Introduction Hypothalamus Pituitary Parts Histology Hormones and it’s Regulation Hormonal disorders and it’s oral manifestations. Conclusion References

1. THE PITUITARY AND THE HYPOTHALAMUS.
BY :MONIKA
1ST YEAR POSTGRADUATE
Department Of public health dentistry

2. Contents:
Introduction
Hypothalamus
Pituitary
Parts
Histology
Hormones and it’s Regulation
Hormonal disorders and it’s oral manifestations.
Conclusion
Refrences

3. INTRODUCTION

4. Hypothalamus:
The hypothalamus is the portion of the anterior end of the
diencephalon that lies below the hypothalamic sulcus.
Hypothalamus and pituitary acts as a single unit due to
their structural and functional relationship.
The anterior pituitary is connected with the
hypothalamus through the hypophyseal portal circulation.

6. This allows the hormones of the
hypothalamus to reach pituitary.
The posterior pituitary is an extension of the
hypothalamus and is mainly formed by
dilated ends of the axons of some
hypothalamic neurones.

7. This allows the hormones of the
hypothalamus to reach pituitary.
The posterior pituitary is an extension of the
hypothalamus and is mainly formed by
dilated ends of the axons of some
hypothalamic neurones.

8. Hypothalamic hormones:
hormones Acting on Leading to
GHRH somatotrophs Release of GH.
TRH Thyrotrophs and
mammotrophs
Release of TSH and
PRL
CRH corticotrophs Release of ACTH
GnRH Gonadotrophs Release of LH and
FSH.
Somatostatin Somatotrophs,
thyrotrophs
Inhibition of GH
Inhibition of TSH
Dopamine mammotrophs Inhibition of PRL

10. Principal hypothalamic regulatory mechanism
Function Afferents from Integrating Areas
Temperature regulation Temperature receptors
in the skin, deep tissues,
spinal
cord, hypothalamus,
and other parts of the
brain
Anterior hypothalamus,
response to heat;
posterior hypothalamus,
response to cold
Neuroendocrine
control of:
Catecholamines Limbic areas concerned
with emotion
Dorsal and posterior
hypothalamus
Vasopressin Osmoreceptors,
“volume receptors,”
others
Supraoptic and
paraventricular nuclei

11. Function Afferents from Integrating Areas
Oxytocin Touch receptors in
breast, uterus, genitalia
Supraoptic and
paraventricular nuclei
Thyroid-stimulating
hormone
Temperature receptors in
infants
Paraventricular nuclei
Adrenocorticotrophin
hormone
Limbic system, anterior
pituitary cells sensitive to
circulating blood cortisol
level, suprachiasmatic
nuclei(diurnal rhythm)
Paraventricular nuclei

12. FUNCTION AFFERENTS FROM INTEGRATING
AREAS
Follicle stimulating
hormone and lutenizing
hormone via GnRH
Hypothalamic cells
sensitive to estrogens,
eyes, touch receptors
in skin and genitalia of
reflex ovulating species
Preoptic area
Prolactin via PIH and
PRH
Touch receptors in
breasts, other unknown
receptors
Arcuate nucleus; other
areas (hypothalamus
inhibits secretion)
Growth hormone via
somatostatin and GRH
Unknown receptors Periventricular nucleus.

13. function Afferents from Integrating areas
thirst Osmoreceptors located
in the organum
vasculosum of the
lamina terminalis.
Lateral superior
hypothalamus
hunger Glucostat cells sensitive
to rate of glucose
utilization; leptin
receptors
Ventromedial, arcuate,
and paraventricular
nuclei; lateral
hypothalamus
Sexual behaviour Cells sensitive to
circulating estrogen and
androgen
Anterior ventral
hypothalamus plus, in
the male, piriform
cortex

14. function Afferents from Integrating areas
Defensive reactions Sense organs and
neurocortex
Limbic system and
hypothalamus
Control of body rhythms Retina via
retinohypothalamic
fibers
Suprachiasmatic
nuclei

15. THE PITUITARY GLAND.
The pituitary gland is an endocrine gland, about the size of pea.
Weighing 0.5 grams to 1grams in humans.
It is situated at the base of brain.
OTHER NAME: HYPOPHYSIS CEREBRI.
Most of the pituitary hormones control other endocrine glands.

