ATI TEAS Practice Science Test

Correct Answer: C

Rationale: The correct answer is C: Hypothalamus. The hypothalamus is a major structure of the limbic system responsible for regulating various essential functions like emotions, behavior, and physiological processes. It plays a crucial role in the control of thirst, hunger, body temperature, and hormonal regulation. The brainstem (A) is involved in basic life functions like breathing and heart rate, but it is not a part of the limbic system. The spinal cord (B) primarily functions in transmitting sensory and motor signals but is not directly related to the limbic system. The cerebral cortex (D) is responsible for higher-order thinking, sensory processing, and motor functions but is not a major structure of the limbic system.

Correct Answer: A

Rationale: The correct answer is A: Artificial/active immunity. The MMR vaccine provides artificial immunity because it is a vaccine created in a laboratory rather than acquired naturally. It induces active immunity by stimulating the body to produce its antibodies against measles, mumps, and rubella. This type of immunity is long-lasting and provides protection by training the immune system to recognize and fight off these diseases in the future. Choice B (Artificial/passive) is incorrect because passive immunity involves receiving pre-formed antibodies rather than activating the immune system to produce its antibodies, which is the case with the MMR vaccine. Choice C (Natural/active) is incorrect because natural immunity is acquired through exposure to the actual disease, not through vaccination. Choice D (Natural/passive) is incorrect because natural passive immunity is passed from mother to baby through breast milk or placenta, not through vaccination.

Correct Answer: B

Rationale: The correct answer is B because endocrine glands release hormones directly into the bloodstream. Therefore, an extensive network of blood vessels is necessary to facilitate the direct release of hormones into the blood for systemic circulation. The other choices are incorrect because: A: Filtering waste from the blood is the function of the kidneys, not the endocrine glands. C: Blood does not "empty" into the endocrine system; rather, hormones are released into the bloodstream. D: Endocrine glands do not filter waste; instead, they produce and release hormones into the blood for various physiological functions.

Correct Answer: B

Rationale: The correct answer is B: Ribcage. The ribcage is a bony structure that surrounds and protects the lungs. It consists of ribs, sternum, and thoracic vertebrae, forming a protective cage around the vital organs in the thoracic cavity. The ribs provide a barrier against external forces and help maintain the shape and integrity of the lungs. The other choices are incorrect because the femur is a bone in the leg, the scapula is a bone in the shoulder, and the skull protects the brain, not the lungs.

Correct Answer: A

Rationale: The correct answer is A: Diffusion. Gas exchange in the respiratory system occurs through diffusion, where oxygen moves from the alveoli in the lungs to the blood and carbon dioxide moves from the blood to the alveoli. This process is driven by a concentration gradient, allowing for the exchange of gases between the air and blood. Exhalation (choice B) is the process of expelling air from the lungs, not the mechanism of gas exchange. Inspiration (choice C) is the process of inhaling air into the lungs, but it is not directly involved in gas exchange. Ventilation (choice D) refers to the movement of air into and out of the lungs and is necessary for gas exchange to occur but is not the actual mechanism of gas exchange itself.