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Brein Chapter 3+4 Flash cards

Brein Chapter 3+4 Flash cards

Last update 

Items (71)

  • Association neuron interposed between a sensory neuron and a motor neuron; thus, in mammals, interneurons constitute most of the neurons of the brain.


  • Chromosomal abnormality resulting in mental retardation and other abnormalities, usually caused by an extra chromosome 21.

    Down syndrome

  • Sensory neuron with one axon and one dendrite.

    bipolar neuron

  • Branching extension of a neurons cell membrane that greatly increases the surface area of the cell and collects information from other cells.


  • Tight junctions between the cells that compose blood vessels in the brain, providing a barrier to the entry of an array of substances, including toxins, into the brain.

    blood brain barrier

  • Loss of sensation and movement due to nervous-system injury.


  • Protein embedded in a cell membrane that allows substances to pass through the membrane on some occasions but not on others.


  • Mass of new tissue that grows uncontrolled and independent of surrounding structures.


  • Alteration of an allele that yields a different version of the allele.


  • Neuron that carries incoming information from sensory receptors into the spinal cord and brain.

    sensory neuron

  • Protrusion from a dendrite that greatly increases the dendrites surface area and is the usual point of dendritic contact with the axons of other cells.

    dendritic spine

  • Branch of an axon.

    axon collateral

  • Having two different alleles for the same trait.


  • Alternate form of a gene; a gene pair contains two alleles.


  • Nervous-system cell that provides insulation, nutrients, and support and that aids in repairing neurons and eliminating waste products.

    glial cell

  • Opening in a protein embedded in the cell membrane that allows the passage of ions.


  • Distinctive interneuron found in the cerebellum.

    Purkinje cell

  • Neuron that carries information from the brain and spinal cord to make muscles contract.

    motor neuron

  • Protein in the cell membrane that actively transports a substance across the membrane.


  • Hereditary disease characterized by chorea (ceaseless, involuntary, jerky movements) and progressive dementia, ending in death.

    Huntingtons disease

  • Knob at the tip of an axon that conveys information to other neurons.

    terminal button

  • Distinctive interneuron found in the cerebral cortex.

    pyramidal cell

  • Folded-up polypeptide chain.


  • Juncture of soma and axon where the action potential begins.

    axon hillock

  • Glial cells in the central nervous system that myelinate axons.


  • DNA segment that encodes the synthesis of a particular protein.


  • Core region of the cell containing the nucleus and other organelles for making proteins.

    cell body

  • Glial cell in the peripheral nervous system that myelinates sensory and motor axons.

    Schwann cell

  • Star-shaped glial cell that provides structural support to neurons in the central nervous system and transports substances between neurons and blood vessels.


  • Product of technology in which number of genes or a single gene from one species is introduced into the genome of another species and passed along and expressed in subsequent generations.

    transgenic animal

  • Glial cells that originate in the blood, aid in cell repair, and scavenge debris in the nervous system.


  • Glial cell that makes and secretes cerebrospinal fluid; found on the walls of the ventricles in the brain.

    ependymal cell

  • Having two identical alleles for a trait.


  • Nervous-system disorder that results from the loss of myelin (glial-cell covering) around neurons.

    multiple sclerosis

  • Brain cell that brings sensory information from the body into the spinal cord.

    somatosensory neuron

  • Inherited birth defect caused by the loss of genes that encode the enzyme necessary for breaking down certain fatty substances; appears 4 to 6 months after birth and results in retardation, physical changes, and death by about age 5.

    Tay-Sachs disease

  • Refers to a normal (most common in a population).

    wild type

  • Glial coating that surrounds axons in the central and peripheral nervous systems; prevents adjacent neurons from short-circuiting.


  • Buildup of pressure in the brain and, in infants, swelling of the head caused if the flow of cerebrospinal fluid is blocked; can result in retardation.


  • Root, or single fiber, of a neuron that carries messages to other neurons.


  • Junction between one neuron and another that forms the information-transfer site between neurons.


  • Electrical charge across the cell membrane in the absence of stimulation; a store of potential energy produced by a greater negative charge on the intracellular side relative to the extracellular side.

    resting potential

  • Difference in charge between two regions that allows a flow of current if the two regions are connected.

    voltage gradient

  • Transgenic technique that combines genetics and light to control targeted cells in living tissue.


  • Large, brief reversal in the polarity of an axon.

    action potential

  • Refers to the state of an axon in the repolarizing period during which a new action potential cannot be elicited (with some exceptions), because gate 2 of sodium channels, which is not voltage sensitive, is closed.

    absolutely refractory

  • Movement of ions from an area of higher concentration to an area of lower concentration through random motion.


  • Brief depolarization of a neuron membrane in response to stimulation, making the neuron more likely to produce an action potential.

    excitatory postsynaptic potential

  • Graph that records electrical activity through the skull or from the brain and represents graded potentials of many neurons.


  • Reverse movement of an action potential into the dendritic field of a neuron; postulated to play a role in plastic changes that underlie learning.

    back propagation

  • Decrease in electrical charge across a membrane, usually due to the inward flow of sodium ions.


  • A microscopic insulated wire or a salt-water-filled glass tube of which the uninsulated tip is used to stimulate or record from neurons.


  • Differences in concentration of a substance among regions of a container that allow the substance to diffuse from an area of higher concentration to an area of lower concentration.

    concentration gradient

  • Refers to the state of an axon in the later phase of an action potential during which increased electrical current is required to produce another action potential; a phase during which potassium channels are still open.

    relatively refractory

  • Graded potentials that occur at approximately the same location and time on a membrane are summed.

    spatial summation

  • Increase in electrical charge across a membrane, usually due to the inward flow of chloride or sodium ions or the outward flow of potassium ions.


  • Device that measures the flow and the strength of electrical voltage by recording the difference in electrical potential between two bodies.


  • Propagation of an action potential at successive nodes of Ranvier; saltatory means jumping or dancing

    saltatory conduction

  • Gated protein channel that opens or closes only at specific membrane voltages.

    voltage-sensitive channel

  • The part of an axon that is not covered by myelin.

    node of Ranvier

  • Device that serves as a sensitive voltmeter by registering the flow of electrons to measure voltage.


  • Ion channel on a tactile sensory neuron that activates in response to stretching of the membrane, initiating a nerve impulse.

    stretch-sensitive channel

  • Small voltage fluctuation in the cell membrane restricted to the vicinity on the axon where ion concentrations change to cause a brief increase (hyperpolarization) or decrease (depolarization) in electrical charge across the cell membrane.

    graded potential

  • Brief hyperpolarization of a neuron membrane in response to stimulation, making the neuron less likely to produce an action potential.

    inhibitory postsynaptic potential

  • Illness resulting from the loss of the immune system s ability to discriminate between foreign pathogens in the body and the body itself.

    autoimmune disease

  • On a muscle, the receptor ion complex that is activated by the release of the neurotransmitter acetylcholine from the terminal of a motor neuron.

    end plate

  • Voltage on a neural membrane at which an action potential is triggered by the opening of Na+ and K+ voltage-sensitive channels; about 250 millivolts relative to extracellular surround.

    threshold potential

  • Receptor complex that has both a receptor site for a chemical and a pore through which ions can flow.

    transmitter-sensitive channel

  • Graded potentials that occur at approximately the same time on a membrane are summed.

    temporal summation

  • Passage of an electrical current from the uninsulated tip of an electrode through tissue, resulting in changes in the electrical activity of the tissue.

    electrical stimulation

  • Propagation of an action potential on the membrane of an axon.

    nerve impulse