Since it is a light-absorbing pigment, chlorophyll is called a photoreceptor. Also note that there are two types of chlorophyll: chlorophyll a and chlorophyll b. Function. Chlorophyll molecules are contained inside chloroplasts, which are the food producers of the cell found
Calcitonin has an opposite effect, as it decreases the levels of calcium in the blood. Overall, PTH has a strong effect on the blood concentration of calcium, whereas calcitonin has a more moderate effect and is not critical in helping the body maintain normal blood calcium levels.
Calcitonin is a 32 amino acid protein secreted by the parafollicular C cells of the thyroid in response to high [Ca 2+ ] ext. It induces a decrease in serum calcium by inhibiting osteoclast activity and by increasing urinary excretion of Ca 2+ .espite its direct effect of increasing Ca 2+ reabsorption, excessive PTH secretion increases urinary Ca 2+ excretion because of the high load of filtered Ca 2+ resulting from hypercalcaemia. At any given Ca 2+ load, Ca 2+ clearance is decreased by PTH and increased in the absence of PTH.