In Class Notes (2/10/25) Flashcards
It has hydrophobic fatty acid tails and hydrophilic phosphorous heads:
The phospholipid bilayer
Can anything pass through the membrane without help?
No
What are the major ions inside the neuron?
Large anions (negatively charged) that can’t leave, and potassium (K+).
What are the major ions outside the neuron?
Sodium (Na+) and Chloride (Cl-)
What are cations?
Positively charged ions.
Does K+ or Na+ diffuse faster?
K+ diffuses out faster than Na+ diffuses in.
It is the passive (no energy required) movement of ions across the membrane:
Diffusion
What are the three main ways ions pass through the membrane?
Diffusion, electrostatic pressure, and the sodium-potassium pump.
Which ion has more leak channels?
Potassium (K+) has more leak channels than Sodium (Na+).
What allows certain ions to pass through the membrane?
Ion “leak” channels, which are proteins embedded in the membrane.
Which ion is more permeable, Potassium (K+) or Sodium (Na+)?
Potassium (K+)
What always pushes ions toward equilibrium?
The Gradients
Why is the resting membrane potential closer to K+ equilibrium than Na+?
Because K+ is more permeable than Na+.
What happens in certain glial cells regarding the resting potential?
The resting potential reaches K+ equilibrium.
What is the resting potential in neurons compared to glial cells?
It is slightly more negative in neurons.
What is the function of the sodium-potassium pump?
It moves ions against their concentration gradient.
Does the sodium-potassium pump use energy?
Yes
What is the net charge inside the neuron due to the sodium-potassium pump?
A net -1 charge
