DSA Hypothalamus & Limbic System Flashcards
This is a small, anatomical region of the diencephalon. It integrates info from the forebrain, brainstem, and spinal cord.
Hypothalamus
The primary role of this is in homeostasis – water and electrolyte balance, food intake, temperature, BP, circadian rhythm, stress responses, and body metabolism.
Hypothalamus
What does the rostral/anterior portion of the Hypothalamus merge with?
Optic chiasm
What does the caudal/posterior portion of the Hypothalamus merge with?
Tegmentum
PAG (midbrain)
The Hypothalamus forms the floor and ventral walls of which ventricle?
3rd ventricle
These form the posterior part of the hypothalamus and are adjacent to the cerebral peduncles.
Mammillary bodies
These are small swellings between the mammillary bodies and the optic chiasma and tract.
Tuber cinereum
This arises from the tuber cinereum and narrows into the infundibulum and attaches to the pituitary gland.
Median eminence
What are the longitudinal divisions of the Hypothalamic Nuclei?
Anterior region – superior to Optic Chiasm
Tuberal region – superior to and including tuber cinereum
Mammillary/Posterior region – superior to and including the mammillary bodies
What are the divisions of the Hypothalamus from medial to lateral?
Periventricular zone – periaqueductal gray (midbrain) through in the wall of 3rd ventricle
Medial zone
Lateral zone
What divides the medial and lateral zones of the hypothalamus?
Fornix
This portion of the hypothalamic nuclei is composed of diffusely arranged neurons with few ‘named’ nuclei. It contains the medial forebrain bundle and damage results in a decrease in feeding behavior with a resultant weight loss.
Lateral zone
This portion of the hypothalamus overlaps with the anterior and posterior (mammillary) regions. This is where neurons are arranged in distinct nuclei.
Medial zone
What are the nuclei of the Supraoptic region (within medial zone)?
Supraoptic/Paraventricular Nucleus
Suprachiasmatic Nucleus
Anterior Nucleus
The Supraoptic/Paraventricular Nucleus contains ________ and ________ that is released from the posterior pituitary.
Oxytocin (PVN)
ADH (SON)
Lesions in what nucleus can result in diabetes insipidus (DI) which causes increased water intake and increased urination.
Supraoptic/Paraventricular Nucleus
This nucleus receives retinal input and is involved in circadian rhythms (day/night cycles). Damage to this area may modify, or abolish, these rhythms.
Suprachiasmatic Nucleus
This nucleus has a range of visceral/somatic functions and temperature regulation.
Anterior Nucleus
What are the nuclei of the mammillary/posterior region (within the medial zone)?
Medial Mammillary Nucleus
The Medial Mammillary Nucleus has afferents from the _________ via the fornix, efferents to the ________ and _________, and lesions will result in an inability to process short-term events into long-term memory.
Hippocampus
Thalamus
Brainstem
What are the nuclei of the tuberal region (within the medial zone)?
Ventromedial Nucleus
Dorsomedial Nucleus
This nucleus is considered to be a “satiety center”. Lesions cause excessive eating and abnormal weight gain.
Ventromedial Nucleus
This nucleus subserves functions of emotional behavior. Stimulation causes sham rage and destruction results in decreased aggression and feeding.
Dorsomedial Nucleus
The blood supply of the hypothalamus is via small perforating arteries of the…
Circle of Willis
What arteries supplies the anteromedial group, which includes the preoptic area, supraoptic region, septal nuclei, and rostral portions of the lateral hypothalamic area.
Branches from Anterior Communicating A. and ACA (A1 segment)
What arteries supplies the posteromedial group, which includes the tuberal and mammillary regions.
Perforating arteries from the Posterior Communicating A. and PCA (P1 segment)
The rostral portion of the Posterior Communicating A. supplies the ________ region, while the caudal part of the artery supplies the _______ region.
Tuberal
Mammillary
This is the largest single imputes to the hypothalamus (afferent). It arises from the subiculum and hippocampus.
Fornix
This afferent route interconnects the septal nuclei, hypothalamus, and midbrain tegmenjtum. It course through the lateral hypothalamic zone.
Medial forebrain bundle (MFB)
These create an afferent route via the stria terminalis and ventral amygdalofugal pathways. Both target septal nuclei, preoptic area, and medial hypothalamic zone.
Amygdalohypothalamic fibers
This efferent hypothalamic pathway originates as a well-defined bundle from the medial mammillary nucleus. It bifurcates into mammillothalamic and mammillotegmental tracts that project to the anterior nucleus (thalamus), an important part of circuit of Papez.
Mammillary Fasciculus
This efferent hypothalamic pathway is from the lateral preoptic area and projects to the dorsomedial nucleus (thalamus) and amygdaloid nucleus (via the stria terminalis and ventral amygdalofugal pathway).
Hypothalamothalamic fibers
T/F. All vital functions of the hypothalamus are controlled through reflexes mediated by autonomic (or endocrine) systems.
True
This is the progressive degeneration of mammillary bodies, hippocampal complex, and dorsomedial thalamic nucleus. It impedes the retention of newly acquired memory. Short-term memory can’t be made into long-term memory. Patients will also confabulate, which means they’ll combine fragmented memories into a synthesized memory of an “event” that never occurred.
Korsakoff’s Syndrome
What causes Korsakoff’s Syndrome?
Thiamine deficiency (typically associated with chronic alcoholism)
This is a result of bilateral temporal lobe lesions that abolish the amygdaloid complex. It results in behavior changes such as visual agnosia, hyperorality, hyper metamorphosis, placidity, hyperphagia, and hyper sexuality.
Kluver-Bucy Syndrome
This occurs when the uncus and possibly parahippocampal gyrus move downward over the edge of the tentorium cerebelli. It initially compresses the midbrain, but can cause damage that extends into lower brainstem levels. Signs include dilated pupil and abnormal eye movements with double vision ipsilateral to problem area. Weakness of extremities opposite to dilated pupil, and as it progresses respiration is affected and abnormal reflexes appear.
Uncal Herniation
This occurs from bilateral lesions of the hippocami. There is a profound deficit in anterograde episodic memory (cannot learn new material), combined with spared procedural and working memory. Patients IQ and formal reasoning are fairly normal.
Hippocampal Amnesia
