Electrocardiogram
Beep!âĂ¬Ā¦Beep!âĂ¬Ā¦Beep! is the audible rhythmic sound made as the strength of the heart muscle is measured. The signal cadence has a characteristic record that varies in every individual. This record is called an electrocardiogram, or ECG.
In the body, an array of systemic neural responses constantly occur, emitting electric currents. The electric currents can be detected on the surface of the body, and if a person is hooked to an amplifier, these impulses are recorded by an electrocardiograph.
Most of the information obtained is about the heart because the heart sends out electric currents in waves. This âĂ¬Å“wave of excitationâĂ¬Ā¯ spreads through the heart wall and is accompanied by electric changes. The wave takes place in three distinct steps.
Initially, the âĂ¬Å“wave of excitationâĂ¬Ā¯ accompanied by an electric change lasts for approximately 1 to 2 seconds after the contraction of the cardiac muscle. The electric impulses are discharged rhythmically from the sinoatrial (SA) node, the pacemaker of the heart. This spread of excitation over the muscle of the atrium indicates that the atrium has contracted.
Next, the peak of the ECG reading is due to the atrioventricular (AV) node, causing the ventricle to become excited.
Finally, the ventricles relax, and any changes in the wave indicate to trained medical staff any abnormalities within the heart.
What is the best summary of the passage?
- A. Electric currents within the body result from the heart's electrostatic charges. Trained medical staff can identify heart abnormalities.
- B. Each individual exhibits unique electric currents on the body's surface, which the ECG records and measures.
- C. The ECG systematically captures the stages of the 'wave of excitation' within the heart, originating from the SA node to the AV node, in three distinct steps.
- D. The ECG records the body's electric currents, detectable on the body's surface through an amplifier.
Correct Answer: C
Rationale: The passage discusses how the electrocardiogram (ECG) measures the 'wave of excitation' in the heart, detailing the three distinct steps from the SA node to the AV node. Option A is incorrect as it oversimplifies the process and does not focus on the ECG's specific function. Option B is partially correct but lacks the key point about the stages of excitation and the nodes involved. Option D is too general and does not highlight the specific process of the 'wave of excitation' as explained in the passage. Therefore, Option C is the best summary as it accurately reflects the systematic measurement and recording of the 'wave of excitation' within the heart by the ECG.
You may also like to solve these questions
Centuries ago, in the country of Siam, now known as Thailand, it was the custom of the rulers
that displeased them by giving the offender a white elephant. Because the animal was could not
be made to work as other elephants did, but still had to be fed hundreds of pounds of fruit and cared for in the most lavish style. The recipient could not give the elephant to anyone else, as it was the ruler, who would be greatly displeased should the recipient not receive the gift graciously or care for in a grand style. This monetary burden could be a major liability to the
recipient and in many cases they became impoverished.
This is the origin of the term "white elephant" as it is used today to denote an unwanted gift. The way of gift exchange played during the holiday season is an offshoot of this. In this game, everyone brings, and the gifts are exchanged by drawing numbers and picking a gift in turn. The
second person can choose or steal the first one. It is all in good fun, and people enjoy giving silly
gifts and "stealing" someone else.
What is implied by the article?
- A. Siam was renamed Thailand in the past.
- B. People enjoy giving and receiving gifts.
- C. The author dislikes parlor games.
- D. Elephants are easy to take care of and train.
Correct Answer: B
Rationale: The correct answer is B: 'People enjoy giving and receiving gifts.' The passage discusses the custom of giving unwanted white elephants as gifts in ancient Siam, leading to financial burdens for the recipients. It then transitions to how the term 'white elephant' is used today to denote an unwanted gift and mentions a gift exchange game played during the holiday season. The passage emphasizes the enjoyment people have in giving and receiving gifts, as seen in the holiday gift exchange game described, rather than focusing on disliking parlor games or the ease of taking care of elephants.
Mr. Rogers' Biography
"It's a wonderful day in the neighborhood!" This familiar line always began the Mister Rogers' Neighborhood program on PBS. The amazing Fred Rogers brought a special message to children around the world. He believed that each person is unique and wonderful in his or her own way and we should accept others just the way they are without trying to change or improve them. Mr. Rogers spread his tolerance message far and wide through the daily broadcasts of his television show, his many books, and finally after his retirement through his website specifically designed for children. Through these venues, Mr. Rogers helped children deal with the real world things that bothered them, such as doctor visits, haircuts, and new siblings.
Fred Rogers left a legacy of kindness, acceptance, and an unending love of learning for all generations
Why did the author write the passage?
- A. He wanted to criticize Fred Rogers' methods.
- B. He aimed to entertain readers with fictional stories.
- C. He wanted to inform readers or the audience about Fred Rogers.
- D. He sought to compare Fred Rogers to other television personalities.
Correct Answer: C
Rationale: The correct answer is C. The passage provides information about Fred Rogers, his beliefs, his impact on children through his television show, books, and website, as well as his legacy of kindness, acceptance, and love of learning. The author's intent was to inform readers or the audience about Fred Rogers and the positive messages he shared. This is evident from the content focusing on Mr. Rogers' messages, his outreach to children, and the legacy he left behind.
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.
What is produced in the Calvin cycle during photosynthesis?
