusion is too slow to move • • • molecules from one place to another because the distances are too far, convection convection is necessary. Convection, in the form of cytoplasmic streaming, is used to circulate molecules throughout large cells. Convection, in the form of xylem and phloem transport, is used to circulate molecules throughout the plant. Convection, in the form of the circulatory system, is used to circulate molecules throughout the animal. 2 Normal Concentrations of the Cellular Components of the Blood Sugar, Nutrients, Oxygen and Carbon Dioxide Diffuse Passively Down their Concentration Gradient through the Interstitial Fluid Between Interstitial the LeakyCapillaries and Each Cell of the Body Cell of Red Blood Cells Travel Single File in ThinThin-Walled Porous Capillaries Sugars and Amino Acids Enter the Blood Stream at the Small Intestine Sugars and amino acids move passively (from high to low concentration) through the interstitial fluid into the leaky capillaries that penetrate each villus. capillaries villus The Path of a Sugar Molecule or an Amino Acid from the Small Intestine to the Liver from to • The capillaries iin the villi converge into venules capillaries n villi venules • which converge into the hepatic portal vein which hepatic supplies the liver. liver In the liver, the hepatic portal vein divides up into liver hepatic venules venules and then capillaries, which are a single capillaries single epithelial layer thick. 3 The Path of a Sugar Molecule or an Amino from to Acid from the Liver to the Heart From the liver, the capillaries converge into liver venules venules and into a large vein, called the vena vein vena cava that empties into the heart. heart Human Human Heart www.redbubble.com The Path of a Sugar Molecule or an from Amino Acid from the Heart • The blood flows from the right atrium to the right to the lungs where it becomes oxygenated. lungs Definitions of Arteries and Veins • The arteries always carry blood away from the arteries always away from heart. Except for the blood in the pulmonary artery, the blood is usually oxygenated and reddish. Th The veins always carry blood toward the carry bl th heart. Except for the blood in the pulmonary vein, the blood is usually not oxygenated and it appears “bluish”. In the body, most capillaries connect the arterioles arterioles, which carry blood away from the venules heart, to the venules, which carry blood toward the heart. right right ventricle and out the pulmonary artery pulmonary • From the llungs, oxygenated blood flows through From the ungs oxygenated blood flows through • the pulmonary the pulmonary vein to the left atrium, to the left left left ventricle and then to a large artery called artery the aorta. aorta The aorta, which is one inch in diameter, ramifies aorta arteries arterioles and capillaries into other arteries, arterioles and capillaries, where the sugar molecules come into contact with every cell in the body, including the cells in the mucosa of the small intestine. • • 4 Venous blood is actually dark red. I do not (yet) understand why blood looks so blue when it is in the veins. Tissue Layers in Blood Vessels • Capillaries: – Single epithelial layer only Portal Veins While most veins drain directly into the vena cava and the heart, heart, portal the portal veins do not drain directly into not drain directly into the the vena cava and the drain heart, heart, but drain • Veins and Arteries: Veins and Arteries: – Epithelial layer, smooth muscle layer, and an elastic connective tissue layer • The smooth muscle and connective tissue layers are thicker in the arterial system, thicker which is under high pressures, than in the venous system. For example, the through capillaries into other organs. drains drains into the liver. hepatic hepatic portal vein How Did Harvey Discover that the Blood Moves from the Heart to the Arteries and Back by way of the Veins? In Harvey’s Words…. “The blood doth enter into every member through the arteries, and does return by the veins, and that the arteries are the vessels carrying the blood the vessels carrying the blood from from the heart, and the veins are the vessels and wayes by which the blood returns to the heart itself; and that the blood in the members and extremities does passe from the arteries into the veins.” Angelina Jolie Too much exercise, not enough food • In the arm, the (reddish) arteries are arteries deeper deeper than the (bluish) veins. veins Consequently, a loose ligature blocks the venous flow and a tight ligature blocks fl ti li bl both the venous and arterial flow. – When the ligature is loose, the veins are blocked and they swell. The hand becomes flushed and there is a pulse. – A tight ligature stops the pulse but does not cause swelling. The hand becomes cold and is normally colored. 