Blood Circulation

what do blood cells do?

carry blood from heart to all tissues of the body and back to the heart

vessels are constructed to:

-dilate

-constrict

-or neither

T/F No exchange between the actual blood in the vessels UNTIL blood get to capillaries

True

Capillaries

made only of endothelia cells (one cell thick)

T/F All cells are in body are within 0.2mm of a cap

True

how many ways for movement of fluid through capillaries

3 ways

1 way capillaries movement

diffusion of lipid-soluble substances through plasma membranes

2 way of capillaries movement

diffusion of lipid-insoluble substances through endothelial pores

Bulk flow (3rd way)

pressure-driven filtration/reabsorption of fluid (water) and solutes (dissolve substances)

metarterioles

-short vessel that connects arteriole to venules

-way for blood to bypass capillary beds

what are the fluid dynamics in capillaries

-hydrostatic pressure

-colloid osmotic pressure

hydrostatic pressure

forces fluid OUT of caps and arterial end

colloid osmotic pressure

pulls fluid BACK INTO caps at venoud end

walls of capillaries

• continuos capillary

• fenestrated capillary

• sinusoidal capillary

25.4mm=

1in

excess fluid in the interstitial space

edema