Exam 4: HESI-A2-Reading

Brain Freeze "Brain Freeze" headaches-known to scientists as sphenopalatine ganglioneuralgia -are most often triggered when cold food or drink comes into contact with the roof of your mouth. In order to discover more about this phenomenon, researchers at Harvard Medical School hooked volunteers up to trans-cranial Dopplers, machines that allow scientists to study blood flow in the brain. The volunteers were then given cups of ice water and instructed to drink it using a straw held right up against the roof of the mouth. The volunteer gave a signal when he or she felt a "brain freeze" headache begin and another signal when it ended. This experiment allowed the scientists to observe changes in brain blood flow before, during, and after a "brain freeze" headache. The scientists found that when the subjects were experiencing a "brain freeze", the anterior cerebral artery (a major blood vessel in the brain) dilated rapidly. Because the artery becomes wider, more blood flows into the brain. This creates an increase in pressure inside the skull, which is what causes the pain. As soon as the artery shrinks to its normal size, the "brain freeze" headache disappears. This may explain why "brain freeze" headaches hurt, but it does not tell us why they happen in the first place. Scientists do not yet have any definite answers to this question, but they do have some ideas. One theory suggested by the researchers at Harvard Medical School is that a brain freeze is a way of protecting the brain from cold. When the anterior cerebral artery dilates, it allows a flood of warm blood inside the brain, thus keeping it warm. What is the main purpose of this passage?

Trans fats Trans fats are unsaturated fats found in many processed foods. Though their prevalence makes them a part of many people's diet, excessive consumption of trans fats can lead to a variety of serious health problems. Certain trans fats are found naturally in some animal products, such as beef and milk. However, the main source of trans fats for many people is processed foods. Partially hydrogenated vegetable oils are trans fats that are often found in shortening, packaged baked goods, and fried foods. Restaurants and food manufacturers often choose to use partially hydrogenated oils because they are less expensive, have longer shelf lives, and require less refrigeration than non-hydrogenated oils. Although trans fats may be less expensive for food manufacturers to use, and thus cheaper for consumers to purchase, excessive intake of these substances can cause significant health risks. Like saturated fat, trans fat raises the level of LDL ("bad") cholesterol in the body. Unlike saturated fat, however, trans fat also lowers the amount of HDL ("good") cholesterol in the body. Therefore, trans fat has a far more negative overall effect on cholesterol levels in the human body than saturated fat. Studies have also linked the consumption of trans fats to increased risk of heart disease, diabetes, obesity, cancer, liver dysfunction, depression, and memory disorders. What is the correct meaning of the word 'prevalence' in the first paragraph?

Light Pollution I grew up in the city, a place so full of streetlights, spotlights, and searchlights that the sky was never dark enough to see the Milky Way. But last year, I went on a camping trip through the Grand Canyon. When I saw the night sky for the first time, I was in awe. I could not believe how many stars there were. As cities push farther and farther into the wilderness, they create light pollution, the brightening of the night sky by artificial light sources. Light pollution not only hinders our ability to see the beauty of the stars, but it might be causing other problems as well. Light pollution also disrupts the lives of certain animals. For example, too much artificial light can prevent newly-hatched sea turtles from finding the ocean. Owls and other birds that hunt at night can injure themselves by flying into brightly lit buildings. So what is the solution? Obviously, we cannot turn off all of the lights every night. But we can reduce the amount of light we send into the sky. Homeowners should use motion sensors on outdoor lights. Cities should turn off (or at least dim) streetlights after midnight. Businesses and office buildings should turn off their lights when they close for the day. Turning off the lights will help animals and restore the night sky to its former glory. Question: What is the main idea of the passage?