5 Harvey Demonstrated the Direction of Blood Flow in Veins The Circulation of the Blood by Carolyn William Harvey Eberhard Stephen William Harvey Snyder Harvey Demonstrated the Direction of Blood Flow in Veins •Harvey ligated the arm and noticed that there were localized regions, which he called venous valves, where the swelling was greatest. •When he pressed on the vein with his finger, the portion of the vein closest to the heart disappeared. •When he pushed the blood toward the hand, the vein refilled, indicating that the venous valve is a one-way valve that ensures that the venous blood takes a one-way trip to the heart. Harvey Harvey Guessed that the Blood Must Circulate Guess: What is the volume of the heart? Say 75 ml. Guess: What is the pulse rate? Say 70 beats/min. Mathematical model using dimensional analysis: (Volume of heart) (1 emptying volume/beat)(pulse rate) (75 ml/vol)(1 liter/1000ml)(1vol/beat)(70 beats/min) liter/1000ml)(1vol/beat)(70 beats/min) =_5.25_ liters/min • The heart pumps in one minute, a volume equal to all the all blood in the human body. • Conclude: The blood must circulate. That is, the blood does not travel unidirectionally from the liver to the rest of the body. The Motion of the Heart The beating of the heart was too fast guessed for Harvey to see. Yet, he guessed that there was an orderly motion to the orderly heart beat just as there was an orderly motion of mechanical devices. Harvey Wanted to Study Motion at the Frontier of Time In order to observe the orderly motion of the heart, Harvey studied cold-blooded coldanimals as well as warm-blooded warmanimals that were slowly dying. “… in the lock of a piece, by the drawing of the spring, the flint falls, strikes the steel, fires the powder, enters the touch hole, discharges, the balls flie out, pierces the mark and all these motions by reason of the swiftness of them, appear in the twinkling of an eye.” “This is more evident in the hearts of toads, serpents, frogs, house-snails, houseshrimps, crevises and all manner of little fishes. For it shews itself more manifestly in the hearts of hotter bodies, as of dogs, swine, if you observe attentively till the heart begins to die, and move faintly, and life is as it were departing from it.” 6 Valves in the Pump Prevent the Blood from Flowing Backwards • The atria pump blood into the ventricles, the ventricles pump blood to the rest of the body. – The right ventricle pumps blood to the lungs. – The left ventricle pumps blood through the aorta to The left ventricle pumps blood through the aorta to the the rest of the body. • The atrioventricular valves (tricuspid (right) atrioventricular (right) bicuspid (left)) and bicuspid (left)) prevent blood from flowing backwards from the ventricles to the atria. The semilunar semilunar valves (pulmonary (right) and aortic aortic (left)) prevent blood from flowing backwards from the arteries to the ventricles. President, Cardiologist and Musician Remember: What Goes on the Web, Stays on the Web!!!! Contraction of Heart Increases Blood Pressure • Diastole: The heart is relaxed (0.4 s). The relaxed (0.4 • atrioventricular valves open and blood flows open from the veins into all four chambers of the heart. The pressure in the arteries is low. low Systole: The atria contract (0.1 s) and then th the ventricles contract (0.3 s) giving the (0 th typically systolic lub-dub sound of a beating lubheart. The force of the ventricular contraction closes closes the atrioventricular valves and atrioventricular opens opens the semilunar valves. Contraction of semilunar the heart forces blood into the arteries. The blood pressure in the arteries increases blood increases since blood is pumped into the arteries faster than it can flow into the arterioles. • 7 To understand which valves close and open when the ventricles contract, compare the atrioventricular valves and the semilunar valves. Diastole asymmetrical asymmetrical orientation of the dilate or relax”. comes from the Greek word “to comes from the Greek word