Practice Science TEAS Test

Correct Answer: B

Rationale: The correct answer is B: Melatonin. Melatonin is a hormone produced by the pineal gland that plays a key role in regulating the sleep-wake cycle. It helps control the body's internal clock and signals when it's time to sleep. Cortisol (choice A) is a stress hormone, thyroxine (choice C) regulates metabolism, and insulin (choice D) controls blood sugar levels, but they do not directly regulate the sleep-wake cycle. Melatonin is the only hormone among the choices specifically associated with sleep regulation.

Correct Answer: D

Rationale: Step-by-step rationale: 1. A: The atrioventricular valves lie between the atria and the ventricles - This is true for both the tricuspid valve (right side) and the mitral valve (left side). 2. B: The pulmonary semilunar valve lies between the right ventricle and the pulmonary trunk - This is accurate, as the pulmonary semilunar valve separates the right ventricle from the pulmonary artery. 3. C: The atrioventricular valves prevent backflow into the atria when the ventricles contract - This is true as the AV valves close to prevent backflow during ventricular contraction. 4. Therefore, the correct answer is D, as all the statements are correct and accurately describe heart valve anatomy and function.

Correct Answer: B

Rationale: The correct answer is B: Pineal gland. The pineal gland secretes the hormone melatonin, which plays a crucial role in regulating the body's circadian rhythm. Melatonin helps control the sleep-wake cycle, making it responsible for maintaining the body's internal clock. The other choices are incorrect because the thyroid gland regulates metabolism (A), the pancreas regulates blood sugar levels (C), and the hypothalamus controls various bodily functions but is not directly responsible for maintaining the circadian rhythm (D).

Correct Answer: D

Rationale: The correct answer is D: Thyroid. The thyroid gland produces hormones such as thyroxine and triiodothyronine, which play a crucial role in regulating metabolism. These hormones control the body's metabolic rate, affecting processes like energy production and consumption. The thymus (A) is responsible for immune function, the pituitary gland (B) regulates various hormones but not specifically metabolism, and the pancreas (C) produces insulin and glucagon to regulate blood sugar levels, not metabolism directly. In summary, the thyroid gland is the correct choice as it specifically regulates metabolism through thyroid hormones.

Correct Answer: B

Rationale: The correct answer is B: Sudoriferous gland. Sudoriferous glands, also known as sweat glands, are responsible for producing sweat to regulate body temperature. They are distributed throughout the skin and play a vital role in maintaining homeostasis. Sebaceous glands (A) produce sebum, hair follicles (C) are responsible for hair growth, and melanocytes (D) produce melanin for skin pigmentation. Therefore, B is the correct choice as it directly relates to sweat production in the skin.