PTSD in Female Veterans Post-traumatic stress disorder (PTSD) is a severe anxiety disorder that affects millions of people around the world. Individuals can develop PTSD after experiencing any event that results in psychological trauma. Symptoms of PTSD involve flashbacks to the traumatic event, nightmares, obsessive behavior, anger, insomnia, difficulty concentrating, and hypervigilance. Individuals who suffer from PTSD can experience significant difficulties in social relationships, have lower self-esteem, and have trouble maintaining employment. People with PTSD experience a higher risk of committing suicide and developing a substance abuse disorder. Although PTSD can affect any individual, military veterans are especially susceptible. Furthermore, within this population, women are more than twice as likely as men to develop PTSD. Although studies investigating precisely why women are more likely than men to experience PTSD have not yet been completed, some experts have theorized that low unit cohesion is a major factor. Unit cohesion, defined as the mutual bonds of friendship and support among members of a military unit, is thought to be helpful in reducing the incidence of developing PTSD. Women are more likely than men to experience low unit cohesion for a variety of reasons. One of the most obvious factors is the relatively lack of females in the military; currently, women make up only 20% of the armed forces. Pervasive male prejudice against women is another factor that can diminish unit cohesion for female soldiers. Perhaps the biggest impediment to achieving quality treatment for women suffering from wartime PTSD is a shortage of research. While both the VA and independent agencies have completed hundreds of studies researching the prevention of and treatment for PTSD amongst general military populations, there have been no studies completed that solely target women. More must be done to help the women who have sacrificed so much for their country. Question: What can be inferred about women who find themselves in combat roles?

The future of space travel may not lie with humans, but with robots. At the dawn of the space age, space travel required human astronauts-they were simply more capable than robots. But humans developed technology that steadily made robots more attractive. Astronauts have to breathe, eat, and drink to keep going. But robots can travel to the ends of the solar system free of such constraints. They can do more, go further, and because they don't require costly life-support systems, they can do it all more often. Of course, they still require human direction. Nevertheless, we should all look for more robotic space travelers in the future. Which of the following is true according to information found in the passage?

Wrinkles Skin wrinkles are caused by a variety of factors. Some of these factors are intrinsic, meaning that you cannot control them because they occur naturally. Others are extrinsic, meaning that they are caused by circumstances outside of the body. One intrinsic factor is aging. As you age, your skin loses collagen, which is the protein responsible for keeping your skin elastic. With less collagen, your skin becomes thinner and more fragile. Aging also reduces the functioning of sweat and oil glands, which work to keep the skin looking smooth. You also lose fat in the deeper layers of your skin as you age. This fat loss causes your skin to sag and develop deeper wrinkles. The two most common extrinsic factors are exposure to ultraviolet radiation (UV rays) and smoking. UV rays in sunlight break down your skin's connective tissue and collagen fibers. To prevent the appearance of wrinkles (as well as protect yourself from skin cancer), you should always use UV-blocking sunscreen. The nicotine in cigarettes is the most likely link between smoking and wrinkles. Nicotine narrows the blood vessels, reducing the blood supply to your skin tissue. This deprives your skin of oxygen and important nutrients, causing damage that contributes to wrinkles. Question: Why does the author include the detail "nicotine narrows the blood vessels" in paragraph 3?

Garlic Breath Anyone who has ever had a delicious piece of garlic bread knows that there is a price to pay for eating it: the dreaded garlic breath. What makes garlic so good at making your breath smell so bad? The main culprit is a compound called allyl methyl sulfide. As your body digests the garlic, the sulfide is released into your bloodstream. From there, it travels through your body until it is eliminated through your digestive system, your urine, or out of your pores. However, some of the allyl methyl sulfide also crosses from the bloodstream into the air that fills your lungs. As you breathe this air out, the garlic smell goes with it. This is why no matter how many pieces of gum you chew, how often you brush your teeth, or how much mouthwash you swish, a garlicky meal can give you stinky breath for days. Recent research shows that the best way to combat the effects of garlic on your breath is to eat a raw apple or some raw mint leaves while you consume garlic. Both apples and mint leaves contain polyphenolic compounds that can neutralize the allyl methyl sulfides in garlic. Question: What can be inferred from the passage?

