Lecture 10 & 11 Notes- Sawey Contemporary Issues in Biology 10003-045
Lecture 10 & 11 Notes- Sawey Contemporary Issues in Biology 10003-045 BIOL 10003-045 (30055)
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This 6 page Class Notes was uploaded by Bowen Notetaker on Friday February 19, 2016. The Class Notes belongs to BIOL 10003-045 (30055) at Texas Christian University taught by Michael Sawey in Winter 2016. Since its upload, it has received 132 views. For similar materials see Contemporary Issues in Biology (Lec w/Lab) in Biology at Texas Christian University.
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Date Created: 02/19/16
Bio Lectures 10 & 11. Week of 2/15/2016. By: Bowen B. Lecture 10- Circulatory System and Heart Disease Intro o The body is composed of millions of proteins and the body is operating as a “machine” and runs on the energy of ATP. o Realize that the digestive system, respiratory system, circulatory system, and urinary system are all connected. Functions of the Heart o There are two main functions: Pump blood to the lungs to pick up oxygen and get rid of carbon dioxide. Pump blood throughout the body delivering oxygen, nutrients, hormones, and other materials to the cells of the body and picks up waste materials from the cells for removal from the body. The heart can be viewed as two distinct “pumps” o One on the right side and the other on the left. o Each side of the heart has two chambers; an atrium on top and a ventricle below. o Valves are present between the atria and the ventricles that keeps blood flowing in one direction o Blood flows quickly through the four chambers of the heart. o Blood vessels that carry blood to and from the heart deliver nutrients, hormones, oxygen, and other materials. o The “lub-dub-pause” sound of the heart comes from the opening and closing of the valves during the cardiac cycle. Control of Heart Beat o The heart muscles cells contract due to electrical signals generated by the nervous tissue contained within the hear (not from the brain and spinal cord). o There are 3 masses of nervous tissue in the heart that general these signals SA Node: neural cells that stimulate the contraction of the atria that sends blood through the AV valves to the ventricles of the heart. AV Node: neural tissue that carries the impulse down the ventricles and causes the ventricles to contract forcing the blood out of the heart. Purkinje Fibers: neural cells that carry the impulse throughout the ventricular muscle tissue. Electrocardiogram o A cardiogram measures the electrical activity of the heart muscle cells during each phase of the cardiac cycle. o P Wave: prior to atrial contraction o ORS: prior to ventricular contraction o T Wave: occurs when ventricles recover from contraction Blood Vessels o Arteries: carry blood away from the heart to the body o Veins: return blood from the body back to the heart Only in drawings….. o Oxygenated blood is bright red o De-oxygenated blood is darker red (magenta-ish) o Veins appear blue through your skin (the blood is dark red) Diet and Heart Disease o Diets that are rich in saturated fat are believed to increase the proportion of LDL cholesterol to HDL cholesterol (LDL and HDL will be explained later) o And increased ratio of LDL to HDL has been shown to increases deposition of cholesterol molecules on damaged areas of blood vessels This can lead to blockage of arteries and heart disease. Soooo if an artery of the heart becomes blocked, the heart muscles are starved of oxygen and eventually die. Fat Synthesis o All fats are made of a glycerol molecule and three fatty acid chains o In an unsaturated fat, some of the hydrogens are missing. o These two different fat types are thought to affect the circulatory differently by altering the ration of HDL to LDL cholesterol. Cholesterol o LDL (Low-Density Lipoprotein): the “bad” cholesterol that deposits fatty particles in your blood vessels to form plaques and block the arteries. o HDL (High-Density Lipoprotein): the “good” cholesterol that carries fatty particles from your blood vessels. o Recommendations: total of 200 md/dL or less is healthy LDL below 130 and HDL above 45 How Atherosclerosis Develops o When an artery has sustained damage, fats can begin to deposit on the inner lining of the vessel. o Overtime, more and more fat will accumulate and begin to cause a blockage o If the fat plaque ruptures, a blood clot can form which will completely prevent blood from flowing through the vessel. Heart Attack o If an artery of the heart becomes blocked, the cells that it provides oxygen to eventually become deprived and eventually die. Coronary Bypass o When a blockage reduces blood flow to an area of the heart a bypass maybe be needed to restore blood flow to the heart muscle. The replacement vessel is often taken from the upper leg or mammary area and inserted into the aorta then grafted to the damaged vessel below the blockage. Rationale for Mediterranean Diet o Rationale is that men living in Mediterranean area had lower rates of heart disease compared to American men. o They ate a Mediterranean-type diet with little red meat and much of the fat intake was olive oil (and unsaturated fat) o These men also worked hard in the fields and exercised more o So correlation does not prove causation The Lyon Diet Heart Study of 1994 o Test subjects with heart disease using Mediterranean diet, had a reduced risk of a second heart attack by 50-70% Blood Pressure o Measured in 2 ways Systolic pressure: the pressure generated