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.
3D LASER SCANNER FOR PALEONTOLOGY TECHNOLOGY
Answer: B - transports oxygen and carbon dioxide for the respiratory system
The cardiovascular system consists in the heart and all blood vessels. Blood vessels lead the blood from the heart to the rest of the body and then brings it back. It's in the lungs, part of the respiratory system, where the gas exchange is going to happen. What that means is that oxygen is going to enter the blood while the carbon dioxide needs to be eliminated.
(If the option A, said carries hormones FROM the endocrine system, that would be also correct.)
Answer: A
I hope this helped you :)
And can I please get brainliest?
