Exam 4: HESI-A2-Reading

Lyme Disease Lyme disease is caused by ticks. More specifically, Lyme disease is caused by Borrellia bacteria, which are carried by ticks. When ticks infected with this bacteria bite humans, the bacteria can be transmitted into the bloodstream, causing an illness known as Lyme disease. The symptoms of Lyme disease include fever, headache, fatigue, and joint and muscle pain. One of the most noticeable signs is a rash that looks like a series of red rings radiating out from the bite. This usually appears a week after the tick bite. However, not everyone with Lyme disease gets this rash. The good news is that Lyme disease can be treated with antibiotics. Most people recover quickly and fully. However, if Lyme disease is not treated properly, patients can suffer from debilitating symptoms weeks, months, and even years after the bite. This condition is known as post-treatment Lyme disease (PTLD) or chronic Lyme disease (CLD). To protect yourself from Lyme disease, always cover your skin with clothing or insect repellent when hiking or camping. If you get bitten by a tick, remove the tick right away; most cases of Lyme disease require the tick to be attached for 36 to 48 hours. If red rings appear, see a doctor right away. Lyme disease can be harmful, but it is preventable and treatable with early intervention. Question: What can be inferred from patients with chronic Lyme disease (CLD)?

Guide dogs Guide dogs are service animals that are specially trained to help visually impaired people. Most guide dogs are Labrador Retrievers, Golden Retrievers, or German Shepherds, breeds known for their intelligence, gentleness, and friendliness. Puppies that might become guide dogs are monitored from a very young age by trainers. Puppies that demonstrate a good temperament and willingness to learn begin their training at about 16 months of age. Puppies that have been selected for training live with their trainer's family for about a year. Trainers teach the puppies to walk in straight lines, avoid obstacles, and stop at curbs. The dog learns how to focus on the owner instead of distractions, such as food, toys, or other animals. Guide dogs learn how to obey their owners, but also when to refuse their owner's commands when it might lead to danger, such as crossing a busy street. When the dog is full-grown, the trainer brings it in for a final assessment. If the dog passes the test, it is placed with a visually impaired person in need of a service animal. If the dog fails the assessment, however, it often remains as a pet with the trainer's family. Although trainers might be sad to part with the dog that they have bonded with, they know that their former charge has become an invaluable resource for someone in need. What could be the author's purpose for writing this passage?

Mercury in Fish Mercury is a highly toxic metal found in neon signs, fluorescent lights, older thermometers, and certain kinds of telescopes. It can also be found in something that many people eat on a regular basis: fish. The mercury we might find in a can of tuna is most likely an indirect result of the coal industry. Mercury, which is naturally found in coal, is released into the air when coal is burned. It finds its way into waterways via mercury-laced rain. Mercury accumulates in certain kinds of fish through a process called biomagnification. Biomagnification occurs when a substance enters the food chain in small amounts at the very bottom and then increases in concentration in animals higher up on the food chain. Once a fish eats another creature containing mercury, the mercury does not leave that fish's body, but instead is stored in fat. Therefore, the mercury continually accumulates as more mercury-contaminated fish are eaten. Despite the toxicity of mercury and the widespread nature of fish contamination, there is no need for the public to be overly apprehensive. Many popular fish, such as salmon, catfish, or tilapia, are generally safe to eat. Other fish, especially tuna and grouper, should only be eaten in moderation. Young children and pregnant women should be especially cautious about how many servings of mercury-contaminated fish they have per week. It is recommended that people in these groups not eat more than 2 servings of mercury-contaminated fish per week. Fish with the highest levels of mercury include shark, swordfish, and king mackerel. All people should avoid eating large amounts of these kinds of fish, and no one should eat these fish more frequently than once a month. Question: Which detail is included regarding safety when eating fish?

