Card Set Information

2011-02-05 19:02:57

The baisc structure and function of neurons.
Show Answers:

  1. Plasma cell membrane
    A flexible yet sturdy barrier that surrounds and contains the cytoplasm of a cell. Protects contents of cell, makes contact with other cells, and mendiates entry and exit of substances.
  2. Cytoplasm ( divided into two parts)
    The contents that make up the cells interiour.
  3. Cytosol (cytoplasm)
    The fluid portion of the cytoplasm that surrounds organelles, made up of 75-90% water plus other various components.
  4. Function of Cytosol
    The site of many chemical reactions required for a cell's existence
  5. Organelles (cytoplasm)
    Specialized structures that have characteristic shapes and perform specific functions in cellular growth, maintenance, and reproduction. There are 6 main components.
  6. Ribosomes (organelles)
    Tiny organelles composed of a type of RNA and various proteins. Function - sites of protein synthesis
  7. Endoplasmic reticulum (organelles)
    Extensive network of folded membranes that extends from the nuclear envelope throughout the cytoplasm. Function - it syntgesizes fatty acids and steroids and detoxifies drugs and other harmful substances.
  8. Golgi complexes (organelles)
    3-20 flattend membranous sacs with bulging edges stacked on one another. Function - modify, sort, and package proteins for transport to different destinations. Forms lysosomes.
  9. Mitochondria (organelles)
    Double-membraned organelle with a fluid filled space in between, referred to as the powerhouse of the cell. Function - site of ATP synthesis
  10. Lysosome (organelle)
    A membrane enclosed vesicles that contains digestive enzymes. Function- digest worn - out organelles
  11. Cilia and flagella (organelle)
    Motile hair-like projections containing microtubing. One moves fluid around the cell wilebthe othere moves the entire cell.
  12. Nucleus
    A sherical or oval structure in the cell, most prominent feature of the cell. Functions - contains the hereditary factors called genes that controls cellular structure and directs activities.
  13. Neurons
    Convert stimuli into nerve impulses (action potentials) and conduct these impulses to other neurons, muscle tissue or glands.
  14. The 3 parts of a neuron
    • Cell body
    • Dendrites
    • Axon
  15. Cell body (neuron)
    Contains a nucleus surrounded by cytoplasm with tipical organelles.
  16. Dendrites (neuron)
    Short, tapering and highly branched extentions off the cell body. Functions as the receving portion of a neuron
  17. Axon (neuron)
    Long, thin, cylindrical projection that joins the cell body at a cone - shaped elevation. Function - propagates nerve impulses toward another neuron, muscle fiber, or gland cell.
  18. Axon hillocks (axon)
    A small conical elevation that originates from the cell body.
  19. Axon collateral (axon)
    Several side branches off the axon typically at a right angle.
  20. Axon terminals (axon)
    The axon and its collaterals end into many fine processes.
  21. Synaptic end bulbs
    The tips of some axon terminals swell into bulb-shaped stuctures.
  22. Synaptic vesicles
    Are membrane enclosed sacs that store chemicals called neurotransmitters.
  23. Multipolar
    Several dendrites and one axon (most neurons in the cns).
  24. Bipolar
    One main dendrite and one axon on both sides of the cell body.
  25. Unipolar
    Sensory neurons that originate in the embryo.
  26. Absolute refractory Period
    A second action potential cannot be initiated, even with very strong stimulus.
  27. Membrane potential
    electrical voltage difference across the membrane.
  28. Astrocytes
    • Star-shaped, with many processes
    • Provides nutrients to neurons
    • Help form blood brain barrier
  29. Refractory Period
    The period of time which an excitable cell cannot generate another action potential.
  30. Repolarizing Phase
    • Resting membrane potential restored
    • Slowing of Na+ inflow and increase of K+ outflow causes potential to change from +30 mV to 0 mV to -70 mV.
  31. Microglia
    Protect CNS cells from disease by engulfing invading microbes.
  32. Resting membrane potential
    Term used to describe voltage difference across membrane; average value is -70mV
  33. Oligodendrocytes
    • Smaller than astrocytes, with fewer processes; round or oval cell body
    • Forms supporting network around CNS neurons.
    • Produces myelin sheath
  34. Depolarizing phase
    • Threshold - when stimulus causes membrane to depolarize to a critical level, typically -55mV
    • Inflow of Na+ causes potential to change from -55mV, passes 0mV and reaches +30mV
  35. Efferent(motor)
    carry information out of the brain and spinal cord.
  36. Afferent (sensory)
    Carry sensory information into the brain and spinal cord.
  37. After-hyperpolarizing phase
    • Membrane potential drifts toward the potassium equilibrium potential (about -90mV).
    • Return to -70mV occurs when K+ channels close.
  38. Ependymal
    • epithelial cells arranged in a single layer, may be ciliated.
    • Lines ventricles of the brain and central canal of the spinal cord
    • Forms Cerebral Spinal Fluid and assists in circulat.
  39. Association(interneuron)
    Processes sensory information by analyzing, storying and making decisions regarding appropriate responses.
  40. Relative refractory period
    period of time during which a second action potential can be initiated, but only by a larger-than-normal stimulus
  41. Schwann Cells
    • flattened cells that encircle the PNS axons.
    • participates in regeneration of axons.
  42. satellite cells
    • flattened cells arranged around the cell bodies of neurons in ganglia.
    • Support neurons in PNS ganglia.