35 Questions
What are the chemical components that support the neuronal membrane at rest?
Water, ions, phospholipids, and proteins
What drives the ions to pass the neuronal membrane, making it electrically excitable?
The membrane potential
What is the basis of membrane potentials in neurons?
Ions that can pass the membrane
What is the process activated by skin deformation in the nervous system?
Activation of cutaneous mechanoreceptors
What type of reflex is initiated by the flexor withdrawal in response to a stimulus?
Flexor withdrawal reflex
What are the key characteristics of water in intra- and extracellular fluids?
Polar solvent
Define cations and provide examples of cations.
Positively charged ions, e.g. Na+, K+, Ca++
What is the result of the plasma membrane maintaining a concentration gradient of different ions?
The excitability of neurons
What is the function of ion pumps?
To push ions against the concentration gradient and produce ion concentration gradients
What is the equilibrium potential for an ion?
The membrane potential at which the net ionic flow is 0
What are the two effects of K+ ions accumulating at the outside of the neuron?
Diminish the concentration gradient and turn the inside more electrically negative than the outside
What is the Nernst equation used for, and what does it take into account?
The Nernst equation is used to calculate the equilibrium potential of each ion (EION). It takes into account the charge of the ion, temperature, and the ratio of outside and inside concentrations of the ion.
How is the equilibrium potential (EION) affected when the intracellular K+ concentration quadruples?
The equilibrium potential (EION) for K+ increases.
What determines the membrane potential (Vm) according to Goldman's equation?
The relative permeabilities of Na+, K+, and Cl- ions.
How is the resting membrane potential (Vm) affected by an increase in extracellular K+ ions?
An increase in extracellular K+ ions depolarizes the resting membrane potential (Vm).
What are the main chemical components that support the neuronal membrane at rest?
Water, ions, phospholipids, and proteins
What drives the ions to pass the neuronal membrane, making it electrically excitable?
The ions that can pass the membrane and the driving forces behind their movement
What is the significance of the equilibrium potential in the context of neuronal membrane potentials?
The equilibrium potential determines the membrane potential for a specific ion based on its concentration gradient and the ion's charge
What are the key characteristics of water in intra- and extracellular fluids?
Polar solvent
Explain the process activated by skin deformation in the nervous system.
Flexor withdrawal reflex
What are the 5 important points to consider about equilibrium potentials (EION)?
- Large changes in Vm but minuscule changes in ion concentrations. 2. Net difference in electric charge. 3. Ion current (Iion) is proportional to Vm-Eion and to the conductivity of the membrane to that ion (gion). 4. Difference of concentration allows the calculation of Eion using the Nernst equation. 5. Eion are essentially constants.
What determines the membrane potential (Vm) according to Goldman's equation?
Concentration gradient and permeability of the membrane to different ions
How does the resting membrane potential (Vm) respond to an increase in extracellular K+ ions?
An increase in extracellular K+ ions depolarizes the Vm.
What factors determine the membrane potential (Vm) according to Goldman's equation?
According to Goldman's equation, Vm is determined by the relative permeabilities of Na+, K+, and Cl- ions at a given time.
What is the structure of K+ channels and how do they impact the resting potential?
K+ channels consist of 4 transmembrane subunits with a hairpin pore, and mutations in these channels can lead to hereditary neurological disorders.
What is the role of ions in making a neuron electrically excitable?
Ions maintain the resting membrane potential of the neuron
Which equation is used to calculate the equilibrium potential for an ion?
Nernst's equation
What is the key factor in determining the membrane potential according to Goldman's equation?
Relative permeability of ions
What is the key characteristic of water in intra- and extracellular fluids?
Polar solvent
What is the function of ion pumps in neuronal signaling?
Maintain the resting membrane potential
What determines the movement of ions across the neuronal membrane according to Ohm's law?
Electrical potential (V)
What happens to the equilibrium potential (EK) if the extracellular potassium ion concentration ([K+]o) equals the intracellular potassium ion concentration ([K+]i)?
EK remains unchanged
What determines the membrane potential (Vm) according to Goldman's equation?
The relative permeabilities of multiple ions and their concentrations inside and outside the cell
How does the resting membrane potential (Vm) respond to an increase in extracellular potassium ions ([K+]o)?
Vm depolarizes
What drives the ions to pass the neuronal membrane, making it electrically excitable?
Both concentration and electrical gradients
Test your knowledge of ion concentration and gradients in neurons with this quiz. Explore the effects of potassium ions on the neuron's interior and exterior, as well as their impact on electrical charge differentials.
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