أسئلة المحاضرة 13 فسيولوجي (قبل التعديل)

<p>Excitability.</p> Signup and view all the answers

<p>It contains a larger number of nerve fibers.</p> Signup and view all the answers

<p>Conductivity.</p> Signup and view all the answers

<p>Interneurons.</p> Signup and view all the answers

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

<p>Myelin sheath.</p> Signup and view all the answers

<p>Na+</p> Signup and view all the answers

<p>Leak or passive channels</p> Signup and view all the answers

<p>Active transport mechanisms</p> Signup and view all the answers

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

<p>Na+ and Cl-</p> Signup and view all the answers

<p>16 gm/dl</p> Signup and view all the answers

<p>Ligand gated channels</p> Signup and view all the answers

<p>Passive diffusion of K+ ions</p> Signup and view all the answers

<p>It creates an electric charge separation.</p> Signup and view all the answers

<p>The balanced diffusion and repulsion forces.</p> Signup and view all the answers

<p>It directs ions from high concentration to low concentration.</p> Signup and view all the answers

<p>Negative charges inside the cell creating repulsion.</p> Signup and view all the answers

<p>When a cell is only permeable to K+ ions.</p> Signup and view all the answers

<p>Net diffusion of the ion ceases.</p> Signup and view all the answers

<p>It creates an unequal distribution of charges.</p> Signup and view all the answers

<p>It maintains high Na concentration outside and high K concentration inside the cell.</p> Signup and view all the answers

<p>It causes Na+ ions to accumulate inside the cell.</p> Signup and view all the answers

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

<p>To determine the equilibrium potential for different ions.</p> Signup and view all the answers

<p>It is a local change with variable magnitude and duration.</p> Signup and view all the answers

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

<p>They facilitate passive diffusion of ions across the membrane.</p> Signup and view all the answers

<p>Sub-minimal stimulus</p> Signup and view all the answers

<p>The selective permeability of the cell membrane to different ions</p> Signup and view all the answers

<p>K+</p> Signup and view all the answers

<p>Concentration gradients of ions across the membrane</p> Signup and view all the answers

<p>Voltage-gated channels</p> Signup and view all the answers

<p>The concentration gradient favors Na+ ions moving from outside to inside the cell</p> Signup and view all the answers

<p>To establish the resting membrane potential through ion balance</p> Signup and view all the answers

<p>It contributes to the net negativity of the resting membrane potential.</p> Signup and view all the answers

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

<p>They are primarily responsible for maintaining RMP.</p> Signup and view all the answers

<p>Net diffusion of the ion ceases.</p> Signup and view all the answers

<p>The potential difference resulting from charge separation due to ionic diffusion.</p> Signup and view all the answers

<p>They are repelled by the negative charges inside the cell.</p> Signup and view all the answers

<p>K+ ions will escape from the outside surface of the cell.</p> Signup and view all the answers

<p>Concentration gradient towards low concentration.</p> Signup and view all the answers

<p>Their diffusion is stopped by accumulated ionic charges.</p> Signup and view all the answers

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

<p>Negative charge accumulation inside the cell.</p> Signup and view all the answers

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

<p>Divide by +2.</p> Signup and view all the answers

<p>It will equal the equilibrium potential for Na+.</p> Signup and view all the answers

<p>Passive diffusion of multiple ions through leak ion channels.</p> Signup and view all the answers

<p>It involves electrical changes that propagate when stimulated by an effective stimulus.</p> Signup and view all the answers

<p>The RMP becomes progressively lost.</p> Signup and view all the answers

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

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

<p>Sensory neurons</p> Signup and view all the answers

<p>Myelin sheath</p> Signup and view all the answers

<p>Potential difference</p> Signup and view all the answers

<p>Active transport mechanisms</p> Signup and view all the answers

<p>They comprise multiple nerve fibers grouped together.</p> Signup and view all the answers

<p>Presence of negatively charged proteins inside the cell</p> Signup and view all the answers

<p>They connect sensory and motor pathways within the CNS.</p> Signup and view all the answers

<p>The myelin sheath insulates the axon, enhancing the speed and efficiency of nerve impulse conduction.</p> Signup and view all the answers

<p>Excitability is the ability of nerve fibers to respond to stimuli and generate an action potential.</p> Signup and view all the answers

<p>A nerve trunk is composed of numerous nerve fibers, each consisting of an axon covered by a myelin sheath and Schwann sheath.</p> Signup and view all the answers

