#02: Blood I Continued/Blood II

Question 1

Forms of Hemoglobin

Answer 1

· There are 3 forms of hemoglobin. Oxyhemoglobin (when hemoglobin is maximally loaded with oxygen), deoxyhemoglobin (without oxygen) and carinohemoglobin (when hemoglobin is binded to oxygen).

Question 2

Fetal Hemoglobin

Answer 2

· Fetal Hb is the main hemoglobin in the fetus during last 7 months of pregnancy. It is made up of 2 alpha chains and 2 gamma chains. Has a higher affinity for oxygen then regular hemoglobin. This is because the baby isn’t breathing in oxygen from the air but from the mother’s circulation, so a higher affinity is required.

Question 3

Bohr Effect

Answer 3

· Bohr effect is when Hb binds to CO2 and H+. This interactions facilitates the release of O2 at the tissue.

Question 4

Haldane Effect

Answer 4

· Haldane Effect is when deoxygenated blood Hb has a higher affinity for CO2 and protons then in oxygenated blood. Removes CO2/H+ from blood stream.

Question 5

Anemia

Answer 5

Anemia is a disorder when there’s failure of the blood to oxygenate tissues.

Question 6

Anemia Due To Insufficient # of RBCs

Answer 6

o Insufficient Number of RBCs
§ Hemorrhage, the result of blood loss.
§ Pernicious, a deficiency of vitamin B12. This vitamin is used to mature blood cells.
§ Aplastic, a disorder of the red bone marrow.

Question 7

Anemia Due to Iron Deficiency

Answer 7

o Low Hb- Iron Deficient
§ If you have iron deficiency, oxygen can’t be grabbed, anemia.
§ Thalassemias, underproduction.
§ Sickle-cell anemia- point mutation.

Question 8

Macrocytic Anemia

Answer 8

o Macrocytic anemia occurs when the average size of circulating erythrocytes is too large and spongy to be used. Deficiencies in both vitamin B12 and folic acid uptake result in the production of enlarged erythrocytes. Major concern for gastric bypass.

Question 9

Microcytic Anemia

Answer 9

o Microcytic anemia is caused by iron deficiency. RBCs become smaller then should be. Most likely not making enough Hb.

Question 10

Sickle Cell Anemia

Answer 10

o Sickle Cell Anemia is an autosomal recessive disorder that occurs when a person inherits two copies of the sickle-cell gene. Erythrocytes become sickle-shaped, making them unable to flow efficiently through the blood vessels to body tissues and more prone to destruction by rupture (hemolysis).
§ It results from a single amino acid mutation in the Hb-beta chain.
§ Hb “sticks” together in the deoxygenated state (RBC’s have so much Hb this clumping changes their shape to a C) and decreases Hb’s ability to bind O2 or move thru small vessels.

Question 11

Carbon Monoxide Poisoning

Answer 11

o Carbon Monoxide can bind iron in hemoglobin, thus blocking its ability to bind O2.
§ Treatment is through putting someone in a hyperbaric chamber. Can supersaturate air with oxygen to compete with carbon monoxide to bind to Hb.
§ Cyanide poisoning works similarly to CO2 poisoning, but allosterically, binds somewhere other than the iron.

Question 12

Erythropoesis

Answer 12

Erythropoesis is the process by which RBCs are formed.

Question 13

Erythropoesis Through Life Stages

Answer 13

o In 1st and 2nd months, RBCs form in embryonic yolk sac.
o In 2nd to 5th months, RBCs form in liver and spleen.

In adults, RBCs form in red bone marrow, which are in various bones. (Vertebra, sternum, ribs, skull, scapula, pelvis)

Question 14

What’s Required To Form RBC

Answer 14

o To form RBCs, it requires iron, vitamin B12, and folic acid.

Question 15

Control of Erythropoiesis

Answer 15

o Control of Erythropoiesis
§ Hypoxia occurs as a result of low blood oxygen. It increases RBC production by increasing formation and release of erythropoietin (a glycoprotein hormone produced by the kidneys).
· Erythropoietin increases RBC production in two ways. Increase the production of proerythroblasts, and decreases the time required for erythrocyte maturation.
· Hypoxia increases erythropoietin release, which increases RBC production and the O2 carrying capacity of blood, which leads to eventual increase in blood O2, reversing hypoxia.
§ In cases of hyperxia, or too much blood oxygen or RBCs, erythropoietin levels are decreased.

Question 16

Polycythemia

Answer 16

· Polycythemia is the condition of having too many RBCs in blood, elevated hematocrit. The affected person has same total blood volume, but many more erythrocytes than are healthy. Blood becomes thick and viscous, putting a tremendous strain on the heart. Could also cause problem with unintentional blood clotting.

Question 17

Polycythemia: Abnormality vs. Advantage

Answer 17

o An abnormality when bone marrow abnormalities are reason for it.
o Can be an advantage. Increases oxygen carrying capacity, which can be especially useful at high altitudes.

Question 18

Lance Armstrong

Answer 18

o Lance Armstrong partook in blood doping, getting infusions of packed RBCs to create artificial polythemia and become more athletically capable. Can also obtain by getting EPO (erythropoietin) supplement or train at higher altitudes to create it.

Question 19

RBC Life-Span

Answer 19

· Due to lack of nucleus and organelles, erythrocytes have a short life span. A mature RBC can’t synthesize proteins to repair itself or replace damaged membrane regions.

Question 20

Erythrocyte Disposal

Answer 20

o Old RBCs are phagocytized in liver and spleen by cells called macrophages. Some components are stored to be recycled, while others are excreted.

Question 21

Erythrocyte Disposal: Heme Group

Answer 21

§ The heme group in Hb is converted into a green pigment called bilverdin. It is then eventually converted into a yellow-green pigment called bilirubin. It’s a component of bile, which is produced by liver. It is released into blood when it binds albumin and is then later excreted by liver in bile. Bile helps to emulsify fats. After, the bilirubin in the GI tract is modified into other products that appear in urine from kidneys and feces from GI tract.

Question 22

Erythrocyte Disposal: Iron Ion

Answer 22

§ The iron ion in Hb is removed and transported by a beta-globulin protein called transferrin to the liver where the iron ion is passed to another protein, called ferritin. Ferritin is stored in the liver and will be transported to red bone marrow later for RBC production. Iron must be transported like this because it is very reactive and could become a free radical.

Question 23

Erythrocyte Disposal: Proteins

Answer 23

§ RBC membrane proteins and globin proteins are broken down into free amino acids, some of which the body uses for protein synthesis to make new RBCs.

Question 24

Hematuria

Answer 24

· Hematuria is blood in urine.

Question 25

Hemoglobinuria

Answer 25

· Hemoglobinuria is Hb lost in urine. Acute tubular necrosis is a common cause of death associated with major trauma. It destroys the kidneys.

Question 26

Liver Failure

Answer 26

· Liver failure can occur when excessive bilirubin in blood causes skin and sclera to turn yellow (Jaundice).