Which of the following vessels carries oxygenated blood?

Cytokines are chemicals released by one type of immune cell to directly activate another type of immune cell.

They are small proteins that act as messengers between cells and play a key role in regulating the immune response.

Choice B. Lysozymes is not the correct answer because lysozymes are enzymes that break down bacterial cell walls and do not directly activate other immune cells.

Choice C. Perforin is not the correct answer because perforin is a protein that forms pores in the membranes of target cells and does not directly activate other immune cells.

Choice D. Granzymes is not the correct answer because granzymes are enzymes that enter target cells and trigger apoptosis (cell death) and do not directly activate other immune cells.

The hypothalamus is a region of the brain that synthesizes antidiuretic hormone (ADH), also known as vasopressin.

ADH is then transported to the posterior pituitary gland via neurohypophysial capillaries, where it is stored until it is ready to be secreted into the circulation.

Choice A. Pineal gland is not correct because it is a small endocrine gland located in the brain that secretes the hormone melatonin, which regulates sleep-wake cycles, but it does not synthesize ADH.

Choice B. Thymus is not correct because it is a gland located in the chest that produces hormones involved in immune system development, but it does not synthesize ADH.

Choice D. Pancreas is not correct because it is a gland located behind the stomach that secretes hormones such as insulin and glucagon, which regulate blood sugar levels, but it does not synthesize ADH.