Flashcards in Chapter 3 - Neuronal Membrane at Rest Deck (18):
What is an action potential?
What are their characteristics?
Don’t diminish over distance
Signals of fixed size and duration
Info encoded in frequency, distribution and number of neurons firing
What is excitable membrane?
Cells capable of generating and conducting ap
What is a resting membrane doing?
Cytosol along inside surface of membrane has neg electrical charge compared to outside
Called resting membrane potential
Where is water?
What is responsible for action potential in water?
Inside neuron, cytosol, extracellular fluid
What insulates ions from each other?
Spheres of hydration
Clouds of water with opposite poles
What are cations and anions?
Net positive charge
Net negative charge
What is the neuronal membrane made of?
Isolates cytosol from extracellular fluid
What are the three types of proteins?
How is a protein composed?
Central alpha carbon covalently bonded to hydrogen atom, amino group (NH3+), carboxyl group (COO-), R group
R group varies and is responsible for size and chemical relationships in which participates
What are the four levels of structure of proteins?
Primary chain joined by peptide bonds
Secondary Alpha helix coil
Tertiary shaped by R groups
Quaternary structure forms larger molecule from bonding polypeptide chains
Each polypeptide contributing to quaternary is called subunit
Which parts of r groups are hydrophobic and philic?
Regions with exposed polar R groups are hydrophilic
Nonpolar R groups are phobic
Proteins suspended in membrane with phobic inside membrane and philic ends in water on either side
What are ion channels?
Four to six similar proteins to form pore
Ion selectivity K for K etc.
What is ion pump?
How do ions get across membrane?
Diffusion and electricity
What is the resting potential of a neuron’s membrane potential?
Vm = -65 millivolts
Four points about charged membranes
1. Large charges in membrane potential are caused by minuscule changes in ionic concentrations.
2. The net difference in electrical charge occurs at the inside and outside surfaces of the membrane.
3. Ions are driven across the membrane at a rate proportional to the difference between the membrane potential and the equilibrium potential.
4. If the concentration difference across the membrane is known for an ion, the equilibrium potential can be calculated for that ion.
What is the Nernst equation?
To calculate the equilibrium potential for an ion