Synapses+NLL

Synapses (2nd assignment of CONTROL FREAK)

Motor Neuron p.234
 * What is a motor neuron?** Motor neurons are nerve cell that conducts nerve impulses away from the central nervous system and innervates effectors (muscles and glands). Muscle fibers are stimulated to contract by motor neurons whose axons are in nerves. The axon of one motor neuron can stimulate from a few to several muscle fibers of a muscle because each axon has several branches. Each branch of an axon ends in an axon terminal that lies in close proximity to the sarcolemma of a muscle fiber.
 * What is the name neurotransmitter released by motor neurons?** Axon terminal contain synaptic vesicles that are filled with the neurotransmitter acetylcholine. When nerve impulses, traveling down a motor neuron, arrive at an axon terminal, the synaptic vesicles release ACh into the synaptic cleft.
 * How does botox prevent muscle contraction?** Botox is the trade name for botulinum toxin A, a neurotoxin produced by a bacterium. Botox prevents wrinkling of the brow and skin about the eyes because it blocks the release of ACh into the synaptic cleft, and therefore muscle contraction never occurs.

Cocaine p.268
 * What does cocaine interfere with at the synapses?** Cocaine is a powerful stimulant in the CNS that interferes with the re-uptake of dopamine at synapses.
 * What is the effect?** The result is a rush of well-being that last 5-30 minutes. Although it seemed at first that cocaine could relieve depression, it soon became apparent that cocaine is extremely addictive and its use is very harmful. During cocaine sprees, the drug is taken repeatedly and at ever-higher doses. The result is sleepiness, lack of appetite, increased sex drive, tremors, and “cocaine psychosis,” a condition that resembles paranoid schizophrenia. During the crash period, fatigue, depression, and irritability are common, along with memory loss and a confused state of cognition.

Methamphetamine p.268
 * What neurotransmitter does meth resemble?** Methamphetamine has a structure similar to that of dopamine, and its stimulatory effect mimics cocaine.
 * What is the effect?** Because the addition of the methyl group is fairly simple, methamphetamine is often produced from amphetamine in makeshift home labs. It is available as a powder or as crystal. The crystals are smoked, and the effects are almost instantaneous, and nearly as quick as when it is snorted. The effects last 4 to 8 hours when smoked. The effects of fatigue, maintain wakefulness, and temporarily elevate the mood of the user. After the initial rush, there is typically a state of high agitation that, in some individuals, leads to violent behavior.

Heroin p. 268
 * Where is heroin derived?** Heroin is derived from the resin or sap of the opium poppy plant, which is grown from Turkey to Southeast Asia and in parts of Latin America.
 * What is heroin converted to that can bind opiate receptors in the brain?** Heroin is the most abused opiate because it is rapidly delivered to the brain, where it is converted to morphine.
 * What do the opiate receptors do?** Morphine binds promptly to opioid receptors, and the result is a rush sensation and euphoric experience. Opiates depress breathing, activate the reward circuit, block pain pathways, cloud mental function, and sometimes cause nausea and vomiting. Long-term effects of heroin use are addiction, hepatitis, HIV/AIDS, and various bacterial infections because of shared needles.

Marijuana p. 269 What does smoking THC cause? When THC reaches the CNS by smoking a “joint,” mild euphoria, along with alterations in vision and judgment, occur. Distortions of space and time can also occur in occasional users. In heavy users, hallucinations, anxiety, depression, rapid flow of ideas, body image distortions, paranoia, and psychotic symptoms can result.
 * What is THC?** THC is a cannabis plant
 * What is anandamide?** Anandamide is an endogenous cannabinoid neurotransmitter found in animal and human organs, especially in the brain.
 * What is the relationship between THC and anandamide and cannabinoids?** Both THC and anadamide belong to a class of chemicals called cannabinoids. It would seem, then, that THC mimics the actions of anadamide.
 * Why are the receptors that bind cannabidoids important?** Receptors that bind cannabinoids are located in the hippocampus, cerebellum, basal ganglia, and cerebral cortex, brain areas that are important for memory, orientation, balance, motor coordination, and perception.