Endocrine system

1. Shri Vishnu College of Pharmacy (Autonomous)
Affiliated to Andhra Univ., Visakhapatnam; Approved by AICTE and PCI, New Delhi, and recognised by APSCHE
ENDOCRINE SYSTEM
Prepared by
Grandhi Sandeep Ganesh
Dept. of Pharmacology

2. PITUTARY GLAND
 Pituitary gland is the master gland of the body.
 The pituitary gland some times called
hypophysis
 It is the smallest structure in the head and main
part of endocrine gland
 The normal adult pituitary gland is reddish-
grey bean shaped gland
 It is also called the Master gland because it
produces the hormones that control other
glands and many body functions including
growth
 Several hormones produced in the
hypothalamus are stored in pituitary gland and
released into blood

3. PITUTARY GLAND
Anatomy of pituitary gland
The pituitary gland is a pea sized, weighs about 500 mg
 It is of 1 cm in diameter
 The pituitary gland lies in the Hypophyseal fossa (Sella turcica) of the
Sphenoid bone below the hypothalamus
 A fold of durameter covers the pituitary gland and has an opening for the
passage of infundibulum (stalk) connecting the gland to the hypothalamus
Anterior pituitary gland
 It is an up growth of glandular epithelium form the pharynx
 It secrete peptide hormones
Posterior pituitary gland
 It is formed form the nervous tissue and nerve cells, surrounding by
supporting glial cells, stores hormones secreted by hypothalamus.

4. HORMONES OF PITUTARY GLAND

5. ANTERIOR PITUTARY GLAND
Hormones
 Growth hormone (GH)
 Thyroid stimulating hormone (TSH)
 Adrenocorticotrophic hormone (ACTH)
 Prolactin
 Gonadotrophins
 Luteinizing hormone (LH)
 Follicle stimulating hormone (FSH)

6. GROWTH HORMONE
 Stimulates the growth of bones, muscle and other organ by increasing protein
synthesis
 Affects protein, fat and carbohydrate metabolism
 Too little secretion of growth hormone can be result of abnormal development of
the pituitary gland
 Growth hormone release is stimulated by growth hormone releasing hormone
 Growth hormone release is supressed by growth hormone releasing inhibiting
hormone
 Its secretion is stimulated by hypoglycemia, exercise and anxiety
 Its secretion is greater during night than day time

7. THYROID STIMULATING HORMONE
 The release of this hormone is stimulated by the thyrotrophin releasing hormone
form the hypothalamus
 It is inhibited by somatostatin released from hypothalamus
 It stimulates the growth and activity of thyroid gland
 Thyroid gland secretes the thyroxine (T4) and tri-iodothyronine (T3)
 When blood level of thyroid hormone is high, secretion of TSH is reduced
 When too much TSH is secreted, it cause the thyroid gland to enlarge and
secrete too much thyroxin

8. ADRENOCORTICOTROPHIC HORMONE
 Adrenocorticotrophic hormone (ACTH) secreted by the release of
Corticotrophin releasing hormone (CRH) form hypothalamus
 ACTH level is highest at midday and lowest at midnight
 It stimulates the synthesis and secretion of adrenal cortical hormone
 ACTH stimulate the adrenal gland (cortex) to secret a hormone called
glucocorticoids
 It is stimulated by the hypoglycemia, stress, exercise and other emotional states
 Its secretion is supressed when blood level of ACTH rises

9. PROLACTIN
 It is also known as lactogenic hormone
 This hormone is secreted during pregnancy for lactation
 It is stimulated by prolactin releasing hormone from hypothalamus
 After birth suckling stimulates the prolactin secretion and lactation
 It inhibits Dopamine from hypothalamus
 Prolactin hypersecretion in males causes erectile dysfunction

10. GONADOTROPHINS
 Anterior pituitary gland secretes to Gonadotrophins i.e., follicle stimulating
hormone (FSH) and luteinizing hormone (LH) before the puberty
Follicle-stimulating hormone
 In both male and female it stimulates the production of gametes ( Ova and sperms
form ovaries and testis respectively)
 In females it stimulates maturation of ovarian follicle and secrete estrogen by
ovaries
Luteinizing hormone
 It is also called interstitial cell stimulated releasing hormone
 In males it stimulates the interstitial cells to secrete testosterone

11. POSTERIOR PITUITARY GLAND
 The hormones of posterior pituitary gland are synthesized in the nerve cell
bodies, transported along the axons and stored in vesicles within the axon
terminals in the posterior pituitary gland
 Nerve impulse form hypothalamus trigger the exocytosis of vesicles and
releasees their hormone into blood stream
 The two hormones released form posterior pituitary gland are
 Oxytocin
 Anti diuretic hormone (ADH, Vasopressin)

12. OXYTOCIN
 It is called as anti stress hormone
 It is produced in both males and females, but its main physiological roles seem to
take place in the female.
 In female, oxytocin is involved in a number of important physiological actions
 Stimulates the contraction of uterus
 Stimulates the contraction of the myoepithelial cells that eject milk form the
brest

13. VASOPRESSIN
 It is also called as antidiuretic hormone
 The main effect of the vasopressin is to reduce the urine output
 Its secretion is determined by osmotic pressure by circulating osmoreceptors in
blood
 High water concentration increases the volume and pressure of your blood.
Vasopressin raised blood pressure by constricting (narrowing) blood vessels.

