Why does the frog sciatic nerve give a graded response?

The sciatic nerve of the frog is constituted of a bundle of nerve fibers. Each of the nerve fiber has a varying threshold for which the membrane potential is disturbed. This is the reason why graded potential is observed as each nerve fiber depolarizes until a threshold in the sciatic nerve ( following summation of all individual depolarization events) is reached to trigger an action potential.

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation:

ionic bonds are two oppositely charged ions that attract. a sodium ion has a 1 positive charge; a chloride ion has a 1 negative charge. sodium and chloride have oppostive charged ions that attract which forms an ionic bond. a chemical bond formed when two atoms share electrons is called