Last Seen: Sep 19, 2023 @ 1:50am 1SepUTCBlood
Blood & Hematology
The human body is made up mostly of water; ~60 – 65% (40 L)
Body’s transport system plays key role in balancing fluids in the body’s
compartments“
river of life” Marieb
strictly speaking, blood is not a “body fluid” like tears, mucous, or saliva or
urine
it is a living tissue consisting of cells within a liquid ‘matrix’
Average person (150lb) has ~4.8 L of blood = 8% body weight
loss of 15-30% of blood pallor and weakness
loss of >30% severe shock, death
arterial blood: bright red = oxyhemoglobin
venous blood: darker red
Composition:
plasma 55% of volume
formed elements 45%
=RBC’s, WBC’s, Platelets
Plasma
the liquid part of blood
clear straw colored fluid
plasma consists of liquid solvent mostly water
and solutes without the formed elements
93% water
7% solutes
1000’s of different solutes
most solutes are proteins (=plasma proteins)
also: salts, ions, gasses, hormones, nutrients, wastes, enzymes
some of virtually every chemical found anywhere in the body
can be found in the blood
project now underway to identify every chemical in blood
serum = plasma with clotting factors removed
plasma proteins (8% of blood):
most proteins in blood do not readily pass through capillaries into
interstitial spaces
1. albumins
(with other proteins) contribute to viscosity, osmotic pressure
& blood volume
helps buffer the blood
transports many solutes by binding to them:
eg. drugs, penicillin, pigments, fatty acids, bile salts
2. globulins
some are antibodies, part of immune system
some help transport solutes
some involved in clotting
3. fibrinogen
soluble precursor to fibrin = framework for clotting
Formed Elements
about 45% of whole blood
erythrocytes (RBC’s) –most, 45%, of formed elements
leukocytes (WBC’s)
thrombocytes (Platelets)
all three are produced by stem cell
Erythrocytes
main job is to carry oxygen to cells
also deliver some carbon dioxide to lungs
most abundant of the three types of formed elements
99% of formed elements; ~5.5 mil/µl (µl=mm3)
equivalent to 2.5 trillion blood cells in whole body
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