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 (B)</p> Signup and view all the answers

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

<p>Neurons (B)</p> Signup and view all the answers

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

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

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

<p>100 billion (B)</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 (C)</p> Signup and view all the answers

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

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

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

<p>Act as an electric insulator (D)</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 (D)</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 (B)</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 (D)</p> Signup and view all the answers

What is the approximate resting membrane potential of skeletal muscles?

<p>-90 mV (B)</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 (A)</p> Signup and view all the answers

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

<p>10:1 (C)</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 (C)</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 (A)</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% (A)</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 (A)</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 (A)</p> Signup and view all the answers

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

<p>-70 mV (A)</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% (D)</p> Signup and view all the answers

What is the main cause of the resting membrane potential?

<p>Potassium diffusion (B)</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 (D)</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 (C)</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 (A)</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 (D)</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 (A)</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 (A)</p> Signup and view all the answers

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