Hypothalamuspituitary_HS2015

7/23/2019 Hypothalamuspituitary_HS2015

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The Hypothalamic pituitary axis-1

Anterior pituitary gland

Dr Harprit Singh

[email protected]


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Learning Outcomes

Understand the layout of the

hypothalamus and pituitary gland

Describe the hormones secreted by the

hypothalamus and how they regulate

anterior pituitary hormones.

Eplore detail structure and function of

anterior pituitary hormones and targeting

tissue


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Hypothalamus

!ontrols many acti"ities related to homeostasis

#rincipal intermediary between ner"ous system

and endocrine system

Has se"eral important connections with the

pituitarygland.

$egulates the secretion of hormones from the

pituitary


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Hypothalamus Hormones &

ActionHormone Action on anterior

pituitary gland

%hyrotropin&$eleasing Hormone

'%$H(

$elease of thyroid stimulating

hormone '%SH(

)onadotropin&$eleasingHormone ')n$H(

$elease of leutini*ing hormone'+H( and follicular stimulating

hormone ',SH(

!orticotropin&$eleasingHormone '!$H( Stimulates adrenocorticotropichormone 'A!%H( release

)rowth Hormone&$eleasinghormone ')H$H(

$elease of )rowth hormone

Somatostatin -nhibits release of )rowth

hormone


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Hypothalamus Hormones &

ActionHormone Action on distant tissues

via posterior pituitarygland

Antidiuretic hormone 'ADH"asopressin(

/ytocin


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PITUITA! "LA#$

Pituitary %hypophysis gland & attached to thehypothalamus "ia a stalk & the -0,U0D-1U+U2

/nly 3.4cm in diameter

Di"ided structurally into 5 parts

Anterior lobe & A$'#OH!POPH!(I( & 678 of

total mass

Posteriorlobe & #'UOH!POPH!(I(


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Hypothalamus)Pituitary

Mescher AL: Jungueiras Basic Histology: Text & Atlas, 12 thEd


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Human pituitary H9E 7: ; A# 'anterior(< ## 'posterior(

AP

PP


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1lood supply to the pituitary gland are through superior and

inferior hypophyseal arteries

%he superior hypophyseal arteries feeds into thehypophyseal portal "ein that consist of=

#$-2A$> #+E?US

SE!/0DA$> #+E?US

*lood supply


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Mescher AL: Jungueiras Basic Histology: Text & Atlas, 12 thEd


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0eurones of the dorsal< "entral media and infundubularnuclei etend their aons to the primary pleus of

hypophyseal portal "ein

0eurohormones get released from end terminus of aon

and enter primary pleus. %hese hormones then tra"el down to secondary pleus

where they get released and act on endocrine cells of pars

distalis.

Endocrine cells release rele"ant hormones into secondary

pleus which then enters circulation

Hypothalamus-Adenohypophysis

communication


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Felner, E.I. and Umpierrez, G.E. (2013) Endocrinepathophysiology. 1sted. altimore! "olters #l$%er&'ippincott


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egulation o+ HPA


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Felner, E.I. and Umpierrez, G.E. (2013) Endocrine pathophysiology. 1 sted. altimore! "olters #l$%er&'ippincott "illiams "ilins


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Hormone producing cells


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,ell Type (tainA++inity

o+ Total,ells

HormoneProduced

Somatotropiccells

Acidophilic 7: )rowthHormone

2ammotropicor actotropic

cells

Acidophilic 37&5: #rolactin

)onadotropiccells

1asophilic 3: ,HS+H

%hyrotropiccells

1asophilic 7 %SH

!orticotropiccells 1asophilic 37&5: A!%H

2elanotrophs !hromophobe 7 2SH


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"O.TH HO/O#'

Single chain 33 amino acid polypeptide )H causes cells to grow and multiply & increases

rate at which amino acids enter cells and are

built into proteins

Acts particularly on skeletal muscle and bone

#romotes fat catabolism 'burn fats for energy(

Accelerates rate at which glycogen 'in li"er( iscon"erted into glucose


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egulation o+ "ro0th Hormone

Hypothalamus releases two regulating factors

called=

)rowth hormone releasing factorhormone

')H$H(

)rowth hormone inhibiting factor ')H-, or

somatostatin(


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Action o+ "ro0th Hormone

Actions of )H on growth are mediated by growth

promoting substances known as Insulin-lie "ro0th

2actors'-),(

Small peptides made in li"er under influence of )H Structurallysimilar to insulin

)rowth&promoting effects much more potent than insulin


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E*ercise, stress, sleephypoglycaemia

Hyothala!us"H#H $o!atostatin

Ant %ituitary"roth hor!one

'i+er

'"()1

one,m$scle

tiss$egro%th

Increaselood

gl$cose


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TH!OI$-(TI/ULATI#"

HO/O#' %T(H

Also called thyrotropin

Stimulates synthesis and secretion of hormones produced by

the thyroid gland

Secretion controlled by regulating factor produced by

hypothalamus= %hyrotropin releasing factor '%$,(


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-old stress, e*ercise, pregnancy

Hyothala!us"H#H $o!atostatin

Ant %ituitary T$H

T* T+

T$H

"%#

cAM%

#elease o- T*.T+Thyroid


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Action of %hyroid hormones

Cardiovascular

Increase -, / and

Metabolic

Increase asal metaolic rate

Increase 2cons$mption

Neurological

Increases %ae$lness, memory, alertnessGrowth and development

one gro%th ater irth


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tress, e*ercise, hypoglcaemia

Hyothala!usorticotroin releasing hor!one

Ant %ituitaryATH

ATH

"%#

cAM%

cortisol-ortis

ol

4drenalcorte*


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!ortisol

!ortisol is stress hormone

2aintain blood glucose le"el

2aintain glycogen le"els in li"erStimulates protein catabolism in muscle

+ipolysis in adipose tissue

#ame another hormone released 3y

adrenal gland4


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/'LA#O,!T'-(TI/ULATI#" HO/O#' %/(H

Stimulates the dispersion of melanin granules inmelanocytes

+ow le"els of hormone B pale skin

High le"els of hormone B darkening of the skin

$egulated by=

/elanocyte-stimulating hormone releasing +actor'2$,(

/elanocyte-stimulating hormone inhi3iting +actor'2-,(


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ANY QUEST!NS

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Hypothalamuspituitary_HS2015