Chapter 12 Blood

 Type of connective tissue  Functions –Transporting substances to maintain homeostasis  Travels through the vessels

Blood Volume  8% of body weight  Typical adult has 5 liters of blood

Blood Composition  Formed elements –Erythrocytes –Leukocytes –Thrombocytes  Fluid element –Plasma

Blood Sample  45% cells by volume  Hematocrit –% of blood sample that is packed cells (most of which are the RBC’s)  35% Plasma

Erythrocytes  RBC Characteristics –Biconcave disks Thicker on outside and thin on middle Adaptation for function of gas transport

Erythrocytes  RBC Characteristics –1/3 hemoglobin by volume Deoxyhemoglobin –Hemoglobin without O 2 Oxyhemoglobin –Hemoglobin with O 2

Erythrocytes  RBC Characteristics –Cyanosis Blue –Only a good color if you are a SMURF! Abundant deoxyhemoglobin

Erythrocytes  RBC Characteristics –Develop from proerythroblast –Several intermediate stages –Young stages have nucleus –Mature RBC lacks nucleus

Red Blood Cell Counts  Males –4.6 – 6.2 million/cc  Females –4.2 – 5.4 million/cc Why are females lower in this count?

Red Blood Cell Breakdown  Macrophages in liver and spleen phagocytize damaged cells  Hgb is broken down to heme and globin  Heme is decomposed into Fe and biliverdin

Red Blood Cell Breakdown  Fe is reused for new Hgb synthesis or stored as ferritin in the liver.  Some biliverdin is converted into bilirubin  Bilirubin and biliverdin excreted in bile as pigments.

Red Blood Cell Production  Done in the red bone marrow.  Erythropoietin –Hormone produced by kidneys –Lack of cells it is produced to stimulate cell production –Triggered by O 2 levels

Red Blood Cell Production  Life of RBC 120 days.  Production is regulated by negative feedback.

Red Blood Cell Production  Dietary factors –B 12 and folic acid significantly influence RBC production –Fe required for RBC synthesis  Anemia –Lack of Fe or Hgb. Other types also

Leukocytes  Function –Protection against disease  Two major types –Granulocytes –Agranulocytes

Granulocytes  Have grainy looking cytoplasm  Types –Neutrophils –Nucleus has two – five lobes –Phagocytosis/First on the scene –54% of blood sample

Granulocytes  Eosinophils –Bilobed nucleus –Prevalent in allergic reactions and parasitic worm infections –1 – 3% of blood sample

Granulocytes  Basophils –Similar to eosinophils in shape –Release histamine – promotes inflammation –Releases heparin – blood thinner –Less than 1% of blood sample

Agranulocytes  Lack grains in cytoplasm –Monocytes Largest of all leukocytes Phagocytosis 3 – 9% of blood samples

Agranulocytes  Lymphocytes –T-cells directly attack anything foreign –B-cells produce antibodies for longer term protection –25 – 33% of blood sample

Leukocyte infection fighting  Diapedesis –Allows them to leave circulation –Ameboid movement  Positive Chemotaxis –Release of chemicals that signal other cells to the area.

Pus  Contains WBC’s  Dead microorganisms  Fluid

White Blood Cell Counts  5,000 – 10,000 cells per cc.  Leukocytosis –More than 10,000 cells per cc  Leukopenia –Less than 5,000 cells per cc

White Blood Cell Counts  Differential blood count –Separates and counts each specific type of white blood cell

Plasma  92% water  Contains organic and inorganic molecules

Plasma  Functions –Transporting nutrients, gasses and vitamins –Helps regulate fluid and electrolyte balance –Maintaining a favorable pH.

Plasma Proteins  Most abundant of dissolved substances.  Three major plasma protein –Albumins –Globulins –Fibrinogen

Albumins  Smallest of plasma proteins  Make up 60% of the proteins  Synthesized in the liver  Function to maintain blood osmotic pressure

Globulins  Three types – 36% of proteins –Alpha Made in liver Transport lipids and fat soluble vitamins –Beta Same as Alpha

Globulins  Gamma –Synthesized in lymphatic tissue –Constitutes the antibodies of immunity

Fibrinogen  Synthesized in liver  Makes up 4% of proteins  Soluble protein that plays the role in blood coagulation

Gasses  Oxygen  Nitrogen  Carbon dioxide

Nutrients  Amino acids  Sugars  Lipids

Plasma Lipoproteins  Chylomicrons –Have a high concentration of triglycerides –Transports dietary fats to muscle and adipose tissue

Plasma Lipoproteins  Very low-density lipoproteins VLDL –High concentration of triglycerides/ Made in liver –Transports triglycerides from liver to adipose tissue

Plasma Lipoproteins  Low-density Lipoproteins LDL –High concentration of cholesterol/Made from VLDL molecules –Delivers cholesterol to various cells including liver

Plasma Lipoproteins  High-density Lipoproteins HDL –Relatively high concentration of protein and low concentrations of lipids. –Transports to the liver chylomicron remnants.

Nonprotein Nitrogenous Substances NPN  Amino acids  Urea  Uric acid  Creatine  Creatinine

Plasma Electrolytes  Na KK  Ca  Mg  Cl  HCO 3  PO 4  SO 4

Blood Clotting  Hemostasis  Three Steps –Blood Vessel Spasm –Platelet Plug Formation –Blood Coagulation

Blood Vessel Spasm  Damage to a vessel causes a vasospasm  Lasts only a few minutes but sets into motion the next two steps

Platelet Plug Formation  Platelets will stick to anything rough or jagged.  Sends out serotonin so smooth muscle will contract again.  Plug forms to stop bleeding

Blood Coagulation  Forms a blood clot  Complex and requires clotting factors  Major event in blood clot formation is conversion of fibrinogen to fibrin.

Blood Coagulation  Tissue damage release tissue thromboplastin. This along with Ca +2 produces prothrombin activator

Blood Coagulation  Prothrombin activator and Ca +2 combine with Prothrombin to form Thrombin

Blood Coagulation  Thrombin and Ca +2 combine with fibrinogen to form fibrin  Fibrinogen is soluble  Fibrin is insoluble  Blood clotting is positive feedback mechanism

Blood Coagulation  Thrombus –Stationary blood clot  Embolus –Moving blood clot

Blood Typing  Genetically determined  ABO blood grouping used  Based on presence or absence of antigens on RBC

Blood Typing  Antigens –On the RBC membrane –Specific shape like puzzle pieces  Antibodies –Found in plasma –Reciprocal shape to antigens

Blood Typing AA –A antigens –anti-B antibodies BB –B antigens anti-A antibodies

Blood Typing  AB –Both A and B antigens –No antibodies OO –No antigens –Both anti-A & anti-B antibodies

Blood Typing  O = universal donor  AB = universal recipient  Transfusion reactions occur due to agglutination – clumping of RBC

Rh factor  Discovered in Rhesus monkeys  Antigen D –Present is Rh positive –Absent in Rh negative  Anti-D antibody

Erythroblastosis Fetalis  If Rh negative mother has Rh positive fetus can develop this with subsequent children  Use Rhogam to prevent this.