Fluid Compartments

Question 1

What is the most plentiful cation in the plasma?

Answer 1

Sodium

Question 2

What is the most plentiful cation inside the cell?

Answer 2

Potassium (This is due to Na+/ K+ATPase pumps pumping 2 x K+into the cell for every 3 x Na+ which are pumped out the cell

Question 3

Is Cl- found in a higher concentration inside the cell or out?

Answer 3

Found in much higher concentration outside the cell

Question 4

What is the main intracellular anion?

Answer 4

Organic Phosphate

Question 5

What does phosphorylation of proteins do?

Answer 5

Key for the activation and inactivation of certain proteins

Question 6

What is the difference in the osmolarity between the blood and the intracellular compartment?

Answer 6

They are identical, so there is not much of an osmotic effect

Question 7

What is the concentrations of Na+ inside the cell and outside the cell?

Answer 7

Outside = 150mmol/L

Inside = 10mmol/L

Question 8

What is the concentrations of K+ inside the cell and outside the cell?

Answer 8

Inside = 150mmol/L

Outside = 5mmol/L

Question 9

What is the concentration of Cl- inside and outside the cell?

Answer 9

Inside = 5mmol/L

Outside = 110mmol/L

Question 10

What is the definition of diffusion?

Answer 10

D​iffusion is the spontaneous movement of a solute down a concentration gradient until the solute molecules reach an equilibrium

Question 11

Is the inside of the cell more acidic or more alkaline than the plasma?

Answer 11

Inside of the cell is more acidic- although the difference in pH is small, since the concentration of H+ ions determines pH and this follows a logarithmic scale, an small increase indicates a 2 fold increase in the concentration of H+ ions

Question 12

What is meant by osmolarity?

Answer 12

A measure of the concentration of all the solute particles in a solution

Question 13

What is an osmole?

Answer 13

The number of moles of solute which contribute to the osmotic pressure of a solution

Question 14

What is the osmolarity of a solution which has a 150 mmol Conc of NaCl, 1 mmol/L conc of CaCl2 and 2mmol/L conc of glucose?

Answer 14

150 x 2 ions in NaCL = 300
1 x 3 ions in CaCl2 = 3
2 x 1 compound in glucose = 2

Total = 305

Question 15

What is meant by tonicity?

Answer 15

The strength of a solution as it affects the final cell volumes - depends on both cell membrane permeability and solution composition

Question 16

What happens to cells when they are placed in hypertonic solutions?

Answer 16

The cell shrinks

Question 17

What is meant by a hypertonic solution?

Answer 17

A hypertonic solution is one where the solute osmolarity outside the cell is much greater than those of inside the cell. therefore, there is a low water concentration outside the cell, and hence water will move from outside the cell into the solution, resulting in a shrinkage of the cell

Question 18

What happens when a cell is placed inside a hypotonic solution?

Answer 18

The cell swells

Question 19

What is a hypotonic solution?

Answer 19

A solution in which the solute osmolarity is low in the solution. Therefore the concentration of water is higher outside the cell than inside, and so water moves from the outside solution into the cell , resulting in the swelling of the cell

Question 20

What is an isotonic solution?

Answer 20

Where the osmolarity of the impermeant solutes outside the cell is the same as those inside the cell

Question 21

What happens to the cell volume when placed in an isotonic solution?

Answer 21

Nothing - stays the same size

Question 22

Why do cells of the body not burst?

Answer 22

The cells don’t burst because the Na+K+-ATPase maintains the concentration of Na+ ions much lower inside the cell than outside.

The ATPase makes the membrane “effectively impermeable” to Na+ because any Na+ that diffuses in down the Na+ concentration gradient is actively pumped out again. Thus there is no net movement of Na+ across the membrane.

Question 23

What substances can diffuse across the lipid bilayer?

Answer 23

Gases like oxygen and carbon dioxide and other hydrophobic molecules like steroids

Question 24

Why are transplanted organs cooled when transported to their recipient?

Answer 24

When any tissue loses its blood supply, ischaemic changes occur, but these can be significantly slowed by rapid cooling of the tissue/organ to +4°C.

Question 25

How are the organs cooled to 4 degrees?

Answer 25

They are perfused with cold solutins via the arterial supply

Question 26

What important pump stops working in transplanted organs below 15 degrees?

Answer 26

Na+ / K+ ATPase

Question 27

What is the name of the solution which organs being transplanted are perfused with?

Answer 27

University of Wisconsin solution

Question 28

What is UoW solution intended to do?

Answer 28

reduce hypothermic cell swelling and enhance preservation.

Question 29

Three main factors serve to reduce cell swelling in UW-infused tissues:

Answer 29

Lack of Na+ or Cl- (therefore no influx possible).

Presence of extracellular impermeant solutes (lactobionate ions, raffinose).

Presence of a macromolecular colloid (starch)

Question 30

How much plasma leaks out of blood vessels a day?

Answer 30

8L

Question 31

What are ways in which molecules transverse the endothelial cell layer?

Answer 31

1. Lipid soluble substances-pass through epithelial cell
2. Water soluble substances = pass through tight H2O junctions
3. Plasma proteins generally cannot get across the epithelial cell membrane

Question 32

Where is there a higher concentration of plasma proteins?

Answer 32

Inside the plasma is much higher than that of outside the capillary

Question 33

What is the colloid osmotic pressure?

Answer 33

The pulling force of the higher concentration of plasma proteins intside the vessel compared to outside

Question 34

What is the hydrostatic pressure of the blood?

Answer 34

The pushing force which is generated through the flow of blood through the vessel, pushes molecules through the capillary pores

Question 35

What is the balance between oncotic and hydrostatic pressure in a normal situation?

Answer 35

Net leakage due to the hydrostatic pressure being slightly greater than the colloid osmotic pressure

Question 36

What is an oedema?

Answer 36

An accumulation of fluids within tissues

Question 37

What causes an oedema?

Answer 37

An imbalance between the hydrostatic pressure being a lot greater than the oncotic pressure due to increased pore size, so when blood forces molecules out the capillary pores, many more molecules can pass

Question 38

What are the effects of a leaky capillary?

Answer 38

Proteins are lost into the interstitial space due to increased pore size, this reduces the oncotic colloid pressure which means fluids are more rapidly pushed out from the capillary

Question 39

What is the system which combats the issue of capillaries leaking fluid?

Answer 39

Lymphatic system collects interstitial fluid that is destined to return to the blood

Question 40

What features of lymphatic capillaries results in the net flow of fluids from tissues into the lymphatic capillaries?

Answer 40

L​ymphatic capillaries are blind ended and have a low internal pressure which results into the net flow of fluids from tissues into the lymphatic capillaries.

Question 41

What does oedema indicate?

Answer 41

Inflammation

Question 42

Why do overweight individuals often have swelling?

Answer 42

Individual is likely to have high blood pressure which means increased hydrostatic pressure in vessels - this pushes fluid out of the vessels and can lead to an accumulation of interstitial fluid

Question 43

Why might a breast cancer survivor have swelling of the upper limb on the side of her breast tumour?

Answer 43

Breast cancer patients are likely to have their axillary nodes removed in order to limit the extent of spreading, which can removes the pathway of drainage from the upper limb on the affected side, resulting in the accumulation of fluid

Question 44

What is the primary cause of elephantitis?

Answer 44

When parasitic worms block lymphatic vessels which prevents the drainage of lymph

Question 45

When does oedema occur?

Answer 45

When the leakage of plasma into the interstitium exceeds the capacity of the lymphatics to collect and return it to the circulation - oedema will result as the fluid accumulates in the interstitial space