30 Questions
What is the function of the nervous system related to receiving sensory information?
Sensory functions
What is the approximate number of neuroglial cells compared to neurons in the nervous system?
10 to 50 times more
What is the main function of neuroglial cells in the nervous system?
To support and protect neurons
How many pairs of Peripheral Nervous System (PNS) are there?
31 pairs
What is the term for the structural units of the nervous system?
Neurons
What is the function of the nervous system related to controlling muscle activity?
Motor functions
What is the approximate number of neurons in the nervous system?
100 billion
What is the function of the cell body or soma in a neuron?
Control the metabolic activity of the neuron
What type of neuron conducts impulses from the CNS to effector organs?
Motor neuron
What is the function of the myelin sheath in nerve fibers?
Act as an electric insulator
What is the term for the junction between the axonal terminal of one neuron and the dendrites or cell body of another neuron?
Neuroneural junction
What is the definition of resting membrane potential in nerve fibers?
The potential difference between the outside and inside of the nerve fiber during rest
What is the primary reason for the negative value of the resting membrane potential?
The inner surface of the cell membrane is negatively charged relative to the interstitial fluid
What is the approximate resting membrane potential of skeletal muscles?
-90 mV
What is the purpose of the two microelectrodes used to measure the resting membrane potential?
To measure the membrane potential
What is the ratio of Na+ ions in the ECF to the ICF?
10:1
What is the function of the leak channels in the cell membrane?
To allow the diffusion of ions
What is the main reason for the diffusion of ions through the cell membrane?
The ion channels are selectively permeable
What percentage of the Resting Membrane Potential is a passive process due to diffusion of ions through leak ion channels?
90-95%
What happens to Na+ ions when the Na-K pump is inhibited by cooling?
They accumulate inside the cell
What is the primary function of Schwann cells in the peripheral nervous system?
To form myelin sheath
What is the approximate value of the Resting Membrane Potential in nerve fibers?
-70 mV
What percentage of the Resting Membrane Potential is an active process due to the electrogenic Na-K pump?
5-10%
What is the main cause of the resting membrane potential?
Potassium diffusion
What type of nerve fibers carry impulses from receptors to the central nervous system?
Sensory (afferent) nerve fibers
What is the approximate concentration of potassium ions inside the cell compared to outside?
30-40 times greater
Why do potassium ions continue to diffuse out of the cell until positive charges outside the membrane repel their outflow?
Due to the high permeability of the membrane to potassium ions
What prevents chloride ions from diffusing into the cell?
The repulsion force by negative charges inside the cell
What is the function of the sodium-potassium pump?
To maintain a high concentration of sodium ions outside and potassium ions inside the cell
What is the direction of sodium ion diffusion in a resting neuron?
From outside to inside the cell
Test your knowledge of the nervous system and neurons in dentistry. This quiz covers the structure and types of neurons, properties of nerve fibers, and resting membrane potentials. Assess your understanding of the mechanisms of development of RMP in neurons.
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