| A | B |
|---|
| Alzheimer's disease | Symptoms are problems with memory, such as forgetting things, getting lost, and being mildly confused, and cognitive defects, such as problems with language, difficulties in recognizing objects, and inability to plan and organize events; Widespread damage to the brain, particularly the hippocampus; No cure yet |
| Genes | Chains of chemicals arranged like rungs about a twisting ladder; contain chemical instructions to program the development of millions of individual parts into a complex body and brain |
| Glial cells | Three functions: providing scaffholding to guide the growth of developing neurons and support mature neurons, wrapping around neurons to form a kind of insulation to prevent interference from other electrical signals, and releasing chemicals that influence a neuron's growth and function |
| Neuron | A brain cell with two specialized extension: one for receiving electrical signals and second, longer extension for transmitting electrical signals |
| Mind-body question | Asks how complex mental activities, such as feeling, thinking, and learning, can be explained by the physical, chemical, and electrical activities of the brain |
| Cell-body | A relatively large, egg-shaped structure that provides fuel, manufactures chemicals, and maintains the entire neuron in working order |
| Dendrites | Branchlike extensions that arise from the cell body that receive signals from other neurons, muscles, or sense organs and pass these signals to the cell body |
| Axon | A single threadlike structure that extends from, and carries signals away from, the cell body to neighboring neurons, organs, or muscles |
| Myelin sheath | Separate tubelike segments composed of fatty material that wraps around and insulates then neuron; Prevents interference from electrical signals generated by adjacent axons |
| End bulbs/ terminal bulbs | Tiny bulbs that are located at the extreme ends of the axon's branches; Miniature containers that store chemicals called neurotransmitters |
| Synapse | An infinitely small space that exists between an end buld and its adjacent body organ (heart), muscles, (head), or cell body |
| Peripheral Nervous System | Made up of nerves, which are located throughout the body except in the brain and spinal cord |
| Nerves | Stringlike bundles of axons and dendrites that come from the spinal cord and are held together by connective tissue; Carry information from the senses, skin, muscles, and the body's organs ro and from the spinal cord; Nerves in peripheral system have the ability to regrow or reattach if severed or damaged |
| Central Nervous System | Made up of neurons located in the brain and spinal cord |
| Multiple sclerosis | A disease that attacks the myelin sheaths that wrap around and insulate cells in the central nervous system |
| Axon membrane | Contains chemical gates that can open to allow electrically charged particles to enter or can close to keep out electrically charged particles |
| Ions | Chemical particles that have electrical charges; two rules: opposited attract and like charges repel |
| Nerve impulse | The series of separate action potentials that take place segment by segment as they move down the length of the axon |
| All-or-Nothing law | If an action potential starts at the beginning of an axon, the action potential will continue at the same speed, segment by segment, to the very end of the axon |
| Resisting state | The axon has a charge, or potential; it resembles a battery. The charge, or potential, results from the axon membrane separating positive ions on the outside from negative ions on the inside |
| Sodium Pump | A transport process that picks up any sodiym ions that enter the axon's chemical gates and returns them back outside; responsible for keeping the axon charged by returning and keeping sodium ions outside the axon membrane |
| Action potential | A tiny electric current that is generated when the positive sodium ions rush inside the axon; the enormous increase in sodium ions inside the axon causes the inside of the axon to reverse its charge |
| Transmitter | A chemical messenger that carries information between nerves and body organs, such as muscles and heart |
| Neurotransmitters | About a dozen chemicals that are made by neurons and then used for communication between neurons during the performance of mental or physical activities |
| Alcohol (ethyl alcohol) | A psychoactive drug that is classified as a depressant, which means that it depresses the activity of the central nervous system |
| Reflex | An unlearned, involuntary reaction to some stimulus |
| Afferent neurons | Sensory neurons; carry information from the senses to the spinal cord |
| Interneuron | A relatively short neuron whose primary task is making connections between other neurons |
| Efferent neurons | Motor neurons; carry information away from the spinal cord to produce responses in various muscles and organs throughout the body |
| Phantom limb | Feeling vivid sensations or movements coming from a limb that has been amputated |
| Reuptake | A process through which some neurotransmitters, such as dopamine, are removed from the synapse by being transported back into the end bulbs |
| Curare | A drug that enters the bloodstream, reaches the muscles, and blocks receptors on muscles; neurotransmitters that activate muscles are blocked, and muscles are paralyzed |
| Mescaline | A drug that causes physiological arousal as well as visual hallucinations |
| Parkinson's disease | Symptoms of tremors and shakes in the limbs, a slowing of voluntary movements, muscle stiffness, problems with balance and coordination, and feelings of depression; as disease progresses, patients develop peculiar walk and may freeze in space for minutes or hours at a time |
| Basal ganglia | A group of structures located in the center of the brain that are involved in regulating movements |
| Stem cells | Cells that have the amazing capacity to change into and become any one of the 220 cells that make up the human body, including skin, heart, liver, bones, and neurons |
| Stereotaxic procedure | Fixing a patient's head in a holder and drilling a small hole through the skull; the holder has a syringe that can be precisely guided to inject cells into a predetermined location in the brain |
