Man, Machine, and Homeostasis

2011 ◽  
pp. 141-148
Author(s):  
James R. Munis
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Fundamental Principle ◽  
The Body ◽  
Set Point ◽  
Autonomic Nervous ◽  
Claude Bernard ◽  
Shed Light

Physiologist Claude Bernard lived in a time when very little was known about the mechanisms underlying physiologic findings, and he had ample access to clues garnered from observing machines. Let's consider homeostasis (a concept championed by Bernard), an example for which an engineered machine shed light on a fundamental principle of physiology. Homeostasis is simply the tendency of the body to maintain important physiologic variables (eg, heart rate, blood pressure, PACO2) at constant, preset values. An example is a simplified mechanical governor that could be used to regulate the rotational speed of a steam engine shaft. ‘Autoregulate’ might be a more apt word because the governor performs without external help or guidance, provided it is designed and built properly. It doesn't take much imagination to see an analogy between the mechanical governor and the autonomic nervous system. Both maintain specific variables at a constant set point through a process of feedback loops.

scholarly journals TO STUDY THE EFFECT OF REGULAR YOGIC ACTIVITY ON THE FUNCTION OF AUTONOMIC NERVOUS SYSTEM: A COMPARATIVE STUDY.

2020 ◽  
Vol 4 (8) ◽  
Author(s):  
Abhay Choudhary ◽  
Arun Pathak ◽  
Sheela Kumari
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Systolic Blood Pressure ◽  
The Body ◽  
Relaxation Techniques ◽  
Autonomic Nervous ◽  
Hand Grip ◽  
Significant Difference

Aims: to know the influence of yoga on autonomic functions of the body. Material and Methods: The present prospective case control study was conducted among patients visited the OPD, Darbhanga Medical College and Hospital, Bihar, India. The findings were tabulated and subjected to statistical analysis. Case group (N=30): subjects who were performing regular yoga asanas and relaxation techniques for at least 5 years. Control group (N=30): age and gender matched subject who were not performing yoga asanas and relaxation techniques or were not engaged with any other type of physical exercises. Results: Amongst the sympathetic nervous system parameters, statistically significant difference existed between cases and controls for the Resting Heart Rate, Resting Diastolic Blood Pressure, Hand grip systolic blood pressure and Hand grip systolic blood pressure (p<0.05) respectively. Conclusion: yogic activity significantly alters the sympathetic activity like heart rate and blood pressure. Keywords: Autonomic Nervous system, Yoga, Heart Rate, Blood Pressure

Heart Rate and Blood Pressure Changes During Autonomic Nervous System Challenge in Panic Disorder Patients

2010 ◽  
Vol 72 (5) ◽  
pp. 442-449 ◽  
Author(s):  
Jose M. Martinez ◽  
Amir Garakani ◽  
Horacio Kaufmann ◽  
Cindy J. Aaronson ◽  
Jack M. Gorman
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Panic Disorder ◽  
Autonomic Nervous ◽  
Pressure Changes

Blood Pressure and Orthostatic Hypotension: Faints, Near-Faints, and Lightheadedness

2013 ◽  
Author(s):  
J. Eric Ahlskog
Keyword(s):  
Blood Pressure ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Orthostatic Hypotension ◽  
Vessel Diameter ◽  
Upright Position ◽  
Grocery Store ◽  
The Body ◽  
Autonomic Nervous ◽  
Neurodegenerative Process

Case example: Mrs. H. feels lightheaded intermittently during the day. This happens exclusively when she is up and about. Sometimes she notes graying of vision with these episodes. The feeling is not spinning (i.e., not vertigo). She has fainted twice when standing in line at the grocery store. If she sits, she feels much better. It is worse in the morning but may recur any time of the day. She feels fine while lying in bed at night. Older adults often worry about high blood pressure (BP), yet the opposite problem, low BP, is common among those with DLB or PDD. This is because the Lewy neurodegenerative process impairs the autonomic nervous system. The specific condition that may afflict those with DLB or PDD is orthostatic hypotension. The term orthostatic implies the upright position (i.e., standing); hypotension translates into low BP. Thus, the low BP occurring in these Lewy disorders develops in the upright position; conversely, it is normal or even high when lying down. When standing or walking, the BP may drop so low that fainting occurs. Among people with orthostatic hypotension, the BP is normal when sitting, although in severe cases, even the sitting BP is low. Whereas most people with DLB or PDD do not experience symptoms of orthostatic hypotension, it is sufficiently frequent to deserve attention. It often goes undiagnosed, even when fainting occurs. Unrecognized orthostatic hypotension may limit activities and impair the person’s quality of life. The first half of this chapter provides further background, with focus on BP measurement and recognition of orthostatic hypotension. The last half addresses treatment. The normal autonomic nervous system senses the position of our body with respect to the pull of gravity. It is able to reflexively counter gravity’s downward pull on the blood volume when standing (gravity tends to draw blood toward our feet when standing). An important mechanism for countering gravity’s pull is the constriction of blood vessel diameter in the lower half of the body. These vessels reflexively constrict during standing, in effect forcing blood up to the brain. The autonomic nervous system mediates these and other reflexive changes to stabilize BP.

