Hypothalamus

Thermoregulation

The anterior and posterior hypothalamic nuclei work to regulate body temperature by cooling down and heating up the body, respectively.

Mnemonic

• The Anterior hypothalamic nucleus is for Cooling (A/C = Air Conditioning).
• The Posterior hypothalamic nucleus is for Heating (“You’ve got a hot posterior!”).

Food intake

• Lateral Hypothalamus (LH)
  • Function: Hunger center.
  • Stimulated by: Ghrelin.
  • Inhibited by: Leptin.
  • Lesion: Anorexia, failure to thrive (infants).
  • Mnemonic: Lateral injury makes you Lean.
• Ventromedial Hypothalamus (VMH)
  • Function: Satiety center.
  • Stimulated by: Leptin.
  • Lesion: Hyperphagia, obesity, savage behavior.
    • Note: Often injured in Craniopharyngioma.
  • Mnemonic: VentroMedial injury makes you Very Massive.
• Hormonal Regulation
  • Ghrelin:
    • Source: Stomach (gastric cells).
    • Action: ↑ Appetite (Stimulates LH).
    • Mnemonic: Ghrelin makes you hunGry / Ghrelin Grows the stomach.
  • Leptin:
    • Source: Adipose tissue.
    • Action: ↓ Appetite (Stimulates VMH, Inhibits LH).
    • Deficiency: Mutation leads to congenital obesity.
    • Mnemonic: Leptin keeps you Thin.

Mnemonic

• The lateral nucleus will make you fatter-al.
• The ventro-meal nucleus will make you feel full.

Mnemonic

• Ghrelin is released when your stomach is growlin’.
• Lep-thin will make you thinner.

Circadian rhythm

The suprachiasmatic nucleus maintains a consistent daily biological cycle known as the circadian rhythm.

Mnemonic

If you get enough sleep, you can be charming and chiasmatic (charismatic).

Water balance

The supraoptic nucleus produces vasopressin which helps to regulate thirst and fluid balance.

Mnemonic

Look (“-optic”) at the clouds above (“supra-”) you to tell if it’s going to rain (water).

Social bonding

The paraventricular nucleus produces oxytocin, a hormone involved in prosocial behaviors, sexual reproduction, uterine contraction, and breast milk release.

Mnemonic

Parental Viewing is Needed for the “mature themes” of the ParaVentricular Nucleus.

Hormone release

The hypothalamus performs a wide variety of essential functions in the body.

Mnemonic

The six H’s of the hypothalamus: Hot, Hungry, Hourly, Hydrated, Horny, and Hormonal.