Fluids and osmosis

Question 1

What are the fluid compartments within the body?

Answer 1

Intracellular fluid, Interstitial fluid, Extracellular fluid

Question 2

What is extracellular fluid composed of?

Answer 2

Plasma, Interstitial fluid and Transcellular fluid

Question 3

What is the composition of the body compartments?

Answer 3

Water freely moves between all compartments. Protein is kept within the intracellular and extracellular compartment. Potassium is kept within the intracellular compartment and Sodium is exchanged between the interstitial fluid and extracellular fluid.

Question 4

Define osmolarity?

Answer 4

Osmolarity is the concentration of a solution expressed as the total number of solute particles per litre

Question 5

Is the osmolarity for all the body compartments the same?

Answer 5

Yes

Question 6

What units do we use for osmolarity?

Answer 6

Osmole per litre. mOsm/L

Question 7

Define osmolality?

Answer 7

Concentration of a solution expressed as the total number of solute particle per kilogram

Question 8

What is body fluid osmolality maintained between?

Answer 8

280-295 mOsmol/kg

Question 9

How does the body monitor water change within it ?

Answer 9

By looking at changes in ECF osmolality.

Question 10

Describe what happens to cell volume when there is a high presence of inorganic anions within the cell

Answer 10

High inorganic anion presence causes more water to be retained by the cell, lowering water concentration. This leads to increase in water movement within the cell eventually leading to cell lysis.

Question 11

How can cell lysis be prevented ?

Answer 11

It can be prevented by ion movement and solute expulsion.

Question 12

When using osmolarity to compare two solutions, what the terms can be used?

Answer 12

Isosmotic, hyperosmotic and hyposmotic

Question 13

Define Isosmotic?

Answer 13

Solutions containing equal [solute] regardless of permeable or non-permeable solutes

Question 14

Define hyperosmotic?

Answer 14

Solution osmolarity ([Solute]) of one solution is greater compared to another solution.

Question 15

Define Hyposmotic?

Answer 15

Solution osmolarity ([solute]) of one solution is lower compared to another solution.

Question 16

Define tonicity?

Answer 16

The ability of an extracellular solution to make water move into or out of a cell by osmosis

Question 17

What is tonicity related to?

Answer 17

Tonicity is related to osmolarity.

Question 18

What are the three terms used to describe tonicity??

Answer 18

Hypertonic. Isotonic and Hypotonic

Question 19

When can I use the term hypertonic?

Answer 19

When the extracellular fluid has a high osmolarity than the cell. SO water moves out of the cell into the fluid.

Question 20

When can I use the term Isotonic?

Answer 20

When the extracellular fluid has the same osmolarity as the cell, so there is no net movement of water.

Question 21

When can I use the term hypotonic?

Answer 21

When the extracellular fluid has a lower osmolarity to the cytoplasm of the cell. So water moves into the cell.

Question 22

What happens to a cells volume when the cell is places in a hypertonic solution

Answer 22

The cell will lose water to the solution and will shrink in volume.

Question 23

What happens to a cells volume when placed in a isotonic solution?

Answer 23

Volume remains the same as there is no net movement of water.

Question 24

What happens to a cells volumes when placed in a hypotonic solution?

Answer 24

The cells volume will increase, so it swells because net H2O movement is into the cell.

Question 25

How is osmotic balance achieved?

Answer 25

Osmotic balance can be achieved by the extrusion of Na+ this prevents the cell from bursting and uses an active Na+/K+ ATPase pump, giving rise to a voltage difference.