feeback loops

• control of hormone secretion is required to regulate the amount of hormones released into the body

• often this control comes from feedback mechanisms

• the thyroid feedback mechanism is a negative feedback loop

homeostasis

• when thyroxine levels get too high, the hypothalamus is triggered to stop the impulse

• thyroid secrets thyroxine into blood, which increases metabolism

• pituitary secretes thyroid-stimulating hormone

• hypothalamus secretes hormones into the pituitary (TRH)

Improper functioning of the endocrine gland may cause:

• hyposecretion- not enough hormone is released

• hypersecretion- too much hormone is released

• all endocrine disorders are caused by either the hyposecretion or hypersecretion of hormones