Download Pituitary Gland

Pituitary Gland
Prepared by Yousaf khan
Nomenclature
• Pituitary
– Greek
• ptuo (to spit)
– Latin
• Pituita (mucus)
– Mucus was produced by
the brain and was
excreted through the
nose by the pituitary
Pituitary
• Pituitary
– “Master” gland
– Pituitary gland also called the hypophysis
– Small gland ( about 1 cm in diameter and 0.5 to 1 gm in
weight)
– That lies in the sella turicica
– Connect to the hypothalamus by the pituitary stalk
– Most of the pituitary hormones control other endocrine
glands
Pituitary Gland
Pituitary gland is divisible into two distinct
Portion
• Anterior pituitary ( adenohypophysis)
- originate from the glandular tissue
• Posterior pituitary ( neruohypophysis )
- consist of neural tissue and is essentially
an extension of the brain
• b/w avascular zone called pars intermedia
Pars intermedia
Pituitary gland
As the extension of brain the posterior pituitary
Contain axon from neuron in the hypothalamus,
These neuron produce two hormone release
From the posterior pituitary
Pituitary
Portal System
• Hypophyseal arteries
– From carotid
– Superior
• 80-90% to adenophysis
– Inferior
• Posterior pituitary
• Posterior lobe
– Rich nerve supply
– Unmyelinated nerves
Hormones Of The Anterior Pituitary
• 6 main hormones secreted by the adenohypophysis:
– Growth hormone
• GH promotes growth of the entire body by affecting
protein formation, cell multiplication and cell
differentiation
– Thyroid-stimulating hormone
• TSH control rate of secretion of thyroxine and
triiodothyronine by the thyroid gland and these
hormones control the rate of most interacellular
chemical reaction in the body
– Adrenocorticotropic hormone
• ACTH control the secretion of some of the
adrenocortical hormones
Hormones Of The Anterior Pituitary
– Prolactin
Prolactin promotes mammary gland
development and milk production
– Follicle-stimulating hormone
– Luteinizing hormone
• control growth of the ovaries and testes as
well as their hormonal and reproductive
activities
Hormones of the posterior pituitary
gland
• The two hormones secreted by the posterior
pituitary play other roles
• Antidiuretic hormone ( also called
vasopressin) control the concentration of
water in the body fluids.
• Oxytocin help express milk from the glands of
the breast to the nipples during suckling and
help in the delivery of the at the end of
gestation
Major Pituitary Gland Hormones
Growth Hormone (GH)
Gland source: adenohypophysis
Cell: somatropes
Hormone: Growth hormone ( GH: Somatotropin)
Chemistary: Single chain of 191 amino acids
Physiologogical Action:
Stimulates body growth: stimulate secretion of
IGF-1, stimulate lipolysis, inhibits action of insulin on
carbohydrate and lipid metabolism
Adrenocorticotropic hormone
Gland source: adenohypophysis
Cell: corticotropes
Hormones: adrenocortictropic hormones
Chemistary: single chain of 39 amino acids
Physiological action: stimulate production of
glucocorticoids and androgen by the adrenal
cortex
Thyroid stimulation hormone
Gland source: Adenohypophysis
Cell: Thyrotropes
Hormones: TSH
Physiological action: stimulates production of
thyroid hormones by thyroid follicular cell,
Maintain size of follicular cell
Follicle-stimulating hormon
Source of gland: Adenohypophysis
Cell: Gonadotropes
Hormone: FSH, Luteinizing hormone
Chemistry: Glycoprotein of two subunits, alpha
( 89 Amino acid) and beta ( 112 amino acid) and Glycoprotein of two
subunits, ( 89 Amino acid) and beta ( 115 amino acid)
Phsiological Action:
Stimulates development of Ovarian follicles, regulates spermatogenesis in
the
testis, causes ovulation and formation of the corpus luteum in the ovary,
stimulates production of estrogen and progesterone by the ovary, stimulates
testosteron production by the testis
Prolactin (PRL)
Gland source: adenohypophysis
Cell: lactotropes, mamotropes
Chemistry: single chain of 198 amino acid
Physiological action:
Stimulates milk secretion and production
Hormones Of The posterior Pituitary
Antidiutetic Hormone
Physiological action:
Increases water reabsorption by the kidney and
cause vasoconstriction and increase blood
pressuer
Oxytocin
Physiological action:
Stimulates milk ejection from breasts and
uterine contraction
Thank you