2. UNIT B: Human Body Systems Chapter 8: Human Organization Chapter 9: Digestive System Chapter 10: Circulatory System and Lymphatic System: Section 10.7 Chapter 11: Respiratory System Chapter 12: Nervous System Chapter 13: Urinary System Chapter 14: Reproductive System

3. Chapter 10: Circulatory System and Lymphatic System In this chapter, you will learn about the structure and function of the circulatory system and lymphatic system. UNIT B Chapter 10: Circulatory System and Lymphatic System TO PREVIOUS SLIDE What is the composition of blood, including blood cells? What organs and structures control the flow of blood throughout the body? In 2013, Lance Armstrong confessed to long-term blood doping and the use of banned substances. Blood doping involves artificially boosting the blood’s ability to bring more oxygen to muscles. Aerobic capacity and endurance improve where there are additional red blood cells available to carry oxygen.

4. 10.7 Innate and Adaptive Immunity The lymphatic system works with the immune system to protect the body from pathogens, toxins, and other invaders. Immunity is a condition where the body is protected from various threats (pathogens, toxins, cancer cells). There are two main types of immunity. Innate immunity: Fully functional without previous exposure to substances Adaptive immunity: Initiated and amplified after specific recognition of substances UNIT B TO PREVIOUS SLIDE Section 10.7 Chapter 10: Circulatory System and Lymphatic System

5. Mechanisms of innate immunity can be divided into at least four types: Physical and chemical barriers Inflammatory response Phagocytes and natural killer cells Protective proteins UNIT B TO PREVIOUS SLIDE Section 10.7 Chapter 10: Circulatory System and Lymphatic System Innate Immunity

6. Physical and Chemical Barriers UNIT B TO PREVIOUS SLIDE Section 10.7 Chapter 10: Circulatory System and Lymphatic System Physical barriers Skin and mucous membranes lining the respiratory, digestive, and urinary tracts are physical barriers to pathogens Chemical barriers Oil glands in the skin secrete chemicals that weaken or kill certain bacteria The acidic pH of the stomach kills many types of bacteria or inhibits their growth Bacteria that reside in the intestine and other areas remove nutrients and block binding sites that could be used by pathogens

7. Inflammatory Response UNIT B TO PREVIOUS SLIDE Section 10.7 Chapter 10: Circulatory System and Lymphatic System Inflammatory response A series of events that is initiated when there is damage to tissues by physical trauma, chemical agents, or pathogens Inflamed areas have four signs: redness, heat, swelling, pain o Mostly due to capillary changes in the damaged area At least three types of cells in the skin and connective tissue play a role in the inflammatory response: o Mast cells o Macrophages o Dendritic cells

8. UNIT B Section 10.7 Chapter 10: Circulatory System and Lymphatic System TO PREVIOUS SLIDE Figure 10.23 Inflammatory response. Due to capillary changes in a damaged area and the release of chemical mediators, such as histamine by mast cells, an inflamed area exhibits redness, heat, swelling, and pain. The inflammatory reaction can be accompanied by other reactions to the injury. Macrophages and dendritic cells, present in the tissues, phagocytize pathogens, as do neutrophils, which squeeze through capillary walls from the blood. Macrophages and dendritic cells release cytokines, which stimulate the inflammatory and other immune reactions. A blood clot can form to seal a break in a blood vessel.

9. Inflammatory Response UNIT B TO PREVIOUS SLIDE Section 10.7 Chapter 10: Circulatory System and Lymphatic System Mast cells Reside in the skin, lungs, and intestinal tract Respond to damage by releasing histamine o Histamine causes capillaries in the area to dilate and become more permeable, allowing fluids to escape to tissues and cause swelling o Swollen area stimulates free nerve endings, causing pain o Increased blood flow causes skin to redden and warm

10. Inflammatory Response UNIT B TO PREVIOUS SLIDE Section 10.7 Chapter 10: Circulatory System and Lymphatic System Macrophages and Dendritic Cells Both are phagocytic cells Release various proinflammatory cytokines, which are chemical messengers that influence other immune cells o Interleukin-8: attracts other immune cells to the scene o Colony-stimulating factor: causes bone marrow to produce more white blood cells

11. Phagocytes and Natural Killer Cells UNIT B TO PREVIOUS SLIDE Section 10.7 Chapter 10: Circulatory System and Lymphatic System Phagocytes Engulf pathogens into an endocytic vesicle, which fuses with a lysosome in the cell; pathogen is destroyed by compounds in the lysosome Includes neutrophils and monocytes o Neutrophils: the first white blood cells to enter an inflamed area; may accumulate to form pus o Monocytes: migrate from blood and differentiate into macrophages in tissues if inflammatory reaction continues

12. Phagocytes and Natural Killer Cells UNIT B TO PREVIOUS SLIDE Section 10.7 Chapter 10: Circulatory System and Lymphatic System Natural killer (NK) cells Large, granular cells that kill some virus-infected and cancer cells by cell-to-cell contact NK cells induce target cells to undergo apoptosis o Seek out and kill cells that lack a type of “self” molecule, called MHC-I (major histocompatibility class I), on their surface o Some virus-infected and cancer cells lack MHC-I, which makes them susceptible to destruction by NK cells

