HIS 4-8 Blood Flashcards
pH of blood
7.4 (slightly alkaline)
% composition of formed blood cells. RBC vs WBC and platelets.
99% RBC, 1% WBC and Platelets
Haem
Haem: Essential part of hemoglobin. Contains Fe2+ bound by 4 N’s. Haem is also found in other biologically important hemoproteins such as myoglobin and cytochrome. It is mainly synthesized in the mitochondria of liver and bone marrow, while degraded in the spleen.
Myoglobin
Myoglobin has very high affinity for O2 and slow dissociation. This allows myglobin to hold its breath for longer. Found in muscle tissue.
It harbors only one heme group, whereas hemoglobin has four. Although its heme group is identical to those in Hb, Mb has a higher affinity for oxygen than does hemoglobin. This difference is related to its different role: whereas hemoglobin transports oxygen, myoglobin’s function is to store oxygen.
Myoglobin O2 bonding
Bonds only one O2 and does not have co-operative binding, therefore high k50, higher affinity, and lower disassociation.
Hyperbolic dissociation curve as opposed to sigmoidal.
Hemoglobin and O2 bonding, affinity and disassociation.
Hemoglobin has cooperative binding. Bonding with heme causes slight conformational shift, owing to increased affinity. This is allosteric regulation and co-opterativity. Upon the bonding of an O2, some salt bridges are broken and the Hemoglobin enters a more relaxed state.
So it has a lower affinity than myoglobin. The affinity increases as O2 binds. Therefore, affinity increases where O2 is high (lungs) and decreases where O2 is low (tissues). It also means that O2 dissociates at a higher partial pressure of O2, therefore responding to small changes in O2 concentration. The fourth O2 bind has an affinity 300x greater than the 1st.
Hemoglobin structure
quaternary structure, composed of 4 globular polypeptide chains (composed of two α and two β subunits) held together by noncovalent interactions. Each chain has a haem bound to an Fe+ by N bonds. Each Hgb molecule can bind 4 O2.
Fetal hemoglobin structure
Fetal hemoglobin has gamma chains in place of beta.
Bohr effect
BOHR Effect: Oxygen is released more easily at lower pH (or increased CO2). This is in addition to the allosteric effect and so the sigmoidal curve shifts to the right in low pH.
How, and in what 2 ways is CO2 carried away from tissue?
70% of CO2 is carried as carbonic acid. CO2+H20 = H2CO3, reaction catalyzed by carbon anhydrase. In blood, H2CO3 releases H+. This H+ is acidic but it is mopped up by side chains of amino acid residues.
The other 30% bond to the nitrogen of an amino group.
2,3-biphosphoglycerate. Where does it come from and how does it effect hemoglobin?
Byproduct of glycolysis. It binds to deoxy hb and decreases the affinity for O2, therefore increasing the disassociation tendency. This moves the sigmoidal curve to the right and encourages hb to release its O2 in the tissues. In anemia or anaerobic metabolism, 2,3-biphosphoglycerate is produced in abundance and has the secondary effect of enhancing O2 disassociation.
How many RBS are formed per second?
2-3 million
Haematocrit
Hematocrit, aka packed cell volume, is the lab measurement of RBS in blood. Should be 45%.
Name the 4 granulocytes
Neutrophils (95%)
Basophils
Eosinophils
mast cells
Name the 2 agranulocytes
lymphocytes (B/T and natural killer cells), and monocytes (which differentiate into macrophages and dendritic cells).
Neutrophils
Neutrophils: 95% of granulocytes. First line of defense. Phagocytes. Elevated count indicates infection.
Basophils
Synthesize and store histamine and heparin.
Eosinophils
Eosinophils: Combat viral and parasitic infections. Play a role in allergic response. Secrete histamine.
Phagocytes
Cells that protect the body by ingesting harmful foreign particles, bacteria, and dead or dying cells.
Name the 2 lymphocytes
T and B cells
Monocytes
Monocytes: Enter tissues and engulf bacteria (macrophages) as well as process and remove old RBCs.
Macrophage
monocytes-a type of phagocyte.
CAD: Cell adhesion molecules
Cell adhesion molecules allow cells to secure themselves at sites of infection.
Proerythroblast
Erythopoiesis begins with proerythroblast and goes undergoes 7 stages of mitosis, each time replicating and becoming more developed.
Nutrients needed for erythropoiesis
B12, amino acids, Folate, Iron.
Anemia
Anemia: Occurs from too little hemoglobin.
Causes:
- decreased erythropoiesis
- decreased hemoglobin in RBCs
- increased haemolysis
- Increased blood loss
(B12 or folate deficiency, leukemia, marrow failure-aplastic anemia), over destruction of RBC’s (genetic), or morphological.
Aplastic anemia
Caused by marrow failure
Pallor
Anemia sign; loss of skin or mucous membrane color in eyes.