neuron function part 2

Question 1

Voltage decreases with what?

Answer 1

Distance

Question 2

Higher resistance of intracellular and extracellular fluids cause what?

Answer 2

greater decrease in voltage along axon

Question 3

lower resistance of membrane causes what?

Answer 3

greater decrease in voltage along axons

Question 4

membrane bound receptors bind to what?

Answer 4

NT

Question 5

receptors transduce the chemical signal to an electrical signal by doing what?

Answer 5

Changing ion permeability of membrane

Question 6

Change in ion permeability causes what?

Answer 6

Change in membrane potential

Question 7

Gated ion channels: when Na or Ca channels open what happens?

Answer 7

depolarization

Question 8

When K channels open what happens?

Answer 8

Hyperpolarization

Question 9

depolarization is caused by what?

Answer 9

EPSP

Glutamate
nicotinic

Question 10

What causes hyperpolarization?

Answer 10

IPSP’s

GABA Glycine

Question 11

integration of graded signals:

what is a graded signal?

Answer 11

summation of individual actions of ligand-gated ion channel proteins, and decrease over time and space. They do not typically involve voltage-gated sodium and potassium channels

Question 12

graded potentials travel what type of distances?

Answer 12

Short - incrementally larger response with more active receptors

Question 13

conduction with decrement:

magnitude of graded potentials decrease with what?

Answer 13

Increasing distance from open ion channel

Question 14

decrement is due to what?

Answer 14

leakage of charged ions across membrane

electrical resistance to cytoplasm

electrical resistance of membrane

Question 15

what are the characteristics of AP’s? (4)

Answer 15

Triggered by net graded potentials at axon hillock do not degrade over distance

travel long distances along membrane

all or none

must reach threshold potential to fire

Question 16

Ap’s occur only when membrane potential at axon hillock reach what?

Answer 16

threshold

Question 17

what is the absolute refractory period?

Answer 17

cell incapable of generating a new ap

Question 18

What is relative refractory period?

Answer 18

More difficult to generate new AP

Question 19

What is the order of activity for voltage gated channels (4)

Answer 19

• na channels open (depolarization)
• k channels open more slowly (repolarization)
• na channels close through inactivation
• k channels close slowly