Neurology Anatomy Physiology
December 14, 2021
Contentsneurons and Nerves
The Brain & Spinal Cord
Peripheral Nervous System
Autonomic Nervous System
Senses: Eye diagrams, Hearing, Smell, Taste, Taste & Tongue Sensation, Balance
Memory , Memory types, Creation of Memory
Altered States manipulations and abuses. Natural neuromodulators can aid the release or inhibit the reabsorption of neurotransmitters; still others delay the breakdown after reabsorption, leaving them in the tip to be reused by the next nerve impulse. Mood, pleasure, pain, and other mental states are determined by particular groups of neurons in the brain that use special sets of neurotransmitters and neuromodulators. For example, mood is strongly influenced by the neurotransmitter serotonin. It is believed that depression results from a shortage of serotonin. It is difficult to treat depression directly with serotonin because the chemical has too many other side effects. However, depression can be successfully treated with drugs that act as serotornin neuromodulators (Figure 02d). Prozac, the
Figure 02d Neuromodulator
world's top-selling antidepressant, inhibits the reabsorption of serotonin, increasing the amount in the synapse by slowing down its removal.
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When a neuron cell is exposed to a neurotransmitter for a prolonged period, it tends to lose its ability to respond to the stimulus with its original
intensity. This is known as habituation, which is the result of the cell producing fewer receptors for that particular neurotransmitter. If someone takes a drug that acts as a
neuromodulator (such as cocaine), which causes abnormally large amounts of neurotransmitter (dopamine in this case, Figure 02e) to remain in the synapses for long periods of
time, it would generate more pleasure messages. Such action reduces the number of receptors in the neuron. Next time a higher dosage is required to maintain the pleasurable
sensation. The result is addiction. Cocaine is a stimulant discovered in the mid-1800s. Many physicians at first considered it a miracle drug, prescribing it for all sorts
of physical and mental ailments; it was even added to soft drinks. Today United States law forbids the importation, manufacture, and use of cocaine for nonmedical purposes, and
even the medical use is extremely limited.
Figure 02e Drug Addiction
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Table 01 summarizes the properties of some important neurotransmitters.