BRS

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BRS Neuroanatomy

Paraventricular nucleus

Third ventricle

Arcuate (tuberal) nucleus

Supraoptic nucleus

Optic chiasm

Tuberohypophyseal tract

Supraopticohypophyseal tract

Superior hypophyseal artery

Infundibulum

Hypophyseal portal veins

Sinusoids of infundibular stem

Oxytocin ADH

Anterior lobe (adenohypophysis)

Posterior lobe (neurohypophysis)

Hypophyseal vein

Inferior hypophyseal artery

FIGURE 13.8. Hypophyseal portal system. The paraventricular and supraoptic nuclei produce ADH and oxytocin and transport the substances via the supraopticohypophyseal tract to the capillary bed of the neurohypophysis. The arcu ate nucleus of the infundibulum transports releasing hormones via the tuberohypophyseal tract to the sinusoids of the infundibular stem, which drain into the secondary capillary plexus in the adenohypophysis. ADH, antidiuretic hormone. (Modified with permission from Fix JD. High-Yield Neuroanatomy . 3rd ed. Lippincott Williams & Wilkins; 2005:133.)

XIII. FUNCTIONAL CONSIDERATIONS

A. Autonomic function

1. Anterior hypothalamus ■ The ANS is regulated by hypothalamic nuclei. 2. Posterior hypothalamus

■ has a stimulatory effect on the parasympathetic nervous system. ■ has a stimulatory effect on the sympathetic nervous system.

B. Temperature regulation

1. Anterior hypothalamus ■ helps regulate and maintain body temperature. ■ destruction causes hyperthermia. 2. Posterior hypothalamus ■ helps produce and conserve heat. ■ destruction causes the inability to thermoregulate.

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C. Water balance regulation

■ ADH controls water excretion by the kidneys.