Practice TEAS Science Test

Correct Answer: C

Rationale: The correct answer is C: IgG. IgG is the only antibody that can cross the placenta due to its smaller size and ability to bind to neonatal Fc receptors. This allows for passive immunity to be transferred from mother to fetus. IgA is mainly found in mucosal secretions, IgD functions as a B cell receptor, and IgM is primarily involved in the primary immune response. IgG is the most abundant antibody in the circulation and plays a crucial role in protecting the fetus from infections.

Correct Answer: D

Rationale: The correct answer is D: Cardiovascular. The cardiovascular system is responsible for transporting dissolved oxygen from the lungs to the spleen. Step 1: Oxygen is inhaled into the lungs during respiration. Step 2: Oxygen diffuses into the bloodstream through the alveoli in the lungs. Step 3: The oxygen-rich blood is pumped by the heart to the spleen and other body tissues. The immune system (A) is responsible for fighting off infections, not oxygen transport. The endocrine system (B) regulates hormones, not oxygen transport. The respiratory system (C) is involved in the exchange of gases in the lungs but does not transport oxygen to the spleen.

Correct Answer: B

Rationale: The correct answer is B: Thyroxine. Thyroxine is produced by the thyroid gland and plays a crucial role in regulating the body's metabolism by controlling the rate at which cells use energy. Insulin is a hormone that regulates blood sugar levels, not metabolism. Melatonin is responsible for regulating sleep-wake cycles, not metabolism. Adrenaline, also known as epinephrine, is involved in the fight or flight response and does not directly regulate metabolism.

Correct Answer: B

Rationale: The correct answer is B: Depolarization of the SA node. The P-wave in an ECG represents atrial depolarization, which is initiated by the SA node. This electrical signal spreads through the atria causing them to contract. Choice A is incorrect because the P-wave corresponds to atrial depolarization, not repolarization. Choice C is incorrect as the QRS complex represents ventricular depolarization. Choice D is incorrect as the T-wave represents ventricular repolarization. Therefore, the SA node depolarization is accurately represented by the P-wave in an ECG.

Correct Answer: B

Rationale: The correct answer is B because the pericardium is actually a double-walled sac around the heart, not a single-walled layer. The outer layer is the fibrous pericardium, and the inner layer is the serous pericardium. Choice A is correct because the pericardial fluid between the layers reduces friction. Choice C is also correct because the pericardium helps prevent overfilling of the heart. Choice D is correct as well, as the pericardium does protect and anchor the heart. Therefore, the only incorrect statement is B, as the pericardium is not a single-walled layer.