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Hypothalamus
Introduction :
° It is
a di encephalic structure.^ It in
just
situated below thalamus
in the ventral
part g^ diencephalon^ .
. (^) It in formed (^) by groups y nuclei (^) , scattered in the walls (^) and
floor
g
third ventricle.
- (^) It extends from optic chiasma to (^) mamill any body^ . Nuclei
g Hypothalamus :
- (^) Three groups in Anterior^ or preoptic group ( as^ Middle^ or^ tuberal^ group (3) Posterior^ or
mammillary group
Functions
g Hypothalamus
:
- (^) It in important (^) for
homeostasis.
° (^) It regulates (^) many
vital
functions g
the body like endocrine^ functions , hunger , thirst^ , emotions^ , sexual^ functions etc.
- (^) Secretion g posterior^ pituitary hormones (^).
° Control
g
Anterior pituitary .
- (^) Control g Adrenal^ Cortese by ACTH ° Control g Adrenal medulla^ by emotional stimuli^.
Regulation g^ Autonomic Nervous^ System.
Regulation og
Heart Rate.
Blood Pressure -
- cis^ Heat^ loss^ center^ in^
preoptic
nucleus
- Regulation g (^) Body temperature^ -^ I^ g Ant . hypothalamus -
dis Heat
gain center (^) in (^) posterior
- Regulation g^ Hunger & (^) food intake .
hypothalamus
is feeding center nucleus - ciii
satiety
center
- Regulation y^ water balance. cis Thirst (^) mechanism
dis ADH^ mechanism
Regulation g^ sleep^
and Wakefulness
- Role in^ behaviour^ and^ emotional^ changes .
Regulation g^ sexual
function
- Role^ in^ response to^ smell^.
- Role in^ Circadian^ rhythm^ .
cos (^) Peplidetlechanism Ghrelin secreted (^) in →
stimulated
feeding center → Inc. appetite stomach & food intake^ .
During fasting )
- Peptides which (^) increases the food intake^ : which^ decreases ca )^ Ghrelin^ food^ intake : ( bi^ N^ europe pled
Y ca^ )^ Leptin
( bi^ Peptide YY ( d^ ,^ Hormonal (^) Mechanism
- : Inhibit food intake ( i,^ somatostatin (^) Cixi Pancreatic^ polypeptide ciis (^) Oxytocin l"^ cholecyst kinin^.
ciii ,
Glucagon (e^ ,^ Thermostalictlechanism
- Temp is inversely proportional^ to body temp^ . ° (^) In fever.^ food^ intake^ Y, ° Exact cause not known but it in suggested that the
preoptic
thermo receptors
may act via feeding
center.
Mechanism g Regulation g^ lala ter^ Balance^ : CII (^) Thirsts :^
( Its^ A (^) DH Mechanism : ECF (^) I
gntcnased
Osmolality
ECF
q
and
stellate,
Suptraopkic nucleus^ ( stimulated^ )
I
Aot released - Causes Retention^ g water^ via^ facultative Reabsor
Applied Physiology
g hypothalamus^
occurs due^ to tumors ,
encephalitis and ischemia. o symptoms detected^ an : ( is^ Disturbance^ in^ Carbohydrate & (^) Fat metabolism.
ciii Disturbance^ in^ sleep due^ to^ lesion^ in^ mami^ Hary
body
. ciii ,^ Disturbance^ in^ ANS ( in^ Emotional^ manifestations . can Disturbance^ in^ sexual^
functions
due to lesion in^ mid^ hypo that
g more^
above
features
can become^ prominent
and results^ in any g^
them :
cis Diabetes^ insipidus ciii (^) Dystrophic
adiposogeni
tale's ciii,^ Kallmann Syndrome
( in^ Laurence^ -^ Moon^ -^ Biedl^ syndrome^
call Narcolepsy.
cut cataplexy.
