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What is the purpose of the chordae tendineae?

The effective functioning of the heart depends on the chordae tendineae opening and closing the flaps of the mitral and tricuspid valve at regular intervals. This ensures constant blood flow between the chambers of the heart and between the heart and the rest of the body. The left ventricle receives oxygen-rich blood from the left atrium through the mitral valve and sends it out into the body. Conversely, the right ventricle receives deoxygenated blood from the right atrium through the tricuspid valve and sends it to the lungs for oxygenation. Blood leaves the heart via the pulmonic and aortic..

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What is blood spatter analysis?

Analysts gather evidence by taking thorough photos and collecting samples for lab testing. They can also set up detailed reconstructions at the crime scene by tying lines of string to trace the spatter angles back to the areas of convergence, or the areas where each blow was initiated. A successful analysis can yield significant information, such as the positions of the victim and attacker, the approximate time when the crime occurred, the number of blows, and whether the attacker was left- or right-handed.

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What type of plate boundary is Mount St. Helens?

The Pacific Plate, the North American Plate and the much smaller Juan de Fuca plate all converge at the Cascade Range in an area known as a triple plate junction. This phenomenon causes very complex interactions between the plates, which is part of what experts believe to have contributed directly to the sudden and violent nature of the Mount St. Helens 1980 eruption, which resulted in 123 deaths.

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What is a laboratory observation?

In a laboratory observation study, the researcher ensures he will be present at the time he wants to observe and record data regarding the subjects. In this setting the researcher is able to observe behaviors that he is unable to observe using the subject's natural environment. However, this artificial setting introduces concerns that the behaviors observed might never happen outside the lab.\nAnother option for the social scientist is to complete the study in the subject's natural environment. The researcher observes subjects' behaviors in the setting where they normally occur...

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How do you explain the relationship between fronts and low pressure systems?

As a warm air mass collides with a cold air mass, the warmer air is less dense and rises to a higher altitude. As it reaches the higher level, it cools, resulting in a lower dew point. The cooling causes the formation of precipitation, most of the time in the form of rain. However, if the temperatures are cold enough, the moisture crystallizes to form snow. If the advancing cold front is above the ground, precipitation forms before the temperatures change at ground level.\nDuring certain times of the year in the United States warm fronts overtake cold fronts. In these cases, the warm air still..

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What is a 555 timer?

The 555 timer gets its name from a set of three resistors in its circuitry, each having a value of 5,000 ohms. The chip has three modes or ways it can be used: monostable, astable and bistable. Each mode generates pulses used by engineers to build circuits such as game paddles, tachometers and waveform generators. The 555 timer is also used by hobbyists in designing fun projects such as metronomes and toy organs.

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What is a match made of?

While there are three necessary ingredients to make a match work, there are other secondary ingredients that have been added to modern matches. For instance, ammonium phosphate is put into the matchstick wood to stifle afterglow once the flame dies. The stick is also bathed in hot paraffin wax to ensure that the flame burns down past the head of the stick, and powdered glass inside the head provides increased friction to aid in striking.

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How can you protect the ozone layer?

Over time, the ozone layer has begun depleting due to man-made chemicals and emissions from vehicles and large appliances. Because of the damage to this extremely important atmospheric shield, Congress passed the Clean Air Act in 1990. The Clean Air Act required companies to stop producing products that damaged the ozone layer. One of these products is chlorofluorocarbons, or CFCs. These were used in a variety of products and caused significant damage to the ozone layer.\nEven though the Clean Air Act regulates the use of chemicals that are harmful to the ozone layer, damage still occurs becau..

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Is there a connection between height and pulse rate?

The NCBI abstract states that the body weight and height of the test subjects have a significant positive correlation to the left ventricular and left atrial dimension as shown in the echocardiographic results. The American Heart Association clarifies that the pulse rate is not correlated to blood pressure. This means that it is not possible to know if a person has high blood pressure or low blood pressure just by measuring pulse rate.

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Can you live without your gall bladder?

While not all gallbladder surgery is vital, some conditions such as acute cholecystitis, or inflammation of the gallbladder, may cause abscesses or gangrene if left untreated, causing septicemia in 20 percent of cases, according to the University of Maryland Medical Center. This is deadly if left untreated, causing the body to go into septic shock.\nTypical gallbladder pain occurs in the upper right side of the abdomen after eating, although acute inflammation causes symptoms such as severe pain and fever, accompanied by nausea and vomiting. More than 600,000 surgeries to remove the gallbladde..

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