B&B Neuro Flashcards
Functions of the hypothalamus
- Homeostatic mechanisms controlling hunger, thirst, sexual desire, sleep-wake cycles, etc
- Endocrine control via the pituitary
- Autonomic control
- Limbic mechanisms
mnemonic: HEAL
contains axons & terminals of neurons whose cell bodies are located in the hypothalamus (supraoptic and paraventricular nuclei are the hypothalamic nuclei that have termination here)
-secretion of oxytocin & vasopressin into circulation
posterior pituitary
region where hypothalamic neurons release regulating factors carried by portal vessels to the anterior pituitary
-these can either stimulate release of hormones or inhibit release of hormones from the glandular (anterior) pituitary
median eminence
4 major regions of hypothalamus
- preoptic area
- anterior (supraoptic) region
- middle (tuberal) region
- posterior (mammillary) region
contains lateral and medial preoptic nuclei
preoptic area
- contains supraoptic & paraventricular nuclei (these contain oxytocin & vasopressin) which project to the posterior pituitary
- contains suprachiasmic nucleus (SCN) or “master clock”
anterior (supraoptic) region of the hypothalamus
nuclei from which descending autonomic fibers originate
paraventricular nuclei
contains the arcuate nucleus, ventromedial nucleus and dorsomedial nucleus
middle (tuberal) region of the hypothalamus
projects to the median eminence to control anterior pituitary
arcuate nucleus
includes the medial mammillary nucleus, intermediate mammillary nucleus, lateral mammillary nucleus & posterior hypothalamic nucleus
posterior (mammillary) region of the hypothalamus
lesion to this area of the hypothalamus causes insomnia
anterior region
lesion to this area of the hypothalamus destroys histaminergic neurons in the TMN, as well as orexin-containing neurons, causing hypersomnia
posterior region
hormones of the anterior pituitary (6)
- ACTH
- Growth hormone
- prolactin
- thyroid-stimulating hormone
- luteinizing hormone
- follicle-stimulating hormone
* note: release is controlled by the hypothalamus via hypophysial portal system
hormones of the posterior pituitary (2)
- oxytocin
2. vasopressin (ADH)
stimulates appetite and lesion to this area of hypothalamus causes weight loss
“tells when to eat”
lateral nucleus of hypothalamus
“lesion lateral loss”
inhibits appetite and lesion to this area of the hypothalamus causes weight gain
“tells when to stop eating”
medial hypothalamus
hormone that increases appetite
Ghrelin
regulates thirst
-activated by hypovolemia or elevated body temp
osmoreceptors of the anterior hypothalamus
Detects increased body temp and activates heat dissipating mechanisms
-lesion causes hyperthermia
anterior hypothalamus
“cool facade” or dog pANTs to cool off
conservation of heat
-lesion causes poikilothermia
posterior hypothalamus
“hot posterior”
feedback loop for cortisol
hypothalamus releases CRH which stimulates release of ACTH by the anterior pituitary. ACTH stimulates adrenals to produce cortisol. Cortisol inhibits release of CRH.
*chronic steroid administration can cause atrophy of adrenals and abrupt discontinuation of steroids can cause life-threatening deficiency of cortisol
Functions of the limbic system
- Homeostatic functions: autonomic & neuroendocrine
- Olfaction
- Memory
- Emotions and drives
mnemonic: HOME
Major structures of the limbic system (9)
- Limbic cortex
- Hippocampal formation
- Amygdala
- Olfactory cortex
- Diencephalon
- basal ganglia
- basal forebrain
- septal nuclei
- brainstem
nuclear complex that lies in the anteromedial temporal lobe & controls emotions and drives
amygdala