This is a short overview of pituitary and pineal gland anatomy, physiology, and disorders of the hormones they secrete.

1. Pituitary and pineal gland

2. Objectives
 Define pituitary gland.
 Discuss the anatomy of the pituitary gland.
 Discuss the role of hypothalamic hormones in the
regulation of pituitary gland secretion.
 Discuss the function of hormones secreted from
the anterior and posterior pituitary gland
 Define pineal gland.
 Discuss the anatomy of the pineal gland.
 Discuss the function of hormones secreted from
pineal gland.
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3. Outline
 Introduction to Pituitary gland.
 Anatomy of pituitary gland.
 Division of pituitary gland.
 Anterior pituitary gland hormones and their
disorders.
 Posterior pituitary gland hormones and their
disorders.
 Overview of Pineal gland.
 Hormone of pineal gland and the disorder of
pineal gland.
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4. Pituitary Gland
“The Master gland of the
body”
 Pituitary gland is the small structure in the head and
main endocrine gland.
 The normal adult pituitary gland is a 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.
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6. Anatomy of Pituitary Gland
 The pituitary gland is a pea
sized, weighs 500 mg located at
the base of brain.
 It is 1cm in diameter.
 The pituitary gland lies in the
Hypophyseal fossa (Sella
turcica) of the Sphenoid bone
below the hypothalamus.
 A fold of duramater covers the
pituitary gland and has an
opening for the passage of
infundibulum (stalk) connecting
the gland to the hypothalamus.
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7. Division of pituitary gland
 It consists of two main parts that originate from
different type of cells.
 Anterior pituitary gland (Adeno hypophysis):
It is an up growth of glandular epithelium from the pharynx.
 It secrete peptide hormones.
 Posterior pituitary gland (neurohypophysis):
It is formed from the nervous tissue and nerve cells, surrounding by
supporting glial cells (pituicytes).
It stores hormones secreted by the hypothalamus.
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8. Relation of Hypothalamus and
Pituitary gland
 The connection between the hypothalamus and the
pituitary gland results from hormones released from
the hypothalamic neurons.
 The hypothalamus has two different connections
with the pituitary gland.
 The connection to the adenohypophysis (the anterior
lobe) is via a special portal blood system.
 Whereas the connection to the neurohypophysis (the
posterior lobe) is directly through neurons.
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9. Blood supply to pituitary gland
 Arterial blood supply:
◦ Superior and inferior hypophyseal arteries,
branches of internal carotid.
◦ Anterior lobe is supplied indirectly by blood
(from hypothalamus).
◦ Posterior lobe is supplied directly.
 Venous drainage:
◦ Containing hormones from both lobes, venous
blood leaves the gland and enter the venous
sinuses between the layers of dura-mater.
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11. Hormones of the pituitary
gland
 The hormones of the pituitary gland send signals to other
endocrine glands to stimulate or inhibit their own
hormone production.
 For example, the anterior pituitary lobe will release
adrenocorticotropic hormone (ACTH) to stimulate
cortical production in the adrenal glands when you’re
stressed.
 The anterior lobe releases hormones upon receiving
releasing or inhibiting hormones from the hypothalamus.
 These hypothalamic hormones tell the anterior lobe
whether to release more of a specific hormone or stop
production of the hormone.
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12. Hormones produced by
anterior pituitary gland
 Growth hormone (GH)
 Thyroid-stimulating hormone (TSH)
 Adrenocorticotrophic hormone (ACTH)
 Prolactin (PRL)
 Gonadotrophins
I. Luteinizing hormone (LH)
II. Follicle-stimulating hormone (FSH)
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13. Growth hormone
 Its release is stimulated by GHRH suppressed by
GHRIH secreted by hypothalamus.
 Secretion is also stimulated by hypoglycemia,
exercise and anxiety.
 Secretion is greater during night sleep than day.
 Dysfunction of the endocrine system‘s control of
growth can result in several disorders.
 Hyper-secretion can cause gigantism ( in children)
or acromegaly( in adult).
 Hypo-secretion lead to pituitary dwarfism.
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14. Thyroid Stimulating Hormone(TSH)
 The release of this hormone is stimulated by the
Thyrotrophin Releasing Hormone(TRH) from the
hypothalamus.
 It stimulates the growth and activity of thyroid
gland.
 Thyroid gland secretes the thyroxine (T4) and
TriIodothyronine (T3).
 Its level is highest during the night.
 When blood level of thyroid hormone is high,
secretion of TSH is reduced
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15. Adrenocorticotrophic hormone(ACTH)
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 Triggers the adrenal glands.
