Fluid Shift across the capillary wall and systemic oedema Flashcards
what acts as the go between the blood and body cells?
interstitial fluid
how many layers of endothelial cells are there in capillaries?
1
f’s: capillaries
allow rapid exchange of gases, water and solutes with interstitial fluid
delivery of O2 and nutrients to the cells
removal of metabolites from cells
What is BF in capillaries dependent of?
the contractile state of the arterioles
f: terminal arterioles?
regulate regional BF to the capillary bed CB in most tissues
f: precapillary sphincters
regulate flow in a few tissues eg mesentery
why is the BF in CB v slow?
to allow time for exchange
what is formed when capillaries unite?
venules
How are exchangeable proteins moved across the capillary wall?
via vesicular transport
How do lipid soluble substances pass across the capillary wall?
via endothelial cells
How do plasma proteins move across the capillary wall?
they don’t
How do small water soluble substances pass across the capillary wall?
across pores
What does fluid movement follow?
pressure gradient
What does the movement of gases and solutes follow?
Fick’s Law of diffusion
What is transcapillary fluid flow passively driven by?
pressure gradients across the capillary wall
d: ultra-filtration
filtration using a medium fine enough to retain colloidal particles, viruses, or large molecules
What is net filtration pressure (NFP) directly proportional to? What is the coeffient?
forces favouring filtration-forces opposing filtration Filtration coefficient (Kf)
Name the forces favouring filtration?
capillary hydrostatic pressure
interstitial fluid osmotic pressure
Name the forces opposing filtration?
capillary osmotic pressure
interstitial fluid hydrostatic pressure
What is the equation for NFP?
(PC + pi i)-(pi C + Pi)
What can be concluded from NFP quation?
starling forces favour filtration at arteriolar end, reabsorption at end of venular end
What is the general name given for the forces involved in transcapillary flow?
starling forces
Name the major forces favouring filtration in systemic transcapillary flow?
Pc capillary hydrostatic pressure
Name the major forces opposing filtration in systemic transcapillary flow?
Pi C capillary osmotic pressure