Ch 39 - Nervous System
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70 terms
Terms | Definitions |
|---|---|
 acetylcholine (ACh) | a neurotransmitter that enables learning and memory and also triggers muscle contraction |
| acetylcholinesterase (AChE) | enzyme that catalyzes breakdown of acetylcholine, preventing sustained muscle contraction from a single nerve impulse |
| action potential | a neural impulse; a brief electrical charge that travels down an axon. the action potential is generated by the movement of positively charged atoms in and out of channels in the axon's membrane |
| association areas | areas of the cerebral cortex that are not involved in primary motor or sensory functions; rather, they are involved in higher mental functions such as learning, remembering, thinking, and speaking |
| autonomic system | the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms. |
| axon | the extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands |
| basal nuclei | important centers for motor coordination, acting as switches for impulses from other motor systems., Neurotransmitter dopamine is largely responsible for activity in this nuclei, internal islands of gray matter |
| brain | that part of the central nervous system that includes all the higher nervous centers |
| brain stem | the part of the brain that lies between the cerebellum and spinal cord that controls the body's involuntary actions, includes the medulla oblongata and the pons |
| cell body | largest part of a typical neuron; contains the nucleus and much of the cytoplasm |
| central nervous system | the portion of the vertebrate nervous system consisting of the brain and spinal cord |
| cephalization | concentration of feeding organs, sensors, and neural structures at the anterior end, the part of the body most likely to make first contact with food or threatening stimuli., Having a head |
| cerebellum | the "little brain" attached to the rear of the brainstem; its functions include processing sensory input and coordinating movement output and balance |
| cerebral cortex | the layer of unmyelinated neurons (the gray matter) forming the cortex of the cerebrum, the intricate fabric of interconnected neural cells that covers the cerebral hemispheres; the body's ultimate control and information-processing center. |
| cerebral hemisphere | either half of the cerebrum |
| cerebrospinal fluid | fluid in the space between the meninges that acts as a shock absorber that protects the central nervous system |
| cerebrum | area of the brain responsible for all voluntary activities of the body, large part of the brain that controls the senses and thinking |
| cranial nerve | A nerve that carries sensory input and motor output for the head and neck region. There are 12 cranial nerves. |
| dendrite | the bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body |
| diencephalon | located between the midbrain and the cerebrum and consists of the thalamus, hypothalamus, optic chiasma, and pineal body |
| dopamine | neurotransmitter that influences voluntary movement, attention, alertness; lack of dopamine linked with Parkinson's disease; too much is linked with schizophrenia |
| dorsal root ganglion | A group of sensory neuron cell bodies found just posterior to the spinal cord on either side. A pair of root ganglia exists for each spinal nerve that expands from the spinal cord. The ganglia are part of the peripheral nervous system (PNS). |
| effector | an organ (a gland or muscle) that becomes active in response to nerve impulses in response to environmental stimuli |
| ganglion | an encapsulated neural structure consisting of a collection of cell bodies or neurons |
| gray matter | Brain and spinal cord tissue that appears gray with the naked eye; consists mainly of neuronal cell bodies (nuclei) and lacks myelinated axons. |
| hypothalamus | limbic system component that regulates hunger, body temperature and other functions |
| integration | process by which neurons coordinate the activities of muscle groups |
| interneuron | Nerves that conduct impulses from sensory neurons to motor neurons, especially in the brain and spinal cord |
| ladderlike nervous system | two nerve cords that extend from the cerebral ganglia to the posterior end of body, In planarians, two lateral nerve cords joined by transverse nerves. |
| limbic system | neural structures at the border of the brainstem and cerebral hemispheres; associated with emotions such as fear and aggression and drives such as those for food and sex. Includes the hippocampus, amygdala, and hypothalamus. |
| medulla oblongata | Lower or hindmost part of the brain, contains centers that control several visceral functions, including breathing, heart and blood vessel activity, swallowing, vomiting, and digestion. |
| memory | the storage and retrieval of what has been learned or experienced. |
| meninges | three layers of connective tissue that cover the brain and spinal cord, consisting of the dura mater, pia mater, and arachnoid mater |
