Question

what does this organ regulate?

a. glucose uptake by cells
b. calcium uptake by bones
c. sodium secretion by the kidneys
d. circulating t3 and t4

Explanation:

Identify the highlighted organ

The anatomical model highlights an organ in bright blue. This organ is situated horizontally across the posterior abdomen, retroperitoneally, nestled in the curve of the duodenum and stretching towards the spleen, anterior to the kidneys and vertebral column. This shape and position uniquely identify the highlighted organ as the pancreas.

Determine the physiological function

The pancreas has both exocrine and endocrine functions. Its endocrine function is carried out by the pancreatic islets (islets of Langerhans), which secrete hormones directly into the bloodstream:

• Insulin (produced by beta cells) decreases blood glucose levels by facilitating glucose uptake into systemic cells (especially skeletal muscle and adipose tissue).
• Glucagon (produced by alpha cells) increases blood glucose levels.

Evaluate the given options

• a. glucose uptake by cells: This is regulated by insulin secreted by the pancreas.
• b. calcium uptake by bones: This is regulated by calcitonin (thyroid gland) and parathyroid hormone (parathyroid glands).
• c. sodium secretion by the kidneys: This is primarily regulated by aldosterone (adrenal cortex) and atrial natriuretic peptide (heart).
• d. circulating T3 and T4: This is regulated by thyroid-stimulating hormone (anterior pituitary) acting on the thyroid gland.

Therefore, the correct option is a.

Answer:

• (a) glucose uptake by cells (Correct answer)
• (b) calcium uptake by bones
• (c) sodium secretion by the kidneys
• (d) circulating T3 and T4