Microcirculation

Front 1

Net filtration pressure:

Back 1

-determiens direction of fluid flow across wall of capillary
NFP = filtration P – absorption P
-if - absorption, + filtration

Front 2

Osmotic pressure: interstium

Back 2

colloidal, interstial oncotic press = osmotic force exerted by proteins in interstiaul fluid 0mmHg
-osmosis outward

Front 3

Osmotic pressure: in cap:

Back 3

-albumin, cap osmotic pres = cap oncotic press
-absorptive force
-osmosis inward, 28mHG

Front 4

Osmotic pressure: definition

Back 4

-pulling or attarcting
Exerted by plasma proteins (albumin) – bc fail to pass thru pores

Front 5

Hydrostatic pressure: in interstitum

Back 5

favors absorption, force fluid inward, surrounded by tight encasements
-true Pif loose subcutaneous tissue < atm p

Front 6

Hydrostatic pressure: in cap

Back 6

favors filtration, falls along cap from arterial to venous
-driving press ↓ along length, while others constance

Front 7

Hydrostatic pressure: definition

Back 7

Pushing or driving force, water source

Front 8

Starling’s hypothesis

Back 8

fluid filtration across cap wall is due to the balance b/w hydrostatic press gradient and oncotic pressure gradient

Front 9

Microcirculation

Back 9

-circulation of blood thru smallest vessls of body- arterioles, caps, venules
-arterioles -> caps regulate flow thru constriction/dilation caps
-metarterioles can bypass cap bed and connect to venules or directly connect to cap bed

Front 10

Composition of microcirculation

Back 10

-arterioles (6)- metarerioles
-caps
-venules (6)
-terminal lymphatic vessels

Front 11

Characteristics of microcirculation

Back 11

-shortest length <1mm
-smallest diamter: 0.008mm
-slowest velocity <1mm/sec

Front 12

Arterioles: muscular

Back 12

--small precap resistance vessels (10-50 n)
Regulate regional BF to cap beds, endothelium ,sympatheic adrenergic innervation, responsive to symp vasoconstriction alpha1/2

Front 13

Venules:

Back 13

-small exchange vessels 10-50 u
-sympathetic innervations

-fluid/macromolecular exchange at venular jnctions

Front 14

Terminal lymphatics

Back 14

-endothelium w/ intercellular gaps w/ highly perm. BM
-simliar to veunles, end as blind sacs
-vasomotion pressent to pump lyph
-sym nerves modulate
-fluid is w/out proteins, high in fat
-draws fluid w/ oncotic pressure, prevent accum protein, helps w/ edema

Front 15

Metarterioles:

Back 15

-contain precap sphincters
-tuft of sm ms at entrace cap
-albumin min distributed

Front 16

AV shunts

Back 16

-channels, connections b/w arterioles/venuls in some vascular beds
-10-15microns diamter, sm ms covering arterial end

Front 17

Vasomotion

Back 17

-response of vas sm ms to local metabolic products or autonomic neural influences

Front 18

Capillaries:

Back 18

-small exchange vessels (6-10u)
-permit rapid exchanges of gases, water, and solutes w/ interstial fluid

Front 19

Continous capillaries:

Back 19

-lowest perm,
-ms, skin. Lung, CNS, tight jntcs, BM continous

Front 20

Fenesterated caps

Back 20

-exocrine glands, renal glomeruli, intestinal muscosa,
-perforations = high perm

Front 21

Discontinuous caps:

Back 21

-liver, spleen, bone marrow,
-large intercell gaps
-gaps in basement mem extremely higher perm

Front 22

Transport materials across cap walls

Back 22

-1) diffusion: conc gradient
2) filtration : prssure gradi of fluid mech press, colloidal osmotic press
3) vesicular transcytosis: endyocytosis, exocytosis

Front 23

Rate of transport:

Back 23

-fxn of charc of membrane
0-relative to props of substance being transported

Front 24

Fluid exchange in arteriolar end

Back 24

-filtration, fluid out of cap

Front 25

Fluid exchange in venular end:

Back 25

-resorption, fluid transported back into cap

Front 26

Fluid exchange in lymphatics:
-

Back 26

-return 10% interstitilal fluid back into caps