{"id":1805,"date":"2020-07-13T10:42:59","date_gmt":"2020-07-13T10:42:59","guid":{"rendered":"https:\/\/murreeroad.org\/Biology10\/?p=1805"},"modified":"2020-07-13T10:45:30","modified_gmt":"2020-07-13T10:45:30","slug":"q-12-what-is-endocrine-system-describe-important-endocrine-glands","status":"publish","type":"post","link":"https:\/\/murreeroad.org\/Biology10\/q-12-what-is-endocrine-system-describe-important-endocrine-glands\/","title":{"rendered":"Q.12 What is endocrine system. Describe important endocrine glands."},"content":{"rendered":"

Q.12\u00a0What is endocrine system. Describe important endocrine glands.<\/strong>
\nAnswer:<\/strong>
\nEndocrine Glands<\/strong>
\nIntroduction<\/strong>
\nEndocrine system regulates the activities such as growth, reproduction, maintenance of glucose concentration in blood, reabsorption of water in kidneys etc.
\nHormones<\/strong>
\nEndocrine system uses chemicals to communicate with its effectors. These chemicals are known as hormones. A hormone is a specific messenger molecule synthesized and secreted by endocrine gland.
\nTypes of Gland<\/strong>
\nThey are of two types:
\n(a) Endocrine Gland<\/strong>
\nThese glands are ductless and release their secretions (hormones) directly into the blood stream. Blood carries the hormone to the target organs or tissues upon which they act.
\n(b) Exocrine glands<\/strong>
\nMany glands in our body are exocrine. Such glands have ducts for releasing their secretions e.g. digestive glands, skin glands etc. Important Endocrine glands 1. Pituitary Gland Structure
\nIt is a pea-shaped gland. Location
\nIt is attached to the hypothalamus of brain.
\nHormones<\/strong>
\nMany hormones of pituitary gland influence the secretions of other endocrine glands. However some hormones of this gland act directly on various tissues of body. Lobes of pituitary gland
\nThere are two lobes of pituitary gland. (a) Anterior lobe Hormones
\nIt produces many hormones.
\n(i) SOMATOTROPHIN<\/strong>
\nOne of its important hormone is somatotrophin (growth hormone).
\nFunction<\/strong>
\nIt promotes the growth of body.
\nDeficiency – Dwarfism<\/strong>
\nIf the production of this hormone is diminished during growing age, the rate of growth decreases. This condition is called dwarfism.
\nOver Production-Gigantism<\/strong>
\nIf this hormone is excessively produced after growing age, it leads to gigantism (very tall and overweight).
\nAcromegaly<\/strong>
\nIf this hormone is excessively produced after growing age, internal organs and body extremities alone grow large. This condition is known as acromegaly. Such persons will have large hand, feet and jawbones.
\n(ii) Thyroid stimulating hormone<\/strong>
\nAnother important hormone secreted by the anterior lobe of pituitary gland is Thyroid Stimulating Hormone (TSH).
\nFunction<\/strong>
\nIt stimulates thyroid gland to secrete its hormones. The remaining hormones of anterior, lobe influence reproductive organs and also control adrenal glands.
\n(b) Posterior Lobe<\/strong>
\n(a) Hormones<\/strong>
\nThe posterior lobe of pituitary gland stores and secretes two hormones i.e. oxytocin and vasopressin (Antidiuretic Hormone ADH).
\n(b) Production of Hormones<\/strong>
\nThese hormones are produced by hypothalamus.
\nFunctions <\/strong>
\n(i) Vasopressin<\/strong>
\n(a) Retaining water and less amount of urine<\/strong>
\nIt increases the rate of reabsorption of water from nephrons. When we have low amount of water in body fluids, pituitary gland secretes vasopressin and so more reabsorption of water occurs from nephrons into blood. In this way, body retains water and less amount of urine is produced.
\n(b) Less water reabsorption and more amount of urine .<\/strong>
\nOn the other hand, when body fluids have more than normal water, there is a decline in
\nthe secretion of this hormone. If pituitary gland does not secrete this hormone in the required amount, less water is reabsorbed from nephrons and there is excessive loss of water through urine. This condition is known as diabetes insipidus.
\n(ii) Oxytocin<\/strong>
\nThis hormone stimulates the contraction of uterus walls in mothers for child birth.
\nIt is necessary for the ejection of milk from breast
\n2. Thyroid Gland<\/strong>
\nThis is the largest endocrine gland in the human body. It produces two hormones.
\nLocation<\/strong>
\nIt is present in neck region below the larynx.
\ni. Thyroxin Hormone <\/strong>
\nIt produces a hormone thyroxin. Iodine is required for the production of this hormone.
\nDeficiency .
\nIf a person lacks iodine in diet, thyroid gland cannot make its hormone. In this condition, thyroid gland enlarges. This disorder is called goitre.
\nHypothyroidism is caused by the under production of thyroxin.
\nEffects <\/strong>
\nLow energy production in body, slowing down of heartbeat.
\nOver-production<\/strong>
\nHyperthyroidism is caused by over-production of thyroxin.
\nEffects \/ Symptoms<\/strong>
\n(i) Increase in energy production<\/p>\n