Sports Drinks When you sweat heavily, your body loses electrolytes and water. The most important electrolytes are potassium and sodium-these substances keep your body's cells working properly. Commercials for sports drinks claim that their products will replenish the electrolytes lost during exercise. However, sports drinks are not really necessary for most people. Eating a normal diet that contains healthy amounts of sodium and potassium will maintain the electrolyte balance in your body. Unless you are exercising very intensely for more than 60 minutes, you do not need to use a sports drink to replace lost electrolytes. Most people believe that sports drinks are healthy beverages-after all, if athletes drink them, they must be good for you. On the contrary, sports drinks are filled with artificial ingredients and sugar. One 20-ounce bottle of an average sports drink contains 34 grams of sugar and 130 calories. These empty calories can actually cause you to gain weight instead of helping to keep you fit. One study presented at the 2012 Obesity Society's annual scientific meeting revealed that teenagers gained an average of 3.5 pounds every two years just by consuming a bottle of sports drink every day. The best beverage for you to drink before, during, or after a workout is water. Water has no sugar, no salt, no calories, and no artificial flavors or colors. Water will rehydrate your body and quench your thirst better than any other drink. Unless you are a serious athlete who regularly exercises for more than 60 minutes at a time, sports drinks ultimately do more harm than good. Question: What is the main purpose of the passage?

Vaping Electronic cigarettes, or e-cigarettes, are electronic devices that provide users with the same nicotine "fix" that they would receive from a traditional cigarette. However, e-cigarettes do not burn tobacco, and thus do not produce the same toxic chemicals as traditional cigarettes. For this reason, many believe that using e-cigarettes (also known as "vaping") is a safe alternative to smoking tobacco. This perception has turned vaping into a billion-dollar industry and has made vaping extremely popular, especially among adolescents. However, even though e-cigarettes do not produce tobacco smoke, they are still not completely safe. E-cigarette vapor contains a variety of toxic chemicals, including formaldehyde and acetaldehyde. Although they are harmless in small amounts, there have not been any studies of the dangers of long-term exposure to these chemicals. Furthermore, the nicotine in e-cigarettes is just as addictive as the nicotine in traditional cigarettes. Withdrawal symptoms from nicotine deprivation include mood swings, anxiety, and changes in appetite. Exposure to nicotine can also be dangerous for people with cardiovascular problems. While vaping may be better for you than smoking traditional cigarettes, more research needs to be done before e-cigarettes can be considered completely safe. People-especially adolescents-should be wary of getting hooked on these "harmless" cigarettes. Question: According to the text, what is true regarding electronic cigarettes?

Antibiotic Resistance Antibiotic resistance occurs when micro-organisms develop means of survival despite exposure to antibiotics. The development of antibiotic resistance can be traced to two main areas of antibiotic misuse: over-prescription by doctors and unnecessary introduction into animal feed by farmers. The overuse of antibiotics by both doctors and farmers has increased antibiotic resistance by inadvertently fostering natural selection for resistance in colonies of bacteria. Bacteria that naturally carry antibiotic-resistant genes survive contact with the antibiotics. These resistant bacteria then reproduce, transferring their resistant genes to future generations of bacteria. Over time, this process yields a colony of bacteria that is fully resistant to antibiotics. Some bacteria even develop a variety of resistance genes; these bacteria are colloquially known as "super bugs" because of their ability to resist the majority of antibiotics. Staphylococcus aureus, the bacteria responsible for what is commonly known as a "Staph infection," is one of the most resistant pathogens. It is estimated that half of all Staph infections in the United States are resistant to penicillin, methicillin, tetracycline, and erythromycin-the four most common drugs used to treat such infections. The ever-increasing strength and population of these "super bugs" may pose a serious threat to human health in the near future. The problem of antibiotic resistance has no easy solution. More funding should be available to scientists working toward the research and development of new antibiotics that will fight resistant bacteria. There are also steps that laypeople should take to help prevent further development of resistant bacteria. Individuals with viral infections should not demand antibiotics from their doctors. Consumers should also put pressure on meat manufacturers to stop adding unnecessary antibiotics into animals' diets. Finally, citizens should petition the government to increase funding for scientific research done to combat the growing problem of antibiotic resistance. Question: Which is NOT included in the author's opinion regarding solving antibiotic resistance?