Paraventricular stimulation with glutamate elicits bradycardia and pituitary responses

1989 ◽  
Vol 256 (1) ◽  
pp. R112-R119 ◽  
Author(s):  
D. N. Darlington ◽  
M. Miyamoto ◽  
L. C. Keil ◽  
M. F. Dallman
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Arterial Blood Pressure ◽  
Excitatory Neurotransmitter ◽  
Autonomic Nervous ◽  
Arterial Blood ◽  
Paraventricular Nuclei ◽  
Measured Activation

The excitatory neurotransmitter, L-glutamate (0.5 M, pH 7.4), or the organic acid, acetate (0.5 M, pH 7.4), was microinjected (50 nl over 2 min) directly into the paraventricular nuclei (PVN) of pentobarbital sodium-anesthetized rats while arterial blood pressure and heart rate and plasma adrenocorticotropic hormone (ACTH), vasopressin, and oxytocin were measured. Activation of PVN neurons with L-glutamate led to increases in plasma ACTH, vasopressin, and oxytocin and a profound bradycardia (approximately 80 beats/min) with little change in arterial blood pressure. Microinjection of acetate had no effect on the above variables. The decrease in heart rate was shown to be dependent on the concentration of glutamate injected and the volume of injectate. The bradycardia was mediated through the autonomic nervous system because ganglionic blockade (pentolinium tartrate) eliminated the response; atropine and propranolol severely attenuated the bradycardia. The bradycardia was greatest when L-glutamate was microinjected into the caudal PVN. Injections into the rostral PVN or into nuclei surrounding the PVN led to small or nonsignificant decreases in heart rate. Focal electric stimulation (2-50 microA) of the PVN also led to decreases in heart rate and arterial blood pressure. These data suggest that activation of PVN neurons leads to the release of ACTH, vasopressin, and oxytocin from the pituitary and a bradycardia that is mediated by the autonomic nervous system.

Control of blood pressure and hindlimb conductance during hemorrhage in conscious renal hypertensive rabbits

1995 ◽  
Vol 268 (6) ◽  
pp. H2302-H2310 ◽  
Author(s):  
G. Weichert ◽  
C. A. Courneya
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Angiotensin Ii ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Similar Pattern ◽  
Ang Ii ◽  
Autonomic Nervous

We examined the response to hemorrhage in conscious normotensive and hypertensive rabbits under control conditions and during efferent blockade of 1) the hormones vasopressin (AVP) and angiotensin II (ANG II), 2) the autonomic nervous system, and 3) autonomic and hormonal inputs. We recorded mean arterial pressure, heart rate, and hindlimb conductance. The response to hemorrhage was unchanged with hormonal blockade alone. Blockade of the autonomic nervous system caused a faster rate of blood pressure decline, but the rate of decrease in hindlimb conductance was maintained at control levels. Blocking the autonomic nervous system and the hormones resulted in rapid blood pressure decline and an increase in hindlimb conductance. Although the three types of efferent blockade had a similar pattern of effects in normotensive and hypertensive rabbits, hypertensive rabbits exhibited less cardiovascular support during hemorrhage than normotensive rabbits. During hemorrhage, hypertensive rabbits had an attenuation of hindlimb vasoconstriction, a reduction in the heart rate-mean arterial pressure relationship, and reduced ability to maintain blood pressure compared with normotensive rabbits.

Classification of Individuals Based on Autonomic Response to Virtual Gaming

2020 ◽  
Vol 17 (9) ◽  
pp. 4385-4393
Author(s):  
S. Chandana ◽  
B. R. Purnima ◽  
Prabhu Ravikala Vittal
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Physiological Stress ◽  
Rio Grande ◽  
The Body ◽  
Autonomic Response ◽  
Autonomic Nervous ◽  
Non Invasive

Modern games consists of digital gaming consoles that involves interaction with a user and has an interface to generate visual feedback through 2D/3D monitor. These games have several psychological side effects like loss of spatial awareness, back pains, insomnia, addiction, aggression, stress, and hypertension. Virtual reality (VR) Gaming is one of the most emerging and novel technologies in the field of entertainment. Evaluation of this new technology has become important in order to analyze the effects of its predecessors (2D and 3D gaming). The main focus of this paper is on detection of stress levels in individuals due to VR gaming and classify them depending on their sympathetic and parasympathetic dominance. This is done through acquisition of electrocardiogram (ECG) and photo plethysmograph signals (PPG) signals and extracting their time domain and frequency domain features before, during and after gaming (Fatma Uysal and Mahmut Tokmakçi, 2018. Evaluation of stress parameters based on heart rate variability measurement. Department of Biomedical Engineering, Erciyes University, Kayseri, Turkey. [email protected], [email protected]., da Silva1, A.G.C.B., Arauj, D.N., et al, 2018. Increase in perceived stress is correlated to lower heart rate variability in healthy young subjects. Departamento de Fisioterapia, Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil. s/n., 81531–980, Curitiba, Parana, Brazil. E-mail: [email protected].). The physiological signal variation is analyzed by performing Heart Rate Variability (HRV) analysis over ECG signals which is one of the fast emerging methods in non-invasive research and clinical tools for assessing autonomic nervous system function (Juan Sztajzel, 2004. Heart rate variability: Aa non-invasive electrocardiographic method to measure the autonomic nervous system. Cardiology Center and Medical Policlinics, University Hospital, Geneva, Switzerland, SWISS MED WKLY 2004;134:514–522. www.smw.ch). Pulse-transmissiontime-variability (PTTV), which is extracted, has high coherence with heart rate variability and is also used as an objective measure of stress. In this paper we obtain the response of an individual during VR gaming and correlate them with the HRV/PTT parameters. The game chosen for the data acquisition was ‘VR city view rope crossing-360 android VR,’ during which data recording is done. It was found that there was a quantitative increase in physiological stress when individuals were exposed to virtual high heights in comparison with time relative to unaltered viewing. Mean Heart rate showed a significant increase during gaming for both boys and girls which indicates that the body is under the influence of a sympathetic activity like a physical exercise.

