04 RBC Synthesis And Degradation Flashcards Preview

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Flashcards in 04 RBC Synthesis And Degradation Deck (42):
1

Produced in response to tissue hypoxia
Stimulates proerythroblast production within minutes

Erythropoietin

2

Produce 2 ATPs
Source of energy by RBCs (they do not consume oxygen)

Anaerobic glycolysis

3

Needed for normal DNA synthesis (maturation)
Absence leads to formation of macrocytes, causing macrocytic megaloblastic anemia, neural tube disorder, neural deficiencies

Vitamin B9 and B12

4

Last stage of RBC with a nuclear membrane
ER reabsorbed

Orthochromatic erythroblast

5

Formation of hemoglobin: rate limiting step

succinylcholine A + glycine = d-ALA

6

Total body iron

4-5 grams

7

Glycoprotein that binds and transports iron
Produced by liver
Secreted into Nile and duodenum
Absorbed in the small intestine

Transferrin

8

Main storage protein for excess iron in liver

Ferritin

9

Additional storage area outside the liver

Hemosiderin

10

After 120 days, RBC would pass through the _____, where they are destroyed

Splenic sinusoid

11

Destruction of RBS: porphyrin is transformed into _____

Bilirubin

12

Present in almost all tissues because they are used in hemoglobin, myoglobin, cytochromes, enzymes

Heme

13

Location of heme synthesis

Bone marrow (85%)
Hepatocytes (15%)

14

Cyclic compounds formed by linkage of four pyrrole rings through methyne bridges
Forms complexes with metal ions bound to the nitrogen atom of the pyrrole rings

Porphyrin

15

Location of heme synthesis in the cell

Mitochondria
Cytosol

16

8-step heme synthesis

Formation of d-ALA
Formation of porphobilinogen
Formation of hydroxylmethylbilane
Coversion of HMB to either uropophyrinogen I or III
Formation of coproporphyrinogen III
Conversion of coproporphyrinogen III to protoporphyrinogen IX
Formation of protoporphyrin IX
Formation of heme

17

Enzyme involved in formation of d-ALA

ALA synthase

18

Cofactor in the formation of d-ALA

Pyridoxine

19

Genetic or acquired disorders due to abnormalities in the biosynthesis of heme

Porphyrias

20

Most common symptoms of porphyrias

Abdominal pain
Photosensitivity
Neuropsychiatric symptoms

21

Defect in uropophyrinogen I synthase

Acute intermittent porphyria

22

Ferrocheletase is affected

Protoporphyria

23

Most common porphyria
Uropophyrinogen decarboxylase defect

Porphyria cutanea tarda

24

Pyridoxine deficiency associated with isoniazid therapy

Sideroblastic anemia with ringed sideroblasts

25

Iron deficiency can cause

Microcytic hypochromic anemia

26

Inactivates two enzymes in heme synthesis: ALA dehydrogenase and ferrocheletase

Lead poisoning

27

Basophilic stippling of RBC
Encephalopathy
Peripheral neuropathy
Lead lines in gums (Burtons line), lead lines in bone

Lead poisoning

28

Nerve affected in wrist drop due to lead poisoning

Radial nerve

29

Nerve affected in foot drop caused by lead poisoning

Peroneal nerve

30

Heme degradation: globin

Degraded to constituent amino acids

31

Heme degradation: iron

Enters iron pool for reuse

32

Heme degradation: porphyrin

Degraded

33

Steps in heme degradation

Formation of bilirubin
Uptake of bilirubin
Formation of bilirubin diglucoronide
Secretion of bilirubin into bile
Formation of urobilins in the intestine

34

Enzyme in formation of bilirubin

Heme oxygenase system of reticuloendothelial cells

35

Deficient in Criglar-Najjar I and II and Gilbert syndrome

Bilirubin glucoronyl transferase

36

Blood bilirubin > 1mg/dL
A normal liver but with abnormally high bilirubin
Abnormal liver with normal bilirubin

Hyperbilirunemia

37

Usually due to increased RBC destruction in adults
Hemolytic anemia, neonatal jaundice, Crigler-Najjar syndrome, Gilbert syndrome, toxic hyperbiliruninemia

Indirect/unconjugated hyperbilirubinemia

38

Usually due to biliary duct obstruction
Regurgitation of bilirubin back into the hepatic veins and lymphatics
Biliary tree obstruction, Dubin-Johnson syndrome, Rotor syndrome

Direct/conjugated hyperbilirubinemia

39

Icterus
Blood bilirubin > 2.5mg/dL with deposition in the tissue

Jaundice

40

Increased hemolysis during birth
Immature hepatic system for the uptake, conjugation, and secretion of bilirubin
Unconjugated bilirubin can enter blood-brain barrier in newborn

Neonatal or physiologic jaundice

41

Induces bilirubin-metabolizing system
Induces degradation of bilirubin

Phenobarbital

42

Converts unconjugated bilirubin to maleimide fragments and geometric isomers excreted in bile

Phototherapy