Biomedical Innovations Unit 3 Tissues of Life A Focus on Blood

Blood Introduction Blood is a special Connective Tissue, and is the major component of the Circulatory System Connective tissue is a group of cells that collectively function to support, connect, and/or separate other tissues and organs. The Circulatory System is comprised of two sub-systems: 1. Cardiovascular System Includes network of blood vessels, blood, and heart Major function is to transport nutrients, gases and hormones to cells and wastes from cells for excretion outside the body 2. Lymphatic System Includes network of lymph vessels, the lymphocyte white blood cell, and lymphoid organs (tonsils, spleen, thymus, bone marrow, and lymph nodes) Major functions are to return fluid that escapes from blood vessels back to the bloodstream AND fight infections and give immunity to disease

Functions Of Blood 1. Transportation 3. Regulation Blood transports dissolved gases, nutrients, hormones and metabolic wastes 2. Protection & Clotting White Blood Cells (WBC) protect the body against foreign molecules Platelets (cell) and clotting proteins in blood minimize blood loss when a blood vessel is damaged (clot) 3. Regulation Blood regulates the pH and electrolyte composition of the interstitial fluids (fluid between cells) Blood regulates body temperature: transfers heat via counter-current exchange

Counter-Current Exchange

Composition of Blood Contains cellular and liquid components Liquid Portion: ~ 55% plasma Cellular Portion: ~ 45% formed elements Normal blood pH is ~7.35-7.45 (neutral) Blood volume Varies inversely with body fat Blood volume as body fat Males typically have 5 to 6 liters (~10.5 to 12.5 pints) Females typically have 4 to 5 liters (~8.5 to 10.5 pints) How can blood volume be determined? How much is a “unit” of donated blood? Volume: Assess: Blood pressure Calculate: Radioactive dye Units: 1 unit donated = ~ 1 pint (0.5L) 1 unit accepted = ~0.75 pint Packed RBC (prBC) A: Direct and Indirect Methods  removal of all blood of an organism (direct), or tag the blood with a volume radioisotopes and then analyze the concentration in a representative sample later. A: ~ 0.5 L, or just shy of 1 pint.

Composition of Blood 55% Plasma 45% Formed Elements 92% - Water 7% - Proteins (fibrinogen, hormones, albumins & globulins) 1% - other solutes (ions, gases, nutrients, wastes, etc.) 45% Formed Elements 99.9% - erythrocytes (Red Blood Cells - RBCs) 0.1% - leukocytes (White Blood Cells - WBCs) & thrombocytes (Platelets) globulins are any of a group of simple proteins that are generally insoluble in water, but soluble in salt solutions and coagulated by heat. albumin consists of all proteins that are water-soluble, are moderately soluble in concentrated salt solutions, and experience heat denaturation.

Composition of Blood - Plasma Figure 19.1b

Composition of Blood – Formed Elements Figure 19.1c

ID the Formed Elements Be able to identify any of the formed elements to RBC, WBC, or Platelet. FYI: this WBC is a neutrophil; the granules are neutrally stained – hence, the name.

Lecture 1a - Review Break Visualize the Composition of Blood Microscopy & Blood Cell Identification Lab

Lecture 1b – Overview: Composition of Blood Hematocrit or Packed Cell Volume (PCV) measure of % RBC Males: 47% ± 5% Females: 42% ± 5% Figure 17.1

Erythrocytes – Red Blood Cells (RBCs) Oxygen-transporting cells 7.5 µm in diameter (diameter of capillary 8 – 10µm) Most numerous of the formed elements Females: 4.3 – 5.2 million cells/mm3 Males: 5.2 – 5.8 million cells/mm3 Made in the red bone marrow in long bones, cranial bones, ribs, sternum, and vertebrae Average lifespan is 100 – 120 days

RBC Structure And Function Have no organelles or nuclei Significance? True for all species? Hemoglobin – oxygen carrying protein Each RBC has 200-300 million hemoglobin molecules Biconcave shape A: Increase more internal volume for hemoglobin = more efficient in oxygen storage/transport ability A: 30% more surface area

Hemoglobin What is the term for when hemoglobin binds with O2? Comprised of four protein chains, each called a globin. Each globin is bound to a red pigment, called a heme molecule. Contains a single Fe atom Each Fe atom can bind to a single O2 molecule How many O2 molecules can each hemoglobin combine with? What is the term for when hemoglobin binds with O2? CO2? Are either a reversible reaction? A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. A: oxyhemoglobin A: carbaminohemoglobin A: yes

Leukocytes – White Blood Cells (WBCs) Protect the body from: infectious microorganisms Cancerous cells Foreign particles Typically, function outside the bloodstream in loose connective tissue Diapedesis - circulating leukocytes leave the capillaries and enter the interstitial fluid Exception? WBCs have a nucleus and are larger than RBCs Most produced in bone marrow Lifespan of 12 hours to several years A: Lymphocytes  active in the humoral response (as well as the cell-mediated response) A: Lymphocytes  lymphoid tissue

