Since the T lymphocytes of immune system undergone maturation and proliferation in the thymus and contribute to the immunity of the body it is called throne of immunity.

Underproduction of hormones by the adrenal cortex alters carbohydrate metabolism. This leads to acute weakness and fatigue. This is called Addison's disease

It is a form of hyperthyroidism. Enlargement of thyroid gland, protrusion of eyeballs, increased basal metabolic rate and weight loss are its symptoms.

Melatonin maintains circadian rhythm of the body.

Adrenaline and noradrenaline are secreted in response to emergency situations. They help prepare the body to fight with emergency. Hence, they are also called as emergency hormones.

Examples of amino acid-derived hormones include epinephrine and norepinephrine, which are synthesized in the medulla of the adrenal glands, and thyroxine, which is produced by the thyroid gland.

Tetraiodothyronin and Triiodothyronine

The thyroid gland is the largest endocrine gland in the body. It is located in the neck, below the larynx, and in front of the trachea. It secretes thyroid hormone, which regulates important metabolic processes connected to our heart rate, body temperature, and energy levels.

(a) Exocrine Glands. These glands have ducts. They secrete their secretions through ducts.
(b) Endocrine Glands. Endocrine glands do not have ducts. They directly secrete their secretions.
(c) Hormone. Hormones are non-nutrient chemicals which act as intercellular messengers and are produced in trace amounts

Inflammatory responses are controlled by steroid hormones called glucocorticoids. Which are secreted by adrenal cortex. Its other functions are to stimulate gluconeogenesis, lipolysis and proteolysis and inhibit cellular uptake and utilisation of amino acids.

It is a type of hormones complement each other's actions and both are needed for full expression of the hormone effects. e.g., the production, secretion and ejection of milk by mammary glands require the synergistic effects of oestrogens, progesterone, prolactin and oxytocin.

Although hormones are present in very small amounts, they effectively regulate many physiological processes. This is the result of signal amplification, an increase in signal strength. For example, a single hormone receptor complex can stimulate the production of many cAMP moleclues. In turn, each cAMP can activate a protein kinase that phosphorylates many protein molecules. In this way, a single hormone molecule can activate many proteins.

Hormones which do not enter the target cells, interact with specific receptors located on the surface of the target cell membarances and generates second messengers (e.g., cAMP) on the inner side of the plasma membrance. The second messenger, in turn, carries out all the hormonal functions.

Heart produce Atrial Natriuretic Factor (ANF) which promotes renal sodium excretion and lowers blood pressure.