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Questions and Answers
What role do microtubules play in neurons?
What role do microtubules play in neurons?
Which part of the neuron is primarily responsible for receiving incoming information?
Which part of the neuron is primarily responsible for receiving incoming information?
In the context of neuron communication, what is the synapse?
In the context of neuron communication, what is the synapse?
What structure in a neuron helps to protect and improve the efficiency of signal transmission?
What structure in a neuron helps to protect and improve the efficiency of signal transmission?
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Which part of a neuron can be considered the initial segment where action potentials are generated?
Which part of a neuron can be considered the initial segment where action potentials are generated?
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Which phase of the membrane potential occurs when it becomes less negative than the resting potential?
Which phase of the membrane potential occurs when it becomes less negative than the resting potential?
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What must be used to maintain ionic gradients across the membrane during a dynamic steady state?
What must be used to maintain ionic gradients across the membrane during a dynamic steady state?
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In the Goldman-Hodgkin-Katz equation, what does Vm represent?
In the Goldman-Hodgkin-Katz equation, what does Vm represent?
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Which type of neuron is primarily responsible for transmitting sensory information to the central nervous system?
Which type of neuron is primarily responsible for transmitting sensory information to the central nervous system?
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What primarily determines the equilibrium potential of an ion at rest?
What primarily determines the equilibrium potential of an ion at rest?
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Which structural classification describes neurons with multiple processes extending from the cell body?
Which structural classification describes neurons with multiple processes extending from the cell body?
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Which ion's equilibrium potential is primarily involved in repolarization of the membrane potential?
Which ion's equilibrium potential is primarily involved in repolarization of the membrane potential?
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What is the main physiological role of interneurons in the central nervous system?
What is the main physiological role of interneurons in the central nervous system?
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How does hyperpolarization affect the membrane potential?
How does hyperpolarization affect the membrane potential?
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Which neuron type is characterized by having two equal processes coming from the cell body?
Which neuron type is characterized by having two equal processes coming from the cell body?
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What role do motor proteins play in axonal transport?
What role do motor proteins play in axonal transport?
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What is the primary structure that facilitates the movement of motor proteins in neurons?
What is the primary structure that facilitates the movement of motor proteins in neurons?
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In which direction can axonal transport occur?
In which direction can axonal transport occur?
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What is a significant consequence of the varicella zoster virus's movement along axonal pathways?
What is a significant consequence of the varicella zoster virus's movement along axonal pathways?
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How do graded potentials travel in a neuron?
How do graded potentials travel in a neuron?
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What is the function of lysosomes in neurons?
What is the function of lysosomes in neurons?
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What initiates action potentials in a neuron?
What initiates action potentials in a neuron?
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What is the energy source required for motor proteins to function in axonal transport?
What is the energy source required for motor proteins to function in axonal transport?
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Which area of a neuron is primarily responsible for conducting electrical signals?
Which area of a neuron is primarily responsible for conducting electrical signals?
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What characterizes the connection between individual neurons?
What characterizes the connection between individual neurons?
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What primarily determines the direction of ion flow across the cell membrane?
What primarily determines the direction of ion flow across the cell membrane?
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Which ion is found in a higher concentration inside the cell compared to outside?
Which ion is found in a higher concentration inside the cell compared to outside?
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What effect do K+ leak channels have on resting membrane potential?
What effect do K+ leak channels have on resting membrane potential?
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Which of the following best describes the distribution of Na+ and K+ in body fluids?
Which of the following best describes the distribution of Na+ and K+ in body fluids?
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What role do negatively charged proteins play in intracellular fluid?
What role do negatively charged proteins play in intracellular fluid?
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What is the primary function of the Na+-K+ ATPase pump?
What is the primary function of the Na+-K+ ATPase pump?
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Which component primarily acts as an insulator in the cell membrane?
Which component primarily acts as an insulator in the cell membrane?