Greek word “to contract”. Systole The terminology will come naturally when you measure your own blood pressure in lab. • Blood Pressure: Systole/Diastole Systole/Diastole • Typically: 120 mm Hg/70 mm Hg • The pulse: 60-75/minute due to the rhythmic pulse 60rhythmic stretching of the arteries caused by the alternation of the systolic and diastolic phases. • The heart beat is initiated by a specialized region • The pacemaker generates electrical signals that electrical • move along the heart and cause it to contract in a rhythmic manner. The signal spreads in such a way that the atria before the contract before the ventricles. pacemaker of the heart called the pacemaker. Electrocardiogram Electrocardiogram The electrical signals can be monitored electrical with an electrocardiogram (EKG). electrocardiogram (EKG). A Defibrillator • If one’s natural pacemaker fails, one can get the heart started with a public or an implantable defibrillator. defibrillator If it continues to fail, one can can get an artificial artificia pacemaker. The kind of terrifying terrifying experiments that served as a basis for Mary Shelley’s Frankenstein Frankenstein, also led to these wonderful technical devices. • • You will do this in lab! 8 Artificial Pacemaker Vivien Thomas and Alfred Bialok Performed the First Heart Surgery http://www.hbo.com/films/stlm/ http://www.pbs.org/wgbh/amex/partners/ Artificial Heart • In 2001, Drs. Gray (l) and Dowling (r) implanted the first AbioCor artificial heart into Robert Tools (c), into Robert Tools (c), a 58-year58-year-old telephone company employee and teacher. He natural heart was removed. Robert Tools lived for 151 days with his artificial heart. http://www.abiomed.com/products/heart_replacement.cfm Artificial Hearts • In 2006, Melissa Mills, a teenager, was given an artificial “Berlin heart” since her natural heart had deteriorated too much while deteriorated too much while she she was waiting for a heart transplant. 146 days later, Melissa’s natural heart got enough rest so that it started pumping again and the artificial heart was removed. Berlin Heart • • The Heart Rate is Regulated • The heart is connected to the nervous system, nervous which can speed up or speed slow slow down the heart rate (pulse) as needed (pulse) as needed. • Atherosclerosis Heart Attacks are Caused by a Blockage in a Coronary Artery, which in the Only Artery that Supplies the Heart Muscle with Sugar and Oxygen • The heart rate (pulse) also responds to the adrenaline released adrenaline released into the blood stream by the adrenal gland in times of “fight or flight” by speeding speeding up. • (hardening of the arteries) is a disease where plaques develop develo on the inside of the arteries. The higher the blood blood pressure, the greater the likelihood that a plaque clot plaque or clot will break off and form a flowing body called an embolus. embolus 9 Heart Attacks are Caused by a Blockage in a Coronary Artery, which Supplies the Heart Muscle with Sugar and Oxygen Stroke Stroke and Pulmonary Embolism • If the blockage forms in an artery in the brain, the brain is deprived of sugar and oxygen and a stroke stroke results. the pulmonary artery, the lung is deprived of sugar and oxygen and a • A blockage iis likely to blockage s • form where there is another plaque another plaque. If the blockage forms blockage forms in a coronary artery, coronary a heart attack will heart result. • If the blockage forms in pulmonary pulmonary embolism results. Plaques and Cholesterol •The plaques are formed by plaques are cholesterol cholesterol deposits. lipoproteins lipoproteins (LDL—bad bad cholesterol cholesterol) and low levels of Nutrition for the Heart – Saturated fats raise LDL (bad). – Trans fats raise LDL (bad) (bad) and lower HDL (good). Omega– Omega-3 fatty acids raise HDL (good). Omegaacids – Omega-6 fatty acids promote clotting of platelets in the blood. •High levels of low-density low- highhigh-density lipoproteins (HDL—good cholesterol) in HDL— the blood is correlated with greater risk for heart attacks. attacks. •Atherosclerotic plaque (→) 10 Blocked Coronary Arteries Can Be Opened by Performing an Angioplasty Now let’s get back to the sugar molecule that left the small intestine and passed through the heart. The sugar molecule is in the blood molecule is in the blood that that leaves the right ventricle via the pulmonary artery and goes to the lung, where the