Neuro 3

Question 1

“excitable” cells

Answer 1

ability to propagate electrical signals over long distances in response to a stimulus

Question 2

two factors that influence the membrane potential

Answer 2

• conc gradient (uneven distribution) of different ions across the membrane
• permeability of membrane to those ions

Question 3

nernts equation

Answer 3

describes membrane potential if membrane were completely permeable to only one ion (equilibrium potential)

Question 4

Goldman-Hodgkin-Katz equation

Answer 4

predicts membrane potential that results from contribution of all ions that can cross the membrane

Question 5

resting membrane potential in most neurons is….

Answer 5

~-70mV

Question 6

resting membrane potential mainly due to…

Answer 6

K+

• slightly from Na+
• minimally Cl-

Question 7

ion movement creates….

Answer 7

electrical signals

Question 8

what can alter membrane potential?

Answer 8

• change in K+ conc. gradient

- change in permeability to ions

Question 9

_______________ need to move to alter the membrane potential

Answer 9

very few ions

Question 10

_________ control ion permeability in neurons

Answer 10

gated channels

Question 11

5 major types of ion channels

Answer 11

• Na+
• K+
• Ca2+
• Cl-
• monovalent cation

Question 12

conductance

Answer 12

ease with which ions flow through a channel

Question 13

mechanically gated channels

Answer 13

open in response to physical forces; found in sensory neurons

Question 14

chemically gated ion channels

Answer 14

respond to ligands, including extracellular neurotransmitters and neuromodulators or intracellular signalling molecules

Question 15

voltage-gated channels

Answer 15

respond to changes in the cells membrane potential

Question 16

what are some variations in gated channels

Answer 16

• voltage for channel opening
• speed at which channel opens/close
• open to depolarization close during repolarization
• some spontaneously inactivate
• major channels have subtypes

Question 17

channelopathies

Answer 17

disrupt flow, alter channel activation/inactivation, cytic fibrosis

Question 18

current

Answer 18

flow of electrical charge carried by an ion

Question 19

ohm’slaw

Answer 19

current flow is directly proportional to electrical potential difference between two points and inversely proportional to the resistance

Question 20

two sources of resistance in a cell

Answer 20

• resistance of phospholipid bilayer

- internal cytoplasmic composition and size of cell

Question 21

Volatage changes across membrane can be classified in what two types of electrical signals?

Answer 21

• graded potentials

- action potentials

Question 22

graded potentials

Answer 22

variable strength signals that travel over short distances and lose strength as they travel and can be depolarizing or hyper polarizing

Question 23

large enough depolarization (excitatory) can induce an….

Answer 23

action potential

Question 24

action potential

Answer 24

very brief, large depolarizations that travel for long distances through a neuron without losing strength

Question 25

graded potentials are generated by…

Answer 25

chemically gated ion channels or closure of leak channels (CNS and efferent neurons)

Question 26

local current flow

Answer 26

wave of depolarization or hyperpolarization that moves through the cell

Question 27

graded potentials lose strength as they move due to….

Answer 27

current leak and cytoplasmic resistance

Question 28

Excitatory Postsynaptic Potential (EPSP)

Answer 28

depolarization

Question 29

Inhibitory Postsynaptic Potential (IPSP)

Answer 29

hyperpolarization

Question 30

subthreshold

Answer 30

graded potential below threshold at trigger zone so no AP

Question 31

suprathreshold

Answer 31

graded potential above threshold at trigger zone so AP