Fluid compartments

Question 1

What are the main fluid compartments and their size?

Answer 1

Intracellular = 55%
Extracellular = 45%
>Interstitial Fluid = 36%
>Blood plasma = 7%
>Transcellular fluid = 2%

Question 2

Define osmolarity

Answer 2

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

Question 3

Define diffusion

Answer 3

The spontaneous movement of solutes from a high to low concentration to form a diffusion equilibrium

Question 4

Define permeability

Answer 4

How easily a solute crosses a membrane

Question 5

Define tonicity

Answer 5

The strength of a solution as it affects final cell volume

Question 6

What are the effects of hypertonic, hypotonic and isotonic solutions on cells?

Answer 6

Hypertonic = shrink
Hypotonic = Swell
Isotonic = No change

Question 7

Provide 3 examples of barriers

Answer 7

• Plasma membrane = separates intra and extracellular fluids
• Epithelial cells = separate interstitial spaces
• Endothelial cells = blood plasma and interstitial fluids

Question 8

State the compartments of extracellular fluid

Answer 8

• Fluid in the apical/luminal extracellular space
• Epithelium
• Basal lamina
• Fluids in the basal extracellular space (the interstitial fluids)
• Fluids of the blood (plasma)
• Interstitial matrix

Question 9

What are the main ionic compositions of each compartment?

Answer 9

EC: (e.g. plasma)
Na+
Cl-

IC: (e.g. in muscle)
K+
Free organic phosphates

• Proteins are low but high in charge
• Low Ca2+ in IC allows for a large change in concentration (an important signalling molecule)

Question 10

What is the pH in and outside of a cell?

Answer 10

IN = 7.1
OUT = 7.4

Question 11

What is the affect of osmosis?

Answer 11

Change cell volume, moves water to the area of higher osmolarity

Question 12

What is tonicity dependant on?

Answer 12

Cell membrane permeability AND solution composition

Question 13

Examples of transport

Answer 13

PASSIVE:
Simple diffusion
Channel mediated
Transporter mediated
(Down an electrochemical gradient)
ACTIVE:
Requires energy
(Against an electrochemical gradient)

Question 14

Outline endo and exocytosis and examples

Answer 14

Encapsulation in membrane as solute enter or before they leave the cell

Endo = nerve growth factors (proteins) entering
Exo = peptide hormones from endocrine glands

*Transcytosis = taken up from outside of the cell and shuttled across

Question 15

What is an oedema?

Answer 15

Swelling of a tissue due to excess interstitial fluid

Question 16

What causes an oedema?

Answer 16

Imbalance in the cycle of fluid exchange in tissues = accumulation of fluid in interstitial spaces
Fluid is lost from blood, into the interstitium and drained by lymphatic vessels
-A sign of inflammatory stimuli and infections

Question 17

What is the function of the lymphatic capillaries?

Answer 17

Collect interstitial fluid that will be returned to the blood circulation

LYMPHOKINETIC MOTION AND PRESSURE GRADIENT
Blood capillaries = Interstitial fluid = Lymph capillaries = lymph veins = Lymph ducts = large circ veins (From high to ow pressure)

Question 18

Inflammatory oedema

Answer 18

Insect Bite
-inflammation causes local blood vessels to become more permeable
-Swelling occurs
>Rate of leakage is greater than the drainage of the lymphatics

Question 19

Hydrostatic oedema

Answer 19

High blood pressure = high hydrostatic pressure

-push fluid out of vessels

Question 20

Oedema in elephantiasis and breast cancer

Answer 20

Elephantiasis = parasitic worms blocking lymph vessels, prevent drainage
Breast cancer = Axillary (armpit) lymph node removed during treatment. Removed pathway of drainage

Question 21

What feature does osmolarity not consider?

Answer 21

Membrane permeability to ions

Question 22

What forces affect the movement of fluid between the capillary and the interstitial space?

Answer 22

Colloid osmotic pressure

Hydrostatic pressure