Biopsychology Exam 1

Toward the front (nose)

Anterior

Toward the back (tail) (not dorsal)

Posterior

Toward the top of the brain

Dorsal

Toward the bottom of the brain

Ventral

Toward the midline

Medial

Away from the midline

Lateral

Central Nervous System (CNS)

Brain and spinal cord

Peripheral Nervous System (PNS)

Motor and sensory neurons that connect to the CNS (everything else)

The brain and spinal cord are two structures in the blank nervous system

Centra l

Schwann Cells

Oligodendrocytes

Axodendritic

axon to dendrite synapse

Axosomatic

Axon to soma synapse

Axoaxonic

Axon to axon synapse

Ions

Electrically charged molecules

Neurons have a blank

Electrical charge

Membrane potential

the difference in electrical charge between the extracellular fluid and the intracellular fluid (difference = approx -70mV)

The inside of a neuron (intracellular) is …

More negative (-) than the outside (extracellular)

Cations are

Positively charged ions

Anions are

Negativity charged ions

Membrane potential of a neuron at rest

-70mV

Gated ion channels are

channels that can be open or closed depending on various environmental conditions (binding of a neurotransmitter or the voltage of the neuron)

Ions are able to move between

the extracellular and intracellular fluids via specialized membrane-spanning proteins called ion channels

Leak ion channels

Are channels that are always open! Doesn’t matter the circumstance

Voltage-Gated ion channels

Opens and closes dependent on the electrical charge of the neuron

Diffusion 1

Is a passive process that’s dependent on a concentration gradient

Diffusion 2

Diffusion through a semipermeable membrane

Electrostatic forces (diffusion 3, attraction)

Ions flow towards oppositely charged ares

Electrostatic forces (Repulsion)

Ions flow towards oppositely charged areas

Electrical Driving Force = …

Electrostatic potential

External positive charges are attracted to …

Negative inside

Internal negative charges are attracted to …

Positive outside

Actively (cell does this)

(Meaning using energy) to push sodium out of the neuron and potassium into the neuron

Passively (cell does this)

(Meaning without using energy) to allow potassium free movement between the inside and outside of a neuron

Potassium is most dense when?

It’s intercellular. Its particularly accomplished through sodium potassium pumps

The sodium potassium pumps push …

3 Na+ out of the neuron for every 2 K+ they pump into the cell

Why do sodium potassium pumps use a lot of energy?

Because it is against the concentration gradient

Potassium wants to move from…

an area of high potassium concentration to a lower concentration area (intracellular -> extracellular).

Potassium can what…

Efflux through leak channels

Electrostatic force maintains…

K+ intracellularly

Potassium is also attracted to the…

Anions and negative ions intracellularly

An equilibrium is obtained when the ….

Opposite forces of the concentration gradient (K+ efflux) is matched with electrostatic force (K+ influx)

Ions move through the neural membrane via ….

Ion channels

Electrical forces drive…

Oppositely charged ions together

Concentration gradient forces…

Identical ions to diffuse away from each other

Why are neurons negatively charged at rest?

They are negatively charged at rest because the sodium potassium pumps maintain more K+ inside the cell and Na+ outside the cell

What do potassium leak channels help maintain?

The resting membrane potential

Ion channels are

Proteins in the membrane that can form pores to allow the passage of ions through them

Voltage gated ion channels are

ion channels that open or close depending on the voltage/electrical charge of the inside of the neuron relative to the outside

Leak channels are

Ion channels that are always open

Anion

Negatively charged ion (chloride)

Cation

Positively charged ion (sodium, potassium, calcium)

Equilibrium Potential

The point in which there is no net flow of ions

Influx

Moving into the cell

Efflux

Moving out of the cell

Inhibitory signals

“Don’t Fire.” Results in hyperpolarization (the neuron gets MORE negative)

Excitatory signals

“Fire Away.” Results in depolarization (the neuron gets LESS negative, and brings it closer to 0mV)

Inhibition (Hyperpolarized)

More negative than at rest

Excitation

More positive than at rest