Week 3- Fluid Compartments and Solutes

Question 1

What are the main cations found in the body and are they extracellular or intracellular?

Answer 1

Na+ is extracellular

K+ is intracellular

Question 2

What are the main anions found in the body and are they extracellular or intracellular?

Answer 2

Cl- is extracellular

Inorganic phosphate is intracellular

Question 3

How the pH inside vs outside cells different?

Answer 3

Inside is slightly more acidic

Question 4

How is the osmolarity in cells vs plasma different?

Answer 4

It’s identical apart from in the kidneys

Question 5

Define diffusion

Answer 5

The spontaneous movement of solute molecules down their concentration gradient until they reach equilibrium

Question 6

Define osmosis

Answer 6

The movement of water molecules down their conc gradient (across a selectively permeable membrane)

Question 7

Define osmolarity

Answer 7

The concentration of solute in a solution

Question 8

What are the limits of using osmolarity as an indicator to cell volume?

Answer 8

It is a bad indicator of cell volume as it doesn’t take into account cell permeability

Question 9

What is tonicity?

Answer 9

A measure of cell volume that takes into account cell membrane permeability and solution composition

Question 10

What is a hypertonic solution?

Answer 10

Osmolarity of solutes outside>inside so CELL SHRINKS

Question 11

What is a hypotonic solution?

Answer 11

Osmolarity of solutes outside

Question 12

What is an isotonic solution?

Answer 12

Osmolarity of solution outside=inside so cell stays the same

Question 13

Why do transplant tissues need to be preserved?

Answer 13

Cells would die even after cooling due to disruption of ionic balance. This is because Na+/K+ ATPase doesn’t work under 15 degrees. This would mean Na+ flows in freely, causing water to flow in and causing cells to burst

Question 14

How are transplant tissues transported?

Answer 14

By placing them in UW solution which has the properties:
No Cl- or Na+ ions present to prevent movement
Starch present
Extracellular impermeant solutes present

Question 15

What are the 2 pressures that determine the flow of fluid in/out of blood vessels?

Answer 15

Colloid osmotic pressure and hydrostatic pressure

Question 16

What is colloid osmotic pressure?

Answer 16

Concentration of plasma proteins is higher than outside, reducing water potential in the vessel and causing water to move into the vessel

Question 17

What is hydrostatic pressure?

Answer 17

Pressure of blood flowing through the vessel which pushes fluid out

Question 18

Which pressure out of colloid and hydrostatic usually dominates? What does this cause to happen?

Answer 18

Hydrostatic, so plasma leaks out of vessels

Question 19

What are some routes by which substances exit blood vessels?

Answer 19

Lipid soluble go through membrane
Water soluble go through gaps
Proteins exit via vesicles
Plasma proteins can’t exit

Question 20

How does oedema arise?

Answer 20

When lymphatic aren’t able to drain lymph at the rate it is draining out

Question 21

What are the 2 types of oedema and how do they differ?

Answer 21

Inflammatory (due to leaky vessels)

Hydrostatic (hydrostatic pressure is too high eg high BP)

Question 22

What is elephantiasis?

Answer 22

When parasitic worms block the lymphatics causing oedema