<p>Conductivity refers to the ability to transmit nerve impulses, while excitability pertains to the response to stimuli.</p> Signup and view all the answers

<p>RMP is established by the uneven distribution of ions, primarily sodium (Na+) and potassium (K+), across the cell membrane.</p> Signup and view all the answers

<p>Motor neurons (efferent neurons) conduct impulses from the CNS to effector organs.</p> Signup and view all the answers

<p>K+ ions contribute to the negative charge inside the cell, which is essential for maintaining the resting membrane potential.</p> Signup and view all the answers

<p>The sodium-potassium pump actively maintains RMP by transporting 3 Na+ ions out and 2 K+ ions into the cell.</p> Signup and view all the answers

<p>Equilibrium is reached.</p> Signup and view all the answers

<p>K+ ions diffuse from an area of high concentration to low concentration.</p> Signup and view all the answers

<p>Charge separation creates an electrical potential that opposes the concentration gradient.</p> Signup and view all the answers

<p>It allows specific ions to pass through based on their concentration gradients and charges.</p> Signup and view all the answers

<p>The repulsion force caused by electrical gradient opposes diffusion.</p> Signup and view all the answers

<p>Na+ ions face difficulty diffusing through passive channels due to the repulsive force.</p> Signup and view all the answers

<p>Equilibrium potential is the electrical potential that balances the concentration gradient for that ion.</p> Signup and view all the answers

<p>High permeability to K+ compared to Na+ establishes a negative RMP.</p> Signup and view all the answers

<p>Sodium (Na+), Potassium (K+), Chloride (Cl-), and Proteins (Protein-).</p> Signup and view all the answers

<p>Leak channels allow specific ions, primarily K+, to move according to their concentration gradients, which helps establish the RMP.</p> Signup and view all the answers

<p>The sodium-potassium pump actively transports three Na+ ions out and two K+ ions into the cell, maintaining the concentration gradients essential for RMP.</p> Signup and view all the answers

<p>Selective permeability allows only certain ions to pass through, which affects the concentrations and, consequently, the resting membrane potential.</p> Signup and view all the answers

<p>The high concentration of K+ inside the cell drives K+ ions to diffuse outward through leak channels.</p> Signup and view all the answers

<p>Potassium (K+) predominantly contributes to negative RMPs, while Sodium (Na+) influences depolarization during action potentials.</p> Signup and view all the answers

<p>The typical resting membrane potential of a nerve cell is approximately -70 mV.</p> Signup and view all the answers

<p>The equilibrium potential for K+ is more negative than the resting membrane potential, reflecting K+'s tendency to diffuse out of the cell.</p> Signup and view all the answers

<p>The sodium-potassium pump actively transports 3 Na+ ions out of the cell and 2 K+ ions into the cell, helping to maintain high Na+ concentration outside and high K+ concentration inside.</p> Signup and view all the answers

<p>The Nernst equation calculates equilibrium potential by using ion concentration gradients inside and outside the membrane along with the valence of the ion.</p> Signup and view all the answers

<p>Decreased metabolic activity causes Na+ ions to accumulate inside the cell and K+ ions to escape, leading to a loss of resting membrane potential.</p> Signup and view all the answers

<p>90-95% of resting membrane potential is due to passive ion diffusion through leak ion channels.</p> Signup and view all the answers

<p>The concentration gradient of K+ ions is primarily responsible for establishing the resting membrane potential in excitable cells.</p> Signup and view all the answers

<p>The Nernst equation is divided by 2 for calcium ions because Ca2+ has a valence of +2, which requires adjustment in the equation.</p> Signup and view all the answers

<p>Graded potentials are local changes in membrane potential due to sub-minimal stimuli, while action potentials are large, propagated changes in membrane potential triggered by effective stimuli.</p> Signup and view all the answers

<p>The 4-5 mV contribution of the Na-K pump signifies its active role in reinforcing the resting membrane potential despite being a smaller percentage compared to passive processes.</p> Signup and view all the answers

<p>The nerve trunk, composed of many axons covered by myelin and Schwann sheaths, facilitates faster impulse conduction by insulating individual nerve fibers.</p> Signup and view all the answers

<p>Excitability allows nerve fibers to detect stimuli and convert them into action potentials, which are essential for signal transmission.</p> Signup and view all the answers