14. ADRENAL GLAND

15. ADRENAL CORTEX
 Adrenal cortex and the adrenal medulla are best considered as two separate
organs, the former endocrine and the latter neurocranial.
Three main zones of adrenal cortex are –
 Zona glomerulosa-mineralocorticoids
 Zona fasciculata-glucocorticoids
 Zona reticularis-androgens
 Ratios and types of enzymes in each zone of the cortex vary, resulting in
different hormonal products for each region.
 Aldosterone levels are primarily controlled by angiotensin II through renin-
angiotensin- aldosterone system and directly by serum potassium levels. ACTH
is less important in controlling this region’s functions that is why glomerulosa
does not get atrophied in cases with total pituitary failure.

16. ZONA GLOMERULOSA
Outermost
 Only zone contains enzyme aldosterone synthase(CYP11B2)
 Aldosterone regulates electrolyte metabolism by stimulating distal nephron cells
to reabsorb Na and Cl and secreting H and K
 Profound effect on total body Na but conc. Remains same due to water
absorption along with sodium total body volume of Na is increased.
 Aldosterone secretion controlled by angiotensin II through renin-angiotensin-
aldosterone system. ACTH have very little role to play.
 This zone does not atrophy even after total pituitary failure.
 Atrial natriuretic peptide is the main inhibitory regulator of aldosterone secretion
providing important link between cardiac, adrenal and renal function.

17. ZONA FASCICULATA
 Produces glucocorticoids
 Cortisol is the primary glucocorticoid in humans
 Enzymes-17-alfa-hydroxylase,21-hydroxylase and11-beta-hydroxylase present
in this zone lead to production of cortisol under the tight control of ACTH
secreted by anterior pituitary.
 Classic feedback mechanism involves hypothalamus-pituitary-adrenal axis.
 Cortisol secretion follows strict circadian schedule maximum secretion during
early morning hours
 Essential for life-modulate complex physiological pathways including—
Metabolism, immunity, maintenance of intravascular volume, regulation of
blood pressure and complex modulation of CNS with effects on mood, sleep and
memory.

18. ZONA RETICULARIS
 Innermost layer
 Enzymes include-17-alfa-hydroxylase and 17,20-lyase
 Lead to production of DHEA- dehydroepiandrosterone and sulfated DHEA
(DHEA-S); and androstenedione
 Under control of ACTH
 Exhibits circadian pattern
 Maximally produced steroid hormone (>20mg/day) but least important for
physiological homeostasis.
 Pharmacological manipulation gives good results in cases of cancer prostate.

20. ADRENAL MEDULLA
 Less than 10% of total adrenal mass.
 Neither function nor embrologically related to cortex.
 Chromaffin cells exhibit characteristics of sympathetic ganglionic cells
 Secretes epinephrine(80%), norepinephrine(19%) and dopamine(1%)
 Collectively called catecholemines
 Produced from amino acid tyrosine and modulate systemic stress response.
 Effect mediated through their bindind to adenorecepters located on target organs.

21.  PNMT enzyme phenyl ethanolamine-N-methyl transferase converts
norepinephrine to epinephrine is present almost exclusively in medullary cells.
 Function of PNMT is enhanced by cortisol the only link between cortex and
medulla.
 Stored in intracellular vesicles. Released in blood through exocytosis.
 Metabolize into three products viz. Metanephrine, normetanephrine and
vanillylmandelic acid(VMA).
 Two enzymes catechol-o-methyltransferase (COMT) and monoamine
oxidase(MAO) are responsible for metabolism of catecholamines.
 Over 90% of metanephrine and >20% of normetanephrine in blood stream are
derived from adrenal medulla.
 Can be measured and useful in diagnosis of pheochromocytomas.
 Excreted in sulfonated form mostly as VMA in urine can be measured.
ADRENAL MEDULLA

