Nokea
Blood Pressure Regulators The body is composed of systems that have evolved and diversified in order to maintain the natural functions and processes they regulate. One such system that has these regulators is the body’s cardiovascular system. The body’s pump, which regulates the flow of vitally needed oxygen to all cells of the body, as well as the discard of carbon dioxide and other waste products, is the heart. Because blood pressure varies at different points within the body, differing components are needed to keep the body’s blood pressure regulated. Three of the basic components are baroreceptors, chemoreceptors, and the kidneys. Baroreceptors are stretch receptors composed of fine branching nerve endings and are contained along the walls of the arteries near the heart and in other areas of the body as well. Impulses are related to this stretching along the arterial walls, which causes these baroreceptors to send out even more impulses to the heart, arteries, and veins, causing the blood pressure to go either up or down. Chemoreceptors are located along the walls of the arteries and monitor changes in oxygen level, carbon dioxide, and pH. Just think! A fall in oxygen causes receptors to send impulses to raise the blood pressure. The kidneys play a role in regulating blood pressure by absorbing salts and water and removing wastes. Hormones secreted by the adrenal cortex cause the kidney to keep or let go of any salt and water. This has an influence on blood volume and consequently on blood pressure.
What does the word 'evolved' mean in the first paragraph?
- A. To spread
- B. To gradually develop
- C. To revolve
- D. To shift
Correct Answer: B
Rationale: The term 'evolved' in the context of the first paragraph means 'to gradually develop.' The sentence refers to the systems in the body evolving and diversifying over time to maintain natural functions. Evolution implies a gradual process of development and change over time, making choice B the correct answer.
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Electrocardiogram
The rhythmic sounds of "beep... beep... beep..." signify the measurement of the heart muscle's strength. This rhythmic signal varies from person to person and is recorded as an electrocardiogram (ECG). Within the body, a complex array of systemic neural responses generates electric currents that can be detected on the skin's surface. When a person is connected to an amplifier, these impulses are captured by an electrocardiograph. Most of the information gathered pertains to the heart, as it emits electric currents in waves. This "wave of excitation" propagates through the heart wall and is associated with electrical changes. The process occurs in three distinct phases. First, the "wave of excitation," accompanied by an electrical change, lasts for about 1 to 2 seconds following the contraction of the cardiac muscle. These electrical impulses are rhythmically discharged from the sinoatrial (SA) node, which acts as the heart's natural pacemaker, signaling the atrium to contract. The peak of the ECG reading is attributed to the atrioventricular (AV) node, which triggers the excitation of the ventricles. Finally, as the ventricles relax, any changes in the wave pattern can alert trained medical personnel to potential abnormalities within the heart.
What are the three phases of the "wave of excitation"?
- A. The discharge from the SA node, the peak ECG, and the excitement of the ventricle.
- B. The excitement of the ventricle, the relaxing of the ventricle, and the systemic neural response.
- C. The contraction of the atrium, the relaxation of the atrium, and the contraction of the ventricle.
- D. The excitation of the atrium, the excitement of the ventricle, and the relaxing of the ventricle.
Correct Answer: D
Rationale: The correct answer is D: 'The excitation of the atrium, the excitement of the ventricle, and the relaxing of the ventricle.' The 'wave of excitation' in the heart occurs in three main steps. Firstly, the excitation starts with the discharge from the SA node, indicating the contraction of the atrium. Secondly, the peak ECG reading is caused by the excitement of the ventricle. Lastly, the wave ends with the relaxing of the ventricle. Understanding these steps is crucial for interpreting electrocardiograms and identifying any abnormalities in the heart's electrical activity.
A BIT ABOUT BICYCLES
Today, bicycles are so common that it's hard to believe they haven't always been around. But two hundred years ago, bicycles didn't even exist, and the first bicycle, invented in Germany in 1818, was nothing like our bicycles today. It was made of wood and didn't even have pedals. Since then, however, numerous innovations and improvements in design have made the bicycle one of the most popular means of recreation and transportation around the world. In 1839, Kirkpatrick Macmillan, a Scottish blacksmith, dramatically improved upon the original bicycle design. Macmillan's machine had tires with iron rims to keep them from getting worn down. He also used foot-operated cranks like pedals, so his bicycle could be ridden at a quick pace. It didn't look much like a modern bicycle, though, because its back wheel was substantially larger than its front wheel. In 1861, the French Michaux brothers took the evolution of the bicycle a step further by inventing an improved crank mechanism. Ten years later, James Starley, an English inventor, revolutionized bicycle design. He made the front wheel many times larger than the back wheel, put a gear on the pedals to make the bicycle more efficient, and lightened the wheels by using wire spokes. Although this bicycle was much lighter and less tiring to ride, it was still clumsy, extremely top heavy, and ridden mostly for entertainment. It wasn't until 1874 that the first truly modern bicycle appeared on the scene. (14) Invented by another Englishman, H.J. Lawson, the "safety bicycle" would look familiar to today's cyclists. This bicycle had equal-sized wheels, which made it less prone to toppling over. Lawson also attached a chain to the pedals to drive the rear wheel. With these improvements, the bicycle became extremely popular and useful for transportation. Today they are built, used, and enjoyed all over the world.
About how long did it take for bicycles to look and feel like they do today?
