Module 9 ML- 5 Flashcards
What percent of the total circulating blood is in the capillaries
5%
What do all the other components of the system do?
serve the overall function of getting adequate blood flow to the capillaries
What is the capillary structure?
8 um diameter with thin wall and various pore sizes
What is a pore within a capillary
gaps between the endothelial cells
What does a single layer of endothlial cells do
maximize the exchange with RBCs
Where do capillaries sit
between arterioles and venules
Do capillaries have smooth muscle
no
Precapillary sphincter
more local of the local controls, blood passes through here before capillaries
Metarteriole
small amount of smooth muslce; the blood goes from the arteries from metarteriole into venule and never goes into the capillary bed
True or false;velcoity is inversely related to cross sectional areas
true
what passes through the endothelial cells
lipid soluble
What passes through the pores
small water soluble substances
What cannot cross the capillary wall
plasma proteins
How do proteins and large solutes move?
eno and exo
What provides the force of diffusion
concentration gradients
Filtration
movement of fluid out of the blood
Absorption
movement of fluid into the blood
What does bulk flow rely on
pressure gradients to distribite and balance fluid volume between the two compartments
What are the two compartments where fluid is moved between
plasma and isf
Capillary Hydrostatic Pressue (pc)
drives movement of blood through and pulses against the vessel walls
Pif
water accumulating in the ISF
Pi C
it is the osmotic force due to plasma protein concentrtation- draws water to them
Pi IF
demands water outside of plasma so it is the osmotic force due to interstitial fluid protein concentration
When NFP is positive then
net filtration
When NFP is negative then
net reabsorption
Pressure at the beginning of the capillaries
35
Pressure at the end of the capillaries
15
Are the forces every equally balanced
no, usually a small net filtration occurs when though the number is the same
All capillaries combinded lose about how much per day
4L/day into ISF
What abosrbs the extra filtrate and escaped proteisn
lympatic system
