Ret Formation And Hypothalamun Flashcards
What does the pineal gland secrete?
Melatonine
External references to locate the hypothalamus
Fornix
Anterior commisure
Lamina terminalis
Optic chiasm and optic nerve
Hypophysis
Line between anterior and posterior commisures
Intercommissural line
Limits of the hypothalamus
Rostral - lamina terminalis
Caudal - midbrain & mamillary bodies
Dorsal - hypothalamic sulcus
Ventral - skull base
Medial - III ventricle
Lateral - substantia innominata & post limb of int capsule
Internal capsule function
Confers the fibres coming from the motor cortex towards the brainstem
Regions of the hypothalamus
Preoptic area
Lateral
Medial: quismatic, tuberal, mamillary
Preventricular
Preoptic area includes
Preoptic nuclei: lateral and medial. It regulates sleeping.
Lateral region includes
Medial forebrain bundle: bunch of fibers that communicates the diencephalon with midbrain, etc. Related to emotions
Dispersed neurons: orexin producing neurons/hypocretin (sleep regulation and food intake), lateral hypothalamic nucleus and tuberal nucleus
Chiasmatic region nucleus
Suprachiasmatic nucleus
Supraoptic nucleus → ADH
Anterior nucleus
Paraventricular nucleus → ADH
Tuberal region nucleus
Arcuate nucleus
Ventromedial nucleus
Dorsomedial nucleus
Mamillary region nucleus
Mammillary nuclei
Posterior nucleus
Location of tuberal region
Just above the infundibulum of the hypophysis
Suprachiasmatic nucleus regulates
Circadian rhythms
Visceral afferents to the hypothalamus
Visceral sensory nucleus in the brain stem (main one: nucleus of the solitary tract)
Spinal cord
Visceral efferents from hypothalamus
Visceral motor nuclei brainstem
Visceral motor structures in the spinal cord
Other structures related to regulation of blood pressure, etc
Mammillothalamic tract
Hipocampus - Fornix - mamillary nuclei- ant thalamus nucleus
Circuit for memory consolidation
Mammillothalamic tract
What does the hypothalamus secrete?
Regulation factors into circulation (sinusoids)
Only nuclei that don’t release regulating factor
Mammillary nuclei
Suprachiasmatic nuclei
Functions of hypothalamus
Hormonal control
Biological rhythms
Control of vegetative system
Emotional reactions
Memory
Sleep regulation
Suprachiasmatic nucleus - regulates the sleep-wake cycle
GABA in HT (preoptic) - promotes sleep
Histamine in post HT - prevents sleep
Orexins in lateral area (isolated groups)
Feeding regulation
Satiety = Ventromedial nucleus of the tuberal region
Hunger = Lateral area
Hormonal regulation
Release ADH —> supraoptic and paraventricular nuclei
Release oxytocin —> post hypophysis
Production of release/inhibitory factors —> multiple nuclei
Emotions regulation
Dorsomedial nucleus mediates emotional reactions and is related to rage
Thermoregulation
Ant and post hypothalamus
Autonomic regulation
Symph —> caudo-lateral region (posterior)
PS —> rostro-medial region (anterior)
Reticular formation - def, includes
“cajón desastre”
It’s a mix of everything in the brainstem that has no name, all the regions in the brainstem which aren’t found forming well-defined nuclei.
It includes many dispersed neurons in the brainstem that don’t form nuclei
Components of the reticular formation
Proper reticular formation
Medial longitudinal fasciculus
Periaqueductal grey matter
Aminergic and cholinergic nuclei
What do we find within the diencephalon?
Thalamus (+ “massa intermedia”)
Epithalamus (pineal gland + habenula)
Hypothalamus (series of nuclei)
Subthalamic region
Neurons that produce ADH are located in
Paraventricular nucleus
Supraoptic nucleus
Regions in medial area
Chiasmatic region
Tuberal region
Mamillary region
Stria terminalis definition
Major pathway between the amygdala and the hypothalamus that provides reciprocal connections between the two structures
Striated terminalis is related to
Amygdaloid complex
Input in limbic system
Input to the hypothalamus comes from the amygdaloid complex, through the Stria terminalis
Output in the lymbic system
Hypothalamic nuclei —> ANS centres through hypothalamo-medullary and hypothalamo-spinal fibres.
Along post longitudinal fasciculus (within periaqueductal grey matter in brainstem)
Proper reticular formation includes
Magnocellular: reticulospinal pathway, locomotion, miction (pons)
Lateral reticular formation (parvocellular): afferent projections, complex reflexes
Respiratory centers (parab.), baropressor center (near NST): medullar/pons.
Medial longitudinal fasciculus includes
Paramedian pontine reticular formation (near the VI CN)
Rostral nucleus of the MLF (near the III CN)
Aminergic and cholinergic nucleus include
Locus ceruleus (NA)
Raphe nuclei (5HT)
PPN, interpeduncular nucleus (Ach)
Substantia nigra and ventral tegmental area (DA)
Periaqueductal gray matter is
A bunch of neurons adjacent to the cerebral aqueduct (grey matter). It’s an area related to pain
