Answer:
A presynaptic neuron knows when and how much of a certain neurotransmitter it has to release into the synapse by the frequency of the action potential.
Explanation:
Two nuerons connect to each other through synapse. When an action potential, or nerve impulse, arrives at the axon terminal, it activates voltage-gated calcium channels in the cell membrane, then the calcium which is present in hi highconcentration outside the neuron than inside, rushes into the cell. The Calcium then allows synaptic vesicles to fuse with the axon terminal membrane, releasing neurotransmitter into the synaptic cleft.
The nuerotransmitter than binds to the receptors at the post-synaptic cleft and causes the opening or closing of the channels, hence, depolarizing or hyperpolarizing the cells.This can produce a change in the membrane potential—voltage across the membrane of the receiving cell.
The correct answer is "a steroid hormone that reduces the amount of fluid excreted in the urine".
Aldosterone is a steroid hormone produced in the adrenal gland, whose main function is the homeostatic regulation of the blood pressure, plasma sodium, and plasma potassium levels.
Aldosterone's main mechanism of action is to regulate the reabsorption of sodium and excretion of potassium in the kidney, which in turn influences the retention of water and the volume and pressure of the blood. Based on all this, aldosterone reduces the amount of fluid excreted in the urine.
Answer:
The rocks and debris would never accrete into a planet.
Explanation:
Gravity is an attraction force and dependents on the mass of the objects but in the absence of the force, the rocks and debris would not come together to form a clump. So, we can say that in the absence of gravity, the rock and debris would never accrete into a planet. So, we can say that in the absence of gravity, the rock and debris would never accrete into a planet.
13, 1781: British astronomer William Herschel discovers Uranus—the first new planet discovered since ancient times - while searching for faint stars. 1787-1851: Four Uranian moons are discovered and named Titania, Oberon, Ariel and Umbriel. 1948: Another moon, Miranda, is discovered. Mar.
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