Hypothalamus & Limbic System Flashcards
What separates the thalamus from the hypothalamus?
Hypothalamic sulcus
The hypothalamus is structurally part of the _____ and functionally part of the _____ system.
Diencephalon; libic
What is the relationship between the hypothalamus and the third ventricle?
forms the walls of the anterior portion of the third ventricle
Which structures form the posterior portion of the hypothalamus?
Mammillary bodies
Which ventricle is hypothalamus bordered by?
Third
Which structure links the hypothalamus to the pituitary gland?
The Infundibulum (originates at tuber cinereum)
What part of the pituitary is the hypothalamus vascularly connected to?
Anterior
What part of pituitary is hypothalamus neurally connected to?
Posterior
What is the function of the anterior area nuclei (e.g., suprachiasmatic, supraoptic, paraventricular, anterior)
Sleep, eating, parasympathetic, circadian rhythms
What is the function of the posterior area nuclei (e.g., posterior nucleus, mamillary bodies)
Sympathetic, upregulation of BT, arousal, wakefulness
The hippocampus is located where relative to the lateral ventricle
Just inferior to the inferior horn
On a coronal section, is the amygdala visible anteriorly or posteriorly to the hippocampus
ANTERIORLY - note that you cannot view the inferior horns of the lateral ventricle in this coronal section
Which for structures (not tracts) are implicated in the Papez circuit?
1) Hippocampus 2) Mamillary bodies (3) Anterior thalamic nuclei; 4) Cingulate cortex
Which 4 fibre tracts are implicated in the Papez circuit
1) Fornix; 2) Mamillothalmic tract; 3) IC; 4) Cingulum
Describe the flow of information in Papex circuit (starting at hippocampus)
what is the lamina terminalis?
Membrane extending from the anterior commissure inferiorly to the rostral edge of the optic chiasm; anterior boundary of the hypothalamus
Which zone (lateral vs. medial) contains most of the functionally important hypothalamic nuclei?
Medial zone
What are the three functional areas of the hypothalamus along the anterior-posterior axis?
Anterior, middle, posterior
Where are the preoptic and anterior nuclei and what is their function?
1) Medial Zone (anterior area); 1) heat loss, response to heat, parasympathetic activity, sleep
Where is the suprachiasmatic nucleus and what is its function
Anterior hypothalamus/medial zone; circadian rhythms, secretes releasing/inhibiting hormones
Where is the supraoptic nucleus and what is its function
Medial zone/anterior; secretes hormones (oxytocin, vasopression, antidiuretic)
Where is the paraventricular nucleus and what is its function
Anterior area (medial zone); hormone secretion from magnocellular and parvocellular cells
Which five nuclei are present in the anterior hypothalamus?
PPASS - paraventricular, preoptic, anterior, supraoptic, suprachiasmatic
What are the three middle/tuberal nuclei
Arcuate, Ventromedial, Dorsomedial
Which hypothalamic nucleus is involved in satiety (hunger suppression)
Ventromedial
Where is the dorsomedial hypothalamic nucleus and what is its function
Middle/tuberal region; circadian and emotional regulation
Where is the arcuate nucleus and what does it do?
Middle/tuberal region, secretes hormones
What are the nuclei of the posterior region?
Posterior nucleus; mamillary body
What is the role of the posterior nucleus? Where is it?
Posteriro region; sympathetic activity; heat response; arousal wakefulness
Which two hypothalamic nuclei have opposing roles?
Preoptic and anterior (parasympathic) vs. Posterior (sympathetic)
Where is the mammillary nucleus; what is its function?
Posterior region; memory
Blood supply to anterior hypothalamus?
Branches from Anterior communicating and anterior cerebral arteries
Blood supply to posterior hypothalamus?
Branches from posterior communicating and posterior cerebral arteries
Which fibre bundle connects the cortices involved in the limbic system?
The cingulum
What does the uncus overlie
Amygdala and anterior hippocampus (i.e., entorhinal cortex)
Another name for the anterior parahippocampal gyrus
Entorhinal cortex
What is the role of the entorhinal cortex (anterior parahipocampal gyrus)
Receives sensory and prefrontal inputs; relays info between hippocampus and cortical regions
What are the four regions of the fornix?
Column (most anterior, posterior to anterior commissure), body, Crus, fimbria
What type of neurons are the primary sensory neurons for the olfactory system?
Bipolar cells; chemoreception happens at dendrites
Where do primary olfactory neurons synapse with secondary neurons?
Olfactory bulb
Where do olfaction signals go after synapsing at the olfactory bulb
To cortex (bypass thalamus)
What type of CN is CNI
SSA - special afferent for olfaction
Where is the olfactory association area?
Entorhinal cortex - BA 28
