RBC Synthesis, Function, and Destruction Flashcards
______ are the most abundant formed elements
RBCs
RBC biconcave shape facilitates what?
O2 and CO2 diffusion and binding with Hb
What are hypertonic RBCs?
Cells Shrink
What are hypotonic RBCs?
Cells swell and Burst
What are Isotonic?
Cell size does not change.
Cells prefer isotonic or hypotonic?
Isotonic.
What is the fragility test?
based on behavior of RBCs when placed in a hypotonic solution of NaCl of varying strength (0.7-.03 percent) to see at which strength hemolysis begins and at which is complete.
What is the fragility tests used for?
helpful in differential diagnosis of anemias
What can cause hemolysis?
Bacterial toxins, wrong transfusion, snake venom.
The number of RBCs/mm3 varies?
inversely with the size of the blood corpuscles.
An increase in the numbers of RBCs/mm3 is called _______, whereas the decrease is called ________.
polycythemia, oligocythemia
What are Three types of Hb:
Type (A adult), Type B (Fetal), Type S (Sickle cell, abnormal)
What is Hemoglobin composed of?
Globin and heme
Hb has _______ groups, each contains ________ ________ that loosely binds to one oxygen molecules.
four heme, iron atom (ferrous form Fe2+).
Each Hb can carry ______ ______ .
four molecules of O2.
HB (g/dl) is is what in man?
15
What is Oxyhemoglobin?
iron in the ferrous state, can carry oxygen.
What compound gives blood its bright red color?
Oxyhemoglobin
Hb that has given up its oxygen is called what and what color is it?
reduced Hb and it is blue in color.
When mucous membranes has a distinctly blue color this is called?
cyanosis (Hb ~ 5g/dl of blood)
When is Methemoglobin formed?
the Iron of the heme is oxidized to ferric form (Fe+++) which cannot carry O2.
What is Carbonmonoxyhemoglobin ?
When Carbon monoxide occupies sites normally occupied by O2.
CMO is short for?
Carbonmonoxyhemoglobin
CMO has a higher affinity by how many times then what?
(250 times) than O2
What is the oxygen starvation that cause death due to inhalation of exhaust fumes?
CMO
What is Hemoglobin in the muscle is called?
Myoglobin.
Myoglobin has what characteristics?
one heme group and capable of transporting one molecule of oxygen.
What is the Affinity of Hb to O2 is affected by?
PCO2, [H+], pH, and the concentration of 2,3 diphosphoglycerate (2,3 DPG)
The presence of higher levels of CO2 and [H+] (decreased pH) in the capillaries of such metabolically active tissue promotes?
release of O2 from oxyhemoglobin
What happens when DPG binds to Hb?
decrease its affinity to oxygen.
What is the Shape of O2 dissociation curve of Hb?
Sigmoid
What does the sigmoidal shape of the curve indicates?
binding of O2 to Hb is cooperative.
What does it mean when binding of O2 to Hb is cooperative?
means binding of O2 to one heme facilitates the binding of O2 to other hemes.
In adult animals RBCs are made where?
in the red bone marrow of the sternum, ribs, vertebrae, pelvis and skull (primary sources).
Before birth where are RBCs made?
liver, spleen and bone marrow.
In adults suffering from massive hemorrhage, RBC can be formed where?
yellow bone marrow of long bones, liver, and spleen.
yellow bone marrow of long bones, liver, and spleen are what type of sources?
Secondary Sources
Kidney erythropoieitin stimulates their production in response to ?
to low O2 in the tissues (Hypoxia)
What is Hypoxia?
low O2 in the tissues
Blood cells are formed from ______ cells, which reside in the _____ ______.
stem, bone marrow.
Stem cells can be committed to form what?
either RBC, WBC, or platelets.
What vitamins are needed for erythropoiesis?
Vitamin B12 and Folic Acid.
Without B12 and Folic acid ___ ______ and ______ ______ can’t occur.
DNA synthesis and cell division.
What are the stages of Erythropoeisis: stages of differentiations?