Leukocytes – White Blood Cells (WBCs) Two types of leukocytes Granulocytes Agranulocytes Relative WBC Count Never Let Monkeys Eat Bananas Figure 17.5

Type Of White Blood Cells Lymphocytes (B Cells and T Cells) % By Volume Of WBC Description Function Neutrophils 60 – 70 % Nucleus has many interconnected lobes; blue granules Phagocytize and destroy bacteria; most numerous WBC Eosinophils 2 – 4 % Nucleus has bilobed nuclei; red or yellow granules containing digestive enzymes Play a role in ending allergic reactions Basophils < 1 % Bilobed nuclei hidden by large purple granules full of chemical mediators of inflammation Function in inflammation medication; similar in function to mast cells Lymphocytes (B Cells and T Cells) 20 – 25 % Dense, purple staining, round nucleus; little cytoplasm the most important cells of the immune system; effective in fighting infectious organisms; act against a specific foreign molecule (antigen) Monocytes 4 – 8 % Largest leukocyte; kidney shaped nucleus Transform into macrophages; phagocytic cells

Lymphocyte Compose 20 – 45% of WBCs Two main classes of lymphocyte The most important cells of the immune system Nucleus – stains dark purple Effective in fighting infectious organisms Act against a specific foreign molecule (antigen) Two main classes of lymphocyte T cells – attack foreign cells directly Active in cell mediated immune response B cells – multiply to become plasma cells that secrete antibodies Active in the humoral immune response Cell-mediated immunity is an immune response that does not involve antibodies but rather involves the activation of phagocytes, natural killer cells, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen. Humoral immunity is the aspect of immunity that is mediated by macromolecules (as opposed to cell-mediated immunity) found in extracellular fluids such as secreted antibodies, complement proteins, and certain antimicrobial peptides; is so named because it involves substances found in the humours, or body fluids. Figure 17.4d

Platelets Structure Functions Small, nearly colorless bodies appearing as irregular spindles or oval disks (~2-4 μm) originate in bone marrow from giant cell megakaryocyte Functions Hemostasis Regulation of blood flow Coagulation, or blood clotting

Summary of Formed Elements Table 17.1

Review Activity Break Blood Disorders

Blood Cell Formation Hematopoiesis – process by which blood cells are formed 100 billion new blood cells formed each day Takes place in the red bone marrow of the humerus, femur, sternum, ribs, vertebra and pelvis Red marrow – actively generates new blood cells Contains immature erythrocytes Remains in epiphyses, girdles, and axial skeleton Yellow marrow – dormant (can become active if needed) Contains many fat cells Located in the long bones of adults

Cell Lines in Blood Cell Formation All blood cells originate in bone marrow All originate from one cell type Blood stem cell (pluripotential hematopoeitic stem cell) Lymphoid stem cells - give rise to lymphocytes Myeloid stem cells - give rise to all other blood cells

Cell Lines in Blood Cell Formation Genesis of erythrocytes (erythropoiesis) Committed cells are proerythroblasts Remain in the reticulocyte stage for 1–2 days in circulation Loss of nucleus Formation of leukocytes (leukopoiesis) Granulocytes form from myeloblasts Monoblasts enlarge and form monocytes Platelet formation (thrombopoiesis) Form from megakaryoblasts break apart into platelets

The Blood Throughout Life First blood cells develop with the earliest blood vessels Late in the second month the liver and spleen take over blood formation Bone marrow becomes major hematopoietic organ at month 7

RBC life span and circulation Replaced at a rate of approximately 3 million new blood cells entering the circulation per second Damaged or dead RBCs are recycled by phagocytes Components of hemoglobin individually recycled Heme stripped of iron and converted to biliverdin, then bilirubin Iron is recycled by being stored in phagocytes, or transported throughout the blood stream bound to transferrin

Red Blood Cell Turnover Figure 19.5

Clotting Mechanisms Know the general stages of blood clotting Stage 1: Source of damage Stage 2: prothrombin  thrombin Calcium, prothrombin activator Stage 3: fibrinogen  fibrin Calcium, thrombin Be able to identify the key difference between intrinsic and extrinsic pathways Stage 1

Clotting Cont. What two conditions increase clotting? What two conditions decrease clotting? How are clots removed? Fibrinolysis A: rough spot in endothelium and slow blood flow A: smooth surface on endothelium and antithrombin molecules (e.g., heparin)

Review Activity Break

You should be able to… Identify and describe: The different types of tissues Functions of the blood Blood composition Plasma & Formed Elements % Hematocrit Blood Cell Formation The process of clotting Blood type based on tests and genetic inheritance Antigen vs. antibody Coagulation vs. agglutination Identify and describe the following blood disorders/conditions: Leukemia Leukopenia Leukocytosis Anemia Polycythemia Blood doping Sickle-cell anemia Embolus Thrombus Erythroblastosis fetalis