MICROANATOMY

Detailed explanation-1: -They are produced in one organ and influence the functioning of another organ called the target organ. A very small amount of hormones is produced and they are destroyed soon after their action. Hormones can be proteins, amino acids or steroids.

Detailed explanation-2: -Peptide hormones are soluble in plasma, act via surface receptors, are fast-acting and short-lived. Thyroid hormones and steroid hormones are insoluble in plasma, act via intracellular receptors to change transcription, are slow-acting and are long-lived.

Detailed explanation-3: -A hormone’s half-life and duration of activity are limited and vary from hormone to hormone. For instance, the biological half-life of luteinizing hormone is 20 minutes, which is shorter than that of a follicle-stimulating hormone (three to four hours), and of human chorionic gonadotropin (24 hours).

Detailed explanation-4: -Hormones are needed in small amounts. They have a low molecular weight. They are secreted at one site and act on a different site. They get used up in their process of action. They regulate various actions and processes. Their actions are irreversible. More items