Rubriblast –> Prorubricytes–>Rubricyte –> Metarubricyte –> Reticulocytes –> Erythrocyte.
What doe erythrocytes lack?
DNA and mitochondria.
When does the synthesis of Hb begin?
Between the prorubricyte and rubricyte.
What occurs between Rubricyte
–> Metarubricyte?
Active ER, RNA,and protein synthesis. Much Hb has been produced by this time.
When does the extrusion of the nucleus in erythropoiesis occur?
between the metarubricyte and reticulocytes.
When division cease in erythropoiesis?
cell division cease between the metarubricyte and reticulocytes.
What matures to an erythrocyte in the peripheral blood?
Reticulocyte
What is the average maturation time of a Reticulocyte?
33 hours
A rise in reticulocyte count indicates what?
increased activity of blood forming tissue.
reticulocyte count increases typically after what events?
hemorrhage, at high altitudes and exercise.
How many RBCs per uL of blood?
5,000,000
How long does blood last after it leaves bone marrow?
120 days.
When they become fragile, they are removed by what?
by macrophages mainly in the liver and spleen.
RBC breakdown
RBC
_______ heme ______
biliverdin (What color is this?)
bilirubin (yellow)
bilirubin+albumin
bilirubin+ glucoronic acid (what organ does this occur)
_____ ___________
bacteria+bile pigments
(What organ does this occurs in?)
Urobilinogen
urine feces
urobilin urobilin (stercobilin)
globin, iron biliverdin (green) bilirubin+ glucoronic acid = Liver Bile Pigment Small Intestines
What happens to Globin and Iron when phagocytosed?
recycled and reused.
90% of the hemolysis occurs when the cells are?
phagocytosed (extravascular).
What happens to heme when RBCs destruct?
is converted to biliverdin (green pigment) and is then reduced to bilirubin (yellow pigment.
When heme is reduced to bilirubin what happens to it?
Free bilirubin is transported , bound to albumin, to the liver.
What occurs in the liver, when bilirubin conjugates with glucoronic acid?
It is secreted in the bile as bile pigment
In the intestines, bacteria acts on bile pigment to form what?
urobilinogen which is secreted in the feces as urobilin or stercobilin
What give the feces its color?
urobilinogen.
Some of the urobilinogen that is absorbed is excreted where and as what?
in the urine as urobilin.
If the liver is diseased and can not process bilirubin, bilirubin combined with albumin appears where?
in high concentrations in the plasma and interstitial fluids.
What disease occurs when liver is diseases and can not process bilirubin?
Jaundice (yellow coloration of the tissues and mucous membranes).
Jaundice can be produced in what other circumstances?
if the bile ducts becomes blocked and bilirubin spill into the plasma.
Increased hemolysis due to hemolytic disease causes what?
the plasma to take a reddish appearance (hematoglobinemia)
What is hematoglobinemia?
the plasma to take a reddish appearance.
What gives urine reddish color?
Hb in urine.
What is it called when Hb causes urine to be reddish in color?
hemoglobinuria.
What is transferrin?
Iron circulated in the plasma, combined with a plasma protein.
What is transferrin used in bone marrow?
used for synthesis of hemoglobin.
Ingested iron reduced to _____ ______ and is absorbed in the ____ _______.
ferrous state, small intestines.
The two factors that affect Fe absorption are?
amount stored and rate of RBC formation
What is Ferritin?
is the storage form of Fe2+ (in liver).
After 2-3 days, Fe2+ is either absorbed into the blood or what?
passed into the intestinal lumen as part of the exfoliated intestinal cells
Fe2+ absorbed in the _______ combines with a _____ _____ called (a__________) to form transferrin.
blood, plasma protein called apotransferrin.
Transferrin transports Fe2+ to the bone marrow for use in what?
mitochondria of the developing erythrocytes for heme production.
Ferritin is the storage form of _____ . The_____ is the principal storage site.
Fe2+, liver
In times of excess, Fe2+ can accumulate in the ______ as _________.
liver, hemosiderin.
__________ _________, rather than excretion, regulates Fe2+ levels in the body.
Controlled absorption
