ATI TEAS Practice Science Test

Correct Answer: A

Rationale: The correct answer is A: ATP. ATP (adenosine triphosphate) is required to drive the sliding filament process during muscle contraction by providing energy for the myosin heads to bind to actin and generate movement. ATP is directly involved in the process of cross-bridge formation and power stroke. Hormones (B) do not directly drive muscle contraction. Potassium (C) is involved in muscle cell excitability but not in the sliding filament process. Water (D) is not directly involved in muscle contraction.

Correct Answer: A

Rationale: The correct answer is A: Cranial and spinal. The dorsal cavity is divided into two subdivisions: the cranial cavity, which contains the brain, and the spinal cavity, which houses the spinal cord. This division corresponds to the anatomical locations of these structures within the back of the human body. Explanation: 1. The cranial cavity is located in the skull, specifically protecting the brain. 2. The spinal cavity runs through the vertebral column, safeguarding the spinal cord. 3. These subdivisions are anatomically and functionally distinct, housing vital components of the central nervous system. Summary: B: Dorsal and ventral - Incorrect. Dorsal and ventral refer to the front and back sides of the body, not specific cavities within the back. C: Lateral and proximal - Incorrect. Lateral and proximal describe directions in relation to the body, not cavities within the back. D: Inferior and superior - Incorrect. Inferior and superior

Correct Answer: D

Rationale: The correct answer is D: Melanocyte-stimulating hormone. Melanocyte-stimulating hormone stimulates the melanocytes in the skin to produce melanin, the pigment responsible for skin color. This hormone darkens the skin by increasing melanin production. A: Follicle-stimulating hormone is involved in reproductive functions, not skin color changes. B: Growth-stimulating hormone primarily affects growth and development, not skin color. C: Thyroid-stimulating hormone regulates thyroid function, not skin color.

Correct Answer: B

Rationale: The purpose of an electrocardiogram (ECG) is to display the heart's rate and rhythm. It measures the electrical activity of the heart, showing how well it is functioning. By analyzing the ECG waveform, healthcare providers can assess the heart's health, detect any abnormalities, and diagnose various heart conditions. It provides crucial information about the heart's electrical impulses, such as the heart rate, rhythm, and any potential irregularities like arrhythmias. Therefore, choice B is correct. Choices A, C, and D are incorrect because an ECG does not indicate the rate of blood flow, identify a person's blood group type, or determine cell type in a blood sample.

Correct Answer: C

Rationale: The correct answer is C: Paracrine. This is because somatostatin is a chemical signal that acts locally on neighboring cells within the pancreas to inhibit insulin secretion. Paracrine signals are released by one cell and act on nearby cells of the same tissue. Autocrine signals act on the same cell that produced them, which is not the case here. Neuromodulators modulate the activity of neurons, not endocrine cells like in this scenario. Pheromones are chemical signals that are used for communication between individuals of the same species, not within the same organism like in this case.