16. Terminologies:
Endocrine glands: The gland which have no ducts and pour their
secretions directly into the blood or into the interstitial fluid.
TYPES:
Classical endocrine glands: hormones which act at some distant
site after being carried by blood. e.g. thyroid gland
Paracrine gland: hormones act on adjacent cells. e.g. somatostatin
from islet cells.

17. Autocrine gland: The secretion of the gland act on the same cell.e.g.
platelet activating factor.

18. HORMONES: They are the chemicals produced within the body by
some specialised cells and have specific effects on the activity of
certain organs through specific receptors.
Classification:
 Chemical nature of hormones:
a. Steroid hormones: cortisol, testosterone, esterogen
b. Protein or peptide hormones: insulin, growth hormone, glucagon
etc.
 Nature of action:
a. General : thyroxine, insulin.
b. Local : somatostatin.

19.  According to the receptors through which the hormone acts:
a. Hormones having intracellular receptor: thyroxine, cortisol.
b. Hormones having membrane bound receptors: insulin, glucagon,
epinephrine.
 According to solubility of the hormones:
a. Water soluble: peptide hormones.
b. Lipid soluble: thyroid hormones.

20. PARTS
ANTERIOR PITUITARY OR
ADENOHYPOPHYSIS.
INTERMEDIATE
POSTERIOR PITUITARY OR
NEUROHYPOPHYSIS.

21. Anterior
pituitary
Pars distalis: largest hormone
producing cell.
Pars intermedia: poorly
defined in human.
Pars tuberalis: upward
extension to the anterior lobe
and attached to pituitary
stalk.

22. Posterior lobe
Infundibular stalk: the stem that
connects the pars nervosa to the base of
brain.
Pars nervosa: the
bulk of posterior
pituitary
Median eminence: this
section of
neurohypophysis is
above the pars tuberalis.

23. HISTOLOGY: Depending on the staining
property, the cells of anterior pituitary are
classified into two types namely
chromophobe and chromophil cells.

24. • Chromophobe cell
• 50% of the total cell
• Have granules and stain
properly
• Non seceretory and
precursors of
chromophil cell
• Chromophil cell
• Large number of
granules and darkly
stained
• Staining cells are:
• Acidophilic cells(33%)
• Basophilic cells(15%)

25. Chromophil cell:
 Acidophil cell:
a. Growth hormone
b. Prolactin
 Basophil cell:
a. Adrenocorticotrophic hormone
b. Thyroid stimulating hormone
c. Follicle stimulating hormone
d. Lutenising hormone (LH in females) or interstial cell
stimulating hormone (ICSH in males)

26. Presently the pituitary cells are also named as
follows:
1. Somatotrophs- growth hormone.
2. Corticotrophs - adrenocorticotrophic
hormone.
3. Thyrotrophs -thyroid stimulating hormones.
4. Gonadotrophs – follicle stimulating
hormones.
5. Lactotrophs- secrete prolactin.

27. HORMONES OF ANTERIOR PITUITARY

28. GROWTH HORMONE:
 SOURCE: acidophil cell of anterior pituitary.
 CHEMISTRY: single chain polypeptide with
191 amino acids.

29. Metabolic effects of Growth Hormone:
 Effect of GH on protein metabolism:
Increase the transport of amino acid through cell
membrane and increasing the acceleration of the protein
synthesis.
Increase RNA translation
Increases transcription of DNA or RNA.
Inhibiting the breakdown of cellular protein.

30.  Effects of GH on fat metabolism:
Causes mobilisation of fatty acids from the
adipose tissues.
 Carbohydrate metabolism:
Decrease in the peripheral utilization of glucose
for the production of energy,
Increase in the deposition of the glycogen in
the cells,
Decrease in the uptake of glucose by the cells.

31. Effect of growth hormone on bones:
Increase in the protein deposits by chondrocytes
and osteogenic cells.
Increase in the multiplication of osteogenic cells.
Increase in the formation of new bones by
conversion of chondrocytes into osteogenic cells.

32. Mode of action:
No direct action on bones.
GH stimulates the liver to secrete somatomedin.
Sometimes inspite of the presence of GH
dwarfism occurs due to absence of
somatomedin.

33. Somatomedin:
It is a polypeptide.
In humans only two types are present :
Insulin like growth factor1, also called somatomedin C
and act on bones and causes growth.
Insulin like growth factor2 acts on the growth of the
foetus.

34. Duration of action of the GH.
The action of hormone lasts for 20mins.
But somatomedin binds with plasma protein very
strongly so molecules of it are released slowly.
The action takes about 20hours.
The mode of action of somatomedin is by the
formation of the second messenger called cyclic
amp.