<p>The negativity inside the neuron is primarily due to higher concentrations of negatively charged proteins and the selective permeability of the membrane.</p> Signup and view all the answers

<p>The sodium-potassium pump actively transports 3 Na+ ions out of the cell and 2 K+ ions into the cell, maintaining the negative internal environment.</p> Signup and view all the answers

<p>Conductivity refers to the ability to transmit action potentials along the nerve, while excitability is the ability to generate an action potential in response to stimuli.</p> Signup and view all the answers

<p>An increase in internal potassium concentrations would likely depolarize the cell, reducing the negativity of the resting membrane potential.</p> Signup and view all the answers

<p>Increased permeability to K+ ions allows more K+ to leave the cell, enhancing the negative charge inside and stabilizing the resting membrane potential.</p> Signup and view all the answers

<p>The variable RMP is due to differences in ion concentrations and permeability among different types of neurons and their ionic environments.</p> Signup and view all the answers

<p>K+ ions.</p> Signup and view all the answers

<p>They are responsible for maintaining the RMP by allowing specific ions to diffuse across the cell membrane.</p> Signup and view all the answers

<p>The selective permeability of the cell membrane restricts Na+ ions from diffusing freely into the cell.</p> Signup and view all the answers

<p>It actively transports Na+ out of the cell and K+ into the cell, counteracting ion leakage.</p> Signup and view all the answers

<p>Cl- ions have a higher concentration outside the cell, contributing to the negative charge inside.</p> Signup and view all the answers

<p>The equilibrium potential is the voltage at which the force of diffusion and electrical gradient are equal for an ion.</p> Signup and view all the answers

<p>Diffusion forces drive ions from areas of higher concentration to lower concentration, crucial for generating action potentials.</p> Signup and view all the answers

<p>K+ ions move out of the cell due to their concentration gradient, which outweighs the electrical gradient acting on them.</p> Signup and view all the answers

<p>The Na-K pump maintains high Na+ concentration outside the cell and high K+ concentration inside the cell.</p> Signup and view all the answers

<p>Cooling leads to the accumulation of Na+ ions inside the cell and the escape of K+ ions from the outer surface, reducing RMP.</p> Signup and view all the answers

<p>90-95% of RMP results from passive processes due to ion diffusion, while 5-10% is from the active process of the Na-K pump.</p> Signup and view all the answers

<p>It is divided by +2 because calcium (Ca) has a valence of +2, affecting the Nernst equation calculation.</p> Signup and view all the answers

<p>Graded potentials result from stimulation by ineffective stimuli and cause local changes in membrane voltage with variable duration and magnitude.</p> Signup and view all the answers

<p>The RMP is maintained by passive ion diffusion through leak channels and active transport via the Na-K pump.</p> Signup and view all the answers

<p>The concentration gradient for Na+ ions drives their movement into the nerve cell, promoting depolarization when channels open.</p> Signup and view all the answers

<p>The high permeability of a membrane to K+ causes K+ to diffuse out, resulting in a negative charge inside the cell and contributing to a lower resting membrane potential.</p> Signup and view all the answers

<p>The resting membrane potential equals the equilibrium potential for an ion when the diffusion force and electrical gradient are equal.</p> Signup and view all the answers

<p>When the diffusion force equals the repulsion force, net diffusion of ions stops and equilibrium is reached.</p> Signup and view all the answers

<p>The equilibrium potential reflects the electrical potential that balances the concentration gradient for a specific ion, which equals the resting membrane potential when only that ion can cross the membrane.</p> Signup and view all the answers

<p>The sodium-potassium pump actively transports Na+ out and K+ into the cell, helping to maintain the concentration gradients essential for the resting membrane potential.</p> Signup and view all the answers

<p>The electrical gradient tends to pull K+ ions back into the cell due to the negative charge inside, opposing the diffusion force that drives K+ out.</p> Signup and view all the answers

<p>Na+ ions encounter repulsion from the negative charges inside the cell, making it difficult for them to pass through the passive Na+ channels.</p> Signup and view all the answers

<p>The concentration gradient of K+ is defined by its higher concentration inside the cell compared to outside, driving K+ to diffuse out.</p> Signup and view all the answers

<p>Charge separation occurs during the diffusion of ions, leading to an accumulation of charges that results in an electrical potential opposing further ion diffusion, defining equilibrium potential.</p> Signup and view all the answers