Hypothalamus DSA Flashcards
Where is the medial preoptic nucleus? What does it do?
Preoptic area of hypothalamus
Contains neurons that make GnRH
What structure does the periventricular zone of the hypothalamus surround?
3rd ventricle
What are the regions of the medial zone of the hypothalamus?
Supraoptic region
Tuberal region
Mammillary region
What hypothalamic structure forms the anterior boundary of the 3rd ventricle?
Lamina terminalis
Where is the medial forebrain bundle located? What does it connect?
Lateral zone of the hypothalamus
Interconnects hypothalamus from the rostral areas (such as septal nuclei) to the caudal areas (Reticular formation)
Stimulation of what hypothalamic nucleus promotes feeding behavior?
Lateral hypothalamic nucleus
Lesion of what hypothalamic nucleus causes increased feeding?
Ventromedial nucleus
Where is the dorsomedial nucleus of the thalamus located? What is its function?
Tuberal region
Regulates emotional behavior (Stimulation produces aggressive behavior)
What is the primary function of the anterior nucleus of the hypothalamus?
Maintenance of body temperature
What nuclei are contained within the supraoptic region of the hypothalamus?
Supraoptic/paraventricular nucleus
Suprachiasmatic nucleus
Anterior nucleus
What nuclei are contained within the tuberal region of the hypothalamus?
Ventromedial nucleus
Dorsomedial nucleus
Arcuate nucleus
What structure transmits hormones from the arcuate nucleus of the hypothalamus to the anterior pituitary?
Tuberoinfundibular tract and hypophysial portal system
What hypothalamic nucleus represents the primary termination point for axons of the postcommissural fornix?
Medial mammillary nucleus
Where do axons of the postcommissural fornix arise from?
Subiculum
What does the mammillothalamic tract transmit?
Axons from medial mammillary nucleus to the anterior nucleus of the dorsal thalamus
What does the mammillary peduncle transmit?
Information from the midbrain reticular formation to the intermediate and lateral mammillary nuclei
Inability to process short-term memory iinto long-term memory may be a sign of a lesion where?
Mammillary body
What does the supraoptic nucleus transmit to the posterior pituitary?
Oxytocin and ADH
What structure does the posterior hypothalamic nucleus merge with?
Periaqueductal gray matter
What is the blood supply to the preoptic area, supraoptic region, septal nuclei, and rostral portions of the lateral hypothalamic area?
Anteriomedial group branching from the A1 segment (ACA)
What is the blood supply to the tuberal and mammillary regions of the hypothalamus?
Rostral portion of P1 => Tuberal
Caudal portion of P1 => Mammillary
What structure provides the largest single afferent input to the hypothalamus?
Fornix
Where does the stria terminalis originate and where does it terminate?
Origin: Corticomedial portion of amygdala
Terminate: Septal nuclei
What are the hypothalamic efferent structures?
Fornix
Medial forebrain bundle
Amygdalohypothalamic fibers
Where do the axons of the ventral amygdalofugal pathway terminate?
Lateral hypothalamic zone
Septal and preoptic nuclei
What does the mammillary fasciculus originate as and where does it go?
Origin: Medial mammillary nucleus => mammillothalamic and mammillotegmental tracts => anterior nucleus of the thalamus
What is the pathway of the hypothalamothalamic fibers?
Lateral preoptic area => project to dorsomedial nucleus (thalamus) and amygdaloid nucleus via stria terminalis and ventral amygdalofugal pathway
What hypothalamic fibers terminate directly in the ANS?
Hypothalamospinal and hypothalamomedullary fibers - arise from PVN
Hypothalamomedullary fibers - terminate in solitary nucleus, dorsal vagal motor nucleus, nucleus ambiguus
Hypothalamospinal fibers - terminate in intermediolateral cell column
What structure do the indirect fibers from the hypothalamus target?
Periaqueductal Gray Matter
What tract transports oxytocin and ADH to the posterior pituitary?
Supraopticohypophysial tract
What parts of the brainstem does the tuberoinfundibular tract convey its hormones?
Median eminence
Infundibulum
What thalamic nucleus is composed of parvicellular, magnocellular, and paralaminar parts?
Medial Thalamic Nuclei
What lateral thalamic nuclei receive and send nociceptive cutaneous input transmitted over somatosensory pathways?
Posterior nuclear complex
A stroke involving what thalamic artery may result in total/dissociated sensory loss? May result in what syndrome?
Thalamogeniculate A.
Dejerine-Roussy Syndrome
What comprises the hippocampal formation?
Subiculum
Hippocampus
Dentate gyrus
What is the major input to the hippocampus?
Cells of Entorhinal cortex via peroforant pathway
What is the path of the Circuit of Papez?
- Medial mammillary nucleus => mammillothalamic tract => anterior nucleus of thalamus
- Thalamus => Thalamocortical fibers => Cingulate gyrus
- Cingulate gyrus => Entorhinal cortex, subiculum, and hippocampus
- Subiculum => Fornix => Mammillary body
What are the amygdaloid efferents?
Stria terminalis
Ventral amygdalofugal pathway
Stria medullaris thalami
What role do the nucleus accumbens and ventral tegmental area play in the limbic system?
Behaviors related to addiction and chronic pain
What happens if there are bilateral lesions in the hippocampi?
Amnesia - deficit in anterograde episodic memory (cannot learn new material) but procedural and working memory is spared
In Korsakoff’s syndrome, what structures undergo degeneration? What function does this impede?
Mammillary bodies, hippocampal complex, dorsomedial thalamic nucleus
Cannot commit short term memory to long term memory
A patient is a chronic alcoholic. Upon exam, he appears to be unable to understand words on a page. He describes events that have not happened. If left untreated, what disorder may this patient be at risk for?
Korsakoff’s syndrome
Where is the lesion if a patient is experiencing phantosmia?
Anterior/Medial Temporal lobe, hippocampus, amygdala, or medial dorsal thalamic nuclei
What has been destroyed in a patient with Kluver-Bucy syndrome?
Amygdaloid complex
What behavior changes might you see in a patient with Kluver Bucy Syndrome?
Visual agnosia
Hyperorality - examines objects w mouth
Hypermetamorphosis - Overreaction to visual stimuli
Placidity - No fear or anger even when appropriate
Hyperphagia - eating lots
Hypersexuality
What CN is involved in uncal herniation?
CN III (Dilated pupil, double vision ipsilateral to hernia)
If an uncal herniation is compressing the brainstem and weakness is seen in the right extremities, where is the lesion?
Left CST
