Phils 10

any change in the concentration of sodium or potassium on either side of the membrane with ___ ___ __ and change the ___ ___

alter the gradients membrane potential

because of this ____ ___, the cytoplasm within the cell has a ___ concentration of potassium while the interstitial fluid outside the cell has a higher concentration of ____

asymmetric distribution higher sodium

___ concentration of the potassium in the Ringer's solution to ___ mEq K+/L caused a membrane potential around ___ mV

increasing 20 -50

the position of this blue line will be used to indicate whether the microelectrode tip is ___ or ___ of a muscle fiber

inside outside

Na+/K+ ATPase pumps transport potassium ions ____ the cell thus maintaining the ___ K+ concentration within the ____

into higher cytoplasm

this glass microelectrode is connected to the input of the ____ by a ___ ___

electrometer orange cable

at ____, the electrical and chemical gradients would be equal and opposite, so no net ___ movement would occur across the membrane

equilibrium K+

the ___ level of potassium in crayfish Ringer's solution is ___ mEq K+/L and the membrane potential of a muscle bathed in this solution was recorded at around ____ mV

extracellular -65

this simulation examines the effect of changing ____ ___ levels on the membrane potential (RMP) of ___ cells in crayfish

extracellular potassium muscle

after completion of this simulation you will be able to observe the relationship between ____ potassium concentration and ____ ____

extracellular; membrane potential

The microelectrode was stuck in several different regions of the muscle during the experimental procedure to: gather data from different muscle fibers within the same muscle of a crayfish. gather data from different types of muscles in the crayfish. gather data from the same muscle fiber within a crayfish muscle.

gather data from different muscle fibers within the same muscle of a crayfish.

you will be sticking muscle fibers with a ___ ___

glass microelectrode

Sodium and potassium ions are asymmetrically distributed across the membrane so that, when compared with the interstitial fluid, the cytoplasm: has a lower concentration of sodium and a lower concentration of potassium. has a higher concentration of sodium and a lower concentration of potassium. has a lower concentration of sodium and a higher concentration of potassium. has a higher concentration of sodium and a higher concentration of potassium.

has a lower concentration of sodium and a higher concentration of potassium.

The concentration of potassium is much ___ in the cytoplasm of a cell than it is in the interstitial fluid ___ the cell

higher outside

___ ions are also pulled into the cell by the ___ charged proteins, but the membrane permeability for ___ is much lower than it is for ____

sodium negatively sodium potasium

what are the most notable cations that negatively charged proteins attract

sodium and potassium

Both the electrical and chemical gradients cause the ___ of ___ into the cell

movement sodium

when Na+/K+ ATPase pumps transport ___ potassium ions into the cell, they also pump ___ sodium ions out of the cell

two three

The chemical gradient creates two opposing forces action on potassium ions: a(n) ___ gradient pulling K+ into the cell and a(n) ____ gradient pushing K+ out.

electrical chemical

Which of the following solutions has the greatest concentration of potassium? 5 mEq K+/L. 10 mEq K+/L. 100 mEq K+/L. 50 mEq K+/L.

100 mEq K+/L.

Which of the following solutions has the lowest concentration of potassium? 100 mEq K+/L. 10 mEq K+/L. 50 mEq K+/L. 5 mEq K+/L

5 mEq K+/L

What was the average membrane potential when the muscle fibers were bathed in a solution with a potassium concentration of 10 mEq K+/L? About -80 mV. About 80 mV. About -50 mV. About -55 mV.

About -55 mV.

Look at your data. What was the average membrane potential when the muscle fibers were bathed in a solution with a potassium concentration of 5 mEq K+/L? About +65 mV. About -65 mV. About -55 mV. About -75 mV.

About -65 mV.

If the action potential threshold of a muscle fiber is -50 mV, which [K+] could ultimately produced an action potential within the muscle fibers of a crayfish? About 5 mEq K+/L. About 20 mEq K+/L. About 10 mEq K+/L. About 50 mEq K+/L.

About 20 mEq K+/L.

the screen of the lab monitor shows a sing channel ____ ____ ____

CH.1: Membrane potential

Insert the blue plug into recording ___ ___ on the __ ___ ___

Input 1 data acquisition unit

the movement of ___ out of the cell is counterbalnced by ___ ___ ___

K+ Na+/K+ ATPase pumps

___ ___ ____ help to maintain RMP potential

Na+/K+ ATPase pumps

Which of the following solutions acted as a control for this experiment? 5 mEq K+/L. 20 mEq K+/L. 100 mEq K+/L. Normal saline.

