Hypothalamus Flashcards
What three systems is the hypothalamus functionally related to?
- Autonomic
- Limbic
- Endocrine
What separates the thalamus from the hypothalamus?
hypothalamic sulcus
What are the three zones of the hypothalamus?
periventricular, medial, lateral
What separates the medial and lateral zones of the hypothalamus?
fornix ventrally
mammillary bodies posteriorly
The lateral zone is traversed by fibers of what?
medial forebrain bundle
The lateral preoptic nucleus is derived from which embryonic layer
telencephalon
The lateral hypothalamic area is involved in what function?
What would a lesion here cause?
feeding center, contains peptide neurotransmitters involved in food intake
Lesion here causes anorexia
What is the function of the tuberomammillary nucleus?
large neurons that release histamine ti the forebrain which plays a role in arrousal and attention, it is actively inhibited during sleep
What are the 4 divisions of the medial zone?
pre-optic
anterior (supraoptic)
middle (tuberal)
posterior (mammillary)
Which nucleus houses neurons that regulate gonadotropin secretion from the adenohypophysis and contains the sexually dimorphic nucleus?
Medial Preoptic Nucleus
Which nucleus receives direct input from the retina and plays a critical role in circadian rhythms?
Suprachiasmatic Nucleus
Which nucleus lies between the supra-chiasmatic and paraventricular nuclei and is involved in temp regulation that dissipates heat? What is one other function of this nucleus?
Anterior Hypothalamic Nucleus
drives parasympathetic nervous system
What would a lesion of the Anterior Hypothalamic Nucleus cause?
Hyperthermia (involves heat dissipation)
What is the function of the paraventricular nucleus?
release neuropeptides such as vasopressin and oxytocin and CRH
also has spinal projections to sympathetic preganglionic neurons
Which two nuclei have roles in autonomic function?
Anterior Hypothalamic Nucleus and Paraventricular Nucleus
What is the function of the supraoptic nucleus?
contains neurons that synthesize vasopressein and oxytocin
Which nucleus is involved in blood pressure regulation and some agression?
Dorsomedial Nucleus
Which nucleus relays ingestion-related signals to the brainstem (satiety center)?
Ventromedial Nucleus
Where is the arcuate nucleus located?
Tuber Cinereum with projections to the median eminence of the adenohypophysis
What is the function of the arcuate nucleus?
controls release of adenohypophyseal hormones, hormone releasing factors, and a prominent role in feeding behavior
Which nucleus is involved in thermoregulation for heat production in response to cold ?
Posterior Nucleus
A lesion bilaterally to the posterior nucleus leads to what condition.
Poikilothermia- inability to thermoregulate
What is the function of the mammillary nucleus?
Limbic, receive input from the hippocampus via the fornix and project to the anterior nucleus of the thalamus via the mamillothalamic tract.
What problem is associated with damage to the mammillary nucleus?
Memory disturbances
What two regions does the fornix connect?
hippocampus to the mammillary bodies
Which tract connects the mammillary bodies to the anterior nucleus of the thalamus?
mamillothalamic tract
What does the stria terminalis connect?
amygdala to the medial zone of the hypothalamus
What complex fiber pathway extends through the lateral hypothalamic zone, interconnecting regions from the septal nuclei to the brainstem?
medial forebrain bundle
What is the name of the tract that conducts fibers from the supraoptic and paraventricular nucleus to the neurohypophysis and what hormones are synthesized by these neurons?
Supraopticohypophyseal tract syntheszies AVP or oxytocin
Which axons carry neuropeptide releasing of inhibiting factors from the arcuate nucleus that act on anterior pituitary cells?
Tuberoinfundibular tract
What is the function of the hypothalamospinal tract and where does it originate?
Descending axons that regulate spinal cord preganglionic neurons of both sympathetic and parasympathetic divisions of the autonomic nervous system
originates in the paraventricular nucleus
Describe Papez Circuit
hippocampus to mamillary body to ant. thalamic nuclei to cingulate gyrus then cingulum back to hippocampus
How is the hypothalamus involved in stress response?
Release of cortisol, and sympathetic connections parasympathetic neurons of the brainstem are actively inhibited
Which nuclei are involved in feeding and energy metabolism?
arcuate, lateral and ventromedial
Which hormone decreased food intake?
leptin
What does a craniopharngioma cause and why?
bitemporal hemianopia due to pressure on the chiasm, pressure on the hypothalamus also results in hypothalamic syndrome of adiposity, diabetes insipidus, temperatures regulation problems, and somnolence
What is a congential tumor that originates from Rathke’s pouch and is the most common supratentorial tumor in children?
craniopharngioma
What is the name of the syndrome that is caused by thiamine deficiency in chronic alcoholism that leads to memory disturbances ?
Korsakoff Syndrome
An adolescent male presents to your clinic and states he is very tired all the time but is craving sex and is eating all of the time even when he isn’t hungry. What is causing his sx and what is the name for the disorder?
Klein-Levin Syndrom- hypothalamic lesion in adolescent males decreased dopaminergic tone
A lesion in the suprachiasmatic nucleus will lead to what?
insomnia can occur from Alzheimers or shift work
