Hormones that bind to receptors inside of target cells are usually

Correct Answer: A

Rationale: The correct answer is A: lipid soluble. Lipid-soluble hormones can easily pass through the cell membrane and bind to intracellular receptors. This binding activates gene expression and affects protein synthesis within the cell. Water-soluble hormones, like choice B, bind to cell surface receptors and activate signaling pathways through second messengers (choice C). Proteins (choice D) are not hormones but rather macromolecules that can act as signaling molecules or receptors. Lipid solubility is crucial for hormones to exert their effects inside target cells, making choice A the correct answer.

Correct Answer: C

Rationale: Step-by-step rationale for why choice C (Insulin) is correct: 1. Insulin is a hormone produced by the pancreas that regulates blood sugar levels. 2. Diabetes mellitus is a condition characterized by high blood sugar levels due to inadequate insulin production or ineffective use of insulin. 3. The deficiency of insulin leads to the inability to properly regulate blood sugar levels, resulting in diabetes mellitus. 4. Glucagon (choice A) is a hormone that increases blood sugar levels, so its deficiency would not cause diabetes. 5. Thyroxin (choice B) is a hormone produced by the thyroid gland and is not directly related to diabetes. 6. Melatonin (choice D) is a hormone that regulates sleep-wake cycles and is not involved in blood sugar regulation. Summary: Insulin is the correct choice because its deficiency directly leads to diabetes mellitus, while the other choices do not play a significant role in the development of this condition.

Correct Answer: C

Rationale: The correct answer is C: Stressful life events. Graves' disease is an autoimmune disorder where the immune system mistakenly attacks the thyroid gland, causing it to produce excess thyroid hormone. Stressful life events can trigger or exacerbate autoimmune conditions like Graves' disease by impacting the immune system's functioning. Trauma, iodine deficiency, and bacterial infection are not direct triggers for Graves' disease. Trauma can cause thyroid issues but not specifically Graves' disease. Iodine deficiency can lead to goiter but is not a direct trigger for Graves' disease. Bacterial infections can cause thyroiditis but are not a common trigger for Graves' disease.

Correct Answer: A

Rationale: The correct answer is A: glucagon is produced by the pancreas and acts on the liver to increase blood glucose levels. Glucagon triggers the liver to break down glycogen into glucose, releasing it into the bloodstream. Melatonin is a hormone produced by the pineal gland and is not involved in glucose regulation. Glucagon does not act on the kidney but specifically targets the liver. Calcitonin is produced by the thyroid gland and plays a role in calcium regulation, not glucose metabolism.

Correct Answer: A

Rationale: The correct answer is A: Autoimmune Mediated. In this case, the patient is presenting with symptoms of hyperthyroidism along with a goiter, which is indicative of Graves' disease, an autoimmune disorder where antibodies stimulate the thyroid gland to produce excess thyroid hormones. The presence of increased iodine uptake in the thyroid scan supports this diagnosis. On the other hand, immune complex mediated diseases typically involve tissue damage caused by immune complexes, not thyroid hormone excess. The cause being unknown or infection-related are not consistent with the symptoms and thyroid scan findings in this case.