Systemic hemodynamic phenomenon accounting for advantageous oxygen supply to, and asymmetry of, the brain

1986 ◽  
Vol 386 (1-2) ◽  
pp. 64-68 ◽  
Author(s):  
George Mchedlishvili ◽  
Manana Varazashvili
1980 ◽  
Vol 238 (4) ◽  
pp. H545-H522 ◽  
Author(s):  
F. C. Fan ◽  
R. Y. Chen ◽  
G. B. Schuessler ◽  
S. Chien

The responses of alterations in regional hemodynamics and oxygen transport rate to hematocrit (Hct) were studied in 20 pentobarbitalized dogs. Hemodilution was carried out by isovolemic exchange with plasma in 12 dogs and the hemoconcentration with packed cells in 8 dogs. The cardiac output and regional blood flows were determined with the microsphere technique. In hemodilution, the increases of blood flow to the myocardium and the brain were out of proportion to the increase of cardiac output; the oxygen supply to the myocardium remained unchanged while that to the brain decreased only slightly. In hemoconcentration, vasodilation occurred in the myocardium and the brain to maintain constant oxygen supply. Splenic vessels had marked vasoconstriction with Hct alteration in either direction. Blood vessels in the liver, intestine, and kidney responded with a milder vasoconstriction and maintained a constant oxygen supply between Hct of 30-55%. Therefore, during Hct alteration, redistribution of blood flow to myocardium and brain occurred. The optimal Hct range for constant oxygen supply was different among various organs.


Author(s):  
A. Mayevsky ◽  
N. Zarchin ◽  
E. Yoles ◽  
B. Tannenbaum
Keyword(s):  

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Haim I. Bicher ◽  
Nodar Mitagvaria ◽  
Marina Devdariani ◽  
Lia Davlianidze ◽  
Marina Nebieridze ◽  
...  

The aim of this study was revealing the temperature changes in rats' brain tissue caused by whole body hyperthermia. The analysis of received results allows to conclude that the brain has a highly secured system of temperature autoregulation against the exogenous temperature changes. The upper limit of this autoregulation (for rats, at least) is in the range of 45°C of environment. An important role in the normal functioning of the brain temperature autoregulation system belongs to Nitric Oxide. The behavioral disorders, observed in animals after whole body hyperthermia (sure within the range of brain temperature autoregulation) are hardly associated with the changes in temperature of the Central Nervous System, but rather have to be mediated by impaired blood circulation and oxygen supply to the brain tissues, caused by the rapid deterioration of the blood rheological properties.


Author(s):  
Salman Assad ◽  
Mujtaba Shahbaz ◽  
Yousaf Ajam

<p class="abstract">One of the interesting and intention seeking topic most commonly discussed all over the world regarding its allowance in Islam and Christianity. Masturbation has been thought as one of the means for releasing stress. However, wanking frequently because of lust obviously has some side an effect medically about which a lot of research works still needs to be done. Some medical experts believe that it may lead to infertility if performed frequently; with decreased sperm count, volume and density. Islam has forbidden the act of masturbating and considered it an act of sin. The reason it is called a sin is due to the overwhelming probability that the individual could get involved in adultery. Both religions endorse the fact that marriage helps to avoid adultery. However, masturbating temporarily decreases sperm count, that is why, if you visit fertility clinics for sperm analysis, they ask you not to masturbate or have sexual intercourse for more accurate assessment. The only time where reduction in sperm per ejaculate becomes an issue clinically is if a couple is having difficulty to conceive, in which case the first suggestion a physician would make is for the man to abstain from masturbation between sessions of sexual intercourse (if there is any concern that this is contributing to fertility issues). Frequent masturbation may also lead to auto-erotic asphyxia. Autoerotic or sexual asphyxia, a potentially lethal sexual practice, refers to sexual arousal that is produced while reducing the oxygen supply to the brain.</p>


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