Human endocrine system


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Human endocrine system

  1. 1. ENDOCRINE SYSTEM Endocrine system helps in the regulation and coordination of body and body activities . The endocrine system and nervous system work together.
  2. 2. HORMONES Reacting to fear, growing taller, and developing male or female characteristics are all activities in the body that are partially regulated by hormones. Hormones are substances secreted (released) by cells that act to regulate the activity of other cells in the body. Hormones act as chemical messengers, carrying instructions that cause cells to change their activities. Hormones act on a specific tissue called target tissue.
  3. 3. The processes in the body that are regulated by hormones include: Overall metabolism Maintenance of homeostasis Growth Reproduction Behavior
  4. 4. GLANDS Glands are organs of endocrine system specialized for secretion of substances like hormones. Some glands secrete their secretions into some organs by ducts, they are called EXOCRINE GLANDS. Other glands release their secretion directly into the bloodstream that called ENDOCRINE GLANDS. Some glands secrete their secretions both into bloodstream and body organs, they are called as MIXED GLANDS
  5. 5. Types of hormones Proteinic Hormones consist of chain of amino acids or related compounds.  Steroid Hormones are lipid like, carbon ring compounds that are chemically similar to cholesterol and bile.
  6. 6. Regulation of hormone secretion The rate of hormone secretion varies with the needs of the body. In many cases the level of a hormone in the blood turns production of the hormone off and on through feedback mechanisms. If high levels of a hormone stimulate the output of even more hormone, the regulation is called positive feedback. In negative feedback, the production of some hormone or substance stops the production of another hormone.
  7. 7. Negative feedback
  8. 8. HUMAN ENDOCRINE GLANDS Pineal Hypothalamus Pituitary Thyroid Parathyoid Thymus Adrenal Pancreas Ovaries Testes
  9. 9. HYPOTHALAMUS  The hypothalamus is the area of the brain that coordinates the activities of the nervous and endocrine systems. It controls many body functions, including body temperature, blood pressure, and emotions. The hypothalamus receives information about external and internal conditions from other brain regions. The hypothalamus responds by giving instructions—in the form of hormones—to the pituitary gland.
  10. 10. Hormones of Hypothalamus Growth Hormone Releasing Hormone (GRH or GH) Adrenocorticotropic Hormone Releasing Hormone (CRH or ACTH) Thyroid Releasing Hormone (TRH or TSH) Gonadotropic Releasing Hormone GnRH (LH – FSH – LTH – RH)
  11. 11. PITUITARY GLAND The pituitary gland is an endocrine gland suspended from the hypothalamus by a short stalk. The pituitary gland secretes many hormones, including some that control endocrine glands elsewhere in the body. Hormones: Tropic Hormones  Growth Hormone  MSH (Melanin Stimulating Hormone) ADH (Antiduretic Hormone) Oxytocin 
  12. 12. Tropic Hormones These hormones stimulate the secretions of other hormones Thyroid Stimulating Hormone (TSH): Thyroid Gland Adrenocorticotropic Hormone (ACTH): adrenal glands Gonadotropic Hormones (LH, FSH, GTH): glands of the reproductive system. Follicle Stimulating Hormone (FSH): Growth and maturation of the egg in the follicle. In the testes, it stimulates the production of sperm.
  13. 13. Growth Hormone Other name SOMATOTROPIN A deficiency in this hormone will result in a condition known as DWARFISM. An excess amount of this hormone causes an abnormal increase in the length. This condition is known as GIGANTISM.
  14. 14. MSH (Melanin Stimulating Hormone) It stimulates production of melanocytes MSH determines the color of the skin. ADH (Vasopressin): Its main function is to regulate the water balance of the body by controlling reabsorption of water in the kidneys. OXYTOCIN: This hormone stimulates the smooth muscle fibers of the uterus to contract during labor. It causes contractions of the channel cells of the mammary glands so that milk can be secreted.
  15. 15. Thyroid and parathyroid gland The thyroid gland, located in the neck, is wrapped around the trachea. The parathyroid glands are located on the back of the thyroid gland.
  16. 16. Hormones Thyroid hormone thyroxin which has iodine in its structure Thyroid hormones regulate the body’s metabolic rate and promote normal growth of the brain, bones, and muscles during childhood. Thyroid hormones also affect reproductive functions and maintain mental alertness in adults.
  17. 17. A high level of calcium in the blood stimulates the thyroid gland to produce a hormone called calcitonin. Calcitonin causes calcium to be deposited in bone tissue rapidly, lowering the blood-calcium level. Parathyroid hormone (PTH) or parathormone released by parathyroid gland. PTH is made and released in response to a falling level of calcium in the blood in order to increase it.
  18. 18. Thyroid gland disorders  The underproduction of thyroid hormones is hypothyroidism.  The overproduction of thyroid hormones is hyperthyroidism.
  19. 19. Pancreas
  20. 20. Pancreas The pancreas contains clusters of specialized cells, called the islets of Langerhans. Two hormones made by the islet cells that interact to control the level of glucose in the blood. Insulin, produced by β cells, is a hormone that lowers blood glucose level by promoting the accumulation of glycogen (glucose) in the liver. The deficiency of insulin is known as diabetes mellitus. Glucagon, produced by α cells, has the opposite effect of insulin—it raises blood glucose levels.
  21. 21. DIABETES MELLITUS Diabetes mellitus (2 TYPES) is a serious disorder in which cells are unable to obtain glucose from the blood, resulting in high blood glucose levels. The kidneys excrete the excess glucose, and water follows, resulting in excessive volumes of urine and persistent thirst. Because cells cannot take up glucose, they use the body’s supply of fats and proteins for energy.
  22. 22. Adrenal glands The human body has two adrenal glands on top of the kidneys. Each almond-size adrenal gland is actually two glands in one: an inner core, called the adrenal medulla, and an outer shell, called the adrenal cortex.
  23. 23. Adrenal gland hormones ADRENAL MEDULLA: It produces epinephrine (adrenalin) and norepinephrine (noradrenalin) as a response to stress situations (fear, danger, cold…) They increase heart rate, blood pressure, blood glucose level, blood flow into heart and lungs (Fight or Flight response) ADRENAL CORTEX: Produces cortisol, aldosterone, small amounts of testosterone Cortisol makes more energy available to the body. Aldosterone helps reabsorb sodium (Na+) ions from the fluids removed by the kidneys so that these ions are not lost in the urine.
  24. 24. Pineal gland The pineal gland is a pea-sized gland located in the brain, which secretes the hormone melatonin. Melatonin seems to be released by the human pineal gland as a response to darkness. Therefore, the pineal gland is involved in establishing daily biorhythms.
  25. 25. Thymus The thymus is a lymphoid organ. It is involved in the immune system during prenatal and postnatal periods by stimulating lymphocyte production by its hormones.
  26. 26. Gonads The main function of the male and female gonads is in the development of the reproductive system and secondary sexual characteristics (even behavior). They are both endocrine and exocrine glands Male gonads TESTES, female gonads OVARIES The ovaries secrete estrogens and progesterone, and the testes produce testosterone. Exocrine function is in the production of gametes (sperm and egg)