General Physiology: Nervous System and Neurons
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Questions and Answers

What is the function of the nervous system related to receiving sensory information?

  • Higher mental functions
  • Motor functions
  • Sensory functions (correct)
  • Regulation of body temperature

    • What is the approximate number of neuroglial cells compared to neurons in the nervous system?

  • 50 to 100 times more
  • 100 times more
  • 10 to 50 times more (correct)
  • 10 times more

    • What is the main function of neuroglial cells in the nervous system?

  • To control muscle activity
  • To regulate body temperature
  • To support and protect neurons (correct)
  • To transmit nerve impulses

    • How many pairs of Peripheral Nervous System (PNS) are there?

    <p>31 pairs</p> Signup and view all the answers

    What is the term for the structural units of the nervous system?

    <p>Neurons</p> Signup and view all the answers

    What is the function of the nervous system related to controlling muscle activity?

    <p>Motor functions</p> Signup and view all the answers

    What is the approximate number of neurons in the nervous system?

    <p>100 billion</p> Signup and view all the answers

    What is the function of the cell body or soma in a neuron?

    <p>Control the metabolic activity of the neuron</p> Signup and view all the answers

    What type of neuron conducts impulses from the CNS to effector organs?

    <p>Motor neuron</p> Signup and view all the answers

    What is the function of the myelin sheath in nerve fibers?

    <p>Act as an electric insulator</p> Signup and view all the answers

    What is the term for the junction between the axonal terminal of one neuron and the dendrites or cell body of another neuron?

    <p>Neuroneural junction</p> Signup and view all the answers

    What is the definition of resting membrane potential in nerve fibers?

    <p>The potential difference between the outside and inside of the nerve fiber during rest</p> Signup and view all the answers

    What is the primary reason for the negative value of the resting membrane potential?

    <p>The inner surface of the cell membrane is negatively charged relative to the interstitial fluid</p> Signup and view all the answers

    What is the approximate resting membrane potential of skeletal muscles?

    <p>-90 mV</p> Signup and view all the answers

    What is the purpose of the two microelectrodes used to measure the resting membrane potential?

    <p>To measure the membrane potential</p> Signup and view all the answers

    What is the ratio of Na+ ions in the ECF to the ICF?

    <p>10:1</p> Signup and view all the answers

    What is the function of the leak channels in the cell membrane?

    <p>To allow the diffusion of ions</p> Signup and view all the answers

    What is the main reason for the diffusion of ions through the cell membrane?

    <p>The ion channels are selectively permeable</p> Signup and view all the answers

    What percentage of the Resting Membrane Potential is a passive process due to diffusion of ions through leak ion channels?

    <p>90-95%</p> Signup and view all the answers

    What happens to Na+ ions when the Na-K pump is inhibited by cooling?

    <p>They accumulate inside the cell</p> Signup and view all the answers

    What is the primary function of Schwann cells in the peripheral nervous system?

    <p>To form myelin sheath</p> Signup and view all the answers

    What is the approximate value of the Resting Membrane Potential in nerve fibers?

    <p>-70 mV</p> Signup and view all the answers

    What percentage of the Resting Membrane Potential is an active process due to the electrogenic Na-K pump?

    <p>5-10%</p> Signup and view all the answers

    What is the main cause of the resting membrane potential?

    <p>Potassium diffusion</p> Signup and view all the answers

    What type of nerve fibers carry impulses from receptors to the central nervous system?

    <p>Sensory (afferent) nerve fibers</p> Signup and view all the answers

    What is the approximate concentration of potassium ions inside the cell compared to outside?

    <p>30-40 times greater</p> Signup and view all the answers

    Why do potassium ions continue to diffuse out of the cell until positive charges outside the membrane repel their outflow?

    <p>Due to the high permeability of the membrane to potassium ions</p> Signup and view all the answers

    What prevents chloride ions from diffusing into the cell?

    <p>The repulsion force by negative charges inside the cell</p> Signup and view all the answers

    What is the function of the sodium-potassium pump?

    <p>To maintain a high concentration of sodium ions outside and potassium ions inside the cell</p> Signup and view all the answers

    What is the direction of sodium ion diffusion in a resting neuron?

    <p>From outside to inside the cell</p> Signup and view all the answers

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