The Cardiovascular System The Blood

Fluids of the Body Cells of the body are serviced by 2 fluids: blood composed of plasma and a variety of cells transports nutrients and wastes interstitial fluid bathes the cells of the body Nutrients and oxygen diffuse from the blood into the interstitial fluid & then into the cells Wastes move in the reverse direction

Functions of Blood Transportation Regulation O2, CO2, metabolic wastes, nutrients, heat & hormones Regulation pH through buffers body temperature coolant properties of water vasodilatation of surface vessels dump heat water content of cells by interactions with dissolved ions and proteins Protection from disease & loss of blood

Physical Characteristics of Blood Denser and more viscous than water Temperature of 38oC (100.4oF) pH range 7.35-7.45 8 % of total body weight (20% of extracellular fluid) Blood volume 5 to 6 liters in average male 4 to 5 liters in average female hormonal negative feedback systems maintain constant blood volume and osmotic pressure

Components of Blood

Plasma Water (~91%) Proteins (~7%) albumins globulins fibrinogen Other Solutes (~1.5%) electrolytes nutrients gases regulatory substances waste products

Formed Elements of the Blood

Hematocrit Percentage of total blood volume occupied by red blood cells female normal range: 38 - 46% (average of 42%) male normal range: 40 - 54% (average of 47%) Anemia not enough RBCs or not enough hemoglobin Polycythemia too many RBCs (over 65%) Dehydration, blood doping in athletes

Hemopoiesis

Red Blood Cells O2 / CO2 transport Provides RBCs their ability to carry oxygen No nucleus Biconcave shape

RBC Lifecycle and Hemoglobin

Control of Erythropoiesis

White Blood Cells Characteristics Nucleus lobed round Granules granular agranular

Lymphocyte Functions: Immune response Direct attack Antibodies Characteristics: Agranular Round nucleus Pale blue cytoplasm

Monocyte Functions: Phagocytosis Become macrophages Characteristics: Large Agranular U-shaped nucleus

Neutrophil Functions: Phagocytize bacteria Characteristics: Nucleus multi-lobed Inconspicuous granules

Eosinophil Functions: Kills parasitic worms Destroys antigen-antibody complexes Characteristics: Nucleus bilobed Red granules

Basophil Functions: Release histamine Contain heparin Characteristics: Nucleus lobed Blue-purple granules

Emigration of WBCs WBCs roll along endothelium, stick to it & squeeze between cells. adhesion molecules (selectins) help WBCs stick to endothelium displayed near site of injury molecules (integrins) found on neutrophils assist in movement through wall Neutrophils & macrophages phagocytize bacteria & debris chemotaxis of both kinins from injury site & toxins

WBC Physiology Less numerous than RBCs 5000 to 10,000 cells per drop of blood 1 WBC for every 700 RBC Leukocytosis is a high white blood cell count microbes, strenuous exercise, anesthesia or surgery Leukopenia is low white blood cell count radiation, shock or chemotherapy Only 2% of total WBC population is in circulating blood at any given time rest is in lymphatic fluid, skin, lungs, lymph nodes & spleen

Differential WBC Count Detection of changes in numbers of circulating WBCs (percentages of each type) indicates infection, poisoning, leukemia, chemotherapy, parasites or allergy reaction Normal WBC counts neutrophils 60-70% (up if bacterial infection) lymphocyte 20-25% (up if viral infection) monocytes 3 -- 8 % (up if fungal/viral infection) eosinophil 2 -- 4 % (up if parasite or allergy reaction) basophil <1% (up if allergy reaction or hypothyroid)

Differential WBC Count

Complete Blood Count Screens for anemia and infection Total RBC, WBC & platelet counts; differential WBC; hematocrit and hemoglobin measurements Normal hemoglobin range infants have 14 to 20 g/100mL of blood adult females have 12 to 16 g/100mL of blood adult males have 13.5 to 18g/100mL of blood

Platelets Myeloid stem cells develop eventually into a megakaryocyte Splinters into 2000-3000 fragments Each fragment enclosed in a piece of plasma membrane Disc-shaped with many vesicles but no nucleus Help stop blood loss by forming platelet plug Granules contain blood clot promoting chemicals Short life span – 5-9 days

Summary of Formed Elements

Hemostasis - sequence of responses to stop bleeding 1. Vascular spasm 2. Platelet plug formation 3. Coagulation (clotting)

Platelet Plug Formation

Blood Clotting

Clotting Cascade

Clotting Factors

Blood Groups and Blood Types

Blood Groups and Blood Types

ABO Blood Group Interactions

Rh Factor Rh+ has Rh antigen no Rh antibody Rh- no Rh antigen no Rh antibody exposure of Rh- to Rh+ will produce antibody

Hemolytic Disease of the newborn (HDN)

Blood Typing

Anemia - reduced oxygen carrying capacity of the blood. 1. Insufficient number of RBCs a. hemorrhagic anemia b. hemolytic anemia c. aplastic anemia 2. Decreased hemoglobin content a. iron-deficiency anemia b. pernicious anemia 3. Abnormal hemoglobin a. thalassemia b. sickle-cell anemia

Sickle-Cell Disease (SCD) Genetic defect in hemoglobin molecule (Hb-S) that changes 2 amino acids at very low O2 levels, RBC is deformed by changes in hemoglobin molecule within the RBC sickle-shaped cells rupture easily = causing anemia & clots Person with only one sickle cell gene increased resistance to malaria because RBC membranes leak K+ & lowered levels of K+ kill the parasite infecting the red blood cells

Hemophilia Inherited deficiency of clotting factors bleeding spontaneously or after minor trauma subcutaneous & intramuscular hemorrhaging nosebleeds, blood in urine, articular bleeding & pain Hemophilia A lacks factor VIII (males only) most common Hemophilia B lacks factor IX (males only) Hemophilia C (males & females) less severe because alternate clotting activator exists Treatment is transfusions of fresh plasma or concentrates of the missing clotting factor

Leukemia Acute leukemia Chronic leukemia uncontrolled production of immature leukocytes crowding out of normal red bone marrow cells by production of immature WBC prevents production of RBC & platelets Chronic leukemia accumulation of mature WBC in bloodstream because they do not die classified by type of WBC that is predominant---monocytic, lymphocytic