Post on 05-Apr-2018
8/2/2019 Interstitial Fluid - Copy
1/40
4/2/12
The
Interstitial fluid
8/2/2019 Interstitial Fluid - Copy
2/40
4/2/12
Tissue cell
=12 L
8/2/2019 Interstitial Fluid - Copy
3/40
4/2/12
Exchange of nutrients and
substances through thecapillary wall
Bulk flowDiffusion
8/2/2019 Interstitial Fluid - Copy
4/40
The kinetic movement of molecules from an area
of high concentration to an area of lowconcentration.
Diffusion
The main mechainism
8/2/2019 Interstitial Fluid - Copy
5/40
8/2/2019 Interstitial Fluid - Copy
6/40
4/2/12
Rate of
diffusion
Molecular size
Solubility
Temperature
Surface area
8/2/2019 Interstitial Fluid - Copy
7/404/2/12
Pathways of diffusion
Water&
watersoluble
proteins lipid
Soluble,O2,CO2
Slit poresFenestae
Pinocytosis
(Vesicular
Transcellular
transport
8/2/2019 Interstitial Fluid - Copy
8/404/2/12
Slit pores
fenestrae
Transcellulartransport
8/2/2019 Interstitial Fluid - Copy
9/40
Bulk flow
= increased diffusion
It is the process by which substances areforced through a membrane because ofdifference in pressure on both sides of themembrane
8/2/2019 Interstitial Fluid - Copy
10/40
4/2/12
Bulk flow=increased diffusion
FILTRATION REABSORPTION
8/2/2019 Interstitial Fluid - Copy
11/40
4/2/12
Filtration
It is an increased diffusionof water and solutesthrough a membrane
towards the opposite side ofhigh hydrostatic pressure.
It is bulk flow of water and
solutes from the plasmainto the interstitial fluidthrough the capillary wall.
8/2/2019 Interstitial Fluid - Copy
12/40
4/2/12
Reabsorption
It is an increased diffusionof water and solutesthrough a membranetowards the same side of
high osmotic pressure.
It is bulk flow of water and
solutes from theinterstitial fluid into theplasma through thecapillary wall
8/2/2019 Interstitial Fluid - Copy
13/40
4/2/12
Fluid Movement depends on
Starling Factors:
1-capillary Pressure
2-Interstitial Fluid Pressure3-Plasma Colloid Osmotic Pressure4-Interstitial Fluid Colloid Osmotic
Pressure
8/2/2019 Interstitial Fluid - Copy
14/40
4/2/12
8/2/2019 Interstitial Fluid - Copy
15/40
4/2/12
At the arterialend.
At thesummit(loop)
At the venous
1-Capillary pressure
8/2/2019 Interstitial Fluid - Copy
16/40
Factors affecting the capillary pressure
1)Capillary
level:Below the heartor
Above the heart
8/2/2019 Interstitial Fluid - Copy
17/40
4/2/12
Factors affecting the capillary pressure
2)Venouspressure:
8/2/2019 Interstitial Fluid - Copy
18/40
4/2/12
2)Venous
pressure:Venous obstruction by a tumor outside or athrombus inside.increased venous pressure by right heart
failure
the enlarged uterus in the last three monthsof pregnancy.Nephrosis.
Factors affecting the capillary pressure
8/2/2019 Interstitial Fluid - Copy
19/40
4/2/12
3) Condition of arterioles:
1- Dilation
2-Constriction
Factors affecting the capillary pressure
8/2/2019 Interstitial Fluid - Copy
20/40
Factors affecting the capillary pressure
4)Arterial blood pressure: Arterial blood pressure tends to Thecapillary pressure
However, acute control of local blood flow bringscapillary pressure back to normal.
8/2/2019 Interstitial Fluid - Copy
21/40
4/2/12
Factors affecting the capillary pressure
Increased arterialpressure
Increased capillarypressure
8/2/2019 Interstitial Fluid - Copy
22/40
4/2/12
5) Visceral characteristics:
In the viscera, the capillary pressure differs
according to the nature of the local mechanism.For example,
The renal glomeruli :60 mmHg.
Factors affecting the capillary pressure
8/2/2019 Interstitial Fluid - Copy
23/40
4/2/12
5) Visceral characteristics:
The intestinal capillaries:10-20 mmHg
Factors affecting the capillary pressure
8/2/2019 Interstitial Fluid - Copy
24/40
4/2/12
5) Visceral characteristics:
The liver : 6 mmHg
Factors affecting the capillary pressure
8/2/2019 Interstitial Fluid - Copy
25/40
4/2/12
5) Visceral characteristics:
The lungs : 8-10 mmHg.