- A. ATP
- B. Glucose
- C. Water
- D. Oxygen
Correct Answer: B
Rationale: During the Calvin cycle, which is the second stage of photosynthesis, the primary product produced is glucose. The Calvin cycle utilizes the ATP and NADPH generated in the light-dependent reactions to convert carbon dioxide into glucose, a simple sugar. Glucose serves as a vital energy source for the plant and is also essential for the growth and development of the organism. Therefore, the correct answer is option B, 'Glucose.' Options A, C, and D (ATP, Water, and Oxygen) are not the direct products of the Calvin cycle but play important roles in different stages of photosynthesis.
It is a well-known fact that it takes the Earth approximately 365 days to orbit the Sun. At the same time, the Earth revolves or spins around itself over the course of 24 hours, which explains why we experience day and night. One half of the Earth is always facing the Sun, while the other half is facing away. As a result, different time zones divide the globe. Moving suddenly from one time zone to another, such as when flying from Asia to North America, can cause jet lag. People often feel tired, wake up suddenly during the night, and cannot return to sleep. It takes time to adjust to a new time zone. Another important factor to consider is the slight tilt of the Earth toward the Sun. The Earth does not stand straight but leans slightly to one side. Therefore, when it revolves around the Sun, the middle part of the Earth is always closer to the Sun and receives more heat. This area is called the equator, and the regions above and below it are known as the tropics. Countries located in the tropics receive a consistent amount of daylight throughout the year, with the Sun rising at 6 AM and setting at 6 PM. In contrast, the tips of the Earth, or the poles, receive hardly any light because they are so far from the Sun. There are two main seasons at the poles: 6 months of summer, when the Sun is always shining (even at night), and 6 months of winter, characterized by constant darkness. Between the tropics and the poles lies the temperate zone, where there are four distinct seasons. The Sun rises and sets at different times throughout the year. In spring and summer, it gets light earlier; in fall and winter, it gets dark earlier. People living in temperate zones take advantage of this variation to maximize their daylight exposure. At the beginning of spring, countries in Europe and North America readjust their clocks by moving them an hour ahead. As a result, the Sun does not set around 7 or 8 PM as usual, but an hour later. This practice is called Daylight Savings Time (DST) and lasts until the beginning of fall, when people move their clocks back one hour to Standard or Regular Time. It is believed that Benjamin Franklin first suggested the introduction of Daylight Savings Time in the 18th century, but the first serious proposal came in 1907 from William Willet. However, his idea was shelved by the British government, which deemed it unnecessary. Daylight Savings Time was first implemented by the German government in 1916 in order to save energy during World War I. Shortly after, the United Kingdom followed suit, with the United States doing the same in 1918. The law was unpopular, as people had to wake up earlier, leading many to experience a feeling similar to jet lag. However, the energy crisis of the 1970s forced the U.S. to establish Daylight Savings Time as law. Studies showed that the introduction of Daylight Savings Time in the spring saved the U.S. 10,000 barrels of oil per day between 1974 and 1975. It also prevented 2,000 traffic injuries and 50 traffic-related deaths, saving the country $28 million. Currently, Americans switch to Daylight Savings Time on the first Sunday in April and revert to Standard Time on the last Sunday in October. As of 2007, the time adjustments occur even earlier in March and November.
Which part of the Earth is closest to the Sun?
- A. The Equator
- B. The tropics
- C. The temperate zone
- D. The Poles
Correct Answer: B
Rationale: The correct answer is B: The tropics. The text explains that the middle part of the Earth, known as the equator, is always closer to the Sun and receives more heat. This area is surrounded by the tropics. Countries at the tropics experience the same amount of daylight throughout the year, with the sun rising at 6 am and setting at 6 pm. In contrast, the Poles (answer D) receive hardly any light due to their distance from the sun, experiencing 6 months of constant darkness in winter. The temperate zone (answer C) lies between the tropics and the Poles, experiencing 4 seasons with varying daylight hours throughout the year. Therefore, the tropics are the part of the Earth closest to the Sun.
The ebb and flow of laughter and silence fills the room as four old friends gather to engage in a
round of Bridge playing. For the beginner, Bridge can be complicated, but with time, effort, and a good teacher, even the novice can become proficient. Composed of two main parts, bidding and playing, Bridge requires the player's undivided attention. The dealer deals the entire deck of playing cards evenly between the for players, with
each person receiving thirteen cards. In the bidding portion of the game, the four suits of cards in the deck are ranked highest to lowest as follows: spades, hearts, diamonds, and finally clubs. However, during play all the suits of cards are
considered equals, and they go from highest to lowest from the ace being high to the two cards
being low. The highest number of tricks wins. A trick is one card played by each player for a
total of four. After the lead player lays down his/her card, the other players follow suit, if
possible. The highest card within the four "same suit" cards played wins the trick and picks up all
four cards. If a player cannot follow suit, he/she plays any card, but to make the game more
interesting and challenging, one suit is named a trump suit which means that if a player plays a
card from the trump suit, it always wins the trick. If two cards from the trump suit are played, the
highest card within the trump suit wins the trick. Obviously, the team with the most tricks wins
the hand.
The passage implies that
- A. Playing bridge requires concentration.
- B. Bridge is an extremely easy game to play.
- C. Bridge is only for older people.
- D. Bridge is only for women.
Correct Answer: A
Rationale: The correct answer is A: 'Playing bridge requires concentration.' The passage mentions that Bridge requires the player's undivided attention, indicating that concentration is necessary to play the game effectively. The intricate details provided about the rules and gameplay of Bridge emphasize the need for focus and mental engagement. While the passage does not suggest that Bridge is easy or exclusively for older people or women, it highlights the complexity and attention required to excel in the game.
Nokea