Hemoglobin

Question 1

Carbon Monoxide Poisoning

Answer 1

binds Hb w/ 250x higher affinity (lower Km) than O2. prevents O2 from being offloaded. increases Hb affinity for O2. shift binding curve to left (higher aff). stabilizes R state (O2 bound, “Relax, breathe O2”). non-specific symptoms…headache, nausea.

Question 2

Methemoglobinemia

Answer 2

oxidation of Fe+2 to Fe+3. inhibits Hb O2 delivery. forms methemoglobin (MetHb), does not carry O2. caused by oxidizing drugs (ex. benzocaine), NITRATES.
pyruvate kinase def or PDH def can cause methemoglobinemia d/t NADH (reducing power) shortage
chocolate-colored blood. cyanotic. blue-baby syndrome.

Methylene blue IV to reduce Fe+3 to Fe+2

Question 3

Sickle Cell Anemia

Answer 3

Glu–>Val (charged to uncharged) mutation in B-globin of Hemoglobin. RECESSIVE disorder: TWO mutated genes needed (SS homozygous)
hypoxic conditions promote self-assembly of HbS into strands, vascular obstruction–>lysis
pain/swelling hands and feet, fever. Jaundice due to heme breakdown and elevated bilirubin. delayed growth, retina damage, susceptible to infection (NOT cystic fibrosis: mucus buildup in lungs, lung infection). chest pain, abnormal chest x-ray (NOT cystic fibrosis: mucus buildup in lungs, lung infection)
malaria resistance

HYRDOXYUREA: Fetal Hemoglobin (HbF) replaces HbS. prevents erythro maturation. inhibits HbS polymerization fibers 
blood transfusions (side effect: iron overloading). prophylactic antibiotics for infection prevention. bone marrow transplant

Question 4

Hemoglobin C

Answer 4

Glu–>Lys (charged to charged) mutation. less severe than sickle cell anemia

Question 5

B Thalassemia Major / Cooley’s Anemia

Answer 5

no B globin in Hb. a»B. ineffective erythropoiesis. microcytic anemia. buildup of iron Fe in heart–>heart failure.
LCR Locus Control Region. mutation may occur in intron/exon. inhibits O2 carrying capacity. anemia.
thalassemia=sea blood. Mediterranean 1:10.
malaria resistance

Question 6

B+ Thalassemia / B Thalassemia Minor

Answer 6

reduced B globin expression. only 1 allele affected. 50% reduction in B-globin expression. little/no symptoms

Question 7

a Thalasemia (-)

Answer 7

no a Globin. still births

Question 8

a+ Thalassemia

Answer 8

50% reduction a globin, more mild microcytic anemia