The endocrine system

The endocrine system

1. THE ENDOCRINE SYSTEM Mr. ANILKUMAR B R( MS.c Nursing ) Lecturer Medical – surgical Nursing

2. THE ENDOCRINE SYSYTEM

3. objectives 1.) To identify and locate the different endocrine organs of the human body. 2.) To differentiate the organs of the endocrine system as to their function and importance

4. introduction The endocrine system is made up of glands that produce and secrete hormones, chemical substances produced in the body that regulate the activity of cells or organs. These hormones regulate the body's growth, metabolism (the physical and chemical processes of the body), and sexual development and function. The hormones are released into the bloodstream and may affect one or several organs throughout the body.

5. Functions of endocrine systems 1. It maintain and regulate functions of the vital organs 2. For growth and development 3. For reproduction 4. Response to injury and stress 5. Energy metabolism 6. For fluid, electrolyte and acid-base balance 7. Reproductive function control

6. hypothalamus

7. WHAT IS HYPOTHALAMUS? The portion of the brain that contains a number of small nuclei with a variety of functions. The control center of all autonomic regulatory activities of the body.

8. hypothalamus

9. hypothalamus The hypothalamus is a section of the brain responsible for the production of many of the body’s essential hormones, chemical substances that help control different cells and organs. The hormones from the hypothalamus govern physiologic functions such as temperature regulation, thirst, hunger, sleep, mood, sex drive, and the release of other hormones within the body.

10. Hypothalamus releasing and inhibiting hormones CORTICOTROPIN RELEASING HORMONE (CRH) THYROTROPIN RELEASING HORMONE (TRH) GROWTH HORMONE RELEASING HORMONE (GHRH) GONADOTROPIN RELEASING HORMONE ( GnRH )

11. FUNCTION of hypothalamus The most important functions of the hypothalamus is to link the nervous system to the endocrine system via the pituitary gland. • It synthesizes and secretes certain “ neurohormones” , often called hypothalamic-releasing hormones, and these in turn stimulate or inhibit the secretion of pituitary hormones.

12. Neurohormones of hypothalamus…

13. PITUITARY GLAND

14. PITUITARY GLAND The pituitary gland or also called ( HYPOPHYSIS) is a round structure about 1.27 cm in diameter and 1gm located on the inferior aspect of the brain. Commonly referred to as “ Master gland”

15. Pituitary gland is divided into the two parts Anterior pituitary Posterior pituitary

16. Pituitary gland is divided into the two parts

17. Anterior pituitary hormones Growth hormone (GH) Adrenocorticotrophic hormone (ACTH ) Thyroid stimulating hormone (TSH) Follicle stimulating hormone (FSH) Luteinizing hormone (LH)

18. Anterior pituitary hormones Growth hormone ( GH) This is the most abundant hormone synthesized by the anterior pituitary. Its release is stimulated by growth hormone releasing hormone (GHRH) Stimulates growth of bone & muscle, prompts protein synthesis and fat metabolism, decrease carbohydrate metabolism.

19. Growth hormone ( GH) Body growth in response to the secretion of GH is evident during childhood and adolescence, & thereafter secretion of GH maintains the mass bone and skeletal muscle. It also regulates aspects of metabolism in many organs ( liver, intestine & pancreas)

20. Adrenocorticotrophic hormone (ACTH) Stimulates synthesis and secretion of adrenal cortical hormones. Corticotrophin releasing hormone (CRH) from the hypothalamus promotes the synthesis and release of ACTH by the anterior pituitary.

21. Adrenocorticotropic Hormone Test Definition Adrenocorticotropic hormone test (also known as an ACTH test or a corticotropin test) measures pituitary gland function.

22. Purpose The pituitary gland produces the hormone ACTH, which stimulates the outer layer of the adrenal gland (the adrenal cortex). ACTH causes the release of the hormones hydrocortisone ( cortisol ), aldosterone , and androgen. The most important of these hormones released is cortisol . The ACTH test is used to determine if too much cortisol is being produced ( Cushing's syndrome ) or if not enough cortisol is being produced ( Addison's disease ).