Light Pollution I grew up in the city, a place so full of streetlights, spotlights, and searchlights that the sky was never dark enough to see the Milky Way. But last year, I went on a camping trip through the Grand Canyon. When I saw the night sky for the first time, I was in awe. I could not believe how many stars there were. As cities push farther and farther into the wilderness, they create light pollution, the brightening of the night sky by artificial light sources. Light pollution not only hinders our ability to see the beauty of the stars, but it might be causing other problems as well. Light pollution also disrupts the lives of certain animals. For example, too much artificial light can prevent newly-hatched sea turtles from finding the ocean. Owls and other birds that hunt at night can injure themselves by flying into brightly lit buildings. So what is the solution? Obviously, we cannot turn off all of the lights every night. But we can reduce the amount of light we send into the sky. Homeowners should use motion sensors on outdoor lights. Cities should turn off (or at least dim) streetlights after midnight. Businesses and office buildings should turn off their lights when they close for the day. Turning off the lights will help animals and restore the night sky to its former glory. Question: What is the best summary of the passage?

Vaping Electronic cigarettes, or e-cigarettes, are electronic devices that provide users with the same nicotine "fix" that they would receive from a traditional cigarette. However, e-cigarettes do not burn tobacco, and thus do not produce the same toxic chemicals as traditional cigarettes. For this reason, many believe that using e-cigarettes (also known as "vaping") is a safe alternative to smoking tobacco. This perception has turned vaping into a billion-dollar industry and has made vaping extremely popular, especially among adolescents. However, even though e-cigarettes do not produce tobacco smoke, they are still not completely safe. E-cigarette vapor contains a variety of toxic chemicals, including formaldehyde and acetaldehyde. Although they are harmless in small amounts, there have not been any studies of the dangers of long-term exposure to these chemicals. Furthermore, the nicotine in e-cigarettes is just as addictive as the nicotine in traditional cigarettes. Withdrawal symptoms from nicotine deprivation include mood swings, anxiety, and changes in appetite. Exposure to nicotine can also be dangerous for people with cardiovascular problems. While vaping may be better for you than smoking traditional cigarettes, more research needs to be done before e-cigarettes can be considered completely safe. People-especially adolescents-should be wary of getting hooked on these "harmless" cigarettes. Question: Which supporting detail is an example of an opinion, rather than factual information?

The Pilomotor Reflex Have you ever experienced the pilomotor reflex? Chances are that you have. The pilomotor reflex is actually something most people experience every day: goosebumps. Goosebumps (also called goose flesh and goose pimples) are small bumps on the skin. They are created when tiny muscles beneath the hairs on your skin contract, pulling the hair into an upright position. They can occur anywhere that you have hair on your body, but they are most common on your arms and legs. Goosebumps are an involuntary reaction to many different sensations, such as cold, fear, or even happiness. Humans are not the only animals that get goosebumps. When cats or dogs are threatened by an enemy, the pilomotor reflex will cause their fur to stand on end. This makes the animal look larger, which might scare away the enemy. Porcupines also experience the pilomotor reflex; a frightened porcupine will raise its quills when it is in danger. This not only makes the porcupine look bigger, but it also frightens enemies away by drawing attention to the sharp quills. The pilomotor reflex can also help animals stay warm by trapping body heat closer to their skin. Because human beings have much less body hair than most other animals, goosebumps do not make us seem larger or more intimidating. They also do not help to keep us very warm, although they do help to prevent some heat from leaving the body. For the most part, the pilomotor reflex is much more important for animals than it is for people. In fact, many scientists think that the pilomotor reflex is actually completely useless for humans. Question: What is the best summary of this passage?

Diabetes There are two types of diabetes: Type 1 and Type 2. Both types of diabetes can cause a variety of serious health risks if left untreated. Some of these health problems include kidney disease, blindness, heart disease, and strokes. About 5-10% of people with diabetes have Type 1 diabetes. Type 1 diabetes most commonly develops in young people. In Type 1 diabetes, the immune system destroys the cells in the pancreas that secrete insulin. Without insulin, the body's cells cannot absorb glucose, and thus cannot produce energy. Symptoms appear after about 90% of the cells have been destroyed. Although most cases of Type 1 diabetes are genetic, some have arisen in people who have had viral infections of the pancreas. Most people who have diabetes (90-95%) have type 2 diabetes, which most commonly develops in people over age 40. Type 2 diabetes results from the inability of tissues to respond to insulin-a condition called insulin resistance. As Type 2 diabetes progresses, the pancreas produces less and less insulin, resulting in a condition called insulin deficiency. There is no cure for either Type 1 or Type 2 diabetes. However, there are ways to manage both types. For Type 1 diabetes, treatment requires receiving regular insulin injections. Type 2 diabetes can also be treated with insulin injections, but can be also be managed with lifestyle changes, such as weight loss, exercise, and reducing intake of carbohydrates. According to the text, what can be inferred from a person who has Type 1 diabetes?

