Medial Zone of Hypothalamus Flashcards
Has what four anatomically distinct zones
Preoptic
Anterior supraoptic nucleus
Middle region
Posterior region
anterior ‘telencephalic’ portion that contains preoptic nucleus that houses neurons to regulate Gonadotorpin secreation from adenophypophysis
Preoptic region
It also contains the interstitial nuclei of the anterior hypothalamus (INAH1- 4), one of which is sexually dimorphic (INAH3) and developmentally regulated by testosterone
Preoptic region
Four subdivisions of the anterior (supraoptic) region
Suprachiasmatic nucleus
Anterior hypothalamic nucleus
Paraventricular nucleus
Supraoptic nucleus
Suprachiasmatic Nucleus (part of the Anterior region) – this compact nucleus is located immediately dorsal to the optic chiasm and receives direct input from
the retina.
It plays a critical role in the control of circadian rhythmicity.
Anterior Hypothalamic Nucleus (Area) – this region lies between the suprachiasmatic and paraventricular nuclei. It is involved in
temperature regulation (containing neurons that sense warmth and initiate responses to dissipate excessive heat) It is also concerned with stimulatory drive of the parasympathetic division of the autonomic nervous system
bilateral lesions of anterior hypothalamic nucleus of the anterior region of hypothalamus
result in hyperthermia.
temperature regulation (containing neurons that sense warmth and initiate responses to dissipate excessive heat) It is also concerned with stimulatory drive of the parasympathetic division of the autonomic nervous system
Anterior hypothalamic nucleus of the Anterior hyothalamus region
Paraventricular Nucleus – this complex nucleus contains distinct populations of neurons that
release neuropeptides that regulate a variety of functions.
Hormones that the Paraventricular nucleus of the anterior hypothalamus makes:
arginine vasopressin (AVP; water conservation), oxytocin (milk let- down and release, also regulation of food intake) corticotropin-releasing hormone (CRH; stress responsiveness).
Additional populations of neurons in the Paraventricular nucleus project to the ________
Here they will:
intermediolateral cell column of the spinal cord (between T1-L2), exciting sympathetic preganglionic neurons, as well as projection to the brainstem.
Supraoptic Nucleus of anterior hypothalamus region– contains neurons that
synthesize AVP and oxytocin. Similar to neurons in the paraventricular nucleus that contain AVP and oxytocin, these cells project to the neurohypophysis where they release these hormones into the general circulation.
The Middle (tuberal region ) of the Anterior region contains what three sets of neurons
- Dorsomedial nucleus
- Ventromedial Nucleus
- Arcuate Nucleus
This nucleus is involved in blood pressure regulation. Also, when stimulated in experimental animals, aggression and savage behavior result.
Dorsomedial Nucleus of the Middle tuberal region
Dorsomedial nucleus is key in
BP regulation and when stimulated we see savage behavior and aggression
This nucleus inhibits the urge to eat when stimulated. (Bilateral destruction results in hyperphagia).
Ventromedial Nucleus of the Middler tuberal region
neurons within this nucleus play an important role in relaying ingestion-related signals to the brainstem.
Ventromedial nucleus in the Middle tuberal region
located ventrally in the tuber cinereum, and via projections to the median eminence and portal vasculature, controls the release (or non-release) of various adenohypophyseal hormones.
Arcuate Nucleus of the middle tuberal region
Neurons found here produce hypothalamic-releasing (and inhibiting) factors, and play a prominent role in feeding behavior.
Arcuate nucleus of middle tuberal region
Fnx of the Arcuate nucleus of the MIddle tuberal region
via projections to the median eminence and portal vasculature, controls the release (or non-release) of various adenohypophyseal hormones.
produce hypothalamic-releasing (and inhibiting) factors, and play a prominent role in feeding behavior.
Parts of the Posterior (mammilary) region of the Medial zone of hypothalamus
Posterior nucleus
Mammillary nucleus
neurons in this area are involved in thermoregulation (neurons sense cold and initiate heat conservation and heat production responses).
Posterior Nucleus of the Posterior mammilary region of medial zone
Bilateral lesions of the Posterior nucleus of the posterior mammillary region result in
an inability to thermoregulate, termed poikilothermia (see below).
actually a series of nuclei within the mammillary bodies which are functionally considered part of the limbic system.
Mammillary Nucleus from the Posterior (mammillary) region of medial zone
Neurons in the Mammillary nucleus receive a major input from the hippocampus via _____.
The mammillary nuclei project to the anterior nucleus of the thalamus via the .
the fornix
mammillothalamic tract
Mammillary nucleus damage:
associated with memory disturbances due to extensive interconnectivity with the hippocampus
