1. The following statement is similar to those you might see on exams. Write a paragraph of 3-5 sentences describing 1) whether
the statement is correct or incorrect and 2) the reasoning for your answer. Your answer should demonstrate your understanding of the physiological concepts underlying the statement and be written professionally. At a chemical synapse, the release of neurotransmitter occurs in response to a graded depolarization of the synaptic terminal.
The statement is correct because, during the chemical synapses, the transmission of information takes place when the presynaptic neuron releases a <u>neurotransmitter</u> that binds to a specific receptor located in the postsynaptic membrane. The release of these neurotransmitters happens almost always when the action potential reaches the synaptic terminal. In the membrane of the synaptic terminal, the number of Ca++ voltage-depended channels is greater than in other parts of the membrane, hence, when the action potential depolarized the membrane, the channels open and the Ca++ defuses actively into the cell. The intracellular concentration of Ca++ is very high and this strong and rapid increase, facilities the depolarization of the membrane and <u>allows the release of the neurotransmitter to the postsynaptic membrane</u>.
Secondary succession happens more often because it occurs after some kind of distribution that still leaves the soil intact (mudslide,bulldozing,shoveling,or scraping off an area)