 It stimulates the synthesis and secretion of adrenal
cortical hormone.
 It is stimulated by the hypoglycemia, stress,
exercise and other emotional states.
 Its secretion is suppressed when blood level of
ACTH rises
 ACTH level is highest at midday and lowest at
midnight.

16. Prolactin
 This hormone is secreted during pregnancy for
lactation.
 It is stimulated by prolactin releasing hormone
(PRH) from hypothalamus.
 During pregnancy, it contributes to development of
the mammary glands.
 After birth it stimulates the mammary glands to
produce breast milk(lactation).
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17. Gonadotropins (FSH and LH)
 Just before puberty two Gonadotropins are secreted
in gradually increasing amounts by the anterior
pituitary gland.
 Its secretion is stimulated by Gonadotropin
releasing hormone (GnRH) or luteinizing releasing
hormone(LRH) from hypothalamus.
 Rising level of this hormone during puberty
enhances the maturation of reproductive organs.
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18.  Follicle stimulating hormone(FSH):
◦ In both male and female it stimulates the
production of gametes (ova and sperms from
ovaries and testis respectively).
 Luteinizing hormone(LH)
◦ IN FEMALES:
 LH and FSH stimulate the secretion of Oestrogen
and Progesterone from corpus luteum during the
menstrual cycle.
 As the level of oestrogen and progesterone rises in
blood, secretion of LH and FSH is suppressed.
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19.  Luteinizing hormone (LH) triggers ovulation in
women , as well as the production of estrogens
and progesterone by the ovaries.
 IN MALES:
◦ LH also called interstitial cell stimulated
releasing hormone (ICSH).
◦ It stimulates the interstitial cells to secrete
testosterone.
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21. Posterior Pituitary Gland
 Posterior pituitary hormones are synthesized in the
nerve cells bodies , transported along the axons and
stored in vesicles within the axon terminals in the
posterior pituitary gland.
 Nerve impulses from hypothalamus trigger the
exocytosis of vesicles (of pituitary gland) releasing
their hormone into blood stream.
 Axon terminal release these two hormone within the
posterior pituitary gland.
1. Oxytoxin
2. Antidiuritic hormone (ADH, Vasopressin)
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22. Oxytocin
 It is also called anti stress hormone.
 Oxytocin is produced in both males and
females, but its main physiological roles seem
to take place in the female.
 In the female, oxytocin is involved in a number
of important physiological actions:
1. Stimulates the contraction of the uterus
(myometrium).
2. Stimulates the contraction of the myoepithelial
cells that eject milk from the breast.
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23. Uterine muscle contraction
 Sensory stretch receptors in the uterine cervix (due
to baby’s head) stimulate the release of oxytocin.
 Oxytocin stimulates the more forceful contraction of
cervix, as the baby’s head is forced further
downwards.
 It is also used clinically for the induction of labor.
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24. Milk Ejection
 Suckling generates sensory impulses that are
transmitted from breast to the hypothalamus.
 This impulses triggers the release of oxytocin from
posterior pituitary gland.
 Oxytocin stimulates the contraction of the milk
ducts and myoepithelial cells for ejection of milk.
 Suckling also inhibits the release of Prolactin
inhibiting hormone (PIH) prolonging Prolactin
secretion and lactation.
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25. Antidiuretic Hormone (ADH,
Vasopressin)
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 The main effect of the antidiuretic hormone is to
reduce urine output (diuresis is the production of a
large amount of urine) therefore it is called
Antidiuritic.
 Its secretion is determined by osmotic pressure by
circulating osmoreceptors in blood.
 Increase water intake > decrease in ADH > increase
in urine output.
 Decrease in water intake > Increase in ADH >
Decrease in urine output.
 It acts on the distal convoluted tubules and
collecting ducts of the nephrons of kidneys.

26. Hypo secretion
 Central Diabetes Insipidus (CDI)
◦ CDI is the most common form of pathology
secondary to low ADH secretion by the posterior
pituitary.
 Oxytocin Insufficiency
◦ Hypo secretion of oxytocin is not a common
pathology but does transpire on rare occasions.
This occurs when the level of oxytocin is well
below the baseline margins.
◦ Low levels of oxytocin would halt uterine
contraction and milk ejection during the birthing
process
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27. Hyper-secretion
 Syndrome of Inappropriate Antidiuretic Hormone
◦ SIADH is excess ADH production from the posterior
pituitary or an ectopic source.
◦ Elevated levels result in excess water retention and
hypervolemic hyponatremia.
 OxytocinToxicity
◦ This is a very rare situation and occurs when the
level of oxytocin is above the baseline margins.
