Blood Vessel Leakage

Question 1

How much plasma do we have at once?

Answer 1

3L

Question 2

How much plasma leaks out of endothelial cell pores a day?

Answer 2

8L

Question 3

What are the three main ways molecules can traverse the endothelial cell layer?

Answer 3

Lipid-soluble substances pass through the endothelial cell.
Small water-soluble substances pass through the pores between cells.
Exchange proteins are moved across by vesicular transport.

Question 4

Can plasma proteins pass through the endothelium?

Answer 4

In general, they cannot as they can’t fit through the pores between cells and cant pass through the membrane.

Question 5

Why is it harder for chemicals to pass through the blood-brain barrier?

Answer 5

The pores are tightly sealed.

Question 6

What contributes to the tendency to push molecules out of the capillaries through pores?

Answer 6

Hydrostatic pressure.

Question 7

What is the colloid osmotic pressure a result of?

Answer 7

Higher concentrations of plasma proteins inside the capillary than outside generates osmotic pressure..

Question 8

What is hydrostatic pressure a result of?

Answer 8

The flow of blood through the vessel.

Question 9

In what direction does colloid osmotic pressure push fluid?

Answer 9

Into the blood vessels (water moves to areas of higher osmolarity).

Question 10

What are the solute and fluid movements across a vessel wall determined by?

Answer 10

The balance of the two opposing forces of the colloid osmotic pressure and the hydrostatic pressure.

Question 11

In general, what has a stronger effect; COP or hydrostatic pressure?

Answer 11

Hydrostatic pressure, resulting in a net leakage.

Question 12

What is oedema?

Answer 12

The accumulation of fluids within tissues.

Question 13

What is oedema caused by?

Answer 13

Caused due to an imbalance in the normal cycle of fluid exchange in tissues causing fluid to accumulate in the interstitial spaces (and so neighbouring cells as the concentration of solutes is decreased outside of the cell).
This can only occur if the leakage of plasma exceeds the capacity of the lymphatic system to collect and return it to circulation.

Question 14

What collects interstitial fluid?

Answer 14

Lymphatic capillaries.

Question 15

What is the route fluid takes from the blood capillaries after entering the interstitial fluid? What is the main overall change in the environment?

Answer 15

1. Blood capillaries.
2. Interstitial fluid.
3. Lymph capillaries.
4. Lymph veins.
5. Lymph ducts in the subclavian region.
6. Large circulatory veins.
   This movement is achieved by the change in pressure, from high pressure in blood capillaries to low pressure in large circulatory veins.

Question 16

What are the three main causes of oedema?

Answer 16

Inflammatory Oedema.
Hydrostatic Oedema.
Compromised Lymphatic Function.

Question 17

What is inflammatory oedema?

Answer 17

Oedema resulting from inflammation. It is one of the cardinal signs of inflammation, swelling, and is the result of histamines.

Question 18

What is hydrostatic oedema? Who is most at risk?

Answer 18

Hydrostatic oedema is a result of high blood pressure, increasing hydrostatic pressure and so pushing fluid out of the blood vessels at a larger rate. People who are overweight are especially at risk of this, due to associated high blood pressure.

Question 19

What are some of the causes of compromised lymphatic function?

Answer 19

Some people with cancer may have had their axillary (armpit) lymph nodes removed, preventing drainage from the upper limb on the same side.

Some parasitic worms can block lymphatic vessels.

Question 20

What is the general destination for drained interstitial fluid?

Answer 20

Lymph fluid returns to the circulation either via the lymphatic ducts in the subclavian region or via lymph nodes.