Does Low Body Temperature Cause Illness? As children, we are often told to dress warmly in the winter so we do not get sick. This is a common piece of advice, but is there any truth behind it? In fact, there is no scientific evidence to suggest that being cold can get you sick. Most illnesses are caused by viruses and bacteria. Illnesses like strep throat, influenza, and the common cold are only spread through contact with other infected people. How cold you are when you come into contact with the virus or bacteria has nothing to do with whether or not you will get sick. The effect of body temperature on contracting illness was tested on human beings in the 1950s. Researchers divided volunteers into two groups: half of them were kept in a warm room and the other half were kept in a cold room. Both groups were then exposed to rhinovirus-the virus responsible for the common cold. The researchers discovered that members of both groups developed colds at the same rate. Since that first experiment, there have been similar experiments performed with a variety of different illnesses. All have yielded the same result: being cold does not make a person more likely to get sick. Of course, it does seem that people do get sick more often when the weather is cold. However, this is because there is some evidence that people do get sick more often in cold weather, but it has nothing to do with forgetting to bundle up when it is chilly. When it is cold outside, people tend to stay inside. With so many people gathered closely together indoors, germs are spread more easily. Germs are spread from person to person, regardless of how cold or warm their bodies are. Why does the author include the detail "Since that first experiment…variety of different illnesses" in paragraph 2?

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: goose bumps. 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, it 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 author's purpose in writing this passage?

Balance Everyone knows that your ears are responsible for your sense of hearing. But did you also know that your ears are also partially responsible for your sense of balance? Your inner ear contains something called the vestibular system, which is a key component in your body's ability to establish and maintain balance. The vestibular system mainly consists of three semicircular canals. Each semicircular canal has a different orientation, allowing them to detect a variety of movements. The canals are filled with a fluid called endolymph. When you move your head, the fluid in the canals also moves; this movement sends signals to the brain about the position of your head. Your brain uses this information to help your body stay balanced. Damage to the vestibular system caused by disease or injury can severely affect a person's balance. Consuming too much alcohol can also temporarily affect the vestibular system. Because alcohol thins the blood, it also changes the viscosity of the endolymph. The thinned-out endolymph sends signals to your brain that your body is rotating even though it is not. This is why many people feel like the room is spinning when they are drunk. Based on the text, which of the following is NOT true regarding the vestibular system?

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 is the best summary for this passage?

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, it 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 meaning of the word contract in the second paragraph?

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: What is the author's purpose in writing this passage?

Lactose Intolerance Lactose intolerance is the inability to digest a sugar called lactose in milk and other dairy products. Adults in most of the world are lactose intolerant, although infants are not. This is because many adults lack an enzyme known as lactase. Lactase, which can be found in cells in the intestine, is the enzyme that breaks down lactose. Many individuals lose the ability to synthesize lactase after age six. However, not everyone does. Whether or not the body continues to produce lactase often depends on ethnicity. While only 5-15% of adults of European descent cannot digest lactose, 80-90% of adults of African and Asian descent are lactose intolerant. Research has shown that people of northern European ancestry contain a genetic mutation that allows the secretion of lactase in adulthood. The main symptom of lactose intolerance is gastrointestinal upset. Lactose intolerant people may experience diarrhea, bloating, abdominal pain, gas, and vomiting after consuming lactose-containing foods and beverages. Although there has been some research into gene therapy as a treatment for lactose intolerance, the current best treatment is either ingesting lactase supplements when consuming dairy products or simply avoiding foods containing lactose altogether. Question: What is the meaning of the word synthesize in the passage?

Dreams The average adult spends almost two full hours every night dreaming. Dreams mainly occur during a period known as REM (Rapid Eye Movement) sleep. While you are in REM sleep, your brain is very active-almost as active as if you were awake. The fact that we dream most often during REM sleep is one of the very few facts about dreams that every scientist agrees on. Scientists do not know exactly which portion of the brain creates dreams or even why we have them in the first place. One theory about their purpose is that dreaming helps the brain to organize and store memories. As your body relaxes, your brain processes all of the information it received during the day. While you sleep, your brain organizes the information into memories; your mind perceives this process as dreaming. Because your mind works differently when you are asleep than it does when you are awake, your dreams may seem confusing, illogical, or just downright silly. Another theory is that dreams allow your mind to work out difficult problems that you encounter while you are awake. The unrealistic, free-flowing nature of dreams allows your mind to consider the problems in creative ways that you would likely never think of during your waking hours. Still, other scientists believe that dreams are random events with no real function. According to this theory, there is no actual reason for dreaming-it is simply what happens when you go to sleep. As you can see, there is no scientific consensus about how or why we dream. There are many different theories, but no proven answers. Until then, you might as well just enjoy the fantastic nighttime adventures you get to go on without ever leaving your bed. Question: On which of the following aspects of dreaming do scientists generally agree?