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What happens when the concentration gradient and the electrical gradient are equal for K+?
What happens when the concentration gradient and the electrical gradient are equal for K+?
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What is the main reason for the selective permeability of the plasma membrane?
What is the main reason for the selective permeability of the plasma membrane?
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In the resting membrane potential, what is a significant factor that keeps negative ions inside the cell?
In the resting membrane potential, what is a significant factor that keeps negative ions inside the cell?
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How is the resting membrane potential described on a relative charge scale?
How is the resting membrane potential described on a relative charge scale?
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What effect does the presence of more K+ leak channels than Na+ leak channels have?
What effect does the presence of more K+ leak channels than Na+ leak channels have?
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Which ion primarily contributes to the electrical gradient needed for the resting membrane potential?
Which ion primarily contributes to the electrical gradient needed for the resting membrane potential?
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What is the primary ion that causes depolarization during stimulation of the plasma membrane?
What is the primary ion that causes depolarization during stimulation of the plasma membrane?
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Which of the following describes the resting membrane potential?
Which of the following describes the resting membrane potential?
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What role does the Na+-K+ ATPase play in the cell?
What role does the Na+-K+ ATPase play in the cell?
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What is the correct formula for calculating the equilibrium potential for a single ion type?
What is the correct formula for calculating the equilibrium potential for a single ion type?
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What occurs after the depolarization phase during an action potential?
What occurs after the depolarization phase during an action potential?
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What is used to counterbalance the efflux of K+ ions due to their concentration gradient?
What is used to counterbalance the efflux of K+ ions due to their concentration gradient?
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What maintains the dynamic steady state of the cell at resting state?
What maintains the dynamic steady state of the cell at resting state?
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Which factor primarily contributes to the negative value of the resting membrane potential?
Which factor primarily contributes to the negative value of the resting membrane potential?
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How does osmotic equilibrium relate to the membrane potential?
How does osmotic equilibrium relate to the membrane potential?
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Which ion type primarily exists at higher concentrations inside a living cell compared to the extracellular fluid?
Which ion type primarily exists at higher concentrations inside a living cell compared to the extracellular fluid?
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What is the primary direction of signal flow for neurotransmission?
What is the primary direction of signal flow for neurotransmission?
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What is the osmolarity of the intracellular fluid based on the provided information?
What is the osmolarity of the intracellular fluid based on the provided information?
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What process occurs at the presynaptic axon terminal before neurotransmitter release?
What process occurs at the presynaptic axon terminal before neurotransmitter release?
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What role do dendritic spines play in synaptic communication?
What role do dendritic spines play in synaptic communication?
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In terms of ion channels, which channel type is more prevalent during resting membrane potential?
In terms of ion channels, which channel type is more prevalent during resting membrane potential?
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What characterizes the condition of a living cell at the resting membrane potential?
What characterizes the condition of a living cell at the resting membrane potential?
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Which type of synapse is associated with excitatory connections?
Which type of synapse is associated with excitatory connections?
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What is retrograde transport in neurons?
What is retrograde transport in neurons?
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What type of signal is transmitted by dendrites to the cell body of a neuron?
What type of signal is transmitted by dendrites to the cell body of a neuron?
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Which structure connects the presynaptic axon terminal and the postsynaptic dendrite?
Which structure connects the presynaptic axon terminal and the postsynaptic dendrite?
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What is the significance of the presence of polyribosomes in dendritic spines?
What is the significance of the presence of polyribosomes in dendritic spines?
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The integration of graded potentials occurs where in a neuron?
The integration of graded potentials occurs where in a neuron?
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What characterizes inhibitory synapses?
What characterizes inhibitory synapses?
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What type of neurotransmission involves signals moving from the terminal to neighboring neurons?
What type of neurotransmission involves signals moving from the terminal to neighboring neurons?
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What is the primary function of the myelin sheath?
What is the primary function of the myelin sheath?
