Parathyroid hormone causes the lowering of blood calcium level. This increases the excitability of nerves and muscles causing cramps and convulsions. Parotid gland is the largest salivary gland, involved in the digestion process. Pancreas is a mixed gland, and it secrete hormones - Insulin and glucagon, maintaining blood sugar levels. Thyroid gland secrete thyroxine $\left(\mathrm{T}_4\right)$ and triiodothyronine $\left(\mathrm{T}_3\right)$, which regulate the basal metabolism of the body.
Related Theory
PTH has effects antagonistic to those of calcitonin by increasing blood calcium levels by stimulating osteoclasts to break down bone and release calcium. secreted by the parafollicular $C$-cells of the thyroid gland.