Flashcards in Hypothalamus, Thalamus, RAS Deck (48)
Explain the boundaries of the hypothalamus.
Dorsal - sulcus limitans
Medial - third ventricle
Rostral - lamina terminalis
Ventral - infundibulum
Caudal - posterior mammillary bodies
Lateral - no precise lateral border
Half way between the optic chiasm and mamillary bodies and represents the median eminence.
Functions of the hypothalamus.
blood osmolality (chemoreceptors), blood pressure control (carotid sinus), childbirth and lactation (oxytocin and prolactin), thermoregulation, food/fluid intake and output control, emotional control (motor aspects), sex drive (sexual orientation/behaviors)
Dysfunction in hypothalamus causing uncontrollable eating.
Prader Willi syndrome
Two pathways of the infundibulum to the pituitary.
Posterior: neural - contains axons that communicate with posterior portion of pituitary gland
Anterior: vascular - “hypothalamic portal system” and carries hormones through vasculature to anterior portion pituitary
Hypothalamic nuclei in the pre-optic and supraoptic tier.
suprachiasmatic nuclei, preoptic nuclei, anterior nuclei, paraventricular nuclei
Hypothalamic nuclei in the tuberal tier.
ventral nuclei, lateral nuclei, dorsal nuclei
Hypothalamic nuclei in the mamillary tier.
posterior nuclei and mamillary bodies
What is medial to the pairs of nuclei in the hypothalamus?
Functions of Pre-Optic Tier/Nuclei.
bladder control, heart rate, temperature
Functions of Supraoptic Tier/Nuclei.
water conservation, oxytocin release
Functions of Tuberal Tier/Nuclei.
Functions of Mamillary Tier/Nuclei.
blood pressure, feeding reflexes, shivering/sweating
Connections of hippocampus.
connected via fornix to septal nuclei (ant. commissural fornix) and to mammillary nuclei (postcommissural fornix); connected via nuclei to anterior nucleus of the thalamus and via that to cingulate gyrus (limbic system)
Anterior Lobe: Adenohypophysis (Pituitary)
Hypothalamo-hypophyseal Portal System: made of intricate channels (venous) of released hormones from various nuclei of hypothalamus trophic hormones are released from pituitary into the body for physiological responses
Which tiers are primarily connected to the anterior pituitary?
pre-optic and tuberal tier
Posterior Lobe: Neurohypophysis (Pituitary)
Hypothalamo-hypophyseal Tract: from paraventricular nucleus and supraoptic nucleus to posterior pituitary; direct neuronal synapses in posterior pituitary
Hypothalamus is major controller of our _________ system.
endocrine (homeostatic mechanisms)
Neurotransmitters released from posterior pituitary?
ADH and oxytocin
The release of trophic hormones from the anterior lobe of the pituitary is considered a fast/slow response.
The release of ADH from the posterior lobe of the pituitary is considered a fast/slow response.
Explain the feedback loops to the hypothalamus for endocrine function.
short feedback loops: pituitary to hypothalamus
long feedback loops: endocrine organs/visceral organs to hypothalamus (neural - visceral organs to the brain and then to hypothalamus; metabolic - electrolytes, pH, CO2 receptors then to hypothalamus
Composes the diencephalon.
hypothalamus, thalamus, epithalamus (optic nerves and tract are an extension of the diencephalon)
posteriorly above the thalamus and interconnected to the hypothalamus & septum basal forebrain (stria terminalis pathway)
Boundaries of the thalamus.
medial boundary: third ventricle
dorsal boundary: epithalamus
lateral boundary: internal capsule (posterior limb)
inferior boundary: hypothalamus
True/false: All sensory systems go through the thalamus.
false - all except smell
General physiological features of the thalamus.
chief sensory and motor relay station, multimodal integration, input/output modulation, alertness
Separates the anatomical divisions of the thalamus.
Y shaped white matter band called intramedullary lamina
What is the largest division of the thalamus?
lateral (closest to posterior limb of internal capsule)