Biology Exam 4

• Which ion most readily leaks across a neuron's membrane, helping to establish the resting potential?

  • Ca2+
  • K+
  • Na+
  • Cl+

  K+
• True/False: It speeds propagation by increasing the density of voltage-gated channels all along the axon.

  False
• True/False: multiple sclerosis is characterized by disrupted myelination of certain neurons in the central nervous system

  True
• True/False: It speeds propagation by preventing cations from leaking out across the membrane as they speed down the axon.

  True
• True/False: It is more commonly observed in vertebrates than in invertebrates.

  True
• In a neuron, what creates the electrochemical gradient favoring the outflow of K+ when the cell is at rest?

  • Na+/K+ -ATPase
  • Voltage-gated K+ channels
  • Voltage-gated Na+ channels
  • Ligand-gated Na+/K+ channels

  Na+/K+ -ATPase
• Which of the following brain regions is responsible for the formation of new memories?

  • Brainstem
  • Cerebellum
  • Frontal Lobe
  • Hippocampus

  Hippocampus
• In the human ear, how do different hair cells respond to different frequencies of sound?

  • Waves of pressure move through the fluid in the cochlea
  • Hair cells are "sandwiched" between membrane
  • Receptor proteins in the stereocilia of each hair cell are different, each protein responds to a certain range of frequencies
  • Because the basilar membrane varies in stiffness, it vibrates in certain places in response to certain frequencies

  Because the basilar membrane varies in stiffness, it vibrates in certain places in response to certain frequencies
• What type of sensory systems do migrating birds use to detect direction?

  Magnetorecption
• True/False: Some smooth muscle tissues are voluntary and others are involuntary.

  False