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 can be inferred from the anterior cerebral artery, based on information in the text?

Guide dogs Guide dogs are service animals that are specially trained to help visually impaired people. Most guide dogs are Labrador Retrievers, Golden Retrievers, or German Shepherds, breeds known for their intelligence, gentleness, and friendliness. Puppies that might become guide dogs are monitored from a very young age by trainers. Puppies that demonstrate a good temperament and willingness to learn begin their training at about 16 months of age. Puppies that have been selected for training live with their trainer's family for about a year. Trainers teach the puppies to walk in straight lines, avoid obstacles, and stop at curbs. The dog learns how to focus on the owner instead of distractions, such as food, toys, or other animals. Guide dogs learn how to obey their owners, but also when to refuse their owner's commands when it might lead to danger, such as crossing a busy street. When the dog is full-grown, the trainer brings it in for a final assessment. If the dog passes the test, it is placed with a visually impaired person in need of a service animal. If the dog fails the assessment, however, it often remains as a pet with the trainer's family. Although trainers might be sad to part with the dog that they have bonded with, they know that their former charge has become an invaluable resource for someone in need. According to the text, what is a possible outcome of training?

Carbon Monoxide Poisoning Carbon monoxide (CO) is a poisonous gas that has is odorless, colorless, and tasteless. These qualities make it possible for you to breathe in toxic amounts of carbon monoxide without realizing that you are in danger. Carbon monoxide is produced when materials that contain carbon, such as wood, coal, gasoline, oil, or natural gas, are burned. If the space where the materials are burned is not ventilated properly, then the carbon monoxide that is released can build to dangerous levels. Inhaling carbon monoxide causes the gas to build up in your bloodstream. CO molecules displace oxygen in your blood, depriving your heart, brain, and other organs of oxygen. Early signs of carbon monoxide poisoning include flu-like symptoms, such as dizziness, drowsiness, headache, blurred vision, nausea, and vomiting. Prolonged exposure to large amounts of CO can lead to unconsciousness, irreversible heart, lung, or brain damage, and death. People who are most at risk of carbon monoxide poisoning include pregnant women, young children, the elderly, and people with serious heart or lung conditions. To prevent carbon monoxide poisoning, people should make sure that places where carbon-containing materials are burned are properly ventilated. Carbon monoxide detectors should also be present in homes, garages, and workspaces. According to the text, which of these is NOT true regarding carbon monoxide?

Father of Surgery Abu al-Qasim Khalaf ibn al-Abbas Al-Zahrawi, also known as Albucasis, is considered by many people to be the "Father of Modern Surgery." Al-Zahrawi was born in Spain in 936 CE, a time when Spain was part of the Islamic empire. One of Al-Zahrawi's greatest contributions was the Kitab al-Tasrif, a 30-volume encyclopedia of medical information. The Kitab al-Tasrif took Al-Zahrawi over 50 years to complete. It contains information about a wide variety of illnesses, injuries, medical conditions, treatments, and surgical procedures. His book includes discussions of dentistry, obstetrics, ophthalmology, urology, and cranial surgery, among many others. He even provides illustrations for over 200 different surgical instruments. In the Kitab, Al-Zahrawi presents the first description of ectopic pregnancy and provides the first evidence that hemophilia is a genetic condition. Surgeons continued to use the information in the Kitab al-Tasrif well into the 1700s. In fact, some of Al-Zahrawi's practices are still being used to this very day. For example, Al-Zahrawi developed a technique to treat gynecomastia (enlarged breast tissue) in men that is still in practice today. Finally, the Kitab also includes something vital for all modern practitioners to keep in mind: a reminder that patients are human beings who must be treated regardless of their wealth or social status. Question: According to the text, which is NOT mentioned as an impact that Al-Zahrawi has had on the medicinal field?

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 true about a DNA sample left at a crime scene?

