Lecture 26: Resting Membrane Potential Flashcards
(22 cards)
What is Neuroscience/Brain Research?
A scientific discipline concerned with the function and structure of the nervous system.
What is the nervous system made up of?
Central Nervous System & the Peripheral Nervous System
More than just the brain
What types of cells is the nervous system made up of?
Neurons and Neuroglia (Help with immunity, insulation and growth support)
What are some examples of Neurological and Psychiatric disorders?
- Alzheimer’s disease
- Motoneuron disease
- Parkinson’s disease
- Autism etc.
What are the parts of a Neuron? What is a basic idea of what each part does?
Dendrite: Receives Signals
Cell Body (Soma): Passively conducts signals
Axon Hillock/Initial Segment: If enough of a signal reaches here, it produces an action potential
Axon: Propagates Action Potential
Axon Terminal: Release Chemical Signal
How do Neurons communicate?
Electrical Signals: Dendrites, Cell Body, Axons
Chemical Signals: Synapses - Neurotransmission
Do all cells have a resting membrane potential? And what type?
Almost all cells have a negative resting membrane potential.
What sort of cells can produce an action potential?
Only ‘excitable tissues’ can produce an action potential in response to a stimulus
Muscles and Neurons
How are intracellular potentials measured today?
- Microelectrode recording technique
- Patch-clamp technique (Breaking the cell membrane and measuring insides directly)
What generates the Resting Membrane Potential?
Unequal Concentration: of ions inside and outside the cell, producing an electrochemical gradient
Unequal Permeability: of ion types through cell membrane
How are the concentration gradients for K+ and Na+ maintained?
Via the Na/K ATPase, more positive ions pumped out -> making neuron interior negative
3 Na out
2 K in
What are the two main types of ion channels in neurons?
Non-gated (‘leak’) channels
Gated channels (voltage-gated, ligand gated, or mechanically gated)
What type of ion leak channels are highly prevalent in neurons?
Many leaky K + channels, but very few leak Na+ channels.
Therefore at rest: PK+ / PNa+ ≈ 40/1
What does the concept of equilibrium potential apply to?
A single ion at a time
What is the concept of a ‘equilibrium potential’ for one ion type?
An intracellular potential at which the net flow of ions is zero according to its
electrochemical gradient.
Write out the full Nernst equation.
Eion = 2.3 x RT/zF x log [ion]o/[ion]i
Write out the simplified Nernst equation.
Eion = 61.5 mV x log [ion]o/[ion]i
What are the concentrations of K+ and Na+ around neurons?
Inside the Neuron:
K+ ~ 100mM
Na+ ~ 15 mM
Outside the Neuron:
K+ ~ 5 mM
Na+ ~ 150mM
What is the Equilibrium potential of Na+?
ENa+ = +60mV
What is the Equilibrium potential of K+?
EK+ = -80mV
Write the Goldman Equation
Vm = 61.5 mV * log PK[K+]o+ PNa[Na+]o
—————————–
PK[K+]i + PNa[Na+]i
