what is the main function of the respiratory system

ATI TEAS 7

TEAS Practice Test Science

1. What is the main function of the respiratory system?

A. To absorb nutrients
B. To exchange gases
C. To transport oxygen
D. To regulate blood pressure

Correct answer: B

Rationale: The main function of the respiratory system is to exchange gases, primarily oxygen and carbon dioxide, between the body and the environment. Option A, 'To absorb nutrients,' is incorrect because the respiratory system is not involved in nutrient absorption. Option C, 'To transport oxygen,' is partially correct, but it doesn't encompass the complete role of gas exchange that includes both oxygen and carbon dioxide. Option D, 'To regulate blood pressure,' is incorrect as blood pressure regulation is primarily controlled by the cardiovascular system, not the respiratory system.

2. All of the following are parts of the respiratory system EXCEPT the:

A. Trachea
B. Bronchi
C. Esophagus
D. Larynx

Correct answer: C

Rationale: The esophagus is part of the digestive system, not the respiratory system. The trachea, bronchi, and larynx are all components of the respiratory system responsible for the passage of air during breathing and speech production. The esophagus, on the other hand, is part of the digestive system, responsible for the transportation of food from the mouth to the stomach through a series of muscular contractions called peristalsis. Therefore, the correct answer is 'Esophagus (C).' Choices A, B, and D are all integral parts of the respiratory system, playing crucial roles in the airway and vocalization processes.

3. Which statement is true about the pH of a solution?

A. A solution cannot have a pH less than 0.
B. A solution always has a pH of 7.
C. A solution's pH is not influenced by its chemical composition.
D. A solution with a pH of 14 is considered acidic.

Correct answer: A

Rationale: The pH scale ranges from 0 to 14, with 0 being the most acidic, 7 neutral, and 14 the most basic. A solution with a pH less than 0 would be outside the defined pH range, as 0 is the lower limit. Therefore, a solution cannot have a pH less than 0. Choice B is incorrect because a pH of 7 is considered neutral, not always the pH of a solution. Choice C is incorrect because a solution's pH is influenced by its chemical composition. Choice D is incorrect as a solution with a pH of 14 is considered highly basic, not acidic.

4. Which of the following enzymes unwinds the double-stranded DNA during replication?

A. Helicase
B. Ligase
C. Nuclease
D. Polymerase

Correct answer: A

Rationale: Helicase is the enzyme responsible for unwinding the double-stranded DNA during replication by breaking the hydrogen bonds between the base pairs. This process creates the replication fork where DNA polymerase can then synthesize new DNA strands. Ligase functions to join Okazaki fragments on the lagging strand, not unwind DNA. Nuclease is involved in DNA repair by removing damaged DNA segments. Polymerase is responsible for synthesizing new DNA strands based on the existing template strands, not for unwinding the DNA.

5. What is the pathway of oxygenated blood from the lungs?

A. Lungs to the left atrium, through the mitral valve into the left ventricle, pumped into the aorta upon contraction, then dispersed to tissues via a network of arteries and capillaries
B. Lungs to the right atrium, through the mitral valve into the right ventricle, pumped into the aorta upon contraction, then dispersed to tissues via a network of arteries and veins
C. Lungs to the left atrium, directly to the right aorta, then dispersed to tissues via a network of arteries and capillaries
D. Lungs to the left atrium, through the septal valve, stored in the left ventricles, then dispersed to tissues via a network of arteries and capillaries

Correct answer: A

Rationale: The correct pathway of oxygenated blood from the lungs is as follows: Oxygenated blood travels from the lungs to the left atrium, then passes through the mitral valve into the left ventricle. From there, it is pumped into the aorta upon contraction of the heart and is then dispersed to various tissues throughout the body via a network of arteries and capillaries. Choice B is incorrect as it incorrectly mentions the right atrium and ventricle, which are associated with deoxygenated blood. Choice C is incorrect as it mentions a direct connection to the right aorta, which does not exist in the circulatory system. Choice D is incorrect as it refers to the septal valve (which is not anatomically correct) and storing blood in the left ventricle, which does not occur in the normal circulation of blood.