BLOOD PHYSIOLOGY Study Notes for Medical Students

BLOOD PHYSIOLOGY Study Notes for Medical Students

  • Total circulating blood is 8% of total body weight
  • Active bone marrow forming the blood cells is called red marrow and inactive marrow is called yellow marrow. Inactive marrow is filled with fats.
  • 75% bone marrow belongs to white blood cells producing myeloid series
  • Neutrophils and monocytes are produced from a single precursor. There are se[arate pools for progenitors of megakaryocytes, lymphocytes, erythrocytes, eosinophils, and basophils
  • Mast cells, Kupfer cells, dendritic cells, osteoclasts and Langerhans cells also originate from bone marrow
  • Best source of hematopoietic stem cells is umbilical cord blood
  • Average half life of neutrophils in circulation is 6 hours
  • Nutrophils, eosinophils, and basophils are collectively called granulocytes/polymorphonuclear cells
  • Eosinophils are abundant in GIT and respiratory mucosa
  • Mast cells are abundant in areas rich in connective tissue eg beneath epithelium
  • Monocyte leave the circulation and become macrophages in tissues. They do not reenter the circulation.
  • Pluripotent uncommitted stem cells become committed by the action of IL1, IL6 followed by IL3(I,3,6 commits the stem cells, kind of love guru )
  • Cytokines are hormone like molecules that act generally in paracrine fashion
  • IL1 increases slow wave sleep and reduces appetite
  • Platelets don’t have nuclei.They have half life of 4 days
  • Splenectomy causes an increase in circulation platelets.
  • Cytoplasm of platelets contains actin, myosin, glycogen, lysosomes, and two types of granules: a. Dense granules: they have nonprotein substances. They contain serotonin and ADP b. Alpha granules: contain clotting factors, PDGF
  • Platelet production is controlled by colony stimulating factor and thrombopoietin. Thrombopoietin controls the maturation of megakaryocytes and is produced by kidney and liver.
  • Osmotic fragility of RBC starts at 0.5% saline. Almost half the RBCs are lysed at 0.40 to 0.42% saline. Complete lysis occurs at 0.35% saline.
  • 2.5 % hb in adults is HbA2
  • Hb F has the ability to decrease the polymerization of deoxygenated HbS. Hydroxyurea causes HbF production and is used in treatment of HbS
  • Blood group antigens are called aglutinogens
  • Blood group antibodies are called agglutinins
  • Blood group antigens are also present in salivery gland, saliva, kidney, pancrease, liver, lungs, testes, semen, and amniotic fluid
  • A and B antigens are actually oligosaccharides that differ in their terminal suger. In RBCs they are mostly OLIGOSPHINGOLIPIDS and in other tissues they are glycoprotiens.(past MCQ)
  • An antigen called H antigen is present in all RBCs in all individuals. In blood group A the A antigen is attached to H antigen, in blood group B the B antigen is attached to H antigen where as in blood group O no antign is attached to H antigen i.e terminal part of blood group O is H antigen(past MCQ). Blood group AB has both antigens at the terminal.
  • Bilirubin rarely penetrates Blood brain barrier in adults. But in neonates and fetus the BBB is permeable to it an in erythroblastosis feotalis it causes KERNICTERUS
  • If whole blood is allowed to clot and clot is removed, remaining is called serum. (plasma minus factor 2,5,8,fibrinogen is called serum)(past MCQ)
  • Serum has high serotonin level due to breakdown of platelets.
  • Thrombomodulin is produced by all endothelial cells except that of microcicculation of brain
  • Thrombin is procoagulant in circulation blood. It becomes anticoagulant when it binds to thrombomodulin
  • Lymph has lower protein content than plasma.
  • Blood Storage

Storage of different blood products

  • Whole blood is stored at 4° C for 3 weeks.
  • Packed cells (RBCs) are stored at 1-6° C for 35 days.
  • FFP (fresh frozen plasma) and cryoprecipitate can be stored at -40° C for 2 years.
  • Platelets are stored at 22° C for 5 days
  • mitral regurgitation =pansystolic murmur
  • mitral stenosis =mid diastolic murmur
  • aortic regurgitation =end diastolic murmur
  • aortic stenosis =ejection Systolic murmur
  • pulmonary regurgitation =diastolic murmur
  • pulmonary stenosis =Systolic murmur
  • throtoxicosis=innocent murmur
  • decrease hematocrit =continuous murmur
  • Gastric Motility increased by GASTRIN
  • Gastric Motility decreased by CCK
  • Intestinal Motility increased by CCK
  • Intestinal Motility decreased by SECRETIN
  • Gastric Emptying increased by Motilin
  • Gastric Emptying decreased by CCK
  • Gastric secretions inhibited by SECRETIN
  • If Newborn to 14 years of age the most common cause is acute lymphoblastic leukemia
  • If age is between 40 to 60 most likely cause will be AML and CML
  • If age is more than 60 most likely causes r CLL and CML.
  • Repeated blood Transfusion…..HAEMOCHROMATOSIS
  • Multiple Transfusions….HYPOCALCEMIA
  • Massive Transfusion. ….HYPERKALEMIA, HYPOCALCEMIA, and HYPOTHERMIA
  • -Eosinophilia present in:
    Hodgkin lymphoma and polyarteritisnodosa.
    -PGI2__by endothelial cells
    -TXA2__by platelets
  • Blood transfusion induced electrolyte balance is as follows:
    -hypocalcemia
    -hyperkalemia
    -hypothermia
    -metabolic acidosis
    -left shift of oxy-hem curve

Hypokalemia and Hyperkalemia Important Points

Hypokalemia aggregates digoxin toxicity
&
Digoxin toxicity causes hyperkalemia
Hypercalcemia cause pancreatitis
&
Pancreatitis causes hypocalcemia
Acidosis causes hyperkalemia
&
hyperkalemia causes metabolic acidosis
Hypokalemia causes alkalosis
&
Metabolic alkalosis causes hypokalemia
Hypokalemia inhibit insulin releases
&
Insulin causes hypokalemia
Insulin deficiency causes hyperkalemia
&
Hyperkalemia causes insulin release.
Hypokalemia causes rhabdomyolysis
&
Rhabdomyolysis causes hyperkalemia
Sodium influx causes depolarization
&
Potassium efflux causes hyperpolarization

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