on the walls of the artery while the ventricles of the heart are contracting. Pressure is high Diastolic pressure: the pressure on the arterial walls while the chambers of the heart are relaxing. Pressure is low. o Normal blood pressure Around or below 120/80 o Onset of hypertension 140/90 o Stage 2 hypertension 160/100 o Malignant hypertension 220/120 or greater Problems of High Blood Pressure o 600 million adults worldwide suffer from hypertension (persistent high blood pressure) o 90% of us will develop blood pressure problems. o Even children are starting to have high blood pressure o If blood pressure is too high it cause damage to the arteries of the circulatory system and allow cholesterol to deposit on the damaged areas. Effect of High Blood Pressure o Blood vessels change as we change o High blood pressure accelerates that process and lead to the deposition of fatty plaque in rough sports along the vessel walls which can lead to heart attack or stroke Treatment for High Blood Pressure o Lose weight, stop smoking, adopt healthful diet, exercise, limit sodium intake, drug therapy, etc Lecture 11- Alcohol and Human Health Controversy Over Use of Alcohol o Recent studies have indicated that there may be health benefits associated with moderate consumption of alcohol. The French Paradox o French consume high amounts of saturated fat o French have low rates of heart disease o This was a surprise because intake of saturated fat is correlated with heart disease. Hypothesis Explaining the French Paradox o French consume wine with each meal o Wine might help with heart disease Published Scientific Studies Found Benefits of Moderate Drinking o Benefits: alcohol beverages offer pharmacological benefits, especially to people at elevated risk of heart disease o Not a Substitute: for exercise, eating a healthy diet, or giving up cigarettes as the best way to stave off heart disease Guidelines of the US Department of Health and Human Services defines moderate drinking as: o No more than one drink a day for most women o No more than two drinks a day for most men o A standard drink is considered to be 12 ounces of beer, 5 ounces of win, 1.4 ounces of 80-proof distilled spirits Why is “moderate” drinking different for women and men? o Women become intoxicated more easily than men do Because women produce less alcohol dehydrogenase (the enzyme that the body uses to detoxify alcohol in the bloodstream) o Women also have less body water than men o Women also tend to be smaller and therefore cannot tolerate as much alcohol Health Risks of Drinking Alcohol o Risk of stroke by bleeding o Risk of vehicle crashes o Interactions with medicines o Shift to heavier drinking o High doses of alcohol can be fatal Risk of Drinking During Pregnancy o Even moderate drinking during pregnancy should be avoided o Drinking is linked to fetal alcohol syndrome Risk of Death vs Alcohol Consumption o Moderate drinking proves to be more beneficial than no drinking at all, but heavy drinking is much worse than no drinking. J-Shaped Curve Hypothesis o If the health effects of drinking were plotted on a graph, according to the amounts of alcohol consumed it would appear in the shape of a “J” Moderate drinkers live longest o A long term study of 1,824 participants ages 55-65 showed that at the end of 20 years: 69% of non-drinkers had died. 60% of heavy drinkers had died. 41% of moderate drinkers had died o Why? Alcohol consumption is typically related to social activities and interactions Social connectedness is vital to maintaining physical and mental health On average, people who never drink show greater signs of depression. The Liver o The liver is the “gateway” to the body o Refers to the fact that after being absorbed across the intestinal lining, all food and liquid molecules move first to the liver o So the liver is first body organ exposed to alcohol and is the organ that is most severely affected by heavy consumption Functions of the Liver o Detoxification of blood including the breakdown of alcohol o Regulation of blood sugar level o Conversion of ammonia to urea o Production of cholesterol o Production of blood proteins o Production of bile Alcohol detoxification in the liver o Alcohol dehydrogenase breaks down the alcohol molecule by removing hydrogen atoms. Alcohol-Induced Liver Disease o Fatty liver: most common form of ALD. Reversible with abstinence o Alcoholic hepatitis: more serious and is characterized by persistent inflammation of the liver Revisable with abstinence o Cirrhosis: persistence scarring of liver Not reversible Alcohol damage o Alcohol and its breakdown products are toxic to the liver cells, killing the cells and causing scar tissue o Cirrhosis of the liver is the permanent scarring of the liver tissue This condition is permanent Cirrhosis interferes with functions of the liver o Detoxification of blood o Regulation of blood sugar levels o Conversion of ammonia to urea o Production of cholesterol o Production of blood proteins Cirrhosis mortality rate is correlated with alcohol consumption rate Up to 24,000 deaths per year are due to cirrhosis Drinking and Cirrhosis o Heaving drinking over a long period of time to have cirrhosis o Cirrhosis does not usually occur with moderate drinking o 10-20% of heavy drinkers develop cirrhosis Binge drinking is defined as drinking 5 or more drinks on a given occasion Binge Drinking in College o On college campuses the binge drinkers are white males in fraternities o
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