(ii) Increase heart beat<\/p>\n

(iii) Frequent sweating<\/p>\n

(iv) Shivering of hands
\nFunction of Thyroxin <\/strong>
\nThyroxin increases the breakdown of food (oxidation) and releases energy in body. It is also responsible for the growth of body.
\nii. Calcitonin Hormone <\/strong>
\nThe thyroid gland produces another hormone called calcitonin.
\nEffects <\/strong>
\nIt decreases the level of calcium ions in blood and promotes the absorption of calcium from blood into bones.
\n3. Parathyroid gland<\/strong>
\nLocation<\/strong>
\nThese are four glands situated on the posterior side of thyroid gland.
\nHormone <\/strong>
\nThis gland produces a hormone known as parathormone.
\nFunction<\/strong>
\nIt increases the level of calcium ions in blood.
\nOver – production <\/strong>
\nWhen there is an increased production of parathormone, more than normal calcium salts are absorbed from the bones and added to blood. Consequently, the bones become brittle.
\nDeficiency<\/strong>
\nIf there is deficiency in the production of parathormone, blood.calcium level falls. It. leads to tetany which affects the function of muscles.
\n4. ADRENAL GLANDS<\/strong>
\nLocation<\/strong>
\nTwo adrenal glands are situated above the kidneys.
\nStructure <\/strong>
\nEach adrenal gland consists of two parts;
\ni. Cortex <\/strong>
\nThe outer part is cortex.
\nii. Medulla <\/strong>
\nThe inner part is medulla.
\nHormone of adrenal medulla <\/strong>
\nAdrenal medulla secretes a hormone called epinephrine or adrenaline in response to stress.
\nEmergency Hormone <\/strong>
\nIt prepares our body to overcome emergency situation. Therefore adrenaline is also termed as an emergency hormone. Hormone of Adrenal cortex
\nThe adrenal cortex secretes many hormones called corticosteroids which maintain the balance of salts and water in blood.
\n5. Pancreas <\/strong>
\nThis organ has two functions:
\nPancreas as Exocrine Gland <\/strong>
\nThe major part of pancreas is a ducted (exocrine) gland. This portion secretes digestive enzymes through a duct into the small intestine.
\nPancreas as Endocrine Gland <\/strong>
\nSome portions of pancreas serve as ductless (endocrine) gland. This portion contains groups of endocrine cells referred to as Islets of Langerhans.
\nHormones of Islets of Langerhans<\/strong>
\nThe islets secrete two hormones i.e. insulin and glucagon.
\n(i) GLUCAGON <\/strong>
\n“It influences the liver to release glucose in blood and blood glucose concentration rises.
\n(ii) INSULIN <\/strong>
\nIt influences the liver to take excess glucose from blood and so the blood glucose concentration falls.
\nDeficiency of insulin <\/strong>
\nIf a person’s pancreas does not make normal quantity of insulin, the blood glucose concentration rises and the person suffers from diabetes mellitus.
\nSymptoms of diabetes <\/strong>
\nPersons with diabetes have:
\ni. Loss of weight
\nii. Weakening of muscles
\niii. Tiredness
\nTreatment of diabetes <\/strong>
\nDiabetes can be controlled by insulin administration. Formerly insulin extracted from animals was used for this purpose. But now. human insulin produced from bacteria through genetic engineering is available.
\n6. GONADS Definition <\/strong>
\nTestes and ovaries are the male and female reproductive organs respectively. They are collectively called gonads.
\nTestes <\/strong>
\nTestes secrete hormones e.g. testosterone, which is responsible for the development of male secondary sex characters such as growth of hair on face and coarseness of voice etc.
\nOvaries<\/strong>
\nOvaries secrete estrogen and progesterone which are responsible for the development of female secondary characters such as the development of breast.
\nThyroid gland
\n\"human
\n\"\"<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Q.12\u00a0What is endocrine system. Describe important endocrine glands. Answer: Endocrine Glands Introduction Endocrine system regulates the activities such as growth, reproduction, maintenance of glucose concentration in blood, reabsorption of water in kidneys etc. Hormones Endocrine system uses chemicals to communicate with its effectors. These chemicals are known as hormones. A hormone is a specific messenger… Read More »Q.12 What is endocrine system. Describe important endocrine glands.<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[23],"tags":[],"_links":{"self":[{"href":"https:\/\/murreeroad.org\/Biology10\/wp-json\/wp\/v2\/posts\/1805"}],"collection":[{"href":"https:\/\/murreeroad.org\/Biology10\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/murreeroad.org\/Biology10\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/murreeroad.org\/Biology10\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/murreeroad.org\/Biology10\/wp-json\/wp\/v2\/comments?post=1805"}],"version-history":[{"count":2,"href":"https:\/\/murreeroad.org\/Biology10\/wp-json\/wp\/v2\/posts\/1805\/revisions"}],"predecessor-version":[{"id":1809,"href":"https:\/\/murreeroad.org\/Biology10\/wp-json\/wp\/v2\/posts\/1805\/revisions\/1809"}],"wp:attachment":[{"href":"https:\/\/murreeroad.org\/Biology10\/wp-json\/wp\/v2\/media?parent=1805"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/murreeroad.org\/Biology10\/wp-json\/wp\/v2\/categories?post=1805"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/murreeroad.org\/Biology10\/wp-json\/wp\/v2\/tags?post=1805"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}