- A. 500 years
- B. 1,000 years
- C. 53 centuries or 5,300 years
- D. 2,000 years
Correct Answer: C
Rationale: It took approximately 53 centuries or 5,300 years for bicycles to evolve and resemble the bicycles we use today. The question refers to the timeline from the first primitive bicycle in 1818 to the appearance of the first truly modern bicycle in 1874. During this period, various inventors made significant improvements in bicycle design, leading to the development of features like equal-sized wheels, pedals, chains for driving the rear wheel, and enhanced stability. These advancements culminated in the creation of a 'safety bicycle' by H.J. Lawson in 1874, which closely resembles the bicycles we are familiar with today.
All That Jazz: Jazz is an American musical art form which originated at the beginning of the 20th century in African-American communities in the Southern United States. It derived from a confluence of African and European music traditions. From its early development until the present, jazz has also incorporated music from 19th and 20th century American popular music. The word jazz began as a West Coast slang term of uncertain derivation and was first used to refer to music in Chicago in about 1915.
Improvisation is one of the key elements of jazz and a fundamental part of the nature of the music. In jazz, the skilled performer will interpret a tune in very individual ways, never playing the same composition exactly the same way twice. Depending upon the performer's mood and personal experience, interactions with fellow musicians, or even members of the audience, a jazz musician/performer may alter melodies, harmonies, or time signatures at will.
Where and when did jazz originate?
- A. Europe, 19th century.
- B. Southern US, 20th century.
- C. West Coast of U.S., 1850.
- D. Chicago, 1915.
Correct Answer: B
Rationale: The correct answer is B: Southern US, 20th century. Jazz originated in the Southern United States at the beginning of the 20th century in African-American communities, as stated in the provided extract. The confluence of African and European music traditions gave birth to jazz during this time. The other choices are incorrect for the following reasons:
A: Europe, 19th century - Incorrect, as jazz originated in the Southern US, not Europe, and specifically in the 20th century.
C: West Coast of U.S., 1850 - Incorrect, as jazz did not originate on the West Coast, but in the Southern US, and not in 1850, but at the beginning of the 20th century.
D: Chicago, 1915 - Incorrect, as Chicago was where the term "jazz" was first used to refer to music around 1915, but jazz itself had already originated in the Southern US before that time.
Photosynthesis is a process used by plants, algae, and certain bacteria to convert light energy into chemical energy stored in sugar molecules. This process is fundamental to life on Earth as it provides the primary source of energy for nearly all organisms. The energy is captured from sunlight by a pigment in the plants called chlorophyll, which gives plants their green color.
During photosynthesis, carbon dioxide from the air and water from the soil react in the presence of light to form sugars and oxygen. The oxygen is released into the atmosphere, which is crucial for the survival of most life forms on Earth. The sugars produced are used by the plant for energy and growth, storing excess energy as starch.
The process occurs in two main stages: the light-dependent reactions and the Calvin cycle. In the light-dependent reactions, energy from sunlight is absorbed by chlorophyll and converted into stored chemical energy in the form of ATP and NADPH. The Calvin cycle uses the ATP and NADPH produced in the light-dependent reactions to convert carbon dioxide into glucose.
Photosynthesis not only sustains plant life but also maintains the atmospheric oxygen levels and is a key factor in the carbon cycle, helping to regulate Earth's climate.
Which gas is crucial for the survival of most life forms and is released during photosynthesis?
- A. Nitrogen
- B. Carbon dioxide
- C. Oxygen
- D. Hydrogen
Correct Answer: C
Rationale: During photosynthesis, oxygen is crucial for the survival of most life forms and is released into the atmosphere. Oxygen is a byproduct of the photosynthetic process, where carbon dioxide and water react in the presence of light to form sugars and oxygen. This released oxygen is essential for the respiration of many living organisms, making it a critical component for their survival. Without the oxygen released during photosynthesis, many organisms would not be able to carry out cellular respiration, which is vital for their energy production and survival.
A Bit About Bicycles: Children begin to taste freedom on bicycles. Historians believe that bicycles began around 3500 B.C. in the Middle East although it took 53 centuries before bicycles were fashioned in the way we know them today.
With over 1500 moving parts, bicycles are complex yet simple machines and amazingly the basic design has not changed since the 1880s. A few tweaks have been added, such as gears and hand-operated brakes, but bicycles remain a steady source of exercise and entertainment for both children and adults. Some forms of bicycling are mountain biking and BMX biking which is similar to cross-country motorcycle racing.
In many countries around the world, bicycles are a necessary part of daily existence. Bicycling in China is imperative if you want to go places, due to the vast population in a relatively small area. Bicycles are coming back in high demand all over the world.
The author intended the reader to
- A. move to China to ride bicycles.
- B. understand a bit about the history of bicycles.
- C. use a bicycle for mountain biking.
- D. believe that bicycles are the only way to exercise.
Correct Answer: B
Rationale: The correct answer is B: understand a bit about the history of bicycles. In the given text, the author discusses the history of bicycles, mentioning their origins in the Middle East around 3500 B.C. and the evolution of bicycles over centuries. The text also highlights the complexity and simplicity of bicycles, their basic design remaining unchanged since the 1880s, and their significance in daily life worldwide. Therefore, the main intention of the author is to provide information about the history and importance of bicycles, making choice B the most appropriate. Choices A, C, and D are incorrect as they are not supported by the content of the text, which focuses on the history and significance of bicycles rather than promoting moving to China, engaging in mountain biking, or suggesting that bicycles are the only way to exercise.