L9

Question 1

what is methemoglobin ?

Answer 1

when Fe++ of heme is oxidized met hemoglobin is formed

Question 2

what can change hemoglobin to met hemoglobin ?

Answer 2

oxidizing agents such as ferricyanide , H2O2, some drugs can also convert hemoglobin to met hemoglobin

Question 3

how is met heboglobin impaired?

Answer 3

it is unable to bind and transport O2

Question 4

WHAT WILL AN INCREASE IN MET HEMOGLOBIN RESULT IN ?

Answer 4

METHEMOGLOBINEMIA IS MANIFESTED AS CYANOSIS (blueish color)

Question 5

What is carboxy hemoglobin ?

Answer 5

carbon monoxied bound to hemeoglobin

it is unsustainable for oxygen transport

Question 6

describe the affinity of CO to Hb

Answer 6

it is 200 times more than that of O2

Question 7

when do clinical symptoms of carboxy hemoglobin manifest ?

Answer 7

when COHb levels exceed 20%

40-60% saturation : coma and death can occur

Question 8

what is glycosylated hemoglobin ?

Answer 8

Hb is nonenzymatically glycosylated when blood glucose enters the erytheycytes

The fraction of Hb glycosylated is proportionate to blood glucose concentration.

Question 9

what information can be learned from HbA1c?

Answer 9

provides information useful for the management of diabetes mellitus.

It reflects the average blood glucose concentration over the preceding 6 – 8 weeks (half-life of an erythrocyte is typically 60 days).

Question 10

what is hemoglobinpathies?

Answer 10

Disorders caused by the synthesis of abnormal Hb molecule.
Sickle cell anemia [HbS] and Hemoglobin C disease [HbC] are examples of abnormal hemoglobins.

Question 11

what is thalassemia ?

Answer 11

genetic disease caused by partial or total absence of one or more alpha or beta chain of hemoglobin

Alpha thalassemia or beta thalassemia are examples.

A superscript indicates whether a subunit is completely absent (α0 or β0) or whether its synthesis is reduced (α− or β−).
Apart from marrow transplantation, treatment is symptomatic.

Question 12

abnormalities in hemoglobin are both extremly rare and benign . but when the mutation does compromise biologic function is it termed as____

Answer 12

hemoglobinpathy

Question 13

In hemoglobin C , what structure is replaced , and by what ?

Answer 13

Glutamate in the 6th position of β-chain is replaced by lysine (acidic amino acid being replaced by basic amino acid).

Question 14

what do the terms heterozygotes and homozygotes mean when talking about hemoglobin C ?

Answer 14

Heterozygotes – no clinical manifestations

Homozygotes – moderate hemolytic anemia

Question 15

hemogloin C random info :

Answer 15

HbC also produces sickling

Exclusively detected in black race

Question 16

what is myoglobinuria

Answer 16

appearance of myoglobin in urine due to massive crush injury to skeletal muscle followed by renal damage

Question 17

when can myglobin be detected in plasma ?

Answer 17

following a myocardial infarction.

Question 18

what is anemias ?

Answer 18

Reductions in the number of red blood cells or of hemoglobin in the blood.

It reflects impaired synthesis of hemoglobin (e.g., in iron deficiency) or impaired production of erythrocytes (e.g., in folic acid or vitamin B12 deficiency).