Blood connective tissue forms mostly in red bone marrow

Functions Transports vital substances Maintains stability of interstitial fluid Distributes heat

3 Types 1. red blood cells or Erythrocytes 2. white blood cells or Leukocytes 3. platelets (cell fragments) or Thrombocytes

Volume varies with. . .

body size changes in fluid concentration changes in electrolyte concentration amount of adipose tissue

≊ 5 liters/ 8% body weight Composition

45% formed elements + 55% plasma Hematocrit: measurement of cell volume to total volume

Origin

Erythrocytes

biconcave discs ⅓ hemoglobin

oxyhemoglobin (arterial blood) deoxyhemoglobin (venous blood)

can readily squeeze through capillaries lack nuclei + mitochondria

Red Blood Cell Counts

number of RBCs in a cubic millimeter of blood reflects blood’s oxygen carrying capacity

adult males ­ 4,600,000 ­ 6,200,000 adult females ­ 4,200,000 ­ 5,400,000 children ­ 4,500,000 ­ 5,100,000

Production low blood oxygen causes kidneys and liver to release Erythropoietin (stimulates

production) vitamin B12, folic acid, and iron are necessary

B12 + folic acid absorbed from small intestine

DNA synthesis Iron

absorbed from small intestine + conserved during RBC destruction for reuse

hemoglobin synthesis

Life Cycle

1. circulate for ≊ 120 days 2. macrophages in spleen + liver destroys worn out RBCs 3. hemoglobin is broken down into heme + globin 4. iron from heme returns to red bone marrow 5. bilirubin + biliverdin excreted in bile

Types of Anemia

Type Cause Defect

Aplastic anemia Toxic chemicals, radiation Damaged bone marrow

Hemolytic anemia Toxic chemicals RBC destroyed

Iron deficiency anemia Dietary lack of iron Hemoglobin deficiency

Pernicious anemia Inability to absorb vitamin B12

Excess of immature cells

Sickle cell disease Defective gene RBC abnormally shaped

Thalassemia Defective gene Hemoglobin deficiency; RBC short­lived

Destruction 1. Squeezing through capillaries of active tissues damages RBC 2. Macrophages in the spleen +liver phagocytize damaged RBC 3. Hemoglobin → heme + globin 4. Heme → iron + biliverdin 5. Iron is made available for reuse in the synthesis of new hemoglobin or is stored in the

liver as ferritin 6. Some biliverdin → bilirubin 7. Biliverdin + bilirubin are excreted in bile as bile pigments 8. Globin → amino acids that are metabolized by macrophages/ released into the blood

Antigens and Antibodies

antigens ­ a chemical that stimulates cells to produce antibodies antibodies ­ a protein that reacts against a specific antigen

ABO Blood Group Based on the presence/absence of two major antigens on RBC membranes

antigen A or antigen B

Blood Types for Transfusion

Blood of Recipient Prefered Blood Type of Donor Permissible Blood Type of Donor (emergency)

A A A,O

B B B,O

AB AB AB,A,B,O

O O O

agglutination ­ clumping of RBC in response to a reaction between an antibody + antigen occurs in wrong blood type transfusion/disorders; blood clumps together

Rh Blood Group Rh positive ­ presence of antigen D and/or other Rh antigens on the RBC membranes Rh negative ­ absence of antigen D and/or other Rh antigens on the RBC membranes

Leukocytes Functions

protects against disease hormones stimulate development

interleukins colony­stimulating factors

2 Types 1. Granulocytes (cytoplasmic granules are present)

Neutrophils (segs, polymorphonuclear leukocyte, or bands (young neutrophils)) light­purple granules in acid­base strain lobed nucleus 1st to arrive at infection phagocytic 54%­64% of leukocytes elevated in bacterial infections

Eosinophils

deep­red granules in acid stain bilobed nucleus defend against parasitic worm infestations 1%­3% of leukocytes elevated in parasitic worm infestations/ allergic reactions

Basophils

deep­blue granules in basic stain release histamine + heparin <1% of leukocytes similar to eosinophils in size + shape of nuclei

2. Agranulocytes (cytoplasmic granules are not present)

lymphocytes slightly larger that RBC large spherical nucleus surrounded by thin rim of cytoplasm T cells + B cells → important to immunity B cells produce antibodies 25%­33% of leukocytes

Monocytes

largest spherical, kidney­shaped, oval/lobed nuclei leave bloodstream to become macrophages 3%­9% of leukocytes Phagocytize bacteria, dead cells, and other debris

Diapedesis → leukocytes squeeze between the cells of a capillary wall and enter the

tissue space outside the blood vessel

Positive Chemotaxis → movement of leukocytes towards the damaged tissue

region because of the chemicals that were released by damaged cells

White Blood Cell Counts

Normal = 5,000 ­ 10,000 per cubic millimeter of blood

Leukopenia low WBC count (below 5,000) Typhoid fever, flu, measles, mumps, chicken pox, and AIDS

Leukocytosis high WBC count (above 10,000) acute infections, vigorous exercise, great loss of body fluids

Differential WBC count lists percentages of types of leukocytes may change in particular diseases

Thrombocytes cell fragments of megakaryocytes 130,000 ­ 360,000 per cubic millimeter of blood

Functions controls blood loss from broken vessels

Plasma

liquid portion of blood (straw colored)

55% blood 92% water

Gases and Nutrients

Gases Oxygen Carbon Dioxide

Nutrients amino acids simple sugars nucleotides lipids

Nonprotein Nitrogenous Substances

molecules containing nitrogen but are not proteins urea ­ product of protein catabolism; about 50% of NPN substances uric acid ­ product of nucleic acid catabolism amino acids ­ product of protein catabolism creatine ­ stores phosphate creatinine ­ product of creatine metabolism BUN ­ blood urea nitrogen; indicate health of kidney

**catabolism means breaking down molecules by metabolic pathways into smaller units producing energy Plasma Electrolytes

absorbed from the intestine/released as byproducts of cellular metabolism Sodium, potassium, calcium, magnesium, chloride, bicarbonate, phosphate, and

sulfate (sodium and chloride are most abundant)

Hemostasis stoppage of bleeding 1. Blood Vessel Spasm

triggered by pain receptors, platelet receptors, platelet release, or serotonin smooth muscle in vessel contracts

2. Platelet Plug Formation triggered by exposure of platelets to collagen

platelets adhere to rough surface to form plug

3. Blood Coagulation

Extrinsic clotting mechanism chemical outside of blood triggers blood coagulation

triggered by thromboplastin (not found in blood) triggered when blood contacts damaged tissue

Intrinsic clotting mechanism

chemical inside blood triggers blood coagulation triggered by Hageman factor (found inside blood) triggered when blood contacts foreign substance

Fate of blood Clots

After forming, a blood clot retracts and pulls the edges of a broken vessel together while squeezing the fluid serum from the clot

plate­derived growth factor stimulate smooth muscle cells and fibroblasts to repair damaged blood vessel walls

plasmin digest the blood clot

thrombus ­ abnormal blood clot embolus ­ blood clot moving through blood

Prevention of Coagulation as a clot forms, fibrin absorbs thrombin and prevents the clotting reaction from spreading antithrombin inactivates additional thrombin by binding to it and blocking its action on

fibrinogen heparin (an anticoagulant)

Green Boxes and Clinical Application

1. Leukemia Myeloid Leukemia

bone marrow produces too many immature granulocytes Leukemia cells crowd out other blood cells

anemia bleeding susceptible to infections

Lymphoid Leukemia lymphocytes are cancerous symptoms similar to myeloid leukemia

Treatments drugs marrow and umbilical cord transplants chemotherapy regimens