Which of the following is the role of the pulmonary artery?

a. Insulin and glucagon: These hormones have opposite effects on blood glucose levels; insulin decreases blood glucose by facilitating cellular uptake, while glucagon increases blood glucose by stimulating glycogen breakdown and gluconeogenesis.

b. Ghrelin and gastrin: Ghrelin stimulates appetite, and gastrin stimulates gastric acid secretion, but they do not directly oppose each other.

c. Calcitonin and melatonin: Calcitonin lowers blood calcium levels, while melatonin regulates sleep-wake cycles; they do not act as antagonists.

d. Androsterone and estradiol: These are sex hormones with different roles but are not direct antagonists; they do not have opposing effects in the body.

a. Endoplasmic reticulum: The ER is involved in protein and lipid synthesis but is not the primary site of ATP synthesis.

b. Ribosome: Ribosomes are involved in protein synthesis but do not play a direct role in ATP production.

c. Mitochondria: Mitochondria are known as the powerhouses of the cell because they generate ATP through cellular respiration. Enzymes in the mitochondria facilitate the release of energy from nutrients, which is then used to recharge ATP molecules.

d. Lysosome: Lysosomes contain digestive enzymes that break down waste materials and cellular debris, but they do not produce ATP.