| meningitis | infectious disease characterized by inflammation of the meninges (the tissues that surround the brain or spinal cord) usually caused by a bacterial infection |
| midbrain | the middle division of brain responsible for hearing and sight; location where pain is registered; includes temporal lobe, occipital lobe, and most of the parietal lobe |
| motor neuron | this carries information from the brain to the muscles; also called "efferent" |
| myelin sheath | a layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next |
| nerve | a bundle of nerve fibers |
| nerve fiber | projection of a neuron, especially the axon that transmits impulses |
| nerve impulse | an electric and chemical message that travels from neuron to neuron |
| nerve net | in cnidarians, a network of nerve cells that lacks a central control; impulses pass in any or all directions to produce a generalized response |
| neuroglia | known as glial cells: connective tissue that supports,nourishes, protects, insulates and organizes neruons |
| neuromodulator | Electrical stimulant of a peripheral nerve, the spinal cord, or the brain; used to ease pain. |
| neuron | a nerve cell; the basic building block of the nervous system |
| neurotransmitter | a chemical that is released by a neuron for the purpose of carrying information across the gaps (synapses) between neurons |
| nodes of Ranvier | gaps in myelin sheath between adjacent Schwann cells |
| norepinephrine | noradrenaline; chemical which is excitatory, similar to adrenaline, and affects arousal and memory; raises blood pressure by causing blood vessels to become constricted, but also carried by bloodstream to the anterior pituitary which relaxes ACTH thus prolonging stress response |
| parasympathetic division | a branch of the autonomic nervous system that maintains normal body functions; it calms the body ever conserves energy |
| peripheral nervous system | the sensory and motor neurons that connect the central nervous system to the rest of the body |
| pons | part of the brain involved in sleep regulation also connects a cerebellum to the cerebral cortex; sleep and wake cycles, controls breathing |
| prefrontal area | The frontmost portion of the frontal lobes, involved in working memory, strategy formation, and response inhibition. |
| primary motor area | sends impulses to skeletal muscles (frontal lobe) |
| reflex | an involuntary and almost immediate movement in response to a stimulus |
| resting potential | An electrical potential established across the plasma membrane of all cells by the Na+/K+ ATPase and the K+ leak channels. IN most cells, the resting membrane potential is approximately -70 mV with respect to the outside of the cell. |
| saltatory conduction | A rapid from of action potential conduction along the axon of a neuron in which the action potential appears to jump from node of Ranvier to node of Ranvier. |
| Schwann cell | large nucleated cells that form myelin around the axons of neurons |
| sensory neuron | a neuron that picks us stimuli from the internal or external environment (such as light, odor, or touch) and converts each stimulus into a nerve impulse |
| sensory receptor | Neuron that reacts to a specific stimulus, such as light or sound, by sending impulses to other neurons and eventually to the central nervous system. |
| serotonin | a neurotransmitter that affects hunger,sleep,arousal,and mood. appears in lower than normal levels in depressed persons |
| somatic system | the division of the peripheral nervous system that controls the body's skeletal muscles |
| spinal cord | a major part of the central nervous system which conducts sensory and motor nerve impulses to and from the brain |
| spinal nerve | A bundle of nerve fibers attached to the spinal cord; conveys sensory information from the body and carries messages to muscles and glands |
| sympathetic division | a branch of the autonomic nervous system and prepares the body for quick action in emergencies; fight or flight; busiest when frightened, angry, or aroused; increases heart rate, increases breathing rate, enlarges pupils, stops digestion; connects to all internal organs; sudden reaction |
| synapse | the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. The tiny gap at this junction is called the synaptic gap or cleft. |
| synaptic cleft | A microscopic gap between the terminal button of a neuron and the cell membrane of another neuron. |
| thalamus | the brain's sensory switchboard, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla |
| tract | a bundle of mylenated nerve fibers following a path through the brain |
| ventricle | one of four connected cavities in the brain |
| white matter | whitish nervous tissue of the CNS consisting of neurons and their myelin sheaths |
| primary somatosensory area | dorsal to central sulcus in parietal lobe. recieves sensory info from skin and skeletal muscles |
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