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