blood is oxygenated. The Path of Oxygen: Breathing Oxygen enters our body through the nostrils nostrils of the nose, where we warm it and humidify it. The Path of Oxygen: Breathing • From the nostrils, the air passes through the pharynx and past the epiglottis, which is open unless we are swallowing food. • The air then passes the larynx (voice air then passes the larynx (voice box), the trachea (windpipe), the two bronchi, the many bronchioles and into the millions of alveoli. • The alveoli are composed of epithelial tissue that borders the capillary system that contains the hemoglobin-containing red blood cells that take up the oxygen through the interstitial fluid. 11 The alveoli create a large surface to volume ratio necessary for gas exchange into and out of the body In order to exchange exchange sufficient oxygen and oxygen carbon dioxide to carbon dioxide to keep keep us alive, the epithelium of the lung surface has a surface area of approximately 100 m2, about the size of a racquet ball court. Cilia in our Respiratory System Keep Our Lungs Clean • The epithelial cells that line our trachea, bronchi and bronchioles contain cilia that cilia push out to the pharynx dust and pollen ca and pollen caught by the the mucus produced mucus produced by the epithelial cells lining the respiratory system. In the pharynx, the mucus-coated particles leave the mucustrachea and enter the esophagus to be eliminated. Nicotine inhibits the movement of the cilia which prevents them from removing the dirty mucus. Why Does Someone Smoke? • To fit in and give you an • • • • • • identity. Because it Because it Because it Because it Because it habit. Because it addiction. feels pleasant. relieves stress. is a reward. is their choice. becomes a becomes an • • 12 But No One Smokes Because It Is Healthy For You…Because it Isn’t Breathing We inhale air in when our diaphragm diaphragm muscle contracts and moves down. This suction negative creates a suction or negative pressure that pulls oxygen-rich air into our lungs. oxygenWe exhale air when our diaphragm relaxes and moves up. This pushes carbon dioxide-rich air out of our lungs. Breathing Provides the Wind for Singing Seasons of Love-Karaoke Seasons of Love-Karaoke2 Seasons of Love (Rent-The Movie) Seasons of Love- 10 Year Anniversary 13 Breathing is Controlled by the Brain • The amount of CO2 in our blood is an indicator of • • whether we are breathing fast and deep enough to keep our cells oxygenated. There is a sensor in the aorta that determines if the amount of CO2 is too high in the blood and if it is, it sends an nerve impulse to the brain. th i This sensor can indirectly tell if the CO2 ratio is too indirectly tell high by measuring the acidity of the blood. If there is acidity of brain too much acid (H+) in the blood, the brain sends an impulse to the diaphragm, increasing the rate diaphragm increasing and depth of our breathing. Remember the relationship between CO2 and H+? CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3- The Circulatory System • Unoxygenated, nutrient-rich blood leaves the nutrient• • small intestine, passes through the liver and the vena cava to the right atrium. It passes through the right ventricle and the pulmonary artery to the lungs, where it exchanges carbon dioxide for oxygen carbon dioxide for oxygen. The oxygenated, nutrient-rich blood leaves the oxygenated, nutrientlung through the pulmonary vein and travels through the left atrium and left ventricle, through the aorta to all the other cells of the body that need nutrients and oxygen for cellular respiration—a cellular metabolic process that will provide chemical energy in the form of ATP and carbon skeletons for the synthesis of proteins, lipids, nucleic acids and coenzymes necessary to build or rebuild the body. Capillary: Capillary: Epithelial Cells are Leaky and are in Communication with the Interstitial Fluid Surrounding All Cells of the Body Cell Respiration: Aerobic Energy Transformations in a Cell Heat Chemical reactions Glucose Carbon dioxide + ATP ATP water + Oxygen Energy for cellular work 14 Organs Must Share a Limited Blood Supply “Rest and Digest” Mode vs. “Fight or Flight” Mode • At any given time, 5-10% of your capillaries • The capillaries communicating with the brain, brain • The capillaries communicating with all the other hear kidne and heart, kidneys and liver are always full. alway skeletal regions of the