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What is typically found at the synapse of a neuron?
What is typically found at the synapse of a neuron?
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Study Notes
Nervous System - Resting Membrane Potential and Neuron
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Objectives:
- Understand the basic principle of resting membrane potential generation.
- Describe the anatomy of a typical neuron and its functions.
Membrane Permeability
- Phospholipid bilayer of cell membranes are impermeable to charged molecules (e.g., Na+, K+, Cl-, Ca++).
- These charged molecules are also insoluble in the hydrophobic membrane core.
- Large water-soluble molecules (e.g., proteins, nucleic acids, sugars) also require channels to cross the membrane.
- Small uncharged polar molecules (e.g., CO2, O2, NH3, water) can cross the membrane freely (often via aquaporins).
Electrolyte Distribution
- Interstitial Fluid: Major electrolytes include Na+, Cl-, and HCO3-.
- Intracellular Fluid: Major electrolytes include K+, HPO42- (phosphate ion), and negatively charged proteins.
Dominant Ions
- Extracellular Fluid: Sodium (Na+) and Chloride (Cl-)
- Intracellular Fluid: Potassium (K+) and negatively charged proteins.
- The selective permeability of the plasma membrane causes uneven distribution of electrolytes, establishing an electrochemical disequilibrium.
Electrical Properties & Potential
- Plasma membranes exhibit ionic conductance allowing ionic currents.
- The concentration gradient dictates ion flow across the membrane.
- The membrane acts as a capacitor, holding charges.
- This electrical gradient creates a transmembrane potential (voltage difference between intra and extracellular spaces).
- Resting membrane potential (RMP) is the potential across the membrane at rest.
Resting Membrane Potential (RMP)
- When a cell is at rest, it maintains a negative membrane potential (-70 mV typically).
- This is due to differences in ion concentrations inside and outside the cell.
- The movement of sodium and potassium ions creates this negative value.
- Na+/K+ ATPase maintains RMP by pumping 3 sodium ions out and 2 potassium ions in this process.
K+ Leak Channels
- Cells have more potassium leak channels than sodium leak channels.
- The concentration gradient pushes K+ out of the cell.
- However, negative ions inside the cell oppose K+ efflux holding a negative resting value.
Equilibrium Potential
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Equilibrium potential (Eion) is the membrane potential at which the concentration and electrical gradient for a specific ion are balanced.
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The loss of positive ions (K+) intracellularly and the presence of -ve charged ions creates an electrical gradient.
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The K+ concentration gradient and the electrical gradient cause an opposing force.
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These forces balance each other, resulting in no net movement of K+ across the membrane.
Physiological Importance
- Maintaining the resting membrane potential is crucial for cell function.
- Maintaining the ionic gradients requires metabolic energy from the cell. This is essential for cellular function, especially for neurons, muscle cells, and other excitable cells.
Neuron Anatomy & Functions
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Neuron: a nerve cell. This is the fundamental functional unit of the nervous system; responsible for transmitting and receiving information.
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Anatomy: Neurons contain a cell body (soma), with dendrites, and an axon.
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Functions:
- Receiving signals from other neurons or sensory receptors.
- Integrating information by processing signals.
- Sending signals to other neurons, muscles, or glands.
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Classification: Based on structure and function (sensory, interneurons, and motor).
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Structural Classification: Multipolar (multiple processes), Bipolar (two processes), Unipolar (single process).
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Functional Types: Sensory, Interneurons, Motor.
Parts of a Neuron
- Cell Body (Soma): Contains the nucleus and organelles.
- Axon: Extends from the cell body and carries signals in an outbound direction, with branches at the end (axon terminals).
- Dendrites: Branching extensions of the neuron. They are the receiving end of signals.
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Description
Test your knowledge on the structure and function of neurons with this quiz. Discover the roles of microtubules, synapses, and the segments responsible for signal transmission. Understand the intricacies of neuron communication and how various components work together.
