What do white blood cells do in the immune system and how are they related to exocytosis?

White Blood Cells protect the body from diseases and foreign invaders. Food is degraded, its nutrients are absorbed by the cell and its waste products are left in the digestive vacuole, which may then leave the cell by exocytosis. Phagocytosis occurs in the scavenging white blood cells of our body. They prowl around looking for invading bacteria and viruses which they engulf and destroy.

Explanation:

osteogenesis imperfecta (oi) refers to a congenital ailment of bones. in the condition, the bones become brittle or fragile. this ailment is a general result of the defect or mutations in the genes (colia1 or colia2). this mutation results in imperfect collagen formation either in quantity or quality wise.  

there are eight kinds of oi defects, and each kind varies with certain distinctions in symptoms. the usual symptoms include frequent bone fractures, loss of hearing in infants, protruding eyes, discoloration of the white in the eyes, respiratory issues, loosening of the joints, short stature, and other symptoms.