Physiology vocab 2: Cell Physiology of Ions 1

Question 1

Cell Physiology

Answer 1

The study of the activities that take place inside a cell to keep it alive

Question 2

Diffusion

Answer 2

The process of molecules moving down a concentration gradient passively

Question 3

Voltage

Answer 3

The difference in electric potential energy between two points in an electric field

Question 4

Transmembrane electric potential

Answer 4

Difference in electric potential between either side of the membrane

Question 5

Chemical gradient of ions

Answer 5

Concentration gradient

Question 6

Fluid compartments

Answer 6

Separate areas where fluid is found in the body

Question 7

Extracellular fluid (intercellular fluid)

Answer 7

Consists of interstitial fluid and plasma. Low in proteins (anions). Contains most of the fluid in the body that is outside cells

Question 8

Intracellular Fluid

Answer 8

All fluid in body inside cells. High in K+ and proteins (anions). Separated from extracellular fluid by cell membrane

Question 9

Transcellular fluid, with example

Answer 9

A specialised type of extracellular fluid with its own separate compartments e.g urine in bladder

Question 10

Plasma

Answer 10

Non-cellular part of blood. High in Na+. Exchanges substances constantly with interstitial fluid through pores of capillary membrane, has a higher protein content than interstitial and similar ion content.

Question 11

Interstitial fluid

Answer 11

Similar to blood plasma but lower protein (anion) content

Question 12

Sequestered

Answer 12

Behind a membrane (inside an organelle)

Question 13

Chelated

Answer 13

Ions specifically bound to e.g. a protein, so high affinity

Question 14

Buffered

Answer 14

Ions non-specifically bound to things so low affinity, so dissociates easily

Question 15

Electric current

Answer 15

Caused by movement of ions

Question 16

Conductance (g)

Answer 16

The tendency to conduct current, given a particular voltage. Reciprocal of resistance

Question 17

Electrical force (on an ion across a membrane)

Answer 17

Based on a few unpaired positive/ negative charges on one side of membrane leading to slightly more negative/positive charge on one side of the membrane, thus leading to a force on ions. Essentially, based on Vm, which varies over time.

Question 18

Chemical force/diffusional force

Answer 18

Based on difference in concentration of ions

Question 19

Membrane Potential, Vm

Answer 19

Electric potential difference between either side of a membrane, based on imbalance between positive and negative charge across membrane

Question 20

Resting Membrane Potential, Vrest

Answer 20

A set point for when there is no activity

Question 21

Equilibrium Potential

Answer 21

When electrical and chemical forces are equal and opposite and so net force on ion is 0.

Question 22

Amount and function of Na+ in cell

Answer 22

Less Na+ inside than outside cell, homeostasis, pH balance and osmotic balance

Question 23

Amount and function of K+ in cell

Answer 23

More K+ inside than outside cell. Osmotic balance and electrolyte balance

Question 24

Amount and function of Ca2+ in cell?

Answer 24

More Ca2+ outside than inside cell. Acts as a second messenger for signals that arrive at cell

Question 25

Amount and function of Mg2+ in cell?

Answer 25

More Mg2+ inside than outside cell. Closes calcium channels (which lead to neurons), meaning less nerve cell activity so Mg2+ affects muscle relaxation through action on cell membrane.

Question 26

Amount and function of H+ in cell?

Answer 26

More H+ inside than outside cell. Much less free H+ than K+ inside cell. Acid-base homeostasis.