Blood (Fluid aspect) Flashcards
What can blood transport
Nutients, Respiratory gasses, wastes, hormones
Blood composition
Plasma 55%
Buffy layer (WBC, platelets)
RBC 45%
What is Normovolemia
Normal blood volume
What is Hypovolemia
Lower blood volume
What is hypervolemia
Higher blood volume
What is Hematocrit (Ht)
Percentage of blood volume occupied by RBC : Ht = (height of RBC/height of whole blood) x 100
Normally 45%
Blood volume % of body weight
Normally blood = 7% = around 5L
Hematocrit =45% so RBC occupy 2,25L
Plasma = 2,75L
Composition of plasma
7% proteins (Albumins, Globulins, Fibrinogen)
90% water
Ions: mostly Na+ Cl- (similar to physiological saline, 0,9% NaCl)
Nutrients, Respiratory gasses, waste
Origin of plasma proteins
Liver: albumin, fibrinogen, alpha1, alpha2, Beta Globulins
Lymphoid tissue: Gamma (y) Globulin
Effect of renal disease on electrophoretic pattern of plasma proteins
Disease causes loss of proteins through urine.
Therefore, Albumin concentration is decreased.
What is electrophoresis with plasma
A drop of plasma is dropped on a side of a gel. Electrical current is put on other end. Proteins migrate towards current at a rate affecte by molelcular weight and the charge of the proteins
Characteristics of plasma proteins 7g%
Albumin: oval shape, MW of 69 kDa, concentration 4g% (smallest but higher number of particles)
Globulins: varied shape, MW 90-800 kDa, concentration 2,7g%
Fibrinogen: long shape, MW 350kDa concentration 0,3 g%
Which has more protein: ISF or Plasma
Plasma
ECF Osmolarity
1M solution of NaCl
58.5 g NaCl/L
0.9 g% NaCl = 9 g/L NaCl
9/58.5 = 0.15 M
NaCl = 2 ions Na+ Cl- so osmolarity is 2x molarity
0.3 Osm = 300 mOsm
Can plasma proteins cross the capillary wall?
No, they are too big
What type of solute contributes to Effective Osmotic Pressure
Non-diffusible solutes
Diffusible solute do not contribute because they become equally distributed on 2 sides of membrane
What is COP of plasma
Colloidal Osmotic Pressure
Pressure exerted by plasma proteins against capillary wall (25mmHg)
(inside plasma)
If COP increases
water flows into plasma
If COP decreases
water flows into ISF
2 Types of fluid transport across capillary wall
Filtration
Osmotic Flow
What is bulk flow
flow of molecules subject to pressure difference
What happens in filtration
Fluid in blood vessel is under pressure, fluid is pushed out of capillary into ISF
What is Osmotic Flow
Plasma proteins pull fluid inside capillaries
Starling forces
Combination of Filtration + Osmotic Flow
Difference between diffusion and Starling Forces
Diffusion is exchange of nutrients, gasses, wastes across capillary wall
Sterling Forces distribute ECF volume between Plasma and ISF
How exchange happens across capillaries
Blood pressure is higher coming from arteries, which causes a net filtration (push out)
at capillary level pressure lowers until net pressure = 25mmHg (COP)
Blood pressure on veins increases until net absorptions is high (pull in)
Constant exchange across length of capillary bed
Lymphatic drainage
Excess fluid sent to lymphatic vessels is returned to the blood.
What happens to fluid filtered out of capillaries
90% is recycled back
10% of fluid is drained by lymphatic vessels
True or False, Wall of lymphatic vessels are highly permeable to all ISF constituents
True
including proteins that leaked from plasma into ISF
Which proteins contribute most to COP
proteins in higher concentration in plasma
inversely related to MW of protein
Is Albumin’s contribution to COP high?
Yes, it is present in plasma in higher concentration 4g%, so it exerts more pressure: 20 mmHg
4 factors affecting transcapillary Dynamics
Hydrostatic pressure
COP
Capillary permeability
Lymphatic Drainage
What is Edema
Accumulation of excess fluid in the interstitial spaces
Causes of Edema
Increased Hydrostatic Pressure
Decreased Plasma Protein concentration
(COP)
Increased Capillary Permeability
Obstruction of Lymphatic Drainage
Consequences of increased Hydrostatic Pressure
blood pressure: more fluid leaves at arterial end but net absorption at veinous end = 0 mmHg)
Consequences of Decreased COP
less protein = less pressure, so at arterial end more fluid can leave (pressure out is higher), and at veinous end less fluid comes in (not enough pressure to pull in)
Consequences of Increased Capillary Permeability
plasma proteins escape, and do oncotic pressure from ISF
arterial end: more fluid leaves
veinous end: not enough fluid enters
Consequences of reduced lymphatic drainage
Damage to lymphatic system = excess fluid is not drained and accumulates in interstitial space
Extreme edema from obstructed lymphatic drainage
Elephantiasis
lymphatic drainage is blocked by parasite infestation
Roles of Plasma Proteins
Distribute fluid between plasma and ISF (by Starling Forces)
contribute to viscosity of plasma
contribute to buffering power of plasma (normal pH of 7,4)
Specific role of Fibrinogen
Essential to clotting
Specific role of Y-globulins
Immunoglobulins: provide specific resistance to infection
Albumin and some globulins
Carriers for lipids, minerals, hormones
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