Lecture #13 - Hypothalamus & Limbic System

Q: Where is the hypothalamus located?

A: Below the thalamus and above the pituitary gland; it contains several nuclei.

Q: What are major components of the limbic system?

A: Prefrontal cortex, cingulate gyrus, hippocampus, amygdala, portions of thalamus, portions of hypothalamus, nucleus accumbens.

Q: What is the primary function of the hypothalamus?

A: Maintain homeostasis; also regulates complex emotions/behaviors with the limbic system.

Q: List major functions of the hypothalamus.

A: Regulates endocrine function, circadian rhythms, thermoregulation, water balance, feeding, reproduction, autonomics, emotional behaviors.

Q: List primary functions of the limbic system.

A: Emotion generation, memory/learning, olfaction, feeding behavior, reproduction, autonomic regulation, reward/punishment systems.

Q: What hypothalamic nucleus sets circadian rhythms?

A: Suprachiasmatic nucleus.

Q: How does the hypothalamus regulate body temperature?

A: Through a temperature setpoint, using peripheral and central thermoreceptors with behavioral and physiological mechanisms (vasoconstriction, shivering, vasodilation, sweating).

Q: Describe the hypothalamic regulation of water balance.

A: Osmoreceptors in hypothalamus sense plasma osmolarity, regulate ADH release from posterior pituitary, controlling water reabsorption in kidneys.

Q: Where is the feeding center located, and what happens if it is lesioned?

A: Lateral hypothalamus; lesion causes anorexia.

Q: Where is the satiety center located, and what happens if it is lesioned?

A: Ventromedial hypothalamus; lesion causes hyperphagia.

Q: Name hormones that stimulate appetite.

A: Neuropeptide Y, ghrelin, orexins.

Q: Name hormones that inhibit appetite.

A: Leptin, insulin, CCK, peptide YY (PYY).

Q: What structures are part of the reward system?

A: Band of limbic tissue from frontal cortex to midbrain, including lateral hypothalamus and nucleus accumbens.

Q: What neurotransmitter is critical in the reward system?

A: Dopamine.

Q: What structures are part of the punishment system?

A: Lateral hypothalamus, hippocampus, thalamus, amygdala, dorsal midbrain.

Q: What is the role of the amygdala in emotions?

A: Generates inner emotions (fear, anger), especially rage, aggression, and fear; connects with prefrontal cortex and hypothalamus.

Q: What happens with amygdala or hypothalamus destruction?

A: Amygdala destruction causes abnormal placidity; hypothalamus destruction can cause rage attacks

Q: What is the role of the hypothalamus in emotions?

A: Coordinates and executes emotional behavior, regulates autonomic and endocrine components of emotions, promotes calm.