◦ High concentrations of oxytocin result in an
overactive uterus, causing hypertrophy and limiting
pregnancy due to insufficient space to hold the fetus.
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28. Diagnosis of growth hormone
disorders
 Blood test to measure levels of growth hormones.
 Insulin-like growth factor 1 (igf-1), which is a
hormone produced by the liver.
 Oral glucose tolerance test:-
◦ Patient will drink a special beverage containing
glucose, a type of sugar.
◦ Blood samples will be taken before and after the
patient drinks the beverage.
◦ In a normal body, growth hormone levels will drop
after eating or drinking glucose.
◦ If patient’s levels remain the same, it means his body
is producing too much growth hormone.
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29. Laboratory Diagnosis of
Thyroid gland disorder
 NormalTSH level practically excludes
abnormalities.
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30. Diagnosis of adrenal disorders
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31. Diagnosis of gonadotropins disorder
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32. Common Pituitary Disorders
 The most common
problem with the pituitary
is the development of a
tumor.
 Other pituitary disorders
can arise from inherited
genetic mutations, be
congenital, be due to
trauma or an impaired
blood supply.
 Common disorders
 Pituitary Tumors
 Growth Hormone
Deficiency
 Hypopituitarism
 Empty Sella Syndrome
 Acromegaly and
Gigantism
 Cushing’s Disease
 Diabetes Insipidus
 Nelson’s Syndrome
 Kallman’s Syndrome
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33. Pineal gland
 It is an important endocrine gland in higher
vertebrates.
 The name is derived from its pinecone like
structure.
 It is also known as ‘third eye’ as this gland receives
its stimuli through vision.
 It was first discovered by Herophilus about 2000
years ago.
 This gland is embryologically derived from
neuroectoderm of diencephalic roof.
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34. Anatomy of pineal gland
 This gland is located on the
dorsal surface of the brain.
 It is embedded in between the
cerebellum and cerebrum.
 The shape is flattened stalk
like structure hence it is called
epiphysis.
 it has sympathetic innervation.
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35. Histology of pineal gland
 Pineal gland consists of two types of
major cells Pinealocytes and Astrocytes.
 Besides these connective tissue cells, mast
cells, nerve fibre etc. also present
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36. Blood Supply
 The arterial supply to the pineal gland is profuse,
second only to the kidney.
 The posterior choroidal arteries are the main
supply; they are a set of 10 branches that arise from
the posterior cerebral artery.
 Venous drainage is via the internal cerebral veins.
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37. Function of pineal gland
 Pineal gland secretes melatonin. It controls
sleepiness and wakefulness.
 Pineal gland controls the sex drive, hunger, thirst
and the biological clock which determines the
body’s normal aging process.
 Melatonin is also known as ‘chronobiotic molecule’
and regulates circadian rhythm together with SCN.
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38.  Secretions require sympathetic stimulus.
 Functions are regulated by light and dark
◦ ↑ in dark
◦ ↓ in light
 Secretions are discharged both in blood capillaries
and in CSF.
 Norepinephrine is the trigger for the pinealocytes to
produce melatonin by activating the transcription of
the mRNA encoding the enzyme arylalkylamine N-
acetyltransferase (AA-NAT), the first molecular step
for melatonin synthesis.
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39. Pathway for secretion of
melatonin within the pinealocyte
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40. Pineal gland disorders
 The dysfunction of the pineal gland produce less
melatonin secretion, which may result in insomnia,
abnormal thyroid function, anxiety, intestinal
hyperactivity, and menopause.
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41. Reference
1. Alzamil, H. (no date) ‗Posterior pituitary‘.
2. Amar,A. P. and Weiss, M. H. (2003) ‗Pituitary anatomy and
physiology‘, 13, pp. 11–23.
3. Anatomy, G. (1970) ‗The normal pituitary gland‘, 4, pp. 1–15.
4. Anatomy,T. and Gland, P. (1986) ‗The Anatomy of the Pituitary
Gland‘, pp. 13–14.
5. Klein, D. C. (no date) chapter 19 -The Pineal Gland and Melatonin.
Seventh Edition,
6. Endocrinology:Adult and Pediatric, 2-Volume Set. Seventh Edition.
Elsevier Inc. doi: 10.1016/B978-0-323-18907-1.00019-6.
7. Møller, M. and Baeres, F. M. M. (2002) ‗The anatomy and
innervation of the mammalian
8. pineal gland‘, pp. 139–150. doi: 10.1007/s00441-002-0580-5.
9. Neurosurg, J. et al. (1985) ‗Review ArticleThe pineal gland:
anatomy, physiology, and clinical significance‘, pp. 321–341.
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