35. Regulation of GH secretion.

36. Ghrelin is a polypeptide hormone
synthesized by epithelial cells of fundus of
stomach, hypothalamus, pituitary, kidney and
placenta and stimulates somatotrophes
directly.

37. Prolactin:
Source of secretion: mammotrophs of anterior
pituitary.
Chemistry: it is a protein with 198 amino acids.
Its secretion is pulsatile i.e. shows no fixed
plasma value.

38. Effects of Prolactin.
It helps in developement of the mammary glands.
After child birth, PRL helps in initiation and maintenance
of lactation with the help of other hormones.
PRL inhibits synthesis and secretion of GnRH and leads
to ammenorrhoea, in lactating women causes lactational
ammenorhoea and PRL in man leads to impotence.

40. Adrenocorticotrophic hormone
Source of secretion: Corticotrophs of the anterior
pituitary.
Chemistry: polypeptide with 39 amino acids.
It is secreted in the form of a large precursor molecule
called prepro-opiomelanocortin.
ACTH acts via membrane receptors with production of
cAMP.

41. Regulation of ACTH.

42. Functions of ACTH
It causes stimulation of the adrenal cortex and is
also trophic to it.
It acts against stress.
It stimulates secretion of glucocorticoids mainly.
It stimulates melanocytes and lipolysis.

43. Biological clock
Various phsiological processes in the body show
rhythmical changes.
These rhythmical changes are due to some
mechanism operating like a clock within the body
hence called biological clock.
There is a increased ACTH secretion in the
morning.

44. Circadian rhythm means the change which
occur daily.
It probably operates through the
hypothalamus which gets information about
the night and day from retina through the
retinohypothalamic fibres via the
suprachiasmatic nucleus.

45. Circadian rhythm means the change which
occur daily.
It probably operates through the
hypothalamus which gets information about
the night and day from retina through the
retinohypothalamic fibres via the
suprachiasmatic nucleus.

46. Thyroid stimulating hormone.
Source of secretion: From the thyrotrophs of the anterior
pituitary gland.
It is glycoprotein in nature and glycosylation helps in the
stability of the molecule.
It is composed of two subunits: alpha and beta.

47. Function of TSH.
It stimulates thyroid acinar cells to secrete
thyroid hormones.
It is also trophic to the thyroid gland.

48. Regulation of TSH.

49. Hormones of Posterior pituitary.
Antidiuretic hormone(ADH)
Also known as vasopressin.
Source of secretion:
The majority of which is released from the supra-
optic nucleus in the hypothalamus.
Chemistry: polypepetide with 9 amino acids.

50. ACTIONS:
Retention and re-absorption of water from distal
convoluted tubule and collecting ducts in the
kidneys.
In absence of ADH, the re-absorption of water does
not occur and dilute urine is excreted and leads to
large amount of water loss through urine.

51. Regulation of secretion of ADH

53. OXYTOCIN
Source of secretion:
Paraventricular nucleus.
Supraoptic nucleus in the hypothalamus.
Chemistry:
Polypeptide having 9 amino acids.

54. Action:
Oxytocin is one of the few hormones to create a
positive feedback loop.
For example, uterine contractions stimulate the
release of oxytocin from the posterior pituitary,
which, in turn, increases uterine contractions and
this positive feedback loop continues throughout
labour.

55. Action on mammary gland: causes contraction
of myo-epithelial cells and ejection of milk.
This reflex is known as milk down reflex.
Milk Ejection Reflex: when the infant sucks the
touch receptors are carried by the somatic
afferent nerve fibers and reach the ventricular
and supra-optic nucleus of the hypothalami.

56. Action on mammary gland: causes contraction
of myo-epithelial cells and ejection of milk.
This reflex is known as milk down reflex.
Milk Ejection Reflex: when the infant sucks the
touch receptors are carried by the somatic
afferent nerve fibers and reach the ventricular
and supra-optic nucleus of the hypothalami.

57. Action of oxytocin on uterus
On pregnant uterus: it causes contraction of the
uterus and helps in the expulsion of foetus.
Non-pregnant uterus: facilitate the transport of
sperm through the female genital tract up to the
fallopian tube by producing the uterine
contractions.

