1. Acetylcholine is the most common. Neurons that release it are called cholinergic. Cholinergic neurons include all preganglionic neurons of the autonomic nervous system, postganglionic neurons of the parasympathetic nervous system and some postganglionic neurons (sweat glands) of the sympathetic nervous system.cetylcholine is the most common. Neurons that release it are called cholinergic. Cholinergic neurons include all preganglionic neurons of the autonomic nervous system, postganglionic neurons of the parasympathetic nervous system and some postganglionic neurons (sweat glands) of the sympathetic nervous system.
Translocation is the movement of materials from leaves to other tissues throughout the plant. Plants produce carbohydrates (sugars) in their leaves by photosynthesis, but nonphotosynthetic parts of the plant also require carbohydrates and other organic and nonorganic materials.t is pressure, generated in the sieve elements and companion cells in source tissues. In leaves, sugar is synthesized in mesophyll cells (the middle layer of the leaf), and is then actively pumped into the phloem, using metabolic energy.
Since sugars are being concentrated and making water flow through osmosis, there has to be fancy name for the movement of phloem. It is called the Pressure-flow Hypothesis. This just means that at the sugar sources (the leaves), sugar is found in high densities, which causes water to flow into cells through osmosis.Then the phloem moves to sugar sinks through turgor pressure. And there it is: pressure causes the phloem to flow, and we have the pressure-flow hypothesis.his just means that at the sugar sources (the leaves), sugar is found in high densities, which causes water to flow into cells through osmosis. Then the phloem moves to sugar sinks through turgor pressure. And there it is: pressure causes the phloem to flow, and we have the pressure-flow hypothesis.