22. THYROID AND
PARATHYROID GLANDS

23. HYPOTHALAMIC-PITUTARY-THYROID AXIS

24. THYROID

25. THYROID GLAND
The thyroid gland is a butterfly
shaped endocrine organ found in
the neck. It is responsible for
regulating the body’s metabolic
rate via hormones it produces.
 Composed of two lobes, left and
right connected by a narrow
isthmus
 Weighs around 25 grams in
adults
 Each lobe being about 5 cm
long, 3 cm wide and 2 cm thick

26. THYROID GLAND
Location
 Located in the anterior neck, between the C5 and T1 vertebrate
 Just inferior to the Adam’s apple and larynx
Anterolateral Posterolateral Posteromedial
• Sternothyroid
• Sternohyoid
• Common carotid
artery
• Internal jugular vein
• Vagus nerve
• Larynx
• Trachea
• Pharynx
• Oesophagus
• External laryngeal
nerve

27. THYROID GLAND LOCATION

28. VASCULAR SUPPLY
 Blood supply to the thyroid gland is achieved by
 Superior thyroid artery
 Inferior thyroid artery
 These are paired arteries arising on both the left and right
Venous drainage
 Venous drainage is carried out by the superior, middle and inferior thyroid
veins which form a venous plexus
 The superior and middle veins drain into the internal jugular veins
 The inferior vein drains into the brachiocephalic vein

29. PHYSIOLOGY
 The thyroid gland is the regulator of Metabolism
 T3 and T4 typically act via nuclear receptors in target tissues and initiate a
variety of metabolic pathways
Metabolic processes increased by thyroid hormones include
 Basal metabolic rate
 Gluconeogenesis
 Glycogenolysis
 Protein synthesis
 Lipogenesis
 thermogenesis

30. HORMONE SYNTHESIS

31. HORMONE REGULATION

32. PARATHYROID GLANDS
 The parathyroid glands are small endocrine glands
 They are responsible for the production of
parathyroid hormone
 It controls calcium levels in the body
Shape
 They are flattened and oval in shape situated external
to the gland itself, but within its sheath
Anatomical location
 They are located on the posterior, medial aspect of
each lobe of the thyroid gland
Size and weight
 Its size is of grain of rice and is about 30 milligrams
weight and 3-4 cms in diameter

33. PARATHYROID GLANDS

34.  Autoimmune = Graves disease
 Infective = De Quervain’s thyroiditis
 Neoplastic = toxic adenoma
 Iatrogenic = drugs such as amiodarone or lithium. Also from over treating
hypothyroidism
Symptoms
 Increased metabolism
 weight loss and increased appetite
 Heat intolerance
 Sweating
 Diarrhoea
 Tremor
 Irritability/restlessness
 Psychosis
 Oligomenorrhoea
HYPERTHYROIDISM

35.  Increased pulse rate
 Atrial fibrillation
 Palmar erythema
 Hair thinning
 Lid retraction
 Goiter, nodules or bruites
HYPERTHYROIDISM

36.  Eye signs – exomphalos, ophthalmoplegia, lid lag and
lid retraction
 Pretibial myxoedema
 Thyroid acropachy
GRAVES DISEASE

37. Diagnosis
 TSH, T4 and T3
 Thyroid autoantibodies - antithyroid peroxidase and
antithyroglobulin antibodies
 TSH receptor antibodies
 Isotope scan
GRAVES DISEASE

38.  Auto immune
 Hashimoto’s thyroiditis
 Primary myoxedema (or primary atrophic hypothyroidism)
 Dietary – iodine deficiency
 Iatrogenic
 congenital
Symptoms
 Tiredness
 Lethargy
 Depression
 Cold intolerance
 Weight gain
 Constipation
 Menorrhagia
 dementia
HYPOTHYROIDISM

39. PANCREAS

40. PANCREAS
 The pancreas is a soft, finely lobulated,
elongated exo-endocrine gland.
 The exocrine part secretes the pancreatic
juice and the endocrine part secretes the
hormone insulin, etc.
 The pancreas (in Greek pan: all, kreas:
flesh).
 Pancreas named because of its fleshy
appearance.
 The pancreatic juice helps in the digestion
of lipids, carbohydrates, and proteins,
whereas the pancreatic hormones maintain
glucose homeostasis

41. LOCATION OF PANCREAS
 The pancreas lies more or less horizontally on the posterior abdominal wall.
 In the epigastric and left hypochondriac regions.
 It crosses the posterior abdominal wall obliquely from concavity of the duodenum to
the hilum of spleen opposite the level of T12– L3 vertebrae.
 The greater part of the gland is retroperitoneal behind the serous floor of the lesser
sac
 The pancreas is “J”-shaped or retort shaped being set obliquely.
 The bowl of retort represents its head and the stem of retort represents its neck,
body, and tail.
 Its measurements are
 Length: 12–15 cm.
 Width: 3–4 cm.
 Thickness: 1.5–2 cm.
 Weight: 80–90 g