Download Serology Notes Blood Volume and Composition Hemocytoblasts

Serology Notes
I.
Blood Volume and Composition
A. Hemocytoblasts (stem cells) in the red marrow create new blood
cells
B. Blood Components
1. 45% hematocrit
a. 99% erythrocytes (rbc)
i.
transport gasses; hemoglobin is the O2
carrying molecule
ii. millions of antigens on cell surface (A, B, O,
and Rh) which may stimulate the production
of antibodies causing agglutination
iii. Rh+ mean a person has the D antigen
b. Leukocytes (white blood cells - wbc) – protect against
infection
i.
neutrophils – most numerous wbc that aides
the immune system through phagocytosis
ii. eosinophils – attack parasites
iii. basophil - cause allergic reactions by releasing
histamines; prevents blood clots
iv. monocyte – largest wbc; phagocytotic
v.
lymphocyte – produce antibodies and
cytokines
c. Platelets/Thrombocytes – repair damaged blood
vessels and initiate the formation of blood clots
2. 55% plasma – mix of water, salts, organic compounds,
vitamins, hormones, electrolytes, and wastes
II.
Serology – the study of bodily fluids, may include antibody-antigen
reactions
A. Presumptive detection of drugs using antibodies
1. inject animal with a specific drug-protein (antigen)
complex of interest
2. animal creates antibodies which are removed from the
serum
3. these animal antibodies are then added to the human urine
specimen and screened for agglutination
B. Identity of 4 blood groups
Type
Antigen
A
A
Antibody Can Give
Blood To
anti-B
A, AB
Can Get
Blood From
O, A
B
AB
O
III.
Forensic characterization of bloodstains
A. Is it blood?
1. luminol – faint, blue luminescence
2. Kastle-Meyer tests or Hemastix - peroxidase activity
3. microcrystalline tests
B. What species does it belong to?
1. precipitin with human antiserum
2. gel diffusion
C. Can it be individualized? DNA tests
IV. Bloodstain patterns
A. The location, distribution, and appearance of bloodstains/spatters
aide in reconstructing and interpreting a crime scene
B. The harder and less porous the surface, the less spatter
C. Shape – the pointed end of stain faces the direction or travel
D. Blood striking a surface at a right angle makes a circular stain; as
the angle decreases, the stain elongates