13. Adaptive immunity is activated when innate defences fail to prevent an infection. The adaptive immune system recognizes, responds to, and usually eliminates antigens from the body. Antigens: any molecules that stimulate an adaptive immune response Adaptive defences take 5 to 7 days to become fully activated and last for many years UNIT B TO PREVIOUS SLIDE Section 10.7 Chapter 10: Circulatory System and Lymphatic System Adaptive Immunity

14. The adaptive immune system depends on the activity of B cells and T cells. Both cells recognize antigens because they have specific antigen receptors Each lymphocyte has only one type of receptor Large diversity of antigen receptors on B and T cells o There are specific B cells and/or T cells for almost any possible antigen UNIT B TO PREVIOUS SLIDE Section 10.7 Chapter 10: Circulatory System and Lymphatic System

15. B Cells and Antibody-Mediated Immunity UNIT B TO PREVIOUS SLIDE Section 10.7 Chapter 10: Circulatory System and Lymphatic System Defence by B cells (antibody-mediated immunity) B cells are activated in a lymph node or the spleen, when their receptors bind to specific antigens Cytokines secreted by T cells stimulate B cells to divide o Most cells become plasma cells, which secrete antibodies −Antibodies are the secreted form of the receptor of the B cell that was activated o Some cells become memory B cells, which allow for long- term immunity −If the same antigen enters again, memory B cells divide and give rise to more plasma cells that can produce the antibody against the antigen

16. B Cells and Antibody-Mediated Immunity UNIT B TO PREVIOUS SLIDE Section 10.7 Chapter 10: Circulatory System and Lymphatic System Antibody Structure Antibodies are also called immunoglobulins (Ig), which are Y-shaped molecules with two arms made of polypeptides o Heavy (long) polypeptide chain o Light (short) polypeptide chain o C (constant) region: set sequence of amino acids o V (variable) region: amino acid sequence varies between antibodies; forms the antigen-binding site

17. UNIT B Section 10.7 Chapter 10: Circulatory System and Lymphatic System TO PREVIOUS SLIDE Figure 10.24 Structure of an antibody. a. An antibody contains two heavy (long) polypeptide chains and two light (short) chains arranged so that there are two variable regions, where a particular antigen is capable of binding with an antibody (V = variable region, C = constant region). The shape of the antigen fits the shape of the binding site. b. Computer model of an antibody molecule. The antigen combines with the two side branches.

18. B Cells and Antibody-Mediated Immunity UNIT B TO PREVIOUS SLIDE Section 10.7 Chapter 10: Circulatory System and Lymphatic System Antigens combine with an antibody at the antigen-binding site in a lock-and-key manner Antigen-antibody reactions can result in immune complexes (antigens combined with antibodies) o Immune complexes may mark the antigens for destruction by a neutrophil or macrophage o Antibodies can “neutralize” toxins by preventing them from binding to cells

19. T Cells and Cell-Mediated Immunity UNIT B TO PREVIOUS SLIDE Section 10.7 Chapter 10: Circulatory System and Lymphatic System Defence by T cells (cell-mediated immunity) T cells have a unique T-cell receptor but cannot recognize antigens on their own o Require antigens be “presented” to the receptors by an MHC (major histocompatibility complex) protein on the surface of another cell There are two types of T cells: o Helper T cells (T H cells) o Cytotoxic T cells (T C cells or CTLs)

20. T Cells and Cell-Mediated Immunity UNIT B TO PREVIOUS SLIDE Section 10.7 Chapter 10: Circulatory System and Lymphatic System Helper T cells (T H cells) Only recognize antigens presented by specialized antigen- presenting cells (APCs) with MHC class II proteins on their surface Cytotoxic T cells (T C cells or CTLs) Only recognize antigens presented by various cells with MHC class I proteins on their surface Some T cells become memory T cells o Live for many years and can quickly initiate immune response to an antigen previously present in the body

21. T Cells and Cell-Mediated Immunity UNIT B TO PREVIOUS SLIDE Section 10.7 Chapter 10: Circulatory System and Lymphatic System Cell-mediated immunity by T C cells Activated T C cells bound to a virus-infected or cancer cell release perforin, which forms pores in the plasma membranes of the abnormal cell o This allows enzymes called granzymes to enter the target cell and induce apoptosis Figure 10.25 Cell-mediated immunity. a. How a T C cell destroys a virus- infected cell or cancer cell.

22. T Cells and Cell-Mediated Immunity UNIT B TO PREVIOUS SLIDE Section 10.7 Chapter 10: Circulatory System and Lymphatic System T C cells are capable of moving on to kill other target cells Figure 10.25 Cell-mediated immunity. b. The scanning electron micrograph shows cytotoxic T cells attacking and destroying a cancer cell (target cell).

23. Check Your Progress 1.Name one physical and one chemical barrier to infection. 2.List the four cardinal signs of inflammation, and explain why each one occurs. 3.Contrast the way that macrophages typically kill pathogens with the method used by natural killer cells. 4.Compare the specific functions of helper T cells and cytotoxic T cells. UNIT B TO PREVIOUS SLIDE Section 10.7 Chapter 10: Circulatory System and Lymphatic System

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25. UNIT B TO PREVIOUS SLIDE Section 10.7 Chapter 10: Circulatory System and Lymphatic System