Pituitary, adrenal, pancreas and sex glands

The pancreas is a mixed gland: it releases digestive enzymes into the intestine and, from the islets of Langerhans, hormones into the blood. Insulin lowers blood glucose: it turns the excess into glycogen stored in the liver; glucagon turns glycogen into glucose and raises blood sugar. If insulin is lacking or does not act well on tissues, blood sugar rises – this is diabetes; only a doctor identifies and treats it, and medicines and diet plans are set by adults and doctors. The sex glands are also mixed: the testes make sperm cells and testosterone, the ovaries make egg cells and estrogen; these hormones bring about secondary sexual characteristics in adolescence. The glands are regulated through the hypothalamus–pituitary system: if stress or the internal environment changes, the hypothalamus activates the pituitary, and the pituitary activates other glands. Long stress harms health, so sleep, activity and talking to someone you trust help.