Transcript Slide 1
HYPOTHALAMUS
Hypothalamus Functions
Controls/integrates ANS.
Raises arterial blood pressure and
increases heart rate (posterior).
Lowers arterial blood pressure and
decreases heart rate (anterior).
Hypothalamus Functions
Reception and integration of visceral
sensory impulses.
Intermediary between nervous and
endocrine systems.
Hypothalamus Functions
Produces ADH and oxytocin.
Involved in psychosomatic disorders.
Associated with rage and aggression.
Controls normal body temperature.
Hypothalamus Functions
Regulates food intake.
Maintains extracellular fluid volume.
Biorhythm oscillator.
Sexual center.
Hypothalamic Nuclei
Mammillary bodies:
Involved in olfactory reflexes and emotional
responses to odors.
Relay stations for olfactory neurons to
inferior colliculi.
Hypothalamic Nuclei
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.
Anterior nuclei:
Caudal continuation of the medial preoptic area.
Hypothalamic Nuclei
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
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
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.