Ductless glands secrete 

The Correct Answer is : Hormones

Key Points

• The endocrine system is a collection of ductless glands that produce hormones and secrete them directly into the bloodstream.
• The glands of the endocrine system include the pituitary, thyroid, parathyroid, adrenal, and pineal glands; the ovaries in females and testes in males; the pancreas, and others. Each of these glands secretes different types of hormones that regulate various functions in the body.
• Hormones are chemical messengers that travel throughout the body coordinating complex processes like growth, metabolism, and fertility. They can influence the function of the immune system, and even alter behavior.
• The mechanism of hormone action is via binding to specific receptor proteins within the target cells, which results in a change in cell function.
• Hormone secretion is often regulated through a mechanism called a negative feedback loop. For example, if a hormone's levels rise above a certain point in the bloodstream, the increased hormone level will trigger a process that lowers it back to the normal range.
• Disorders of endocrine glands can result in too much or not enough hormones, which can lead to a wide range of health problems. Examples include diabetes (a deficiency in insulin production by the pancreas) and hypothyroidism (reduced thyroid hormone production).