Unit 17 - Chapter 48 - Nervous System
Terms
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- Pons
- also participates in some of these activities, having nuclei that regulate the breathing centers in the medulla.
- Cerebellum
- develops from part of the metencephalon. Its primary function is coordination of movement. It receives sensory information about the position of the joints and the length of the muscles, as well as information from the auditory and visual systems.
- Hippocampus
- functional changes at certain synapses seem to be directly related to memory storage and learning.
- Presynaptic membrane
- the surface of the synaptic terminal that faces the cleft.
- Hypothalamus
- one of the most important brain regions for the homeostatic regulation. It is the source of two sets of hormones, posterior pituitary hormones and releasing hormones that act on the anterior pituitary.
- Electroencephalogram (EEG)
- sleep and wakefulness produce different patterns in the electrical activity of the brain which is recorded in an EEG.
- Saltatory conduction
- results in faster impulse transmission in some neurons.
- Postsynaptic cell
- the receiving cell.
- Short-term memory
- reflects an immediate sensory perception of an object or idea and occurs before the image is stored.
- Central nervous system (CNS)
- the brain and spinal cord.
- Myelin sheath
- formed by supporting cells. In the PNS, supporting cells called Schwann cells: form myelin sheaths; in the CNS, supporting cells called oligodendrocytes produce the myelin sheaths.
- Inferior and superior colliculi
- are part of the auditory and visual systems. All fibers involved in hearing either terminate in or pass through the inferior colliculi. The superior colliculi take the form of prominent optic loves and may be the only visual centers.
- Nerve net
- a system of nerves that branch throughout the body.
- Neuron
- functional unit of the nervous system and is specialized for transmitting signals from one location in the body to another.
- Sensory neurons
- communicate information about the external and internal environments from sensory receptors to the central nervous system.
- Interneurons
- integrate sensory input and motor output; they make synaptic connections only with other neurons.
- Cerebral hemispheres
- divided into right and left by the cerebrum.
- Ganglion
- a cluster of nerve cell bodies, often of similar function, in the peripheral nervous system (PNS).
- Limbic system
- some human emotions depend on a functional group of nuclei and interconnecting axon tracts in the CNS called the limbic system. It includes parts of the thalamus and hypothalamus and portions of the cerebral cortex.
- Reticular formation
- passes through the core of the brainstem, part of the reticular formation. The reticular activating system (RAS), regulates sleep and arousal.
- Depolarization
- a reduction in the electrical gradient across the membrane.
- Dendrites
- convey signals from their tips to the rest of the neuron.
- Excitable cells
- have the ability to generate changes in their membrane potentials.
- Medulla oblongata
- contains centers that control several visceral functions, including breathing, heart and blood vessel activity, swallowing, vomiting, and digestion.
- Nuclei
- similar functional clusters in the brain.
- Neuropeptides
- relatively short chains of amino acids, serve as neurotransmitters.
- Synaptic terminals
- relay signals to other cells by releasing chemical messengers called neurotransmitters.
- Synaptic vesicles
- sacs located in the cytoplasm at the tip of the presynaptic axon.
- Neurotransmitter
- the substance that is released as a intercellular messenger into the synaptic cleft.
- Gamma aminobutyric acid (GABA)
- believed to be the transmitter at most inhibitory synapses in the bran, produces IPSPs by increasing the chloride permeability of the postsynaptic membrane.
- Brainstem
- a stalk and caplike swellings at the anterior end of the spinal cord. The brain stem has three parts that function in homeostasis, movement coordination, and conduction of information to higher brain centers: the medulla oblongata, the pons, and the midbrain.
- Epinephrine and Norepinephrine
- function as hormones and a closely related compound called Dopamine.
- Acetylcholine
- one of the most common neurotransmitters in both invertebrates and vertebrates.
- Meninges
- layers of connective tissue that protects the brain and spinal cord.
- Spinal nerves
- originate in the spinal cord and innervate the entire body.
- Postsynaptic membrane
- the plasma membrane of the cell body or dendrite on the other side of the synapse.
- Basal nuclei
- important centers for motor coordination, acting as switches for impulses from other motor systems.
- Epithalamus
- includes a projection, the pineal gland, and a choroid plexus, one of several clusters of capillaries that produce cerebrospinal fluid.
- Inhibitory postsynaptic potential (IPSP)
- voltage change associated with chemical signaling at an inhibitory synapse.
