ATI TEAS Science Questions

Correct Answer: B

Rationale: The correct answer is B: Capillaries. Capillaries are the smallest blood vessels that connect arterioles (small arteries) with venules (small veins). They enable the exchange of oxygen, nutrients, and waste products between the blood and tissues. Arterioles are small arteries that carry blood away from the heart, while venules are small veins that carry blood towards the heart. Veins are larger blood vessels that transport blood back to the heart. Therefore, capillaries specifically serve as the vessels responsible for the exchange of substances between the blood and body tissues.

Correct Answer: A

Rationale: The correct answer is A - Keratinocytes. The epidermis is primarily composed of keratinocytes, which are a type of epithelial cell. Keratinocytes synthesize the protein keratin, providing protection against physical damage and water loss. While epithelial cells are correct, specifying keratinocytes is more precise. Fibroblasts are not the main cell type in the epidermis; they are found in the dermis, where they produce collagen and other extracellular matrix components. Melanocytes are responsible for producing melanin pigment in the skin and are also present in the epidermis, but they are not the predominant cell type like keratinocytes.

Correct Answer: B

Rationale: The correct answer is B: White blood cell. White blood cells are the primary cells responsible for fighting infections and foreign invaders in the body. Red blood cells carry oxygen to tissues, platelets help in blood clotting to prevent excessive bleeding, and plasma is the liquid component of blood that carries cells and nutrients. White blood cells, also known as leukocytes, play a crucial role in the immune system by identifying and destroying pathogens, such as bacteria, viruses, and other harmful substances. Therefore, they are the key players in the body's defense against infections, making them the correct answer in this scenario. While red blood cells, platelets, and plasma have essential functions in the body, they are not primarily responsible for combating infections like white blood cells.

Correct Answer: B

Rationale: Correct. Positive feedback loops enhance or amplify changes, which can sometimes be harmful as they drive processes further from equilibrium. In contrast, negative feedback loops work to counteract deviations from a set point, promoting stability. Choice A, 'Negative feedback loop,' is incorrect because negative feedback loops inhibit or reduce changes, promoting stability. Choice C, 'Inhibitory feedback loop,' is incorrect as it is synonymous with negative feedback loops. Choice D, 'Stimulating feedback loop,' is incorrect as it inaccurately describes the nature of positive feedback loops.

Correct Answer: B

Rationale: Smooth muscle is the correct type of muscle found in the walls of hollow organs like the intestines. It is responsible for movements such as peristalsis, aiding in the movement of food and other materials through the digestive system. Cardiac muscle (Choice A) is found in the heart and is responsible for the heart's contractions, not in hollow organs like the intestines. Skeletal muscle (Choice C) is attached to bones and responsible for voluntary movements, not in hollow organ walls. Voluntary muscle (Choice D) is another term for skeletal muscle, which is under conscious control, unlike smooth muscle in hollow organ walls.