Normal saline.

this difference in charge, called a ___ ___ ___ can be attributed to a difference in the distribution of sodium and potassium ions across the membrane as well as ___ ___ ___ within the cell.

Resting membrane potential negatively charged proteins

Consider the forces pushing potassium across the membrane of a resting cell. The electrical gradient and the chemical gradient both draw potassium into the cell. The electrical gradient draws potassium into the cell while the chemical gradient pushes it out. The chemical gradient draws potassium into the cell while the electrical gradient pushes it out. The electrical gradient and the chemical gradient both push potassium out of the cell.

The electrical gradient draws potassium into the cell while the chemical gradient pushes it out.

What was the relationship between the membrane potential and the concentration of potassium outside the cell? The membrane potential did not change when the extracellular concentration of potassium was increased. The membrane potential became less negative (depolarized) when the extracellular concentration of potassium was increased. The membrane potential hyperpolarized (became more negative) when the extracellular concentration of potassium was increased.

The membrane potential became less negative (depolarized) when the extracellular concentration of potassium was increased.

What does the line on the computer screen represent? The concentration of the saline solution containing NaCl. The potential difference between two probes. The concentration of the saline solution containing KCl. The concentration of the saline solution.

The potential difference between two probes.

a blue plug is connected tot he other end of this ___ cable

blue

potassium ions being pulled into the cell down their electrical gradient creates a ___ ___ where there is more K+ within the ____ of the cell that the _____ fluid

chemical gradient cytoplasm interstitial fluid

these negatively charged proteins attract ____ into the cell from the interstitial fluid surrounding the cell

cations (positively charged ions)

during this experiment you will measure the ___ ___ from fibers in a muscle bathed in a series of ___ solutions containing different levels of ___

membrane potential saline potassium

After completion of this simulation you will be able to use instruments to record and measure ___ ___ from muscle fibers

membrane potentials

Cells have a charge across their membrane with the inner layer of the plasma membrane having a _________________ charge. positive neutral negative

negative

cells have a ___ charge along the inner layer of their plasma membrane and a ____ charge along the outer layer

negative; positive

cells contain a high concentration of _____ charged proteins within their cytoplasm.

negatively

In a resting nerve cell, potassium ions diffuse through membrane channels: into the cell, that is down their chemical gradient. out of the cell, that is down their chemical gradient. equally in both directions; there is no net movement because there is no chemical gradient. equally in both directions; there is no net movement because potassium ions are at equilibrium.

out of the cell, that is down their chemical gradient.

a blue cable is connected to the ____ of the electrometer

output

____ ions are pulled into the cell, down their electrical gradient

potassium

after completion of this simulation you will be able to recognize that increasing the level of ____ in the Ringer's solution bathing the muscle depolarizes the muscle

potassium

In living cells however, the ____ ions are not in equilibrium; there. is a ____ flux of ____ ions out of the cell, ____ their chemical gradient, due to leaky ____ channels that stay ___ continuously

potassium constant potassium down K+ open

Measuring the membrane potential will be done by comparing the ____ between a probe in the ___ and a probe inserted inside a ___ ___

potentials solution muscle cell

any sodium ions that enter the cell are quickly ____, creating a ___ sodium concentration within the ___ ___ outside the cell

removed higher interstitial fluid

What do you think would happen to a muscle that is bathed in a solution with 5 mEq K+/L if the solution suddenly changed to having 20 mEq K+/L? the muscle would contract. the muscle would exhibit no response. the muscle would relax.

the muscle would contract.

The Na+/K+ATPase pump pushes: three potassium ions out of the cell in exchange for two sodium in. three sodium ions into the cell in exchange for two potassium out. three potassium ions into the cell in exchange for two sodium out. three sodium ions out of the cell in exchange for two potassium in.

three sodium ions out of the cell in exchange for two potassium in.

if the ___ for action potential production is -50mV, then changing the extracellular potassium level around a muscle fiber from 5 to 20. mEq K+/L will cause ___ of the membrane and will induce a ___ muscle contraction

threshold depolarization spontaneous

The blue line on the screen of the lab monitor will go up (as the ___ hits the cell) and then down (when the muscle fiber is ____)

tip penetrated