58. Disorders of pituitary gland.
Due to HYPERACTIVITY of Anterior pituitary:
a. Gigantism
b. Acromegaly
c. Cushing syndrome
Due to Hypoactive Anterior pituitary:
a. Dwarfism
b. Acromicria
c. Simmonds disease or pituitary cachexia

59. Due to hypoactive posterior pituitary:
a. Diabetes insipidus
Due to hyperactive posterior pituitary:
a. Syndrome of inappropriate hypersecretion of
ADH(SIADH)
Due to hypoactive anterior and posterior
pituitary:
a. Dystrophia adiposogenitalis or frolich’s
syndrome:

60. Gigantism :
The person affected grows big like a giant and
hence the name of condition gigantism.
CAUSE: due to excessive secretion of growth
hormone before the union of the epiphyses of
the long bones.
The individual grows to a height of 7 to 8ft.

61. Gigantism :
The person affected grows big like a giant and
hence the name of condition gigantism.
CAUSE: due to excessive secretion of growth
hormone before the union of the epiphyses of
the long bones.
The individual grows to a height of 7 to 8ft.

62. Oral manifestations of gigantism:
Enlarged maxilla and mandible.
Marked increase in the vertical dimension of
face.
Large size of teeth (macrodontia ) and early
eruption of teeth.
Macroglossia and hypercemetosis of teeth.

63. Oral manifestations of gigantism:
Enlarged maxilla and mandible.
Marked increase in the vertical dimension of
face.
Large size of teeth (macrodontia ) and early
eruption of teeth.
Macroglossia and hypercemetosis of teeth.

64. Acromegaly
This condition is due to hyperseretion of GH in
adults after fusion of epiphysis with shaft of the
bone.

65. Acromegaly
This condition is due to hyperseretion of GH in
adults after fusion of epiphysis with shaft of the
bone.

66. Oral manifestations of acromegaly:
The striking facial features are:
Protrusion of the supraorbital ridges,
Broadening of nose,
Thickening of lips,
Thickening and wrinkles formation on forehead and
protrusion of lower jaw prognathism. Thus face with
these features are called acromegalic or guerilla face.

67. Oral manifestations of acromegaly:
The striking facial features are:
Protrusion of the supraorbital ridges,
Broadening of nose,
Thickening of lips,
Thickening and wrinkles formation on forehead and
protrusion of lower jaw prognathism. Thus face with
these features are called acromegalic or guerilla face.

68. GENERAL FEATURES OF
ACROMEGALY:
Enlargement of the hands and feet with
bowing of spine called KYPHOSIS.
Joint pain,
General overgrowth of the body hair.
Thyroid gland, parathyroid gland and
adrenal glands show hyperactivity.

69. GENERAL FEATURES OF
ACROMEGALY:
Enlargement of the hands and feet with
bowing of spine called KYPHOSIS.
Joint pain,
General overgrowth of the body hair.
Thyroid gland, parathyroid gland and
adrenal glands show hyperactivity.

70. Cushing’s disease:
characterised by increased secretion
of adrenocorticotropic hormone (ACTH) from
the anterior pituitary .

71. Cushing’s disease:
characterised by increased secretion
of adrenocorticotropic hormone (ACTH) from
the anterior pituitary .

72. Clinical features of cushing’s disease:
Persistent hyperglycemia,
Increased capillary fragility resulting in
ecchymosis, easy brusiability,
Severe osteoporosis leads to pathological bone
fracture under low impact trauma. The bones
commonly affected are maxilla , mandible and
alveolar bone.

73. Abnormal fat deposition in the orofacial region
produces puffy and bilateral edematous swelling-
Moon FACIES.
Abnormal fat deposition on the neck- buffalo hump.
Decreased immunity.
Due to suppression of inflammatory response,
people with cushing’s disease show few sign’s of
inflammation and also demonstrate poor wound
healing and this includes healing of EXTRACTION
SOCKET and JAW FRACTURE WOUNDS.

74. Abnormal fat deposition in the orofacial region
produces puffy and bilateral edematous swelling-
Moon FACIES.
Abnormal fat deposition on the neck- buffalo hump.
Decreased immunity.
Due to suppression of inflammatory response,
people with cushing’s disease show few sign’s of
inflammation and also demonstrate poor wound
healing and this includes healing of EXTRACTION
SOCKET and JAW FRACTURE WOUNDS.

