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BioPsychology Ch 4
Olivarria, Fall 2010
27
Psychology
Undergraduate 3
10/18/2010

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Cards

Term
Membrane Potential
Definition
difference in electrical charge btwn inside and outside of a cell
Term
Resting Potential
Definition

neuron's steady membrane potential of about -70mV

Neuron is polarized

Term
Ions
Definition
charged particles
Term
Cations
Definition
positive charge ions
Term
Anions
Definition
negative charge ions
Term
Ions cause resting potential?
Definition
Ration of negative to positive charges is greater inside neuron than outside
Term
Concentration Gradients
Definition
more likely to move from areas of high concentration to low... get less crowded!
Term
Electrical Gradiant
Definition

-Accumulation of charges

-repulsion of like charges in vicinity

-attraction of opposite charges elsewhere

Term
4 kinds of ions that contribute to resting potential
Definition
  • Na+ Sodium
  • K+ potassium
  • Cl- chloride
  • various proteins-
Term
Cell membrane allows ions through, how?
Definition
Cell membrane has PROTEIN CHANNELS that are very selective to allow passage of ions
Term
Ions in Concentration Gradient
Definition

K+ OUT

A- OUT

 

Na+ IN

Cl- IN

Term
Maintenance of Resting Potential
Definition

Sodium Potassium Pump

Cl- concentration gradient outside--> in

      electrostatic pressure inside  --> out

 

K+ concentration gradient inside--> out

    electrostatic pressure outside--> in

 

Na+ concentration gradient outside--> in

      electrostatic pressure outside--> in

Term
Neurotransmitters
Definition

chemicals that neurons release when they fire

diffuse across synaptic clefts

interact w/ specialized receptor molecules

Term
Depolarize
Definition
Neurotransmitters decrease resting membrane potential
Term
Hyperpolarize
Definition
Neurotransmitters increase resting membrane potential
Term
Excitatory Postsynaptic Potentials (EPSPs)
Definition

Postsynaptic depolarizations

increase likelihood neuron will fire

Term
Inhibitory Postsynaptic Potentials (IPSPs)
Definition

Postsynaptic hyperpolerizations

decrease likelihood neuron will fire

Term
Threshold of Exitaction
Definition
Term
Action Potential
Definition

at threshold, sodium channels open btwn -65 and 50mV

at 50mV, sodium channels close

refractory period, then resting potential again

Term
Summations
Definition

EPSPs and IPSPs can summate

Spacial: simultaneous on diff parts of receptive membrane sum to form greater

 

Temporal: rapid succession at same synapse sum to gorm greater signal

Term

At resting potential, more Na+/K+/Cl-

inside or outside neuron?

Definition

Na+/Cl- greater outside

K+ greater inside

Term
Action Potentials originate...?
Definition
Near the axon hillock
Term
When does a neuron fire?
Definition
When the degree of depolarization of axon hillock exceeds the threshold of excitation
Term
Neurotransmitter release is caused by..?
Definition
Exocystosis
Term
Release of neurotransmitter molecules is often triggered by...?
Definition
Influx in calcium ions
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