23. Thyroid stimulating hormone (TSH) TSH is a hormone that controls thyroid function. It stands for Thyroid Stimulating Hormone . It is actually produced by the brain’s pituitary gland , but stimulates production of the hormones triiodothyronine (T3) and thyroxine (T4) in the thyroid gland. When the blood level of thyroid hormones is high secretion of TSH is reduced & vice versa. The amount and balance of these hormones affects almost every physiological process in the body, particular your body’s metabolism.

24. Several other factors can also influence TSH levels: Inflammation of the thyroid gland Genetics Deficiency or excess of iodine in the diet Poisonous substances and radiation exposure Pregnancy & Thyroid cancer Certain medications- antidepressants, cholesterol lowering drugs, chemotherapy drugs, steroids

25. Normal TSH levels Normal TSH levels for the average adult range from 0.4 ‑ 4.0 mIU /L ( milli -international units per liter)

26. Follicle stimulating hormone (FSH) Follicle stimulating hormone is produced by the pituitary gland. It regulates the functions of both the ovaries and testes. Lack or insufficiency of it can cause infertility or sub fertility both in men and women. In both gender ( male/ female) FSH stimulates production of “Gametes “ ova in female and spermatozoa in males by the gonads ( testis and ovaries).

27. Follicle stimulating hormone (FSH) Females – stimulates growth of ovarian follicle Males – stimulates sperm production

28. Luteinizing hormone (LH) LH is a hormone released by the pituitary gland. In females LH and FSH are involved in secretion of the hormones ( Estrogen and progestone during the menstrual cycle. In males LH , also called “ Interstitial cell stimulating hormone ( ICSH) Stimulates secretion of “ Testosterone” development of intersitial tissue of tstes .

29. Hormones secreted by the anterior pituitary and their functions HORMONES FUNCTIONS Growth hormone (GH) Regulates metabolism ,promotes tissues growth esp. of bones & muscles. Thyroid stimulating hormone ( TSH) Stimulates growth & activity of thyroid gland & secretion of T1 & T 2 Adrenocorticotrophic hormone (ACTH) Stimulates adrenal cortex to secrete glucocorticoids Prolactin (PRL) Stimulates milk production in the breast after child birth Follicle stimulating hormone (FSH) Stimulates production of sperm in the testes , stimulates secretion of oestrogen by the ovaries ,maturation of ovarian follicles, ovulation. Luteinising hormone (LH) Stimulates secretion of testosterone by the testes , Stimulates secretion of progesterone by the corpus luteum

30. Posterior pituitary

31. Posterior pituitary The posterior pituitary is formed from nervous tissues and consist of nerve cell surrounded by supporting “ glial ” cells called “ Pituicytes ”.

32. Posterior Pituitary Hormones Anti diuretic hormone ( ADH) Oxytocin

33. Anti diuretic hormone ( ADH) The main effect of ADH is to reduce urine output ( dieresis is the production of large volvume of urine) The function of ADH is to inhibit or prevent the formation of urine. Increase reabsorption by kidney Secretion of ADH is also stimulated by pain, low blood pressure and drugs such as nicotine, morphine and barbiturates. In trauma situations, a great deal of ADH is released, to counteract blood loss.

34. Posterior Pituitary Hormones The hormones released by the posterior pituitary are actually synthesized in the hypothalamus. They migrate along nerve fibers to the posterior pituitary, and are stored until stimulated to be released into the general circulation.

35. Posterior Pituitary Hormones OXYTOCIN: Oxytocin is responsible for uterine contractions, both before and after delivery. Oxytocin stimulates two target tissues during and after child birth or delivery. 3. The muscle layers of the uterus (myometrium) become more sensitive to oxytocin near term.

36. Oxytocin The oxytocin levels increase during sexual arousal in both males /females. Oxytocin is also responsible for milk ejection during breastfeeding, by contraction of the myoepithelial cells in the lactating mammary gland. It is believed that smell of oxytocin may be involved in social recognition and bonding between mother and baby. Example. If you a breast –feeding mother, hearing your baby cry, thinking about your baby, or smelling your baby can cause the letdown reflexes to occur.

