Neuron Function

Question 1

Form of Neural communication

Answer 1

1. Action Potential
   - Electrical charge that conducts down the axon
   - nerve impulse, neural signal, neuronal firing. (rapid, but brief reversal of membrane potential)
2. Neurotransmission
   - chemicals passed from one neuron to the next

Question 2

Resting membrane potential

Answer 2

difference in electric charge between the inside and outside of a neuron’s cell membrane
(inside is more negative than the outside)

Question 3

Lipid Bilayer

Answer 3

1. Cytoplasm
   - high potassium, low Sodium
2. Extracellular
   - high sodium, low potassium

Potassium ion channels move potassium ions across the membrane (concentration gradient)
- K ions move from cytoplasm to the extracellular fluid

K moves down its concentration gradient, leaving behind net negative charge in the cytosol. (negative charge is around -70mV); electrostatic pressure pushes ions to areas of net opposite charge

Question 4

EPSP alter membrane potential by

Answer 4

depolarizing

Question 5

IPSP alter membrane potential by

Answer 5

hyper polarizing

Question 6

Temporal summation

Answer 6

2 PSPs elicited in rapid succession

Question 7

Spatial Summation

Answer 7

2 simultaneous PSPs

Question 8

Final

Answer 8

resting membrane potential is around 70 mV
- membrane is polarized (+ and -), inside is more negative than outside
RMP is due to passive movement of potassium ions
- post synaptic potentials (PSPs) arrive at the dendrites and soma and alter membrane potential (PSPs can be excitatory or inhibitory)
Summation of PSPs can elicit an action potential

Question 9

Action potential

Answer 9

brief and rapid reversal of membrane potential where the inside becomes positive (+50 mV)
begins at axon initial segment
all or none
results from changes in membrane permeability to rising phase (influx on Na) and falling/hyperpolarization phases (influx of K)
travels the length of the axon by saltatory conduction

Question 10

Inotropic receptors

Answer 10

Ligand-gated ion channels
Depolarizing (EPSP)
Hyper polarizing (IPSP)

Question 11

Metabotropic receptors

Answer 11

G protein coupled receptors
Activate a cascade of intracellular signaling
- G protein
- 2nd messengers

Question 12

Main mechanisms for neurotransmitter deactivation

Answer 12

Reuptake and Enzymatic degradation