Introduction to Psychology

Introduction to Psychology of 97 dendrites, gets passed along when it triggers an action potential, or electrical impulse, that travels down the axon and then triggers activity in whichever neurons, muscles, or glands join up with the axon. Neurons do two important things. Like tiny batteries, they generate electricity that creates nerve impulses. They also release chemicals that allow them to communicate with other neurons and muscles and glands. At rest, the neuron has an electrical resting potential due to the distribution of positively and negatively charged chemical ions inside and outside of the neuron. When stimulated, a flow of ions in and out through the cell membrane reverses the electrical charge of the resting potential, producing an action potential, or nerve impulse. The original ionic balance is restored, and the neuron is again at rest. Neurotransmitters- Are chemical molecules contained in vesicles, or sacs, within the axon terminal. When an action potential, or electrical impulse arrives at the terminal, the neurotransmitters are released into the synaptic cleft. They then bind to receptor sites on the next neuron’s dendrites. The neurotransmitters are chemical substances that carry messages across the synaptic space to the other neurons, muscles, or glands. Different neurotransmitters affect different neurons. Because different neural pathways are made up of different neurons and have different functions, each neurotransmitter affects behavior differently. Endorphins- Most neurotransmitters have their excitatory and inhibitory effects only on specific neurons that have receptors for them. Others, called neuromodulators, have a more widespread and generalized influence on synaptic transmission. These substances circulate through the brain and either increase or decrease the sensitivity of neurons to their specific transmitters. The best-known neuromodulators are the endorphins, which travel through the brain’s circulatory system and inhibit pain transmission, while enhancing neural activity that produces pleasurable feelings. Central Nervous System- The central nervous system includes the brain, which controls many physiological and psychological functions, and the spinal cord, which enables reflexive behavior and relays information to the brain from elsewhere in the body. Brain- Neuroscientists use four different methods to study the brain’s structures and activities, through various research methods. Research Methods- Because of scientific and technical advances, more has been learned about the brain in the past four decades than was known throughout the preceding ages. Neuropsychological Tests- Psychologists have developed a variety of neuropsychological tests to measure verbal and nonverbal behaviors of people who have suffered brain damage through accident or disease. The Trial Making Test is used to assess brain function, testing memory and planning. Scores on the test give an indication of the type and severity of brain damage. The tests are also used to assess learning disabilities and developmental disorders. Destruction and Stimulation Techniques- Experimental studies are another useful method of learning about the brain. In this method, researchers chemically or electrically stimulate the neurons. In chemical stimulations, a tiny tube, or cannula, is inserted into a precise area of the brain so that © 2015 Achieve Page 20