Serology Exam Flashcards
Types of Blood Stains, Blood Stain Pattern, Components of blood, Blood Types, Vocab
Passive Blood Stain Pattern
- Drops created or formed by the force of gravity
- Subdivided into drops, drip patterns, pools, and clots
Transferred Blood Stain Pattern
- created when a wet, bloody surface comes in contact with another surface
- pattern: shoe or hand pattern
- subdivided into contact bleeding, swipe, smear, wipe, and smudge
Projected Blood Stain Pattern
- created when a blood source is subjected to an action greater than the force of gravity
- the size, shape, and number of resulting stains depending on the amount of force used to strike the blood force
High Velocity Stain Pattern
- Force of 100 ft/sec and greater
- Stain size is 1 mm and smaller (mist like appearance)
Medium Velocity Stain Pattern
- Force of 5 to 25 ft/sec
- Stain size 1 to 4 mm (mixture of mist and large drops)
Low Velocity Stain Pattern
- Gravitational pull of 5 ft/sec
- Large stains of 4 mm and greater (drop)
Calculation for angle impact
width/length
Erythrocytes (Red Blood Cells)
- the most abundant cells in the blood and blood its red color
- 5 million red blood cells per cubic microliter
- 40% to 45% of the blood
- Ratio: 600 RBCs per 1 WBCs per 40 Platelets
- hematocrit: % of blood made up of red blood cells frequently measured
- strange shape, no nucleus, can change shape, has hemoglobin
Leukocytes (White Blood Cells)
- part of the immune system and fight infection
- circulate in the blood to be transported to an infection site
- 4,000 to 10,000 WBCs (average 7,000) per microliter
- Ratio: 600 RBCs per 1 WBCs per 40 Platelets
- WBCs increase when there is a sign of an infection
Thrombocytes (Platelets)
- help blood clot by forming a platelet pug, blood clots, or other blood clotting mechanisms
- 150,000 to 400,000 platelets per microliter (average 250,000)
Plasma
- clear yellowish fluid (like a straw); can appear milky after a fatty/greasy meal or when people have a high level of lipids in their blood
- 90% water and 10% protein
Type A Blood
- A Antigens
- B Antibodies
- Clumps with anti-A serum but doesn’t clump with anti-B serum
- Can donate to Types A & AB
- Can accept from Types A & O
Type B Blood
- B Antigens
- A Antibodies
- Clumps with anti-B serum but doesn’t clump with anti-A serum
- Can donate to Types B & AB
- Can accept from Types B & O
Type AB Blood
- A & B Antigens
- No Antibodies
- Clumps with anti-A & anti-B serum
- Can donate to Type AB
- Can accept from Types A, B, AB, & O
Type O Blood
- No Antigens
- A & B Antibodies
- Doesn’t clump with anti-A or anti-B serum
- Can donate to Types A, B, AB, & O
- Can accept from Type O
Rh Factor
The Rh factor is either present (+) or absent (-). Therefore, blood types are described as the type and Rh factor (such as O+ , A+, AB-).
Angle of Impact
The acute angle formed between the direction of a blood drop and the plane of the surface that it strikes.
Back Spatter
Blood directed back towards the source of energy or force that caused the spatter.
Forward Spatter
Blood which travels in the same direction as the source of energy or force which caused the spatter.
Ricochet
The deflection of blood after impact with a target surface that results in staining of a second target surface.
Satellite Spatter
Small droplets of blood that are distributed around a drop or pool of blood as a result of the blood
impacting the target surface.
Spatter
That blood which has been dispersed as a result of force applied to a source of blood. Patterns produced are often characteristics of the nature of the forces which created them.
Spine
The pointed or elongated stains which radiate away from the central area of a bloodstain.
Arterial Spurt/Gash
Bloodstain pattern from blood spurt under pressure from a cut artery.
Cast-off Stains
Blood released or thrown from a blood-soaked object in motion.
Impact Spatter
Blood stain patterns created when a blood source receives a blow or force resulting in the random dispersion of smaller drops of blood.
Blood Chemistry Pt. 1
(1) Blood rich in CO2 is pumped from the heart into the lungs through the pulmonary arteries. (Arteries carry blood away from
the heart; veins carry blood to the heart.)
(2) CO2 in the blood is exchanged for O2 in
the lungs.
(3) Oxygen-rich blood is carried back to
the heart through the pulmonary veins.
(4) Oxygen-rich blood is then pumped
from the heart to the the body through the
arteries.
(5) In the tissues, the arteries narrow to
tiny capillaries where O2 in the blood is
exchanged for CO2.
(6) The capillaries widen into the veins
which carry the CO2-rich blood back to the
heart.
Blood Chemistry Pt. 2
- Blood in the arteries (traveling from the heart) is red-colored,
and blood in the veins (traveling from cells back to the heart) is
also red-colored (not blue). - The blood in the arteries is oxygen-rich; this blood has just
traveled from the lungs (where it picked up oxygen inhaled
from the air) to the heart, and then is pumped throughout the
body to deliver its oxygen to the body’s cells. - The blood in the veins, is oxygen-poor; it has unloaded its
oxygen to the body’s cells (exchanging the O2 for CO2), and
must now return to the lungs to replenish the supply of oxygen. - Noting the color of the blood can tell us whether the blood is
oxygenated or deoxygenated.
Immunoassay
A technique utilizing antibodies to bind specifically to targeted substances in a specimen in order to identify their presence.
Antibody vs. Antigen
Antibody: protein produced by the immune system in response to the presence of a specific antigen.
Antigen: substance that can trigger an immune response in order to produce an antibody as a part of the body’s defense against infection and disease.