Thalamus and Hypothalamus Quiz

Overview of the Thalamus and Hypothalamus

• The thalamus relays all sensory information going to the cortex except smell and plays a role in consciousness, sleep, level of alertness, and processes emotions.
• The thalamic nuclei include VPL, VPM, LGN, MGN, and VL, each with specific inputs and outputs to different areas of the brain.
• The thalamic blood supply comes from the thalamogeniculate and thalamoperforating arteries, and the internal capsule is supplied by the MCA.
• Thalamic (pain) Syndrome, also known as Dejerine-Roussy Syndrome or Central Pain Syndrome, occurs when a lesion destroys the thalamus and can lead to long-term chronic pain.
• The hypothalamus is found below the thalamus and plays a role in autonomic control, body temperature regulation, water balance, and regulating pituitary gland endocrine function.
• The hypothalamic areas include lateral (hunger), ventromedial (satiety), anterior (cooling), posterior (heating), and suprachiasmatic nucleus (circadian rhythm).
• Fever is triggered by pyrogens, inflammatory proteins that enter the brain and stimulate prostaglandin E2 synthesis, which increases the anterior hypothalamus' temperature set point.
• Hypothalamic hormones released by the hypothalamus trigger the pituitary gland to release more hormones, including TRH, CRH, GHRH, GNRH, dopamine, somatostatin, and prolactin.
• Leptin, secreted by adipocytes after food intake, regulates homeostasis by inhibiting the lateral hypothalamus (hunger) and stimulating the ventromedial hypothalamus (satiety).
• Craniopharyngioma is a tumor that puts pressure on the optic chiasm and hypothalamus, causing diabetes insipidus, fatigue, obesity, and loss of temperature regulation.
• The epithalamus consists of the habenula and the epiphysis (choroid plexus and pineal gland) and has tracts running through the thalamus, including the optic, mammilothalamic, and habenulointerpeduncular tracts.
• The habenular nuclei receive afferent fibers from septal and preoptic areas via stria medullaris thalami and give efferent fibers to the interpeduncular nucleus and VTA via the habenulointerpreduncular tract. The pineal gland secretes melatonin into the blood and has an antigonadotropic effect.