The endocrine system

1. THE ENDOCRINESYSTEM
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

7. HYPOTHALAMUS

8. 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.

9. HYPOTHALAMUS

10. 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.

11. Hypothalamus releasing and inhibiting hormones
1. CORTICOTROPIN RELEASING HORMONE (CRH)
2. THYROTROPIN RELEASING HORMONE (TRH)
3. GROWTH HORMONE RELEASING HORMONE (GHRH)
4. GONADOTROPIN RELEASING HORMONE (GnRH)

12. 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.

13. NEUROHORMONES OF HYPOTHALAMUS…

14. PITUITARY GLAND

15. 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”

16. Pituitary gland is divided into the two parts
1. Anterior pituitary
2. Posterior pituitary

17. Pituitary gland is divided into the two parts

18. ANTERIOR PITUITARY HORMONES
• Growth hormone (GH)
• Adrenocorticotrophic hormone (ACTH)
• Thyroid stimulating hormone (TSH)
• Follicle stimulating hormone (FSH)
• Luteinizing hormone (LH)

19. ANTERIOR PITUITARY HORMONES
1. Growth hormone ( GH)
A) This is the most abundant hormone synthesized by
the anterior pituitary.
B) Its release is stimulated by growth hormone releasing
hormone (GHRH)
C) Stimulates growth of bone & muscle, prompts protein
synthesis and fat metabolism, decrease carbohydrate
metabolism.

20. GROWTH HORMONE ( GH)
A) 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.
B) It also regulates aspects of metabolism in many organs
( liver, intestine & pancreas)

21. 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.

22. ADRENOCORTICOTROPIC HORMONE TEST
Definition
• Adrenocorticotropic hormone test (also known as an
ACTH test or a corticotropin test) measures pituitary gland
function.

23. 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 ).

24. 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.

25. 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

26. NORMAL TSH LEVELS
• Normal TSH levels for the average adult range from
0.4 - 4.0 mIU/L (milli-international units per liter)

27. 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).

28. FOLLICLE STIMULATING HORMONE (FSH)
• Females – stimulates growth of ovarian follicle
• Males – stimulates sperm production

29. 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.

30. 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

31. POSTERIOR PITUITARY

32. POSTERIOR PITUITARY
• The posterior pituitary is formed from nervous tissues
and consist of nerve cell surrounded by supporting “glial”
cells called “ Pituicytes”.

33. POSTERIOR PITUITARY HORMONES
• Anti diuretic hormone ( ADH)
• Oxytocin

34. 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.

35. 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.

36. POSTERIOR PITUITARY HORMONES
OXYTOCIN:
1. Oxytocin is responsible for uterine contractions, both
before and after delivery.
2. 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.

37. 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.

38. THYROID GLAND

39. 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 5th,6th and 7th
cervical and 1st thoracic vertebrae. The lobes are
roughly cone-shaped, about 5cm long &3 cm wide.
• Enlarged in preency and menstruation

40. 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.

41. THYROID GLAND

42. BLOOD SUPPLY
• Superior and inferior thyroid arteries
• Superior middle and inferior thyroid arteries

43. NERVE SUPPLY
• Middle cervical ganglion
• Superior and inferior cervical ganglia

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

45. • 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”

46. 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

47. 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.

48. PARATHYROID GLANDS

49. PARATHYROID GLANDS

50. 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.

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

52. 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.

53. ADRENAL GLAND ( SUPRARENAL GLANDS)

54. ADRENAL GLAND ( SUPRARENAL GLANDS)

55. ADRENAL GLAND ( SUPRARENAL GLANDS)

56. 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.

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

58. 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.

59. NERVE SUPPLY
• The adrenal glands have a rich nerve supply.
These nerves are derived from the coeliac plexus
and the thoracic splanchnic nerves.

60. 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.

61. THE OUTER & INNER PART OF ADRENAL GLAND

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

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

64. 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.

65. THYMUS GLAND

66. THYMUS GLAND

67. 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.

68. 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.

69. PANCRATIC ISLETS

70. 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.

71. 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”.

72. 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.

73. 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.

74. 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.

75. PINEAL GLAND

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

77. 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.

78. 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.