eye neurobio

electrochemically: chemicals cause an electrical signal (action potential)

How do neurons transmit messages?

• Sodium (Na+) ions are positively charged
• Potassium (K+) ions are positively charged
• Chloride (Cl-) ions are negatively charged
• Calcium ions (Ca++) are positively charged (+2)

what are the 4 important ions for neuron function, and how are they charged?

negatively charged proteins

transport channels that determines how many of each ion are inside the cell at a time

besides ions, what contributes charges to neuron interactions?

• Extracellular: more Na+ and Cl-
• Intra-cellular: more K+ and negatively charged molecules
(cell is more negatively charged)

at rest, describe ion concentrations inside and outside the cell

oppositely charged ions attract one another

how is movement determined in the electrochemical gradient (charge)?

Ions move from areas of high concentration to areas of low concentration

how is movement determined within a concentration gradient?

1) the Na/K pump pumps 2 K+ ions into cell for every 3 Na+ ions it pumps out

2) leaky K potassium channels facilitate diffusion of K+ out of cell

how is resting potential (-70) maintained?

the opening of sodium channels

what causes depolarization?

1) Depolarization: Membrane potential becomes more positive
(from -70 mV to +40 mV)
2) Repolarization: the return of the membrane potential to resting
potential
3) Hyperpolarization: this is seen in the overshooting region of the
action potential, when the potential dips even more negative
than the resting potential.

what are the 3 steps to an action potential?

Excitatory neurotransmitters

what type of neurotransmitter activates or depolarizes the post-synaptic cell

inhibitory neurotransmitters

what type of neurotransmitter inhibits or hyperpolarizes the post-synaptic cell?

modulatory neurotransmitter

what type of neurotransmitter neither activates nor inhibits the post-synaptic cell, but changes properties of activation

depolarization

Na+ influx through sodium channels is . . .

repolarization

K+ efflux through potassium channels is . . .

glutamate: Excitatory

GABA & glycine: Inhibitory

dopamine: Modulatory

match these neurotransmitters to their type:

glutamate, GABA and glycine, dopamine

ionotropic

which type of neurotransmitter is fast and direct?

metabotropic

which type of neurotransmitter is slow and modulatory?