The term giant is sometimes used when describing nevi. A giant nevus covers a very large part of the body, usually involves the torso, and is usually accompanied by a number of satellite nevi. Satellite nevi (or just satellites) are smaller melanocytic nevi. When a child is born with a giant nevus, it is common for satellite nevi to be present at birth.
Receptors for the various neurotransmitters are located on both the presynaptic and postsynaptic nerve terminals of the neuron.hey are present in all of the nerve cells, but predominately in the ganglia or nerve bundles of invertebrates, and in the central nervous system (brain and spinal cord) of vertebrates. There are many kinds of neurotransmitter chemicals.
Your brain is made up of billions of nerve cells. They communicate by releasing chemical messengers called neurotransmitters. Each neurotransmitter is like a key that fits into a special lock, called a receptor, located on the surface of nerve cells. When a neurotransmitter finds its receptor, it activates the receptor's nerve cell. The nicotine molecule is shaped like a neurotransmitter called acetylcholine. Acetylcholine and its receptors are involved in many functions, including muscle movement, breathing, heart rate, learning, and memory. They also cause the release of other neurotransmitters and hormones that affect your mood, appetite, memory, and more. When nicotine gets into the brain, it attaches to acetylcholine receptors and mimics the actions of acetylcholine. Nicotine also activates areas of the brain that are involved in producing feelings of pleasure and reward. Recently, scientists discovered that nicotine raises the levels of a neurotransmitter called dopamine in the parts of the brain that produce feelings of pleasure and reward. Dopamine, which is sometimes called the pleasure molecule, is the same neurotransmitter that is involved in addictions to other drugs such as cocaine and heroin.