37. Thyroid gland

38. Thyroid gland Largest endocrine gland and butterfly shaped. The thyroid gland is situated in the neck in front of the larynx and trachea at the level of the 5 th,6th and 7 th cervical and 1 st thoracic vertebrae. The lobes are roughly cone-shaped, about 5cm long &3 cm wide. Enlarged in preency and menstruation

39. Thyroid gland 5cm long and 3cm wide and weighs about 25 to 30 gm Consisting of two lobes, one on either side of the thyroid cartilage and upper cartilaginous ring.

40. Thyroid gland

41. Blood supply Superior and inferior thyroid arteries Superior middle and inferior thyroid arteries

42. Nerve supply Middle cervical ganglion Superior and inferior cervical ganglia

43. MAJOR ACTIONS & SOURCE OF Thyroid gland HORMONES Thyroid gland produce two principal hormones they are: Triiodothyronine (T3 ) Thyroxine ( T4 ) This Triiodothyronine and Thyroxine which regulates the metabolic rate of the body.

44. For the functioning of Triiodothyronine and Thyroxine hormone Iodine is essential. The main source of iodine are sea foods, veg grown in iodine rich soil and table salt. The thyroid gland selectively takes up iodine from the blood a process is called “ Iodine trapping”

45. Common effects of abnormal secretion of thyroid hormones HYPERTHYRODISM ( increased T3 & T4 secretion) HYPOTHYRODISM( decreased T3 & T4 secretion) Increased basal metabolic rate (BMR) Decreased basal metabolic rate (BMR) Anxiety, physical restlessness, mental excitability Depression, psychosis, mental slowness, lethargy Hair loss Dry skin, brittle hair Tachycardia, palpitations, atrial fibrillation Bradycardia ( Decrease heart or pulse rate) Warm sweaty skin, heat intolerance Dry cold skin, prone to hypothermia Diarrhea Constipation Weight loss & good appetite Weight gain, Anorexia Exophthalmous in Grave’s disease

46. Thyroid cells CAICITONIN : This hormone is secreted by the para follicular or C- cells in the thyroid gland. The main functions is : 1.Lowers blood calcium and phosphate levels. 2. Bone cells promoting their storage of calcium 3. Kidney tubules inhibiting the re-absorption of calcium.

47. Parathyroid glands

48. Parathyroid glands

49. Parathyroid glands Parathyroid glands are small glands of the endocrine system which are located in the neck behind the thyroid. Parathyroid glands control the calcium in our bodies--how much calcium is in our bones, and how much calcium is in our blood. Calcium is the most important element in our bodies so calcium is regulated very carefully. Parathyroid glands control the calcium.

50. Parathyroid glands There are four small parathyroid glands and its located on posterior surface of the thyroid gland each weighing around 50 g.

51. functions Parathyroid glands The only purpose of the parathyroid glands is to regulate the calcium level in our bodies within a very narrow range so that the nervous and muscular systems can function properly. The main function of parathyroid glands to balance blood calcium levels. Parathorone and calcitonin from the Thyroid gland act in a complimentary manner to maintain blood calcium levels within the normal range.

52. ADRENAL GLAND ( SUPRARENAL GLANDS)

53. ADRENAL GLAND ( SUPRARENAL GLANDS)

54. ADRENAL GLAND ( SUPRARENAL GLANDS)

55. ADRENAL GLAND ( SUPRARENAL GLANDS) The suprarenal glands, also known as adrenal glands, belong to the endocrine system. They are a pair of triangular-shaped glands each about 4cm  long and 3cm thick. They two numbers that sit atop the each kidney. The suprarenal glands are responsible for the release of hormones that regulate metabolism, immune system function, and the salt-water balance in the bloodstream; they also aid in the body’s response to stress.

