Local anesthetics inhibit nerve conduction in a reversible manner without altering the nerve. The inhibition appears rapidly and for a longer or shorter duration depending on the products and the concentrations used. The extent of the territory rendered insensitive to pain depends on the modes of administration of the local anesthetic, either at the level of the nerve endings, or at the level of a nervous trunk, for example.
They act at the level of the neuronal membrane by interfering with the process of excitation and conduction. The anesthetic crosses the axon membrane, rich in lipids, in the form of base before taking up a cationic form on the internal face of the neuron where the pH is more acidic.
At this level, there is a blockage of nerve conduction by decreasing the membrane permeability to sodium ions that occurs during the depolarization phase. As the progression of the anesthetic action along the nerve increases, the threshold of excitability increases and the conduction time increases. This is completely blocked from a certain concentration of local anesthetic.
The nerve fibers are unequally sensitive to the action of local anesthetics: they disappear in order: the painful, thermal, tactile sensations.
 
        
             
        
        
        
Answer: Second one: one person refuses when the other asks to have sex.
Explanation: Abstinence is the act of knowingly not doing something for a purpose. The person refusing is trying to practice abstinence.
 
        
             
        
        
        
Answer:
The statement that is true about leukotrienes is that they create excess mucus in the airways (last option).
Explanation:
Leukotrienes are inflammatory mediators, derived from arachidonic acid, in whose presence occurs increased vascular permeability in tissues, leading to inflammatory processes.
The presence of leukotrienes has been related to the development of allergic reactions, mainly in the respiratory tract, producing edema in the mucosa, contraction of the smooth muscles of the airways and increased production of mucus 
in the airways.
the other options are not correct because leukotrienes:
- <em>Produce contraction of the smooth musculature around the airway.
</em>
- <em>Are related to the production of bronchial asthma.
</em>
- <em>Are inflammatory (chemical) mediators. </em>
 
        
             
        
        
        
Answer:
1)  circulatory and respiratory
2) endocrine
3) circulatory 
4) circulatory and nerves
Explanation:
I think these are right. Sorry if they are not.