19. Role of the autonomic nervous system in blood pressure and heart rate variability in conscious rats

1991 ◽  
Vol 9 (6) ◽  
pp. S429
Author(s):  
C. Cerutti ◽  
M. Lo ◽  
Claude Julien ◽  
Madelaine Vincent ◽  
C. Paultre ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Conscious Rats ◽  
Autonomic Nervous

Autonomic nervous system tests depend on resting heart rate and blood pressure

1991 ◽  
Vol 35 (1) ◽  
pp. 15-24 ◽  
Author(s):  
J.Gert van Dijk ◽  
Monique Koenderink ◽  
Aeilko H. Zwinderman ◽  
Joost Haan ◽  
Cor G.S. Kramer ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Resting Heart Rate ◽  
Autonomic Nervous

Modelling of autonomic regulation in cardiovascular system based on baroreflex mechanism and overwhelming controller

2017 ◽  
Vol 231 (4) ◽  
pp. 299-311 ◽  
Author(s):  
Kartik Sharma ◽  
Tarun Kumar Bera
Keyword(s):  
Blood Pressure ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
Cardiovascular System ◽  
Transfer Functions ◽  
Systolic Pressure ◽  
Bond Graph ◽  
Autonomic Regulation ◽  
The Body ◽  
Autonomic Nervous

The control of cardiovascular system by autonomic nervous system using model-based analysis is very useful to predict blood flow and blood pressure at different locations of human body. The regulation of cardiovascular system by autonomic nervous system is a very complex mechanism, so, an experimental-based model analysis may prove very helpful in studying and analysing its working properly. In this article, a very basic model of cardiovascular system is presented with blood pressure dynamics studied throughout the body. A new bond graph model of the autonomic nervous system embedded with baroreflex system is also presented. Autonomic regulation of ventricular contractility is represented by means of transfer functions. The results in terms of maximum ventricular elastance ([Formula: see text]) and end systolic pressure are shown for two experiments. Another alternative modelling approach to represent the function of nervous system action in blood pressure regulation in terms of an overwhelming controller has been proposed. This controller overwhelms the system properties and therefore helps in managing the unmodelled parts or properties of a system and makes it impeccable for controlling complex systems. All the results and simulations are obtained using Symbols Shakti® software (Bond graph software).

scholarly journals The Heart of an Endurance Athlete: Impact of and Recovery After an Ultra-Endurance Event.

2021 ◽  
Author(s):  
Anton Swart ◽  
Demitri Constantinou
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Nervous System ◽  
Autonomic Nervous System ◽  
The Body ◽  
Mountain Biking ◽  
Vagal Activity ◽  
Autonomic Nervous System Dysfunction ◽  
Autonomic Nervous ◽  
Ultra Endurance

Abstract Background: Acute bouts of ultra-endurance exercise may cause an acute reduction in cardiac function, causing a physiological cascade which releases cardiac biomarkers. This study set out to determine the cardiac stress and recovery of participation in a three-day ultra-endurance mountain biking event of athletes using heart rate variability (HRV) as an outcome measure. Sixteen healthy participants (male and female) participating in a three-day ultra-endurance mountain biking event underwent a five-minute resting electrocardiography (ECG) recording in a supine position. Heart rate variability measurements were recorded two days before the race (baseline testing), after each race day, and at 24-hour post-event (recovery). Results: Time-domain and frequency domain measures showed significant (p≤0.05) changes from baseline in HRV parameters after each race day. The significant changes in HRV parameters reflected an increase in sympathetic activity after each day of the event. Our data revealed that the mean HR and RR variability variables did not return to baseline value after 24-hours of recovery, reflecting autonomic nervous system dysfunction, and that changes persisted for at least 24-hours post-event.Conclusion: Our study shows that competing in an ultra-endurance mountain bike event led to diminished vagal activity and a decrease in HRV throughout the event and persisted for at least 24-hours post-event. The body was under continuous sympathetic dominance during rest as well as during each day of racing, implying each race day can be considered a physiological stress. This may, in turn, cause a disturbance in homeostasis and an increase in autonomic nervous system dysfunction. This has implications for further research, including dysrhythmia risk, and monitoring of athletes in advising a return to strenuous activity.

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