56. ADRENAL GLAND ( SUPRARENAL GLANDS) The right adrenal gland Triangular shape The left adrenal gland semi lunar shape

57. Blood supply A rich blood supply is essential for the optimal function of the adrenal glands. Each gland is supplied by the superior, middle and inferior suprarenal arteries, which arise from the inferior phrenic artery, abdominal aorta and renal artery respectively.

58. Nerve supply The adrenal glands have a rich nerve supply. These nerves are derived from the coeliac plexus and the thoracic splanchnic nerves.

59. ADRENAL GLAND ( SUPRARENAL GLANDS) The adrenal glands are composed of two parts which have different structures and functions: 1. The outer part is the Cortex and the inner part is the Medulla . The adrenal cortex is essential to life but the medulla is not.

60. The outer & inner part of adrenal gland

61. ADRENAL CORTEX The adrenal cortex produces three groups of steroid hormones from cholesterol. They are collectively called “ adrenocorticocoids”. T hey are Glucocorticoids - Cortisol (hydrocortisone) & cortisone are the main glucocorticoids . They are essential for life, regulating metabolism and responses to stress. Mineralocorticoids – Aldosterone is the main mineralaocorticoid . Its functions are associated with the maintains of water & electrolyte balance in the body.

62. Sex hormones ( androgens) - sex hormones secreted by the adrenal cortex are mainly androgens ( Male sex hormone)

63. Adrenal medulla The medulla is completely surrounded by the cortex. And is develops from nervous tissues in the embryo and is part of the sympathetic nervous division.

64. Thymus gland

65. Thymus gland

66. Thymus gland The thymus gland is Located in the upper chest, the thymus gland is a part of the endocrine system and produces several hormones . The thymus gland is “ Heart of the immune system”. Designed to greater destroy infectious microorganisms.

67. Thymus gland The weight of thymus gland 10 to 15 gm at birth and grows until puberty. The thymus is a primary Lymphoid organ where “T” cells lymphocytes develop and undergrow maturation.

68. PANCRATIC ISLETS

69. PANCRATIC ISLETS The pancreatic islets also called “ islets of Langerhans” or island of Langerhans are the regions of the pancreas that contain its endocrine (i.e., hormone-producing) cells. The most common islet cell the Beta cell . Insulin is the major hormone in the regulation of carbohydrates, fat, and protein metabolism.

70. There are three main types of cells in the pancreatic islets. 1 .  (alpha) 20 % cells that secrete “glucagon”. 2 .  (beta) 75% cells that secrete “insulin”. 3 .  (delta) 5% cells that secrete “somatostatin”.

71. INSULIN A hormone produced in the pancreas by the islets of Langerhans, which regulates the amount of glucose in the blood. The lack of insulin causes a form of diabetes mellitus. The main function of insulin is to lower blood levels of absorbed nutrients when they rise above normal.

72. GLUCAGON A hormone formed in the pancreas which promotes the breakdown of glycogen to glucose in the liver and assist insulin in regulating blood glucose in the normal range. 1. Gluconeogenesis: The synthesis of glucose from non- carbohydrate source ( such as amino acids & glycerol) 2 . Glygogenolysis: Glycogen breakdown releases glucose when it is needed.

73. SOMATOSTATIN ( GHRIH) Also known as growth inhibiting hormone The effect of this hormone, also produced by the hypothalamus , is to inhibit the secretion of both insulin and glucagon.

74. PINEAL GLAND

75. PINEAL GLAND Pineal gland, also called conarium , epiphysis cerebri , pineal organ, or pineal body, endocrine gland . Small body attached to the roof of the 3 rd ventricle of the brain. Containing nerves that connect to the hypothalamus 10 mm long and reddish color Secrete the hormone “ Melatonin”

76. Melatonin Melatonin is a hormone made by the pineal gland . Melatonin is major hormone secreted by the pineal gland . Melatonin is controlled by daylight and darkness levels, fluctuate during each 24 hours period the being highest at night and the lowest around mid-day.

77. functions of Melatonin Melatonin helps control sleep and wake cycles. Coordination of the circadian and diurnal rhythms of many tissues ,possibly by influencing the hypothalamus. Inhibition of growth and development of the sex organs before puberty.