neuronal signal

Question 1

what are 3 different kinds of potential?

Answer 1

1. resting
2. graded
3. action

Question 2

what are 3 different types of channels in the pore?

Answer 2

1. passive or leakage
2. chemical
3. voltage

Question 3

chemically gated cells

Answer 3

Example: Na+, K+ gated channel

Closed when a neurotransmitter is not bound to the extracellular receptor
Na cannot enter the cell, K cannot exit the cell

Open when the neurotransmitter is attached to the receptor
Na enters and K exits the cell

Question 4

voltage-gated cells

Answer 4

example: Na+ channels

Closed when the intracellular environment is negative
Na cannot enter the cell

Open when the intracellular environment is positive
Na can enter the cell

Question 5

resting membrane potential

Answer 5

The steady transmembrane potential of a cell that is not producing an electrical signal.

Question 6

changes in membrane potential

Answer 6

types of signals: graded & action

produced by: permeability and concentrations of ions

caused by 3 events: depolarization, hyperpolarization, repolarization

Question 7

graded potentials

Answer 7

• short-lived, local changes in membrane potential
• a decrease of intensity with distance
• strong graded potentials = action potentials
• voltage channels in graded potentials = decremental

Question 8

action potentials

Answer 8

• rapid depolarization of membrane potential
• once stimulation occurs AP takes action
• electrical (chemical signal) impulse = action potential
• ONLY generated by muscle cells and neurons

Question 9

what type of potential is the representation of cell communication?

Answer 9

action potential

Question 10

what is faster-myelinated sheaths or unmyelinated neurons? why?

Answer 10

myelinated sheaths: serve as an insulator, and changes the local membrane potentials can jump from gap to gap in the neuron

unmyelinated neurons: are slower because the action potential must travel the entire length of the axon

Question 11

In response to a stimulus, if the membrane potential becomes more negative than the resting potential, we say the membrane is ________.

Hyperpolarized
Depolarized
Unpolarized

Answer 11

hyperpolarized

Question 12

At resting potential, the ion distribution inside and outside of a neuron is such that ___ ions are most abundant on the outside of the cell, while ___ ions are most abundant on the inside of the cell.

Sodium; potassium
Potassium; sodium

Answer 12

sodium; potassium

Question 13

Graded potentials may become action potential by

Summation
Multiplication
Hyperpolarization
Decreasing frequency

Answer 13

summation

Question 14

Resting membrane potential is approximately

-65mV
-40mV
0mV
+40mV
+65mV

Answer 14

-65mV

Question 15

Threshold membrane potential is approximately

-65mV
-40mV
0mV
+40mV
+65mV

Answer 15

-40mV

Question 16

when do spatial summations occur?

Answer 16

when the currents from nearly simultaneous graded potentials combine