Garlic Breath Anyone who has ever had a delicious piece of garlic bread knows that there is a price to pay for eating it: the dreaded garlic breath. What makes garlic so good at making your breath smell so bad? The main culprit is a compound called allyl methyl sulfide. As your body digests the garlic, the sulfide is released into your bloodstream. From there, it travels through your body until it is eliminated through your digestive system, your urine, or out of your pores. However, some of the allyl methyl sulfide also crosses from the bloodstream into the air that fills your lungs. As you breathe this air out, the garlic smell goes with it. This is why no matter how many pieces of gum you chew, how often you brush your teeth, or how much mouthwash you swish, a garlicky meal can give you stinky breath for days. Recent research shows that the best way to combat the effects of garlic on your breath is to eat a raw apple or some raw mint leaves while you consume garlic. Both apples and mint leaves contain polyphenolic compounds that can neutralize the allyl methyl sulfides in garlic. Question: According to the text, why could the smell of garlic remain in someone's breath for days after having eaten garlic?

Brain Freeze "Brain Freeze" headaches-known to scientists as sphenopalatine ganglioneuralgia -are most often triggered when cold food or drink comes into contact with the roof of your mouth. In order to discover more about this phenomenon, researchers at Harvard Medical School hooked volunteers up to trans-cranial Dopplers, machines that allow scientists to study blood flow in the brain. The volunteers were then given cups of ice water and instructed to drink it using a straw held right up against the roof of the mouth. The volunteer gave a signal when he or she felt a "brain freeze" headache begin and another signal when it ended. This experiment allowed the scientists to observe changes in brain blood flow before, during, and after a "brain freeze" headache. The scientists found that when the subjects were experiencing a "brain freeze", the anterior cerebral artery (a major blood vessel in the brain) dilated rapidly. Because the artery becomes wider, more blood flows into the brain. This creates an increase in pressure inside the skull, which is what causes the pain. As soon as the artery shrinks to its normal size, the "brain freeze" headache disappears. This may explain why "brain freeze" headaches hurt, but it does not tell us why they happen in the first place. Scientists do not yet have any definite answers to this question, but they do have some ideas. One theory suggested by the researchers at Harvard Medical School is that a brain freeze is a way of protecting the brain from cold. When the anterior cerebral artery dilates, it allows a flood of warm blood inside the brain, thus keeping it warm. Based on information given in the text, what can be inferred from the "brain freeze" phenomenon?

Hiccups At some point in your life, you have probably had the hiccups. Hiccups are caused by spasms in the diaphragm, a muscle located at the bottom of your chest. As we inhale, the diaphragm contracts, pulling air into the lungs. As we exhale, the diaphragm relaxes, pushing air back out through the mouth and nose. When we hiccup, the diaphragm jerks downward suddenly, pulling a quick burst of air into our lungs. As the air rushes into your body, it hits the voice box. This causes your vocal cords to snap shut, creating the sound we recognize as a hiccup. Hiccups can be triggered by many different things-eating too much, drinking too fast, sudden change of temperature, stress, fatigue, nervousness, and even excessive laughter can all cause the hiccups. While there are many home remedies for hiccups, there is no evidence to suggest that any of them are actually effective. In fact, most cases of the hiccups go away on their own. Although hiccups are usually harmless, they can be a sign of something more serious. Long-term hiccups might be a result of damage to the nerves that serve the diaphragm muscle. Persistent hiccups might also be caused by certain central nervous system disorders, traumatic brain injuries, drug abuse, or kidney disease. Question: Which of the following is NOT a cause of the hiccups according to the passage?