Synaesthesia Does the number five smell like lemons? Is the sound of a flute purple? Does the letter "R" taste like cinnamon? These questions might seem strange, but to people with synaesthesia, they make perfect sense. Synaesthesia is a neurological phenomenon where the senses get crossed. People with synaesthesia (also called "synaesthetes") experience this phenomenon in different ways. The most common form of synaesthesia is called color-graphemic synaesthesia. People who experience this form of synaesthesia associate letters and numbers with certain colors. For example, the letter "A" might always appear to be red and the number eight might always look blue. Another common form of synaesthesia is chromesthesia: the association of sounds with colors. Some people who experience this phenomenon see bursts of color when they hear everyday sounds, such as dogs barking or water dripping. Others associate specific colors with different musical notes. Although scientists do not yet understand what causes some people to experience synaesthesia, some researchers argue for something called the cross-activation theory. This theory suggests that the regions of the brain responsible for interpreting information from the different senses have become "crossed," that is, the neurons from one sense inadvertently activate the neurons from another sense. There is also evidence to suggest that synaesthesia is a genetic trait. While there is no treatment for synaesthesia, there is also not much demand for a treatment; most synaesthetes report that they find their condition rather pleasant. Question: What is the author's purpose in writing this passage?

Women in Clinical Trials When new drugs or medical procedures are ready to be tested on human subjects, researchers find volunteers for clinical trials. However, far more men than women are used as subjects during these trials. It was widely assumed for many years that women and men would respond to medication in the same way. Therefore, it did not seem to matter whether men or women were participating in clinical trials. Because of this, researchers mostly drew from pools of male volunteers because they were perceived to be more low-risk (and accordingly, less expensive to include in a trial). Women who are pregnant, nursing, post-menopausal or even simply of childbearing age are considered too "risky" to participate in clinical trials. These parameters essentially eliminate all women. However, it is difficult to determine whether this decision to eliminate women was made out of beneficence or paternalism. The main problem with this gender discrepancy is that men and women are physiologically different. Their bodies process medications and respond to treatments differently. The over-representation of men in clinical trials has impeded the progress of understanding how new medications will affect women. Question: Which of the following can be inferred based on information in the passage?

Lactose Intolerance Lactose intolerance is the inability to digest a sugar called lactose in milk and other dairy products. Adults in most of the world are lactose intolerant, although infants are not. This is because many adults lack an enzyme known as lactase. Lactase, which can be found in cells in the intestine, is the enzyme that breaks down lactose. Many individuals lose the ability to synthesize lactase after age six. However, not everyone does. Whether or not the body continues to produce lactase often depends on ethnicity. While only 5-15% of adults of European descent cannot digest lactose, 80-90% of adults of African and Asian descent are lactose intolerant. Research has shown that people of northern European ancestry contain a genetic mutation that allows the secretion of lactase in adulthood. The main symptom of lactose intolerance is gastrointestinal upset. Lactose intolerant people may experience diarrhea, bloating, abdominal pain, gas, and vomiting after consuming lactose-containing foods and beverages. Although there has been some research into gene therapy as a treatment for lactose intolerance, the current best treatment is either ingesting lactase supplements when consuming dairy products or simply avoiding foods containing lactose altogether. Question: Which of the following is NOT true about lactose intolerance?

Does Low Body Temperature Cause Illness? As children, we are often told to dress warmly in the winter so we do not get sick. This is a common piece of advice, but is there any truth behind it? In fact, there is no scientific evidence to suggest that being cold can get you sick. Most illnesses are caused by viruses and bacteria. Illnesses like strep throat, influenza, and the common cold are only spread through contact with other infected people. How cold you are when you come into contact with the virus or bacteria has nothing to do with whether or not you will get sick. The effect of body temperature on contracting illness was tested on human beings in the 1950s. Researchers divided volunteers into two groups: half of them were kept in a warm room and the other half were kept in a cold room. Both groups were then exposed to rhinovirus-the virus responsible for the common cold. The researchers discovered that members of both groups developed colds at the same rate. Since that first experiment, there have been similar experiments performed with a variety of different illnesses. All have yielded the same result: being cold does not make a person more likely to get sick. Of course, it does seem that people do get sick more often when the weather is cold. However, this is because there is some evidence that people do get sick more often in cold weather, but it has nothing to do with forgetting to bundle up when it is chilly. When it is cold outside, people tend to stay inside. With so many people gathered closely together indoors, germs are spread more easily. Germs are spread from person to person, regardless of how cold or warm their bodies are. What is a potential reason as to why the author opened the passage with a childhood reference and a question?