- Peripheral nervous system (PNS)
- nerves that communicate motor and sensory signals between the central nervous system and the rest of the body.
- Membrane potential
- the voltage measured across the plasma membrane.
- Graded potentials
- voltage changes produced by stimulation. The magnitude of change either hyperpolarization or depolarization depends on the strength of the stimulus.
- Thalamus
- is also the main input center for sensory information going to the cerebrum and the main output center for motor information leaving the cerebrum.
- Cerebrospinal fluid
- formed in the brain by filtration of the blood. Circulating through the central canal and ventricles, the cerebrospinal fluid conveys nutrients, hormones, and white blood cells across the blood-brain barrier to different parts of the brain.
- Synapse
- site of contact between a synaptic terminal and a target cell.
- Presynaptic cell
- the transmitting cell.
- Somatic nervous system
- carries signals to skeletal muscles mainly in response to external stimuli. It is considered voluntary because it is subject to conscious control, but a substantial proportion of skeletal muscle movement is actually determined by reflexes mediated by the spinal cord or lower brain.
- Long-term potentiation (LTP)
- an enhanced responsiveness to action potentials by a postsynaptic cell.
- Central canal
- narrow canal of the spinal cord is continuous with fluid-filled spaces, called ventricles, in the brain.
- Motor neurons
- convey impulses from the CNS to effector cells.
- Serotonin
- synthesized from the amino acid tryptophan.
- Long-term depression (LTD)
- decreased responsiveness to an action potential by a postsynaptic cell.
- Autonomic nervous system
- conveys signals that regulate the internal environment by controlling smooth and cardiac muscles and the organs of the gastrointestinal, cardiovascular, excretory, and endocrine systems. This control is generally involuntary.
- Threshold potential
- in an excitable cell, the response to a depolarizing stimulus is graded with stimulus intensity only up to a particular level of depolarization.
- Substance P
- a key excitatory signal that mediates our perception of pain.
- Gated ion channels
- special channels that neurons have that allow the cell to change its membrane potential in response to stimuli the cell receives.
- Sympathetic division
- generally increase energy consumption and prepare an individual for action by accelerating the heat rate, increasing metabolic rate, and performing related functions.
- Voltage-gated ion channels
- have gates that open and close in response to changes in membrane potential.
- Suprachiasmatic nuclei (SCN)
- inside the hypothalamus; functions as a biological clock.
- Axons
- conduct messages toward their tips.
- Amygdala
- a prominent component of the limbic system is a center of convergence for sensory data and a major organizer of emotional information.
- Refractory period
- sets the limit on the maximum rate at which action potentials can be generated.
- Corpus callosum
- a thick band of fibers that connects the right and left side.
- 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.
- Cerebral cortex
- the largest and most complex part of the human brain, and the part that has changed the most during vertebrate evolution.
- Excitatory postsynaptic potential (EPSP)
- the electrical change caused by the binding of neurotransmitter to the receptor.
- Biogenic amines
- neurotransmitters derived from amino acids.
- Motor division
- composed of efferent neurons that convey signals from the CNS to effector cells.
- Reflex
- automatic response.
- Resting potential
- the membrane potential of an excitable cell in a resting state.
- Endorphins
- neuropeptides that function as natural analgesics, decreasing the perception of pain by the CNS.
- Sensory division
- of the PNS of made up of sensory, or afferent, neurons that convey information to the CNS from sensory receptors that monitor the external and internal environment.
- Synaptic cleft
- separates the presynaptic cell from the postsynaptic cell.
- Action potential
- if a depolarization reaches the threshold, action potential will be triggered.
- Cell body
- contains the nucleus and a variety of other cellular organelles.
- Hyperpolarization
- an increase in the electrical gradient across the membrane.
- Cranial nerves
- originate in the brain and innervate organs of the head and upper body.
- Nerve cord
- a thick bundle of nerves usually extending longitudinally through the body from the brain.
- Long-term memory
- stored in the memory bank and can be recalled after several weeks after you originally do something.
- Parasympathetic division
- enhances activities that gain and conserve energy, such as digestion and slowing the heart rate.
- Summation
- additive effect of postsynaptic potentials.
- Effector cells
- the muscle cells or gland cells that actually carry out the body's responses to stimuli.
- Consciousness
- subjective awareness, or the ability to be aware of and make conscious judgments about the environment.
- Blood-brain barrier
- restricts the passage of most substances into the brain, allowing the extracellular chemical environment of the CNS to be tightly controlled.