Match the cells in the diagram to their respective functions.

a) Accelerates Ca²⁺ release from bone: This is a function of parathyroid hormone (PTH), not calcitonin.

b) Stimulates Ca²⁺ excretion by the kidneys: While calcitonin may promote calcium excretion slightly, its main action is on bone, not the kidneys.

c) Increases Ca²⁺ deposition in bone: Calcitonin, secreted by the thyroid gland’s parafollicular (C) cells, lowers blood calcium by inhibiting osteoclast activity and enhancing calcium deposition in bones.

d) Stimulates the formation of calcitriol in the kidneys: This is primarily a function of PTH, which promotes the synthesis of active vitamin D (calcitriol) in the kidneys

a) Hepatic portal system: This carries blood from the gastrointestinal tract to the liver, not the brain.

b) Coronary circulatory system: This system supplies the heart muscle, not involved in hormone transport from hypothalamus.

c) hypophyseal portal system: The hypophyseal portal system is a specialized vascular system that transports releasing and inhibiting hormones from the hypothalamus to the anterior pituitary.

d) Hypothalamus-hypophysial tract: This is a neural pathway used to transport ADH and oxytocin to the posterior pituitary, not the anterior.