In human physiology, which type of body cells are classic target cells that respond to insulin by increasing their uptake and storage of glucose?

Introduction / Context:
Insulin is a key hormone in the regulation of blood glucose levels. It is secreted by the beta cells of the pancreas and acts on several tissues to promote glucose uptake, storage, and use. Identifying which cells respond to insulin is important for understanding diabetes, metabolism, and energy balance. This question focuses on the classic type of cells that show a strong response to insulin by altering how they handle glucose.

Given Data / Assumptions:

• The question asks about body cells that respond to insulin.
• Options include liver cells, endothelial cells, skin cells, and bone cells.
• We assume knowledge of major metabolic roles of different tissues.

Concept / Approach:
Insulin promotes glucose uptake and storage in several insulin sensitive tissues, notably liver, muscle, and adipose tissue. In the liver, insulin stimulates the uptake of glucose from blood and its conversion into glycogen and, when glycogen stores are full, into fat. This helps reduce blood glucose concentration after a meal. Endothelial cells, skin cells, and bone cells are not considered the primary insulin sensitive tissues for blood glucose regulation, even though many cell types may possess some insulin receptors. The liver is a major organ for glucose storage and release, making its cells classic examples of targets for insulin action.

Step-by-Step Solution:
Step 1: Recall the main insulin target tissues: liver, skeletal muscle, and adipose tissue. Step 2: Among the provided options, identify liver cells (hepatocytes) as belonging to one of these classic target tissues. Step 3: Recognise that endothelial cells, general skin cells, and bone cells do not play a central role in insulin regulated blood glucose handling in basic exam oriented physiology. Step 4: Select liver cells as the best answer because they respond strongly to insulin by taking up glucose and converting it to glycogen.

Verification / Alternative check:
Physiological descriptions explain that after a carbohydrate rich meal, insulin secretion rises, and the liver takes up glucose and stores it as glycogen, a process called glycogenesis. When insulin is low, the liver can break down glycogen to release glucose back into the circulation. These observations highlight the importance of liver cells as insulin responsive cells and confirm that they are a key target of insulin action.

Why Other Options Are Wrong:

• Endothelial cells: These line blood vessels and are important for vascular tone and barrier function, but they are not highlighted as primary cells for insulin driven glucose storage.
• Skin epithelial cells: Skin serves protective and sensory roles and does not significantly regulate blood glucose by insulin sensitive uptake in basic discussions.
• Bone cells: Bone cells manage mineral storage and bone remodelling, not rapid insulin mediated regulation of blood glucose.

Common Pitfalls:
Learners sometimes assume that because all cells use some glucose, insulin must act equally on all tissues. In reality, certain tissues like the brain can take up glucose relatively independently of insulin, while others such as liver, muscle, and adipose tissue are particularly sensitive to insulin and play the main roles in lowering blood glucose after meals. Remembering this selective action helps in answering questions about insulin responsive cells correctly.

Final Answer:
Body cells that classically respond to insulin by increasing glucose uptake and storage include liver cells (hepatocytes).