Chapter Six : Hormonal co-ordination in living organism

Main concepts of chapter 7 Hormonal coordination in Living organisms 1- Starling gave the name hormones for these chemicals that coordinate between body organs. 2- Auxins are plant hormones which regulate plant growth because they act as catalysts for important growth enzymes. 3- Endocrine glands are those that secrete their hormones directly into the blood current. 4- Endocrine glands are chracterized by: A- ductless B- Provided with plenty of blood C- Each gland has a specific secretion which contain one or more hormones. 5- The most important endocrine glands in man are: a- pituitary gland or the master gland. b- Thyroid gland or the activity gland c- Parathyroid gland d- Adrenal gland e- Pancrease. f- gonads [ovaries - testes] 7- The pituitary gland is a small oval shaped body 12 mm long, half gram in mass. It consists of two lobes. 8- The anterior lobe is more important than the posterior lobe because it produces more than nine hormones some of them act as activating hormones for other glands. 9- From the hormones of the anterior lobe are growth hormone, TSH, ACTH, FSH, LH, and lactoginic hormone. 10- From the hormones secreted by the posterior lobe are oxytocin hormone which is responsible for controlling involuntary muscles like uterine muscles during delivary and antidiuretic hormone which regulates urine formation and excretion. 11- The deficiency of the growth hormone before puberty leads to dwarfism but after puberty it causes impotence. 12- The excessive secretion of the growth hormone in early childhood causes gigantism but if it happens in adults it causes acromegaly. 13- The thyroid gland lies infront of and on both sides of trachea at the base of the neck; it consists of two small lobes joined together by an isthmus, it is about 6 cm long and weighs 30 - 60 grams. 14- The enlargement of the thyroid gland is called goitre. 15- In case of simple goitre, the enlargement is accompanied by dificiency of the secretion which leads to the decrease of body activities, body temp. and heart beats. 16- In adults, dificiency leads to myxedema, but in infancy it leads to cretinism. 17- The exophthalmic goitre, the enlargement is accompanied by an excessive secretion of the hormone which leads to the increase in the body activities, increase the rate of stored food combustion. 18- Deficiency in the secretion of thyroxine is treated by adding iodine to food, or using the extract of cettle thyroid, excessive secretion is treated by the surgical removal of the enlarged part. 18- The parathyroid glands are 4 small bodies each is as big as wheat grain. 19- Each two bodies are located on one side of the trachea and behind the thyroid gland. 20- Parathyroid gland secretes parathormone hormone. 21- Parathormone hormone regulates caclium and phosphorus levels and keep them constant in the blood. 22- Both calcium and phosphorus are essential for bone, teeth and blood formation. 23- Deficiency of parathormone leads to excitability. 24- Excessive secretion leads to a rise in the calcium and phosphorus level in the blood and they are excreted in large amounts in the urine, this is due to the withdrawal of these elements from the bones which become fragile and more exposed to fractures. 25- The adrenal gland is called emotional galnd or supra renal glands. 26- There are two adrenal glands, each one is completely attached to each kidney. 27- The adrenal gland is yellow, pyramid shaped body about 3 cm long and about 6 - 12 gm. 28- The person will die if the adrenal glands are infected with a disease or removed. 29- Each gland consists of an outer certex and inner medulla. 30- The medulla part secretes adrenaline and the cortex secretes a group of hormones the most important one is the cortisone. 31- The adrenaline causes: a- Constriction of skin and visceral blood vessels. b- increase the heart beats causing rise in blood pressure. c- Muscle blood vessels become wider d- An increase in breathing movements. e- conversion of stored glycogen into sugar. f- secondary symptoms appear like white skin, widening of iris, mouth muscles contract, and fingers tremble. 32- The cortisone hormone has some functions: a- It keeps sodium and potassium constant in the body. b- Regulates the fats and carbohydrated metabolism. c- Increase the ability of the body to resist climatic and psychic disturbances. 33- The increase in the activity of the cortex leads to early sexual maturity in males and appearance of musculine characteristics on females. 34- Pancreas an exocrine gland which secretes the pancreatic juice through the pancreatic duct. 35- Pancreas is also endocrine because there are patches of cells scatterd in the pancreatic tissue which secrete insulin directly into the blood. 36- The scientist langerhans discovered some patches of cells in the pancreatic tissue. 37- The role of insuline is: a- Keep the percentage of of sugar in the blood constant 0.1% i.e. 100 m.gm of glucose in 100 gm of blood. b- help the body cells to use glucose for energy production. c- Stimulate the hepatic cells to absorb the glucose and convert it to glycogen to be stored till needed. 38- In 1922 Banting siolate insuline from the pancreas.