Question

what is the most common inhibitory neurotransmitter in the brain?
y-aminobutyric acid (gaba)
noradrenaline
epinephrine
acetylcholine
norepinephrine
question 48 (1.7 points)
where do most local potentials form in a neuron?
the dendrites
the cell bodies
the axon hillock
the trigger zone
the schwann cells

Explanation:

• For the first question: GABA (γ - Aminobutyric acid) is the most common inhibitory neurotransmitter in the brain. It reduces the excitability of neurons by opening chloride channels and causing hyperpolarization. Noradrenaline (also known as norepinephrine) and epinephrine are more associated with the sympathetic nervous system (fight - or - flight responses) and can be excitatory in some contexts. Acetylcholine can be excitatory or inhibitory depending on the receptor type, but it is not the most common inhibitory neurotransmitter in the brain.
• For the second question: Local potentials (graded potentials) most commonly form in the dendrites. Dendrites receive signals from other neurons, and these signals can cause small, local changes in membrane potential. The cell bodies can also be involved in some local potential - like changes, but dendrites are the primary site. The axon hillock is where action potentials are initiated (if the sum of local potentials reaches the threshold). The trigger zone (which often includes the axon hillock) is related to action potential generation. Schwann cells are glial cells that myelinate peripheral axons and are not directly involved in the formation of local potentials in the neuron's signal - receiving regions.

Answer:

1. γ - Aminobutyric acid (GABA)
2. The dendrites