ATI TEAS Science Practice Test

Correct Answer: C

Rationale: Efferent fibers, which carry motor commands, exit the spinal cord through the ventral aspect, also known as the anterior aspect. The correct answer is C, 'Through the ventral aspect.' Efferent fibers exiting through the ventral aspect are responsible for carrying motor commands from the spinal cord to the muscles and glands. Choices A, B, and D are incorrect. Efferent fibers do not exit through the dorsal, lateral, or anterior aspects of the spinal cord.

Correct Answer: A

Rationale: The correct answer is A: Negative feedback loop. Negative feedback loops work to inhibit the stimulus or reduce the deviation from a set point, maintaining homeostasis by counteracting any changes from the norm. In this case, the negative feedback loop acts to minimize any deviation from the body's internal balance, ensuring stability and optimal functioning. Choice B, a positive feedback loop, amplifies the stimulus or deviation, moving systems away from homeostasis. Choice C, an inhibitory feedback loop, is not a commonly recognized term in the context of feedback mechanisms. Choice D, a stimulating feedback loop, is not a standard term and does not accurately describe a feedback loop's role in maintaining homeostasis.

Correct Answer: C

Rationale: The correct answer is C: Parathyroid glands. The parathyroid glands are responsible for regulating calcium levels in the body. They produce parathyroid hormone (PTH), which helps control calcium levels in the blood by acting on the bones, kidneys, and intestines. The other options, such as the osteotoid gland, pineal gland, and thymus gland, do not play a significant role in calcium regulation. The osteotoid gland is a fictitious term, the pineal gland is involved in regulating sleep-wake cycles and producing melatonin, and the thymus gland is part of the immune system and plays a role in T-cell maturation.

Correct Answer: C

Rationale: Most of the chemical digestion occurs in the small intestine. Enzymes in the small intestine break down nutrients into smaller molecules that can be absorbed by the body. The stomach plays a role in digestion by breaking down food mechanically and initiating some chemical digestion, but the majority of nutrient breakdown and absorption happens in the small intestine. The large intestine mainly absorbs water and salts, with little to no digestion taking place there. The esophagus is a muscular tube that helps move food from the mouth to the stomach and does not participate in digestion.

Correct Answer: A

Rationale: The correct answer is A: Sagittal/Median Plane. This plane divides the body into left and right halves. The Frontal/Coronal Plane (choice B) divides the body into front and back, while the Transverse/Cross-Section Plane (choice C) divides it into top and bottom. The Horizontal Plane (choice D) divides the body into upper and lower portions. Understanding these planes is essential in anatomy as they help describe the orientation and relationships of body structures.