Hypothalamic Control Centers
Nate F. Cardarelli in The Thymus in Health and Senescence, 2019
Hypothalamic secretory dysfunction is common in patients with pineal tumors. A thymic extract was similarly evaluated with hypothalamic cells and found to decrease thymidine synthesis. In general, hypothalamic lesions in the young rat lead to a subsequent depressed humoral immune response in the mature rat. The suprachiasmatic nuclei (SCN) consist of a pair of small, generally ovoid structures in the basal hypothalamus just above the optic chiasm and connected to the pineal gland by the superior cervical ganglion and the nervi conarii. The SCN is in neural communication with a number of surrounding areas of the hypothalamus. The SCN has circadian rhythms that are synchronized with the external light-dark cycle through the eyes. Although the obvious influence of the SCN on circadian rhythm has led to considerable study of its characteristics, other areas of the hypothalamus which might also be involved in such rhythms have had much less scrutiny.
Consciousness, EEG, Sleep and Emotions
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal in Principles of Physiology for the Anaesthetist, 2020
Consciousness may be described as a state of being aware and responsive to one's surroundings. It is produced by sensory stimulation and impulses ascending in the reticular activating system in the brainstem, midbrain, hypothalamus and thalamus interacting with intact cerebral hemispheres. Axons from the non-specific nuclei can also stimulate inhibitory interneurons linked to the thalamic nuclei to produce drowsiness. Lesions diffusely affecting the cerebral hemispheres or directly affecting the reticular activating system can impair consciousness. Sleep may be described as a state associated with loss of reactivity to surroundings or unconsciousness from which one can be aroused by sensory stimulation. There are two different types of sleep: slow-wave sleep and rapid eye movement sleep. Cortisol secretion decreases with the onset of sleep and reaches a trough in the early hours of the morning and increases during the second half of sleep with a peak just after waking.
Critical care and emergency surgery
Stephen Brennan in FRCS General Surgery Viva Topics and Revision Notes, 2017
Diagnostic laparoscopy is safe and effective when used in pregnancy. Several studies have shown that pregnant patients may undergo laparoscopic surgery safely during any trimester without any appreciated increased risk to the mother or foetus. Systemic inflammatory response syndrome differs from sepsis in that sepsis is SIRS with a documented infection. Septic shock is sepsis with refractory arterial hypotension and/or need for inotropes despite adequate fluid resuscitation. The physiological changes occurring in patients with severe sepsis and septic shock are myriad and include changes that are clearly detrimental such as decreased contractility of the left and right ventricle, increased venous capacitance, increased pulmonary vascular resistance, and capillary leak. A damage control laparotomy (DCL) is a laparotomy performed usually for trauma where the primary aim is to control haemorrhage and limit sepsis in the first instance. The central nervous system degeneration, trauma, or neoplasms may affect the hypothalamic regulatory centre.
Cluster headache and the hypothalamus: causal relationship or epiphenomenon?
Published in Expert Review of Neurotherapeutics, 2011
Typical clinical features of cluster headache (CH) include circadian/circannual rhythmicity and ipisilateral cranial autonomic features. This presentation has led to the assumption that the hypothalamus plays a pivotal role in this primary headache disorder. Several studies using neuroimaging techniques or measuring hormone levels supported the hypothesis of a hypothalamic involvement in the underlying pathophysiology of CH. Animal studies added further evidence to this hypothesis. Based on previous data, even invasive treatment methods, such as hypothalamic deep brain stimulation, are used for therapy. However, the principal question of whether these alterations are pathognomonic for CH or whether they might be detected in trigeminal pain disorders in general, in terms of an epiphenomenon, is still unsolved. This article summarizes studies on hypothalamic involvement in CH pathophysiology, demonstrates the involvement of the hypothalamus in other diseases and tries to illuminate the role of the hypothalamus based on this synopsis.
Paroxysmal episodic hypothalamic instability with hypothermia after traumatic brain injury
Published in Brain Injury, 2005
Antonio De Tanti, Giulio Gasperini, Mauro Rossini
This case report describes a patient in vegetative state after severe traumatic brain injury (TBI) with hypothalamic damage and clinical manifestations of autonomic dysfunction. He also presented late onset paroxysmal hypothermia associated with mild bradycardia and hypotension. Hypothermia due to traumatic lesions of the hypothalamus is an uncommon clinical problem and few cases have been reported; no cases could be found in the literature which evidenced periodic hypothermia associated with clinical features of autonomic dysfunction after TBI. In the article, the main causes and the primary pathophysiology of hypothermia after TBI are discussed. The manifestations in this patient have been interpreted as possible consequences of autonomic dysfunction and considered atypical and rare clinical expression of acute post-traumatic hypothalamic instability.
Gestational folic acid content alters the development and function of hypothalamic food intake regulating neurons in Wistar rat offspring post-weaning
Published in Nutritional Neuroscience, 2020
Neil Victor Yang, Emanuela Pannia, Diptendu Chatterjee, Ruslan Kubant, Mandy Ho, Rola Hammoud, Zdenka Pausova, G. Harvey Anderson
Background: Folic acid plays an important role in early brain development of offspring, including proliferation and differentiation of neural stem cells known to impact the function of food intake regulatory pathways. Excess (10-fold) intakes of folic acid in the gestational diet have been linked to increased food intake and obesity in male rat offspring post-weaning. Objective: The present study examined the effects of folic acid content in gestational diets on the development and function of two hypothalamic neuronal populations, neuropeptide Y (NPY) and pro-opiomelanocortin (POMC), within food intake regulatory pathways of male Wistar rat offspring at birth and post-weaning. Results: Folic acid fed at 5.0-fold above recommended levels (5RF) to Wistar dams during pregnancy increased the number of mature NPY-positive neurons in the hypothalamus of male offspring, compared to control (RF), 0RF, 2.5RF, and 10RF at birth. Folic acid content had no effect on expression and maturation of POMC-positive neurons. Body weight and food intake were higher in all treatment groups (2.5-, 5.0-, and 10.0-fold folic acid) from birth to 9 weeks post-weaning compared to control. Increased body weight and food intake at 9-weeks post-weaning were accompanied by a reduced activation of POMC neurons in the arcuate nucleus (ARC). Conclusion: Gestational folic acid content modulates expression of mature hypothalamic NPY-positive neurons at birth and activation of POMC-positive neurons at 9-weeks post-weaning in the ARC of male Wistar rat offspring which may contribute to higher body weight and food intake later in life.
Related Knowledge Centers
- Limbic System
- Medial Forebrain Bundle
- Supraoptic Nucleus
- Pituitary Gland
- Thalamus
- Mammillary Bodies
- Optic Chiasm