Endocrine glands are groups of secretory cells that release hormones directly into the blood. They have no ducts and are richly supplied with capillaries, so their hormones pass straight into the blood and are carried around the body.This is different from exocrine glands, such as the salivary glands and sweat glands, which secrete their products through a duct onto a surface or into a cavity. The pancreas is both: its exocrine tissue secretes digestive enzymes into the pancreatic duct, while its endocrine tissue, the islets of Langerhans, secretes hormones into the blood.
Major endocrine glands and hormones- Hypothalamus: releasing hormones that control the anterior pituitary; it also makes ADH and oxytocin.
- Pituitary gland: many hormones, including TSH, FSH, LH, growth hormone and ADH.
- Thyroid gland: thyroxine, which increases metabolic rate.
- Adrenal glands: the medulla secretes adrenaline (fight or flight); the cortex secretes steroid hormones such as cortisol and aldosterone.
- Pancreas (islets of Langerhans): β cells secrete insulin and α cells secrete glucagon.
- Ovaries: oestrogen and progesterone.
- Testes: testosterone.Each hormone reaches every tissue in the blood, but it only affects cells that have the specific receptor for it. This is why one hormone can act on several different organs while leaving others unaffected, and why one gland, such as the pituitary, can control other glands.
Major endocrine glands and hormones- Hypothalamus: releasing hormones that control the anterior pituitary; it also makes ADH and oxytocin.- Pituitary gland: many hormones, including TSH, FSH, LH, growth hormone and ADH.
- Thyroid gland: thyroxine, which increases metabolic rate.
- Adrenal glands: the medulla secretes adrenaline (fight or flight); the cortex secretes steroid hormones such as cortisol and aldosterone.
- Pancreas (islets of Langerhans): β cells secrete insulin and α cells secrete glucagon.
- Ovaries: oestrogen and progesterone.
- Testes: testosterone.Each hormone reaches every tissue in the blood, but it only affects cells that have the specific receptor for it. This is why one hormone can act on several different organs while leaving others unaffected, and why one gland, such as the pituitary, can control other glands.