Propagation of action potential is led by the influx of Na⁺ into neurons and efflux of K⁺ to the outside.

The order of the reaction of the nervous system:

Afferent (input sensory information) → Interneuron or Integration (processing information) → Efferent (output information to motor nervous) → Response

In the synaptic cleft the acetylcholine coming out of a presynaptic cell has three routes. One is bound to ligand-gated ion channels, another is reabsorbed by the presynaptic cell, and another is broken down by acetylcholinesterase on both presynaptic and postsynaptic membranes.

The sympathetic nervous system increases energy generation in response to stress. Therefore, the stimulation of the adrenal medulla, increase in the production of glucose, and acceleration of heart rate are vital responses to stress. However, an increase in digestion, such as stimulation of the gallbladder, is required in the parasympathetic division during rest.

Norepinephrine (NE) is the neurotransmitter released by postganglionic neurons and accepted on the adrenergic receptor. The neurotransmitter acetylcholine (AE) is released by preganglionic neurons in the sympathetic nervous system. It is also released by preganglionic and postganglionic neurons in the parasympathetic nervous system.

Bounded acetylcholine on the postsynaptic membrane opens cation channels. Depolarized membranes by influx of Na⁺ and efflux of K⁺ creates action potential and this spreads throughout the plasma membranes. Acetylcholine on the postsynaptic membrane does not directly affect the formation of synaptic vesicles.

Neurons are composed of dendrites, cell bodies, axons, and myelin sheath. Action potential is an electrical signal.

The main function of anesthetic is to block the opening of Na⁺ channels. The closed Na+ channels cannot produce action potential.

In the central nervous system the white matter is usually used for transporting information and the grey matter is for processing information. The white matter is situated inside the cerebrum and the grey matter is outside the cerebrum. In the spinal cord, the position of the white and gray matter are reversed.

All are related to the peripheral nervous system. The peripheral nervous system is divided into the autonomic nervous system (involuntary control) and the somatic nervous system (voluntary control). The autonomic nervous system is then divided into the parasympathetic and sympathetic nervous systems. The vagus nerve is contained in the parasympathetic nervous system to innervate the stomach, liver, large and small intestines, lungs, and heart.

All are true. Mature nerve cells do not undergo cell division.

All are true except D. During the rising phase the action potential overcomes the threshold, opening sodium channels and closing potassium channels, and creates a strong positive potential inside the membrane of the neurons.

Forebrain parts are cerebrum and diencephalon (thalamus and hypothalamus) and hindbrain parts are pons, medulla oblongata, and cerebellum.

Saltatory conduction means the fast conduction of action potential along the insulated myelin sheath.

The cerebellum controls motor coordination and balance, and the hypothalamus controls homeostasis and the basic feelings of desire, such as sexual drive, thirst, and hunger. The pons and medulla oblongata regulate the breathing rates. The cerebrum functions in integrating and analyzing sensory information for motor response.

Action potential along an axon is conducted in one direction because reopening of Na⁺ channels is prevented by a refractory period. The transmission message at the synaptic cleft is conducted in one direction as well, because the structures of presynaptic and postsynaptic cells are different from each other.