Endocrine

• Glands are structures which produce hormones and other useful substances
• Types of glands

  • Exocrine
  • Endocrine
• Exocrine glands


  • Release their secretion to the target group through the duct
• Endocrine glands


  • Release their secretion to the blood stream as there are no ducts
• The Endocrine System consists of a number of glands that discharge chemicals called hormones into the blood circulation
• Hormones


  Organic chemical substances produced in small amounts and move by diffusion into the blood, stimulating or inhibiting the activities of target organs
• Hormones control processes such as

  Growth, development, metabolism & response to crises
• Glands in the endocrine system

  • Thyroid glands
  • Parathyroid gland
  • Adrenal gland
  • Pituitary glands
  • Pancreas
  • Gonads
• The thyroid gland is located in the neck region and consists of two lobes on each side of the trachea
• The thyroid gland secretes a hormone called thyroxin, which controls the rate of body metabolism and regulates growth and development in children
• Effects of too little production of thyroxin


  Slow growth and poor mental development in children, tiredness, lack of energy, and goiter in adults, miscarriages and stillbirth in pregnancy
• Effects of too much production of thyroxin


  Higher metabolic rate, weight loss, excessive sweating, irritability
• Iodine deficiency can lead to not producing enough thyroxin, resulting in goiter
• Iodine deficiency disorders such as goiters are common in Ethiopia, affecting women and children more than men
• A simple solution for iodine deficiency and goiter is to include more iodine in the diet
• The parathyroid glands are four tiny structures found embedded on the back surface of the thyroid glands in the neck region
• The parathyroid glands secrete a hormone called parathyroid hormone (parathormone) which controls the level of Calcium and Phosphate ions in the blood
• The endocrine system is the body's chemical communication network.
• Glands


  • Four tiny structures found embedded on the back surface of the thyroid glands in the neck region
• The parathyroid glands secrete a hormone called parathyroid hormone (parathormone)
• Parathyroid hormone controls


  The level of Calcium and Phosphate ions in the blood
• Calcium is necessary in the body for bone formation & for the proper functioning of the nervous & muscular system
• It is important to maintain the level of Calcium in the blood at a correct and constant level
• When the amount of Calcium falls below the required level

  1. The hormone is secreted by parathyroid glands

  2. The hormone promotes the release of Calcium from bones, the absorption of Calcium from food in the small intestine, and the reabsorption of Calcium in the tubules or nephrons of the kidneys

  3. The level of Calcium ions in the blood is brought back to a normal and steady level
• The pancreas is a small pink organ situated below the stomach
• Pancreas


  • Both an exocrine and an endocrine gland
• As an exocrine gland, the pancreas secretes digestive enzymes and releases these enzymes to the duodenum through duct
• As an endocrine gland, the pancreas contains small masses of cells known as islets of Langerhans
• Cells in Pancreatic islets

  • β-cells which produce the hormone insulin
  • α-cells which produce the hormone glucagon
• Insulin and glucagon regulate blood glucose concentration


  Fairly constant at about 90mg glucose/100ml of blood
• Glucagon and insulin


  Produce opposing effects on the glucose level
• Glucagon release


  1. When the concentration of glucose in the blood stream is low, an alpha-cells of the islets of Langerhans secretes the hormone glucagon

  2. The hormone glucagon is transported to the liver, orders the liver to convert some of the stored glycogen to glucose, and maintains the blood-glucose level
• Insulin release


  1. When the concentration of glucose in the blood stream is high, a beta-cells of the islets of Langerhans secretes the hormone insulin

  2. The hormone insulin is transported to the liver, orders the liver to convert the high level of glucose to glycogen, and brings the blood-glucose level back to normal
• Most of us never think about our blood sugar levels because they are perfectly controlled by our pancreas
• When the production of insulin is affected, it results in a condition called diabetes mellitus
• Types of Diabetes Mellitus


  • Type I diabetes: Appears in children and young people, inherited
  • Type II diabetes: Appears later in life, can be linked to being obese or possibly very underweight
• Diabetes mellitus results in a condition called diabetes mellitus
• Types of DM


  • Type I diabetes
  • Type II diabetes
• Type I diabetes


  • Appears in children and young people
  • It is inherited and you can't avoid it
• Type II diabetes


  • It appears later in life and can be linked to being obese or possibly very underweight as well