75. DWARFISM:
It results due to growth hormone defeciency in
infancy or early childhood.

76. DWARFISM:
It results due to growth hormone defeciency in
infancy or early childhood.

77. Oral manifestations:
Small face in comparison to the skull.
Delayed exfoliation of deciduos teeth.
Delayed eruption of permanent teeth.
Underdevelopement of maxilla and mandible.
Lack of development of third molars.

78. PANHYPOPITUITARISM: Due to hypofunction of
pituitary as a whole.
These cases respond well to treatement by growth
hormone.
LARON SYNDROME: disorder characterized by
an insensitivity to growth hormone (GH), usually
caused by a mutant growth hormone receptor.
It causes short stature and an increased sensitivity
to insulin which means that they are less likely to
develop diabetes mellitus type 2.

79. PANHYPOPITUITARISM: Due to hypofunction of
pituitary as a whole.
These cases respond well to treatement by growth
hormone.
LARON SYNDROME: disorder characterized by
an insensitivity to growth hormone (GH), usually
caused by a mutant growth hormone receptor.
It causes short stature and an increased sensitivity
to insulin which means that they are less likely to
develop diabetes mellitus type 2.

80. Dwarfism due to ACHONDROPLASIA:
This condition results due to failure of the
epiphyseal plates to grow due to genetic defects.
The subject is short in height due to decreased
length of the extremities but is other wise
normal.

81. Dwarfism due to ACHONDROPLASIA:
This condition results due to failure of the
epiphyseal plates to grow due to genetic defects.
The subject is short in height due to decreased
length of the extremities but is other wise
normal.

82. Acromicria:
Rare disease in adult characterised by the atrophy of the extremities of
the body
Cause: defeciency of GH realeasing hormone from adults.
Atrophy and degeneration of acidophilic cells in the anterior pituitary.
Clinical manifestations:
Atrophy and thinning of extremities.
The facial bones, especially sphenoid and mandibular, are also
underdeveloped.

83. Acromicria:
Rare disease in adult characterised by the atrophy of the extremities of
the body
Cause: defeciency of GH realeasing hormone from adults.
Atrophy and degeneration of acidophilic cells in the anterior pituitary.
Clinical manifestations:
Atrophy and thinning of extremities.
The facial bones, especially sphenoid and mandibular, are also
underdeveloped.

84. Simmonds disease:
Also called pituitary cachexia.
Cause: due to defeciency of all pituitary
hormones.

85. Syndrome of inappropriate anti-diuretic hormone(SIADH)
Cause: commonly results from malignancies resulting in
damage to the hypothalamus or pituitary which causes
failure of the feedback loop that regulates ADH.
Signs and symptoms:
Lethargy and weakness,
Confusion ,
Cerbral edema,
Muscle cramps,
Decreased urine output.

86. • The following laboratory tests may be helpful in the
diagnosis of SIADH:
• Serum sodium, potassium, chloride, and bicarbonate.
• Plasma osmolality.
• Serum creatinine.
• Blood urea nitrogen.
• Blood glucose.
• Urine osmolality.
• Serum uric acid.
• Serum cortisol.

87. DIABETES INSIPIDUS
CAUSE: can occur with damage to the
hypothalamus or the pituitary.
May be a result of defect in renal tubules do not
respond to ADH.
Diagnostic tests:
Serum sodium
Urine specific gravity
Serum osmolality
Urine osmolality

88. Vasopressin test and water deprivation test:
increased hyperosmolality is diagnostic for
DI.
Hand schuller christian disease’s one of the
feature is DIABETES INSIPIDUS.

89. Fröhlich's syndrome
Fröhlich's syndrome, also called Adiposogenital
Dystrophy, rare childhood metabolic disorder
characterized by obesity, growth retardation, and
retarded development of the genital organs.
It is usually associated with tumours of the
hypothalamus, causing increased appetite and
depressed secretion of gonadotropin.

90. Conclusion:
The endocrine system is responsible for hormonal secretion and
is closely related to the central nervous system, as it diversifies
its functions through the hypothalamus and pituitary glands.
It controls physiological processes and maintains homeostasis.
The neuroendocrine system is responsible for adaptation to
environmental changes.
Therefore, in dentistry, it is important to be aware of the risks
and difficulties that may arise during the dental management of
patients with endocrine disorders, and that visits to the dental
clinics often represent a stressful situation

91. References:
Guyton. Textbook of physiology: 4th edition.
Sembulingam 19th edition.
Mahapatra: Essentials of medical physiology.
Ganong’s: Review of medical physiology.
Shafer’s: Text book of oral pathology.