which valve prevents backflow into the atrium when ventricles contract

ATI TEAS 7

ATI TEAS Science Practice Test

1. Which valve prevents backflow into the atrium when the ventricles contract?

A. Pulmonary valve
B. Tricuspid valve
C. Mitral valve
D. Aortic valve

Correct answer: B

Rationale: The tricuspid valve (right atrioventricular valve) prevents backflow into the right atrium when the right ventricle contracts. This valve ensures that blood flows in the correct direction, preventing regurgitation into the atrium. The pulmonary valve is responsible for preventing backflow into the right ventricle from the pulmonary artery. The mitral valve prevents backflow into the left atrium, and the aortic valve prevents backflow into the left ventricle from the aorta. Therefore, the correct answer is the tricuspid valve as it specifically addresses the scenario of backflow into the atrium during ventricular contraction.

2. Which of the following is a characteristic phenomenon associated with Cherenkov radiation?

A. Alpha particle emission
B. Beta particle emission
C. Gamma ray emission
D. Charged particles exceeding the speed of light in a medium

Correct answer: D

Rationale: Cherenkov radiation is produced when charged particles travel through a medium at speeds greater than the speed of light in that medium. It is not specific to a particular type of particle emission but rather to the speed of the charged particles. This phenomenon results in the emission of a characteristic blue light, which is a visual indicator of charged particles exceeding the speed of light in that medium. Choices A, B, and C are incorrect because Cherenkov radiation is not limited to a specific type of particle emission but is based on the speed of the charged particles relative to the speed of light in the medium.

3. What function do ribosomes serve within the cell?

A. Ribosomes are responsible for cell movement.
B. Ribosomes aid in protein synthesis.
C. Ribosomes help protect the cell from its environment.
D. Ribosomes have enzymes that help with digestion.

Correct answer: B

Rationale: Ribosomes serve a crucial role in protein synthesis by translating mRNA into proteins. They are not involved in cell movement, protecting the cell from the environment, or aiding in digestion. Choice A is incorrect because ribosomes are not responsible for cell movement. Choice C is incorrect because ribosomes do not primarily protect the cell from its environment. Choice D is incorrect because ribosomes do not have enzymes that aid in digestion.

4. As a water wave approaches a shallow beach, what happens to its speed, wavelength, and frequency?

A. Speed increases, wavelength decreases, frequency increases.
B. Speed decreases, wavelength decreases, frequency remains the same.
C. Speed increases, wavelength increases, frequency decreases.
D. Speed, wavelength, and frequency remain the same.

Correct answer: B

Rationale: As a water wave approaches a shallow beach, the speed of the wave decreases due to the change in medium from deep to shallow water. According to the wave equation (speed = frequency x wavelength), if the speed decreases and the frequency remains the same, the wavelength must also decrease to maintain the equation balanced. This phenomenon occurs due to the wavefronts being slowed down by the shallower water, causing the wavelength to decrease while the frequency remains constant. Choice A is incorrect as the speed of the wave decreases in shallow water. Choice C is incorrect because the speed increases in deep water, not in shallow water. Choice D is incorrect as all the wave characteristics change when moving from deep to shallow water.

5. During normal breathing, which muscle is the primary driver of inhalation by contracting and flattening to increase the volume of the thoracic cavity?

A. Diaphragm
B. Intercostal muscles
C. Abdominal muscles
D. Pectoral muscles

Correct answer: A

Rationale: The diaphragm is the primary muscle responsible for inhalation during normal breathing. When it contracts, it flattens, increasing the volume of the thoracic cavity and creating a negative pressure that allows air to flow into the lungs. Intercostal muscles also play a role in expanding the chest cavity during inhalation, but the diaphragm is the main driver of the process. Abdominal muscles are primarily involved in exhalation by pushing the diaphragm upward to expel air from the lungs. Pectoral muscles are involved in movements of the arms and shoulders, not in breathing, making them incorrect choices for this question.