Thyroid hormone (a small iodinated amine) enters target cells in a manner similar to ________.

Correct Answer: B

Rationale: The correct answer is B: steroid hormones, because both diffuse easily into target cells. Thyroid hormone, being a small iodinated amine, can easily pass through the cell membrane and bind to intracellular receptors, similar to steroid hormones. Unlike insulin (choice A), which binds to cell surface receptors, thyroid hormone and steroid hormones enter the cell to exert their effects. Growth hormone (choice C) and glucagon (choice D) do not share the same mechanism of entry into target cells as thyroid hormone, making them incorrect choices.

Correct Answer: C

Rationale: The correct answer is C: nervous. The endocrine system and the nervous system work together to regulate various bodily functions and maintain homeostasis. The endocrine system releases hormones that control metabolism, growth, and reproduction, while the nervous system sends electrical signals to coordinate body movements and responses. Both systems communicate and coordinate with each other to ensure the body functions properly. Choices A, B, and D are incorrect because although they are important systems in the body, they do not play as direct a role in maintaining homeostasis as the nervous system does.

Correct Answer: D

Rationale: The correct answer is D because all the listed hormones are indeed produced by the hypothalamus. Oxytocin and antidiuretic hormone are directly synthesized in the hypothalamus and transported to the posterior pituitary for release. The hypothalamus also secretes releasing and inhibiting hormones that regulate the secretion of hormones from the anterior pituitary. Therefore, choices A, B, and C are incorrect on their own as they do not encompass all hormones produced by the hypothalamus.

Correct Answer: C

Rationale: The correct answer is C: acromegaly. In adults, overproduction of growth hormone leads to acromegaly, characterized by enlarged bones and tissues. Pituitary dwarfism (choice A) results from growth hormone deficiency. Gigantism (choice B) occurs when excess growth hormone is produced before epiphyseal plate closure in children. Myxedema (choice D) is associated with hypothyroidism, not growth hormone overproduction. Therefore, choice C is the correct answer as it specifically refers to the condition resulting from excessive growth hormone in adults.

Correct Answer: D

Rationale: The correct answer is D because calcium plays essential roles in clotting, bone health, nerve conduction, and muscle contraction. Calcium is crucial for the coagulation cascade in clotting, is a key component of bone mineralization, is required for neurotransmitter release in nerve conduction, and is involved in muscle contraction by regulating the interactions between actin and myosin. Choices A, B, and C are incorrect individually because they only represent some of the functions of calcium, whereas choice D encompasses all the vital functions of calcium in the body.