body, including skeletal smooth muscles and the smooth muscles of the share the digestive system must share the blood depending on need—e. g. whether the body is need— in “rest and digest” mode or “fight or flight” mode. have blood flowing through them. Hormones and Nerves Regulate the Distribution of Blood • When you are in “fight or flight” mode, blood goes to all the capillaries in your running muscles but little in your running muscles, but little goes goes to the smooth muscles in your digestive system. During “rest and digest ” mode, the mode, blood goes to all the capillaries supplying blood to the smooth smooth and less goes to the running muscles. • The flow of blood is the arterioles near the precapillary sphincters, around thoroughfare channel. smooth regulated by smooth muscles, known as • Contraction of the Contraction of the • muscles in your digestive system smooth smooth muscles constrict the arterioles near the thoroughfare channel so that blood bypasses bypasses the capillary capillary bed and passes directly from an arteriole to a venule. Regulation of Blood Flow by Vasodilators • While investigating what brandy caused brandy to become spoiled, around 1844, Antoine Balard, one of Louis Pasteur’s Pasteur’s teachers, determined which chemicals were produced. The vapor from amyl amyl nitrite, one of the chemicals he found, momentarily caused his face to become flushed and his heart to beat faster. Amyl Amyl Nitrate Affects Blood Flow and Relieves the Pain of Heart Attacks • Dr. Benjamin Ward Richardson noticed • • capillaries that amyl nitrate caused the capillaries visible visible in a frog’s foot to dilate. dilate Dr Arthur Gamgee observed that amyl Dr. Arthur Gamgee observed that amyl nitrate decreased nitrate decreased blood pressure in animals and man. Sir Thomas Brunton (1867), a physician searching for a cure for heart attacks, vasodilating found that the vasodilating action of amyl nitrite relieved the pain of heart pain attacks. • 15 Accidental Discoveries • Alfred Nobel’s factory produced nitroglycerine nitroglycerine to make dynamite, dynamite Nitroglycerin and Alfred Nobel • How does nitroglycerin work? Certainly it doesn’t cause little explosions in the blood vessels. But without knowing, Alfred Nobel was not interesting in trying it. While sick with heart disease in 1896, Nobel wrote to a friend, “My heart trouble will keep me friend My heart trouble will keep me • • After realizing this, the local which is a controllable mixture of nitroglycerine and silica. Some workers who suffered from Some workers, who suffered from heart heart troubles at home, noticed that they were relieved of their chest pains when they were in the factory. doctors began prescribing nitroglycerine for heart disease. • Nobel refused to follow his doctor’s advice here here in Paris for another few days….Isn’t it the irony of fate that I have been prescribed nitroglycerin to be taken internally! They call it Trinitrin, so as not to scare the chemist and the public.” and take the explosive liquid and died of died heart disease several months after he wrote this letter. Discovery of Vasodilators Ferid Murad found that nitroglycerine, amyl nitrate and other nitrogennitrogencontaining substances that containing substances that caused caused vasodilation, nitric released nitric oxide (NO) and it was the NO that caused the muscles surrounding the blood vessels to relax. nobelprize.org/alfred_nobel NO NO is Naturally Synthesized from Arginine, an Amino Acid Nitroglycerin Nitroglycerin prevents heart damage by acting as a NO donor NO dilates dilates the arteries going to the going to the heart, heart, which increases the oxygen supply to the heart and prevents heart damage. 16 Fact and Fiction about NO, Science, Technology and Business NO is also Important for Sexual Arousal in Men and Women • During sexual arousal, blood goes to the • NO causes the smooth muscles causes smooth sexual organs to cause them to swell. surrounding the arteries leading to the di penis penis in men and the clitoris in women clitoris relax and dilate to relax and these arteries dilate. • This results in an increased blood flow increased • into these organs and consequently they tumescent become tumescent. And to illustrate this… 17 ...
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This document was uploaded on 11/09/2010.

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