Serology Exam

Question 1

Passive Blood Stain Pattern

Answer 1

• Drops created or formed by the force of gravity
• Subdivided into drops, drip patterns, pools, and clots

Question 2

Transferred Blood Stain Pattern

Answer 2

• 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

Question 3

Projected Blood Stain Pattern

Answer 3

• 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

Question 4

High Velocity Stain Pattern

Answer 4

• Force of 100 ft/sec and greater
• Stain size is 1 mm and smaller (mist like appearance)

Question 5

Medium Velocity Stain Pattern

Answer 5

• Force of 5 to 25 ft/sec
• Stain size 1 to 4 mm (mixture of mist and large drops)

Question 6

Low Velocity Stain Pattern

Answer 6

• Gravitational pull of 5 ft/sec
• Large stains of 4 mm and greater (drop)

Question 7

Calculation for angle impact

Answer 7

width/length

Question 8

Erythrocytes (Red Blood Cells)

Answer 8

• 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

Question 9

Leukocytes (White Blood Cells)

Answer 9

• 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

Question 10

Thrombocytes (Platelets)

Answer 10

• 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)

Question 11

Plasma

Answer 11

• 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

Question 12

Type A Blood

Answer 12

• 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

Question 13

Type B Blood

Answer 13

• 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

Question 14

Type AB Blood

Answer 14

• 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

Question 15

Type O Blood

Answer 15

• 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

Question 16

Rh Factor

Answer 16

The Rh factor is either present (+) or absent (-). Therefore, blood types are described as the type and Rh factor (such as O+ , A+, AB-).

Question 17

Angle of Impact

Answer 17

The acute angle formed between the direction of a blood drop and the plane of the surface that it strikes.

Question 18

Back Spatter

Answer 18

Blood directed back towards the source of energy or force that caused the spatter.

Question 19

Forward Spatter

Answer 19

Blood which travels in the same direction as the source of energy or force which caused the spatter.

Question 20

Ricochet

Answer 20

The deflection of blood after impact with a target surface that results in staining of a second target surface.

Question 21

Satellite Spatter

Answer 21

Small droplets of blood that are distributed around a drop or pool of blood as a result of the blood
impacting the target surface.

Question 22

Spatter

Answer 22

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.

Question 23

Spine

Answer 23

The pointed or elongated stains which radiate away from the central area of a bloodstain.

Question 24

Arterial Spurt/Gash

Answer 24

Bloodstain pattern from blood spurt under pressure from a cut artery.

Question 25

Cast-off Stains

Answer 25

Blood released or thrown from a blood-soaked object in motion.

Question 26

Impact Spatter

Answer 26

Blood stain patterns created when a blood source receives a blow or force resulting in the random dispersion of smaller drops of blood.

Question 27

Blood Chemistry Pt. 1

Answer 27

(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.

Question 28

Blood Chemistry Pt. 2

Answer 28

1. 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).
2. 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.
3. 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.
4. Noting the color of the blood can tell us whether the blood is
   oxygenated or deoxygenated.

Question 29

Immunoassay

Answer 29

A technique utilizing antibodies to bind specifically to targeted substances in a specimen in order to identify their presence.

Question 30

Antibody vs. Antigen

Answer 30

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.