Normally there are 4 parathyroid glands in human.
Removal of parathyroid glands:
1-2;cause little physiologic abnormality
3;cause transient hypothyroidism (because small quantity of remaining parathyroid tissue is usually capable of hypertrophy to perform function of all glands)
Chief cells(mainly)-secrete parathyroid hormone(PTH)
Oxyphilcell cells(absent in many animals and young humans-unknown functions.