Ch. 13 Flashcards
What is in our blood?
Fluid (plasma)
Particulate
- proteins (like albumin)
- antibodies
- cytokines
cellular components:
- platelets
- white blood cells (lekocytes and lymphocytes)
- red blood cells (erythrocytes)
Which stem cell line does RBCs and platelets come from?
myeloid stem cell line
What is erythropoiesis?
red blood cell production
describe red blood cells.
most abundant cell in our body
biconcavity and reversible deformity makes them flexible
120 day life cycle
takes oxygen to tissue
What is the purpose of a RBC?
carry oxygen!
What does a RBC need to carry oxygen?
hemoglobin
What does hemoglobin need to be made?
IRON
What does an adult hemoglobin contain?
Two alpha chain proteins
two beta chain proteins
EACH PROTEIN CONTAINS ONE IRON CONTAINING HEME GROUP THAT THE OXYGEN BINDS TO
What does a fetal hemoglobin contain?
two alpha chain proteins
two gamma chain proteins
also has the iron containing heme groups that oxygen binds to
What are some nutritional requirements to synthesize RBCs?
Proteins: amino acids
Vitamins: B (12,6,2), E, and C; folic acid; pantothenic acid; niacin BIG ONES ARE B12 AND FOLIC ACID
minerals: iron and copper
folate
What are some facts she gave about iron?
Absorbed in the gut (smaller quantity) or recycled from old RBCs (where most comes from)
Less than 1mg is loss per day through urine, sweat, epithelial cells or from the gut
Transferrin: the iron transporting protein in the circulation
iron is stored in the liver as ferritin
What are vitamins B12 and Folic acid meant for?
DNA synthesis and maturation of RBC.
How much of our iron is in our hemoglobin?
65% (rest is mostly stored in the liver)
What is the iron cycle?
- Iron that is taking in by the diet is stored in the liver
or red blood cells are taken in by the spleen to be recycled.
- The hemoglobin from the red blood cell is broken down into the heme and the globin, the heme is broken down into bilirubin and iron
the iron is either stored in the liver or spleen, or taken directly to the bone marrow for hemoglobin synthesis
the bilirubin is taken to the liver and secreted with the bile
Iron in the liver or spleen can be released to the bone marrow at any time as well
What stimulates erythropoiesis and maturation of RBCs?
erythropoietin.
What secretes erythropoietin?
kidneys in response to low oxygen levels.
What is the main thing to take from the maturation of RBCs?
In each step of erythropoiesis the nucleus gets smaller and the number of hemoglobins gets larger.
What is the difference between a reticulocyte and a erythrocyte?
A reticulocyte has less hemoglobin than a erythrocyte.
reticulocytes also still have their endoplasmic reticulum
Why are the kidneys dumb when it comes to erythropoietin secretion?
The kidneys will secrete more erythropoietin in response to low oxygen levels, NO MATTER WHAT THE CAUSE MAY BE.
So lets say that someone has chronically low oxygen levels because of a lung disease, the kidneys only know that there has been a decrease in oxygen levels, so it releases that erythropoietin in attempt to increase the amount of RBCs to carry more oxygen, even if we have plenty. Elevated RBC count is called POLYCYTHEMIA. (gives patient reddy red color)
What is the feedback loop for the kidneys and erythropoiesis?
- -decreased population of mature RBC
- decreased hemoglobin synthesis
- decreased blood flow
- hemorrhage
- increased oxygen consumption by tissues
- decreased arterial PO2
- increased secretion of erythropoietin by kidney cells
- increased proliferation of erythroblasts in bone marrow
- increased population of mature erythrocytes in circulation
- increased arterial PO2
- decreased secretion of erythropoietin
What happens after the RBCs 120 day life span, how do they get damages and die?
After the 120 days in circulation, RBCs membranes become weakened.
Because they don’t have any nucleus, they can’t make new membrane components
Because their membrane stays weakened, they will eventually break as they squeeze through capillaries, mainly the capillaries in the spleen because they are designed to make that happen
WBCs eat the RBCs in the spleen, liver, bone marrow, or lymph nodes
The RBCs are processed and unconjugated bilirubin, iron, and amino acids are recycled
What do we have to do with unconjugated bilirubin?
It needs to be conjugated and secreted in bile by the liver.
What is hemoglobin A-1C?
Gives the average blood sugar over the last 120 days of the lifespan of red cells tested. Gives a good test to see how well diabetics have been regulating their sugars over the last few months.
What would happen if someone had to process a lot of red blood cells?
They could get an enlarged liver or spleen because of the extra work they have to do.
How does the unconjugated bilirubin get conjugated?
The liver links it to gluconuride, gets excreted in bile.
What causes jaundice?
If the liver can’t conjugate or it can’t keep up with the amount of unconjugated bilirubin, it ends up out in our blood stream and in tissues.
Is it normal for a 2 week old to have jaundice?
Yes, if it is being breastfed. Something in the breast milk causes it (especially when the infant is low on fluids). BUT IF IT IS IN THE FIRST 24 HOURS OF BIRTH THERE SHOULD BE SOME CONCERN FOR POSSIBLE HEMOLYTIC ANEMIA.
How is jaundice treated in those infants?
Phototherapy, take them outside for a little bit.
What happens when RBCs are destroyed outside of the spleen?
It can turn the plasma red (hemoglobinemia)
If it goes into the urine then it turns the urine coca-cola color (hemoglobinuria). This happens when it is filtered through the kidneys
Why is it not ideal to have red blood cells destroyed outside of the spleen?
It doesn’t allow for the cells to be recycled. Can possibly lead to an iron deficiency.
What are the the normal number of red cells for a man and a woman?
men - 4.2-5.4 (x 10^6 x L)
women - 3.6-5.0 (x 10^6 x L)
What should our normal number of reticulocytes be? (shows the rate of red cell production)
1.0% - 1.5% of total RBC
What is our normal hemoglobin count? (men and women)
men - 14-16.5 g/dl
women - 12-15 g/dl
What is our normal hematocrit (volume of cells in 100ml of blood)? (man and woman)
men - 40%-50%
women - 37%-47%
What is the mean corpuscular volume and its normal value?
Size of the red cell
85-100 fl/cell
What is the mean corpuscular hemoglobin concentration and its normal value?
The concentration of hemoglobin in the red cell.
31-35 g/dl
What is the mean cell hemoglobin and its normal value?
Red cell mass
27-34 pg/cell
What happens to an infants blood cell count at birth and why?
It’s increased!
The intrauterine environment is hypoxic so it stimulates erythropoietin production, which results in polycythemia.
What lowers the blood cell count at birth?
The trauma of birth and the cutting of the umbilical cord.
Based on what you know about an infants hematologic system at birth, what color would they be and why?
They would be very red in color because of their polycythemia.
Describe a childs lymphocytes.
They tend to have more atypical lymphocytes because of frequent viral infections after birth.
Usually see more atypical lymphocytes in the 18 month-5 year range. ESPECIALLY IF IN DAYCARE.
What happens to our erythrocytes and erythropoiesis when we age?
Why?
The life-span of erythrocytes is normal but we replace them slower.
Possible causes:
Iron depletion
Decreased total serum iron
iron-binding capacity decreases
intestinal iron absorption decreases
decreased lymphocyte function leads to decreased iron recycling
What happens to our lymphocyte function as we age?
It decreases.
What happens to our humoral immune system as we age?
It becomes less responsive.
