Structures and functions of the endocrine system

Learning Target

•I can identify the structures and functions of the endocrine system.

•The endocrine system is composed of ductless glands that secrete hormones that are transported throughout the body by blood vessels.

•Hormones are chemical messengers that exert a specific influence on organs and other body tissues.

•The endocrine system regulates the body’s metabolism, growth, and reproductive systems.

•The system consists of the pituitary gland, thyroid gland, parathyroid glands, adrenal glands, pancreas, gonads, and placenta.

Pituitary Glands

•The pituitary gland is located at the base of the brain near the hypothalamus.

•The hypothalamus controls the pituitary gland.

•The pituitary gland is considered the master gland because it secretes many hormones that control other endocrine glands.

Thyroid Gland

•The thyroid gland, which is located near the larynx, regulates the body’s metabolism and iodine uptake.

• Thyroxine, a hormone secreted by the thyroid gland, influences body weight and lean tissue growth.

Parathyroid Glands

•The parathyroid glands are located on the surface of the thyroid gland and secrete parathormone (PTH), which regulates calcium and phosphorus metabolism.

Adrenal Glands

•The adrenal glands are located near the kidney. The adrenal glands secrete hormones to regulate metabolism, maintain blood pressure, and regulate sodium and potassium balance.

Pancreas

•The pancreas secretes hormones as well as digestive enzymes. Insulin, a protein hormone secreted by the pancreas, lowers blood sugar.

•Glucagons, a hormone formed in the pancreas of vertebrates, raises blood sugar and opposes the action of insulin.

Gonads

•Gonads, the testes in males and the ovaries in females, secrete the hormones testosterone and estrogen respectively.

Placenta

•The placenta, the organ that unites the fetus to the uterus, secretes relaxin to relax pelvic ligaments during parturition.

• Parturition the birthing process.