Factors affecting the capillary pressure
8/2/2019 Interstitial Fluid - Copy
26/40
4/2/12
Either slightly positive (+1 or
+2 mmHg) i.e. moves thefluid inwardor
slightly negative (-6 or -8mmHg)i.e. moves the fluid outward.
2-Interstitial fluid
pressure
8/2/2019 Interstitial Fluid - Copy
27/40
4/2/12
Normal value:28 mmHg
Causes of plasmaosmotic pressure
a-75% from the albumin
b-25% from the globulinsc-very small percentagefrom the fibrinogen
3-Plasma colloid
osmotic pressure
8/2/2019 Interstitial Fluid - Copy
28/40
Why the concentration ofproteins in the plasma averages
over three times as much asthat in the interstitial fluid?
(7.5 g/ 100 ml the plasma versus
2 g/ 100 ml in the interstitialfluid).
8/2/2019 Interstitial Fluid - Copy
29/40
4/2/12
4-Interstitial fluid
colloid osmoticpressure
Average is 5 mmHgDepends on interstitialprotein concentration
which varies in differentorgans
6gm/100ml
1.4gm/dl
4gm/100ml
8/2/2019 Interstitial Fluid - Copy
30/40
Dynamics of fluid exchange(tissue fluid formation)
Total inward
force=28+1=29
Total outward force=30+5=40
Net outward force=40-29=11
Total inwardforce=28+1=29
Total outwardforce=15+5=20
Net inward force=29-20=9
8/2/2019 Interstitial Fluid - Copy
31/40
At the arterial end
1. Filtration of fluidthrough capillarypores .
2. It causes 24L ofplasma fluid to befiltered/day out ofcapillary tointerstitial spaces.
1. About 90% of filteredfluid at arterial end arereabsorbed at venousend.
At the venous end
10%
8/2/2019 Interstitial Fluid - Copy
32/40
Click to edit Master subtitle style
4/2/12
However, in some capillaries this balance
is different
Filtration Reabso
8/2/2019 Interstitial Fluid - Copy
33/40
4/2/12
Distribution of fluid between plasmaand interstitial fluid
1.The inward and outward forces are nearly equal.
2. The rate of net movement across the capillarymembrane is normally very low.
3. Volumes of both blood and interstitial fluidnormally changes very little from hour to hour.
Under normal
conditions
8/2/2019 Interstitial Fluid - Copy
34/40
4/2/12
Distribution of fluid between plasmaand interstitial fluid
Decreased blood volume (hypotension) or edema
If filtration >reabsorption
8/2/2019 Interstitial Fluid - Copy
35/40
4/2/12
Distribution of fluid between plasmaand interstitial fluid
Increased blood volume and tissue dehydration
If reabsorption>filtration
8/2/2019 Interstitial Fluid - Copy
36/40
4/2/12
Differences betweenfiltration
anddiffusion
8/2/2019 Interstitial Fluid - Copy
37/40
4/2/12
Lymphatic
CirculationFunctions:
1- The lymphatic systemremoves from the interstitium
albumin and othermacromolecules which haveescaped from themicrocirculation.
2- Lymphatics drain fluid fromthe interstitium to maintain itsnormal structure.
8/2/2019 Interstitial Fluid - Copy
38/40
4/2/12
Lymphatic
CirculationLymphatic flow rate:
2 L/day for the entire body, containing 200g ofproteins. most lymph comes from the liver and GIT
Mechanism of flow:
Lymph is mobilized by the contraction of largelymphatics and skeletal muscles. The lymphatics havean extensive system of one-way valves to maintain the
flow of lymph to the heart.
8/2/2019 Interstitial Fluid - Copy
39/40
4/2/12
Lymphatic
CirculationImportanceThe lymphatic system represents the only mechanismof returning interstitial proteins to the circulatorysystem.
8/2/2019 Interstitial Fluid - Copy
40/40
Click to edit Master subtitle style
/ /
Hr&c.o.pS.V HR C.O.P
70 ml 70 b\m 5 l\m Non
atheletes
During rest
120 ml 45-55 b\m 5 l\m atheletes
120 ml 180 b\m 22-25 l\m Non-atheletes Duringexercise
200 ml 180 b\m 35-36 l\m atheletes