BL Garrington lecture review

Question 1

Characteristicsof RBCs?

Answer 1

Annucleate, biconcave disc, no mitochondria, deformable

Question 2

Types of Hb?

Answer 2

Hb A (alpha and beta), Hb A2 (alpha and delta), Hb F (alpha and Ggamma, A gamma), Hb Gower 1 (lambda and epsilon), Hb Gower 2 (alpha and epsilon), Hb Portland (lambda and gamma)

Question 3

Does embryonic hemoglobin have higher or lower oxygen affinity than adult hemoglobin?

Answer 3

Higher (left shifted curve)

Question 4

Does fetal hemoglobin have higher or lower oxygen affinity than adult hemoglobin?

Answer 4

Higher (left shifted curve)

Question 5

Does Hb A2 have higher or lower oxygen affinity than adult hemoglobin?

Answer 5

Higher (left shifted curve)

Question 6

In which conditions is Hb A2 elevated?

Answer 6

Beta-thalassemia, sickle cell disease, hyperthyroidism, megaloblastic anemia

Question 7

Numbers of Hb genes?

Answer 7

4 alphas on Ch 16, 2 betas on Ch 11

Question 8

RBC membrane proteins involved in deformability?

Answer 8

Ankyrin, spectrin, and actin

Question 9

RBC metabolism?

Answer 9

Anaerobic, depends on G6PD and PDH (for making NADPH and GSH)

Question 10

Define anemia.

Answer 10

RBC deficiency leading to lack of oxygenation to tissues.

Question 11

General causes of anemia?

Answer 11

Lack of RBC production, improper production, hemolysis, bleeding.

Question 12

Non-neoplastic causes of decreased RBC production?

Answer 12

EPO deficiency, Iron deficiency, B12 deficiency, folate deficiency, aplastic anemia

Question 13

Causes of Iron deficiency?

Answer 13

Chronic disease

Question 14

Neoplastic causes?

Answer 14

Leukemia taking up the marrow space

Question 15

Hemolytic anemias?

Answer 15

G6PD deficiency, PDH deficiency, autoimmune hemolytic anemia (cold and warm), transfusion reaction

Question 16

Hemoglobin disorders?

Answer 16

Sickle cell disease, thalassemias (a and b), Hb C, Hb E

Question 17

WBCs?

Answer 17

Neutrophils, Lymphocytes, Monocytes, Eosinophils, Basophils

Question 18

What is the difference between leukemia and lymphoma?

Answer 18

Leukemia occurs in the bone marrow. Lymphoma occurs in the lymph organs

Question 19

What is the difference between thrombosis and embolus?

Answer 19

Thrombosis is a block that builds up on a blood vessel wall. Embolus is a thrombus that breaks off and travels up to another blood vessels.

Question 20

What valence state must iron be in for proper hemoglobin function?

Answer 20

Fe+2

Question 21

What is Fe+3 hemoglobin called?

Answer 21

Methemoglobin

Question 22

When is hemoglobin taut and when is it relaxed?

Answer 22

Taut = deoxygenated; Relaxed = oxygenated

Question 23

Define allostery and positive coopertivity.

Answer 23

Allostery - a conformation change in other binding sites that occurs when an different binding site is occupied. Positive coopertivity - when the binding of one substrate increases the affinity for another substrate

Question 24

Which value is used to compare oxygen affinities of different hemoglobin?

Answer 24

P50

Question 25

What is P50?

Answer 25

The partial pressure of oxygen at which hemoglobin is 50% saturated

Question 26

What environmental conditions alter the shape of the hemoglobin oxygen dissociation curve?

Answer 26

pH, CO2, temperature, 2,3-BPG

Question 27

When hemoglobin oxygen dissociation increases (affinity decreases), is oxygen more or less likely to go into tissues?

Answer 27

More likely

Question 28

What happens to hemoglobin oxygen affinity when the pH goes down? Up?

Answer 28

Shifts to the right (decreased affinity). Shifts to the left (increased affinity)

Question 29

How does CO2 concentration affect the O2 binding curve?

Answer 29

When CO2 in the blood stream increases, it decreases pH

Question 30

How does temperature affect hemoglobin oxygen affinity?

Answer 30

As temperature increases, oxygen affinity decreases (inverse relationship)

Question 31

How does 2,3-BPG affect hemoglobin oxygen affinity?

Answer 31

As 2,3-BPG increases due to RBC anaerobic metabolism, oxygen affinity decreases (inverse relationship)

Question 32

What are Heinz bodies and what causes them?

Answer 32

Precipitated hemoglobin and unstable hemoglobin mutations can cause them

Question 33

What are the possible lab findings of a low affinity hemoglobin variant?

Answer 33

P50 left shifted, may lead to hemolytic anemia, physical signs of tissue hypoxia

Question 34

What are the possible lab findings of a right affinity hemoglobin variant?

Answer 34

P50 right shifted, tissue hypoxia causes increased EPO but no physical signs of hypoxia

Question 35

What is the differential diagnosis of cyanosis?

Answer 35

Unstable hemoglobin, methemoglobin, sulfhemoglobinemia, inadequate oxygenation of hemoglobin, drugs/toxins

Question 36

What does blood with too much methemoglobin look like?

Answer 36

Chocolate brown color

Question 37

What can cause methemoglobinemia?

Answer 37

Cytochrome b5 reductase deficiency (autosomal dominant mutation), drugs/toxins

Question 38

Describe the binding of CO to hemoglobin?

Answer 38

Competitive with O2, higher affinity, long half-life

Question 39

What are signs of CO poisoning?

Answer 39

Cherry red skin, headache, nausea

Question 40

How does a pulse oximeter work?

Answer 40

Uses a photodetector and two emitters to detect levels of deoxy and oxyhemoglobin (660 nm and 940 nm, respectively)

Question 41

Describe ways that a pulse ox can give a false reading.

Answer 41

Improper placement, nail polish, deeply pigmented skin, misinterpretation of presense of CO and methemoglobin

Question 42

What conditions are the pulse ox not helpful in detecting?

Answer 42

Shock, anemia, CO2 poisoning