Hangovers Veisalgia, more commonly known as a hangover, is the name for the range of unpleasant physical effects that occur following the excessive consumption of alcoholic beverages. The most commonly experienced effects include nausea, vomiting, sensitivity to light and sound, headache, thirst, and lethargy. The degree of the hangover's severity is determined by factors occurring both before and after the alcohol is metabolized. The main pre-metabolic cause of veisalgia is the quantity of alcohol consumed. Binge drinking is one of the most notorious contributors to hangovers. Empirical research suggests that even an increase in consumption from four to six beers can result in twice the susceptibility to end up with a hangover. Another pre-consumption factor that contributes to hangovers is the amount of congeners present in the alcohol. Congeners are chemical substances produced during the fermentation process that give the alcohol color, taste, and aroma. Recent studies have shown that alcohol with a high congener content, such as bourbon (which is brown), is three times as likely to cause a hangover as the same amount of a low-congener alcohol, such as vodka (which is clear). Post-metabolic causes of veisalgia have less to do with the amount or kind of alcohol consumed and more to do with genetics. One of the major post-metabolic causes of veisalgia is the production of acetaldehyde. During the initial stages of metabolization, the liver produces an enzyme known as alcohol dehydrogenase. This enzyme works to convert the ethanol present in alcohol into the compound acetaldehyde. Studies have shown that individuals who lack this enzyme-and thus also lack the ability to break down ethanol in the liver-have a much higher rate of hangover occurrence, and experience more immediate and more severe hangover symptoms. Question: Which of the following is probably true of the clear alcoholic beverage gin?

Antibiotic Resistance Antibiotic resistance occurs when micro-organisms develop means of survival despite exposure to antibiotics. The development of antibiotic resistance can be traced to two main areas of antibiotic misuse: over-prescription by doctors and unnecessary introduction into animal feed by farmers. The overuse of antibiotics by both doctors and farmers has increased antibiotic resistance by inadvertently fostering natural selection for resistance in colonies of bacteria. Bacteria that naturally carry antibiotic-resistant genes survive contact with the antibiotics. These resistant bacteria then reproduce, transferring their resistant genes to future generations of bacteria. Over time, this process yields a colony of bacteria that is fully resistant to antibiotics. Some bacteria even develop a variety of resistance genes; these bacteria are colloquially known as "super bugs" because of their ability to resist the majority of antibiotics. Staphylococcus aureus, the bacteria responsible for what is commonly known as a "Staph infection," is one of the most resistant pathogens. It is estimated that half of all Staph infections in the United States are resistant to penicillin, methicillin, tetracycline, and erythromycin-the four most common drugs used to treat such infections. The ever-increasing strength and population of these "super bugs" may pose a serious threat to human health in the near future. The problem of antibiotic resistance has no easy solution. More funding should be available to scientists working toward the research and development of new antibiotics that will fight resistant bacteria. There are also steps that laypeople should take to help prevent further development of resistant bacteria. Individuals with viral infections should not demand antibiotics from their doctors. Consumers should also put pressure on meat manufacturers to stop adding unnecessary antibiotics into animals' diets. Finally, citizens should petition the government to increase funding for scientific research done to combat the growing problem of antibiotic resistance. Question: Which situation most closely aligns with the author's suggestions regarding solving the problem of antibiotic resistance?

DNA analysis Modern forensics-science used in investigating crimes-relies heavily on DNA evidence. Nearly every cell in our bodies contains DNA, the molecule that carries our genetic information. Aside from identical twins, no two human beings have the exact same DNA. Because DNA is present in our hair, blood, skin, and saliva, we leave traces of our DNA just about everywhere we go. Forensic investigators collect and analyze DNA evidence left at crime scenes to identify criminals. On television, this process is quick and conclusive. In real life, however, it is much more complicated. If the material found at the crime scene is too small, too old, or has otherwise been damaged, analyzing the DNA can be difficult. Furthermore, if the sample came from teeth, hair, or bones, it must undergo a different type of analysis called mitochondrial DNA analysis, which uses DNA from a cell's mitochondria instead of the nucleus. Matching mitochondrial DNA is often more difficult than nuclear DNA. Furthermore, forensic experts never suggest that DNA evidence is concrete proof of a suspect's guilt. Forensic science is rooted in probability, not certainty. When the DNA of a suspect is found at a crime scene, it means that the suspect was likely to have been present at the crime scene, but it does not definitively indicate that he or she was guilty of a crime. Question: Which of the following is NOT true about DNA?