which structure serves as the electrical stimulator of the cardiac muscle

ATI TEAS 7

Science TEAS Practice Test

1. Which structure serves as the electrical stimulator of the cardiac muscle?

A. The sinoatrial node
B. The left ventricle
C. The aorta
D. The tricuspid valve

Correct answer: A

Rationale: The correct answer is the sinoatrial node. This node, also referred to as the pacemaker of the heart, is responsible for initiating the electrical impulses that stimulate cardiac muscle contractions. It plays a crucial role in setting the pace and rhythm of the heart's contractions. Choices B, C, and D (the left ventricle, the aorta, and the tricuspid valve, respectively) do not serve as the primary electrical stimulator of the cardiac muscle. While the left ventricle is a chamber of the heart that pumps oxygenated blood to the body, the aorta is the main artery that carries blood away from the heart, and the tricuspid valve is a one-way valve that ensures blood flows properly through the heart, none of these structures initiate the electrical impulses that cause the cardiac muscle to contract.

2. When conducting a research study, which of the following is NOT a good reason for using a computer?

A. A computer can be used to store and sort large quantities of data.
B. Computers can interface with instruments and record data efficiently.
C. Using a computer eliminates all subjectivity and potential bias from an experiment.
D. A computer can perform complex calculations more quickly and accurately than a human can.

Correct answer: C

Rationale: Using a computer does not eliminate all subjectivity and potential bias from an experiment. While computers can assist in data collection and analysis, the design and execution of the research study can still be influenced by subjectivity and bias introduced by researchers. Researchers need to recognize their potential biases and take measures to reduce them throughout the research process. Choice A is correct as computers are valuable for managing large datasets. Choice B is correct as computers can efficiently work with instruments and record data. Choice D is correct as computers excel in performing complex calculations faster and more accurately than humans.

3. What is the significance of the nuclear envelope breaking down during mitosis?

A. It allows the chromosomes to condense and become visible.
B. It allows the spindle apparatus to form and attach to the chromosomes.
C. It allows the sister chromatids to separate.
D. It allows the nuclear material to be evenly distributed to the daughter cells.

Correct answer: B

Rationale: A) The breakdown of the nuclear envelope does not directly cause the chromosomes to condense and become visible. Chromosome condensation is a separate process that occurs before mitosis begins. B) The breakdown of the nuclear envelope is crucial for the formation of the spindle apparatus, a structure made of microtubules that helps separate the chromosomes during cell division. The spindle apparatus attaches to the chromosomes and helps move them to opposite poles of the cell. C) The separation of sister chromatids occurs during anaphase, which is facilitated by the spindle apparatus. The breakdown of the nuclear envelope is not directly involved in this process. D) The even distribution of nuclear material to daughter cells is achieved through the movement of chromosomes by the spindle apparatus, which is made possible by the breakdown of the nuclear envelope.

4. What defines the period of a wave?

A. The time it takes for one complete wave cycle to pass a point
B. The distance between two adjacent crests or troughs
C. The number of waves passing a point per unit time
D. The maximum displacement of particles in a medium due to the wave

Correct answer: A

Rationale: The period of a wave is defined as the time it takes for one complete wave cycle to pass a point. It is a crucial parameter in wave analysis and is typically measured in seconds. The period is directly related to the frequency of the wave, as they are reciprocals of each other. Therefore, the correct answer is the time it takes for one complete wave cycle to pass a point (choice A). The period is not related to the number of waves passing a point per unit time (choice C), the distance between two adjacent crests or troughs (choice B), or the maximum displacement of particles in a medium due to the wave (choice D).

5. Which of the following hormones helps regulate blood pressure by affecting kidney function?

A. Insulin
B. Testosterone
C. Renin
D. Estrogen

Correct answer: C

Rationale: Renin is the hormone that helps regulate blood pressure by affecting kidney function. It is released by the kidneys in response to low blood pressure or low blood volume. Renin plays a crucial role in the renin-angiotensin-aldosterone system, which is responsible for regulating blood pressure and fluid balance in the body. Insulin, testosterone, and estrogen do not directly impact blood pressure regulation through kidney function. Insulin is involved in regulating glucose metabolism, testosterone is a male sex hormone, and estrogen is a female sex hormone. Therefore, the correct answer is Renin (Choice C) because of its specific role in blood pressure regulation through kidney function.