Show Advanced Search

REFINE YOUR SEARCH:

Containing Text
- - -
+
Filter by author or institution
GO
Filter by publication date
From:
October, 2006
Until:
Today
Filter by journal section

Filter by science education

 
 
Sympathetic Nervous System: The thoracolumbar division of the autonomic nervous system. Sympathetic preganglionic fibers originate in neurons of the intermediolateral column of the spinal cord and project to the paravertebral and prevertebral ganglia, which in turn project to target organs. The sympathetic nervous system mediates the body's response to stressful situations, i.e., the fight or flight reactions. It often acts reciprocally to the parasympathetic system.

The Sympathetic Nervous System

JoVE 10840

The sympathetic nervous system—one of the two major divisions of the autonomic nervous system—is activated in times of stress. It prepares the body to meet the challenges of a demanding circumstance while inhibiting essential body functions—such as digestion—that are a lower priority at the moment.

As a student, you may have had the experience of walking into class and finding a surprise exam that you were not expecting. In the moment of realization, you may sense your gut tighten, your mouth goes dry, and your heart starts to race all of a sudden. These are signs of the sympathetic system taking over in preparation to react. While you may not be in immediate danger, the system has evolved to facilitate immediate reaction to stress or threats: blood is directed away from the digestive system and skin to increase energy supplies to muscles. Furthermore, the heart rate, and blood flow increase, and pupils dilate to maximize visual perception. At the same time, the adrenal gland releases epinephrine into the circulatory system. Your body is now primed to take action, whether that means to swiftly flee from danger or fight whatever threat may be at hand. The sympathetic nervous system can be activated by various parts of the brain, with the hypothalamus playing a particularly important role. Sympathetic instructions from the central

 Core: Nervous System

Hypothalamic-Pituitary Axis

JoVE 10879

The response to stress—be it physical or psychological, acute or chronic—involves activation of the Hypothalamic-Pituitary-Adrenal (HPA) axis. The HPA axis is part of the neuroendocrine system because it involves both neuronal and hormonal communication. Its function is to regulate homeostatic systems—metabolic, cardiovascular, and immune—providing the necessary means to respond to a stressor. In response to stress, the neurons in the hypothalamus release corticotropin-releasing hormone, or CRH, into the bloodstream. CRH takes a short journey to the pituitary gland where it stimulates the release of adrenocorticotropic hormone, or ACTH. The site of action for ACTH are the adrenal glands which lay just on the surface of the kidneys. When stimulated, the adrenal glands release two types of stress messages. Neural stimulation initiates the first message—the release of epinephrine and norepinephrine from the adrenal medulla. This activates the sympathetic nervous system resulting in elevated heart rate, blood flow, and respiration—processes designed to activate states of alertness and arousal. These two chemicals are also referred to as adrenaline and noradrenaline, respectively. ACTH initiates the second message—the release of glucocorticoids by the adrenal cortex. In humans, cortisol is the primary hormone

 Core: Endocrine System

A Cross-Disciplinary and Multi-Modal Experimental Design for Studying Near-Real-Time Authentic Examination Experiences

1Department of Engineering Education, College of Engineering, Utah State University, 2Department of Electrical and Computer Engineering, College of Engineering, Utah State University, 3Department of Educational Psychology, College of Education, University of Oregon

JoVE 60037

 Behavior

Human Brown Adipose Tissue Depots Automatically Segmented by Positron Emission Tomography/Computed Tomography and Registered Magnetic Resonance Images

1Chemical and Physical Biology Program, Vanderbilt University, 2Department of Physical Medicine and Rehabilitation, Vanderbilt University School of Medicine, 3Radiology & Radiological Sciences, Vanderbilt University Medical Center, 4Department of Pharmacology, Vanderbilt University

JoVE 52415

 Medicine

Pre-clinical Model of Cardiac Donation after Circulatory Death

1Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 2Deparment of pharmacology and physiology, Faculty of Medicine, Université de Montréal, 3Division of Cardiovascular Surgery, Toronto General Hospital, University Health Network, 4Department of surgery, Faculty of Medicine, Université de Montréal

JoVE 59789

 Medicine

Visualization of 3D White Adipose Tissue Structure Using Whole-mount Staining

1Translational Medicine Program, The Hospital for Sick Children, 2Department of Laboratory Medicine and Pathobiology, University of Toronto, 3Neurosciences & Mental Health Program, The Hospital for Sick Children, 4Department of Biochemistry and Molecular Biology, Smart-Aging Convergence Research Center, College of Medicine, Yeungnam University, 5Banting and Best Diabetes Centre, University of Toronto

JoVE 58683

 Biology

Autonomic Function Following Concussion in Youth Athletes: An Exploration of Heart Rate Variability Using 24-hour Recording Methodology

1Concussion Centre, Bloorview Research Institute, Holland Bloorview Kids Rehabilitation Hospital, 2Faculty of Kinesiology and Physical Education, University of Toronto, 3Rehabilitation Sciences Institute, Faculty of Medicine, University of Toronto, 4Department of Occupational Science and Occupational Therapy, Faculty of Medicine, University of Toronto

JoVE 58203

 Medicine

Measuring Cardiac Autonomic Nervous System (ANS) Activity in Children

1Department of Public Health, Academic Medical Center - University of Amsterdam, 2Department of Epidemiology, Documentation and Health Promotion, Public Health Service of Amsterdam (GGD), 3Department of Biological Psychology, VU University, 4EMGO+ Institute, VU University Medical Center, 5Institute of Health Sciences, VU University, 6Department of Pediatrics, VU University Medical Center

JoVE 50073

 Medicine
More Results...