chapter 11 - nervous system; part 3

Question 1

electrical properties of cells results from what?

Answer 1

results from the iconic concentration differences across the plasma membrane and from the permeability characteristics of the plasma membrane

Question 2

sodium-potassium pump

Answer 2

moves ions by active transport; potassium ions are moved into the cell, and sodium is moved out of it

Question 3

which ions are higher inside of the cell?

Answer 3

potassium and negatively charged proteins and other molecules are higher inside the cell

Question 4

which ions are higher outside of the cell?

Answer 4

sodium and chloride are higher outside of the cell

Question 5

what are the permeability of the plasma membrane to ions determined by?

Answer 5

it is determined by leak ions channels and gated ion channels

Question 6

what type of leak channel is the plasma membrane more permeable to?

Answer 6

potassium; potassium ion leak channels are more numerous than sodium ion leak channels when at rest

Question 7

what are some gated ion channels of the plasma membrane?

Answer 7

ligand-gated channels, voltage-gated ion channels, and other gated ion channels

Question 8

what is a resting membrane potential?

Answer 8

a charge difference across the plasma membrane when the cell is in an unstimulated condition; the inside of the cell is negatively charged compared to the outside of the cell

Question 9

what causes a resting membrane potential?

Answer 9

due mainly to the tendency of positively charged potassium to diffuse out of the cell, which is opposed by the negative charge that develops inside the plasma membrane

Question 10

depolarization

Answer 10

a decrease in the resting membrane potential, can result from a decrease in the k+ concentration gradient, a decrease in membrane permeability to k+, an increase in membrane permeability to Na+, an increase in membrane permeability to Ca 2+, or a decrease in extracellular Ca2+

Question 11

hyperpolarization

Answer 11

an increase in the resting membrane potential, can result from an increase in the k+ concentration gradient, an increase in membrane permeability to k+, cl-, a decrease in membrane permeability to NA+, or an increase in extracellular Ca2+

Question 12

hypokalemia

Answer 12

lower than normal concentration of potassium ions in the blood or extracellular fluid; causes hyperpolarization of the resting membrane potential; causes potassium depletion during starvation, alkalosis, and certain kidney diseases

Question 13

hypocalcemia

Answer 13

lower than normal concentration of calcium ions in the blood or extracellular fluid; causes nervousness and uncontrolled contraction of skeletal muscles, called tetany; causes lack of dietary calcium or vitamin D and low parathyroid gland hormone