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Lycéens au bloc opératoire! :D
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| La Pharmacienne |
Publié le 06-01-2010 21:23
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MedeSpacien rédacteur
Messages : 8494
Inscription : 26.10.08
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Bonsoir Cheburashka, et désolée de ne pas vous répondre avant, on est un peu pris par les révisions.
Je vous ai trouvé quelques liens externes du mécanisme de l'action analgesique des morphiniques :
- Mecanisme de l'action analgesique des morphiniques: Inhibition de la liberation d'acetylcholine au niveau du systeme nerveux central
- Analgésiques morphiniques
- Les Morphiniques
Mes respects. |
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| cheburashka |
Publié le 10-01-2010 08:26
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MedeSpacien Actif
Messages : 51
Inscription : 02.01.09
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Merci beaucoup!! 
Le TPE est fini, il manque juste les schéma sur une diapo.
Malheureusement je ne peut pas le poster maintenant parce que je n'ai pas le texte en bon format ni avec le bon logiciel... |
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| La Pharmacienne |
Publié le 10-01-2010 16:02
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MedeSpacien rédacteur
Messages : 8494
Inscription : 26.10.08
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Bonjour petite sœur 
Chui heureuse pour vous, bravo.
Une fois les TPE corrigé, on aimera que vous le proposer dans la partie Topos
Mes respects. |
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| cheburashka |
Publié le 17-01-2010 09:55
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MedeSpacien Actif
Messages : 51
Inscription : 02.01.09
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voici le TPE fini :
How does general anaesthesia work?
General anaethesia is used for surgeries or to prevent and stop pain.
There are 3 steps in anaethesia : narcosis, analgesia and muscle slackening. The last step is necessary only in abdominal surgeries, or surgeries which necessit relaxed muscles to not bother the surgeon.
1- Narcosis
Narcosis is one of the three steps to anaesthetize the patient. The patient has to sleep during the surgery, that is to say his electric brain activity decreases very much.
The most common narcotic are barbiturates (for example propofol).
The propofol is a barbiturate. Its formula is C12H18O. However, propofol doesn't have the same molecular structure as other barbiturates.
The narcotic agent must be liposoluble, because it acts in the brain.
In the brain, there is the GABA neurotranmitter, acted on 40% of the synapses. When it is attached to GABAA receptor, it allows the transmission of Cl- ions which makes the neurone excitability decrease. But the GABA is not the only transmitter which can be attached to GABAA receptor, there is also the propofol. Therefore, propofol works on the brain receptor GABAA and it makes the brain excitability decrease.
2- Analgesia
The analgesic agents are painkillers. The most common used are morphinics.
They act on 3 principal types of morphinic receptors : µ, κ, δ. Depending on the agent, there is a different affinity with these receptors : this affinity defines the amount of analgesic needed to have an effect.
Morphinic spin offs interrupt the cholinergic transmission to the cortex of painful stimuli in the hypothalamus and stop the conscious appreciation of pain. Furthermore, other direct or undirect effects of morphinics on proteins, which can pass the hematoencephalic barrier, probably contribute to the inhibitory action of central origin which transmits pain.
The diffusion of the analgesic agent :
-takes place in the brain
-the more it is concentrated, the more it acts.
-the more the agent is liposoluble, the faster it acts. (sufentanyl's liposolubility is 96%, so its action is the fastest.)
The effects :
when used, the analgesic agent provoke loss of consciousness, reduce breathing (if the quantity of agent is very big, the patient does't breath at all), reduces thorax laxicity (so it can cause problems for artificiel respiration), but it doesn't stop myocontraction (except for Dolosal).
It also causes vomiting, increases gastric pH and can change the body's temperature.
3.Curarisation
This is the third step in anaesthesia but it is not necessarily used. A curare is used to cause a flabby and reversible paralysis, so that is makes surgery easier. However it must always be used with a narcotic and an analgesic because it does not induce narcosis and analgesia.
They act on the motor end plate.
Then, we have to know that the message which controls a movement is transmitted from a nerve to a muscle thanks to the acethycholine neurotransmitter.
Succinylcholine is a curare whose formula is C14H30N2O4. The chemical structure of curare is similar to that of acethylcholine.
When an anaethesist uses succinylcholine, it is attached to acethylcholine receptors on the muscle (called nicotinic receptor) and it provoques an inhibition of the recepto, so that acethycholine can't communicate the message of a movement.
Normally, acethylcholine is destroyed by acethylcholinesterase enzyme. However, this enzyme has no efficiency with succinylcholine, which can only be destroyed by plasmic pseudo-cholinesterase, which is created by the liver.
So, as long as succinlycholine is attached to nicotinic receptor it can't stimulate the muscle.
Conclusion :
The choice of the anaesthesic agent doesn't depend only on science. It can be change because of dangerous effects on the patient (allergy, anaphylactic shock) but it is also an ethic choice. Anaesthesists know that some drug addicted people come to have some morphine (which creates dependence), but they have to make the choice of anaesthetizing the patient or not, if he is really in danger. |
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| La Pharmacienne |
Publié le 17-01-2010 16:28
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MedeSpacien rédacteur
Messages : 8494
Inscription : 26.10.08
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Bravo Cheburashka,
Il est excellent votre TPE et avec un bon anglais, bravo!
Bonne continuation |
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| La Pharmacienne |
Publié le 17-01-2010 16:31
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MedeSpacien rédacteur
Messages : 8494
Inscription : 26.10.08
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Le voici le lien directe vers le TPE dans la partie "exposés" :
--> How does general anaesthesia work?
Mes respects. |
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| La Pharmacienne |
Publié le 24-01-2010 20:24
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MedeSpacien rédacteur
Messages : 8494
Inscription : 26.10.08
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Bonsoir,
Avez vous eu la note finale de votre TPE Cheburashka ?
A vous.. |
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| M Benatta |
Publié le 25-01-2010 06:48
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MedeSpacien formateur
Messages : 989
Inscription : 01.02.08
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ce topo devrait etre publié avec les articles medespace et pourquoi pas dans le medespace-magazine,à condition de mettre les références bibliographiques. |
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| La Pharmacienne |
Publié le 25-01-2010 11:20
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MedeSpacien rédacteur
Messages : 8494
Inscription : 26.10.08
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Bonjour ,
C'est une bonne idée, on attend Cheburashka pour qu'elle nous donne les références et le tout je vais l'envoyer sur Google Docs au Big Boss, et le comité de rédaction s'en charge de le corriger et le publier aussi..
Bravo Cheburashka. |
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