Transcript Slide 1

HYPOTHALAMUS
Hypothalamus Functions
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Controls/integrates ANS.

Raises arterial blood pressure and
increases heart rate (posterior).
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Lowers arterial blood pressure and
decreases heart rate (anterior).
Hypothalamus Functions
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Reception and integration of visceral
sensory impulses.
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Intermediary between nervous and
endocrine systems.
Hypothalamus Functions
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Produces ADH and oxytocin.
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Involved in psychosomatic disorders.
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Associated with rage and aggression.
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Controls normal body temperature.
Hypothalamus Functions
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Regulates food intake.
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Maintains extracellular fluid volume.
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Biorhythm oscillator.
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Sexual center.
Hypothalamic Nuclei
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Mammillary bodies:
Involved in olfactory reflexes and emotional
responses to odors.
Relay stations for olfactory neurons to
inferior colliculi.
Hypothalamic Nuclei
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Supraoptic nuclei :
Send projections (axons) that release
neurohormones into capillaries in the
posterior pituitary:
Oxytocin
Vasopressin
Hypothalamic Nuclei

Suprachiasmatic nuclei:
Located immediately above optic chiasma.
Acts as a master biologic clock, controlling circadian
and circannual rhythms.
Set to light-dark cycle by a direct retinal projection to
the suprachiasmatic nucleus.
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Anterior nuclei:
Caudal continuation of the medial preoptic area.
Hypothalamic Nuclei
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Paraventricular Medial Division:
Projects to the median eminence.
Secretes releasing or inhibiting hormones
into hypothalamo-hypophyseal portal
system:
Corticotropin releasing factor.
Thyroxin releasing factor.
Somatostatin.
Dopamine.
Hypothalamic Nuclei

Paraventricular Intermediate
magnocellular division:
Sends projections to the posterior pituitary
that release oxtocin and vasopressin
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Paraventricular lateral division:
Receives large number of inputs from
brainstem nuclei, other hypothalamic nuclei,
limbic system, etc. and projects to a number
of sympathetic structures.
Hypothalamic Nuclei
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Medial preoptic area
Much larger in males than in females
Contains cells that release gonadotropinreleasing factors to the median eminence
into the hypothalamo-hypophyseal portal
system.
Involved in temperature regulation
HYPOTHALAMUS

Tuberal level:
Previously considered to be a feeding center
and a pleasure center.
Lesions here reduce eating behaviors.