Lecture Outline - Chapter 7

7.1 Lymphatic System (p. 142, Fig. 7.2)
	1.	The lymphatic system consists of lymphatic vessels and lymphoid organs. It removes excess tissue fluid, absorbs fats in the small intestine, and defends the body against disease.
	2.	Lymphatic Vessels Transport One Way (p. 142)
		a.	Lymphatic capillaries drain excess tissue fluid (lymph). 
		b.	Smaller lymphatic vessels merge to form the thoracic and right lymphatic ducts, which empty lymph into the subclavian veins.
	3.	Lymphoid Organs Assist Immunity (p. 143, Figs. 7.3, 7.4)
		a.	Lymph nodes occur in groups in certain regions of the body and house lymphocytes and macrophages.
		b.	The spleen is structured like a lymph node but filters blood. 
		c.	The thymus gland produces the hormone thymosin, which is thought to help T lymphocytes mature.
		d.	Red bone marrow is the site of production of red and white blood cells. 
7.2 Nonspecific Defenses (p. 144)
	1.	Immunity refers to the body's ability to ward off pathogens, and includes both nonspecific and specific defense mechanisms.
	2.	Barring Entry (p. 144)
		a.	Skin and mucous membranes are mechanical barriers. 
		b.	Acidic conditions in the stomach kill many pathogens.
		c.	Normal microscopic flora inhabiting the body (i.e., large intestine, vagina) prevent pathogens from taking hold.
	3.	Phagocytizing the Enemy (p. 144, Fig. 7.5)
		a.	The inflammatory response, characterized by redness, pain, swelling, and heat, is mobilized whenever a wound occurs.
		b.	Injured tissues release bradykinin, which stimulates nervous impulses that trigger pain and stimulates mast cells to release histamine. Capillaries dilate, and redness and swelling result as proteins and fluids escape from them.
		c.	Neutrophils and monocytes (macrophages) squeeze through capillary walls and attack pathogens in the wounded area. 
	4.	Chemo Warfare (p. 146, Fig. 7.6)
		a.	The complement system is a group of plasma proteins that are able to poke holes in bacteria, causing them to burst, and that also enhance phagocytosis.
		b.	Interferon is a protein produced by virus-infected cells that triggers surrounding cells to produce substances that interfere with viral replication.
7.3 Specific Defenses (p. 146)
	1.	Immunity is a specific response, the action of B and T lymphocytes.
		a.	B lymphocytes (B cells) divide into plasma and memory cells. The plasma cells produce antibodies that attack and neutralize foreign antigens.
		b.	Some T lymphocytes (T cells) directly attack antigen-bearing cells, while others regulate the immune response.
		c.	Lymphocytes recognize specific antigens with antigen receptors that lymphocytes bear on their cell surfaces.
	2.	B Cells Make Plasma and Memory Cells (p. 147, Fig. 7.7)
		a.	When a B cell encounters the antigen that matches its receptor, it divides repeatedly, producing plasma cells and memory cells.
		b.	Plasma cells are antibody factories.
		c.	The clonal selection theory states that a B cell does not produce a clone of plasma cells until its specific antigen is encountered.
		d.	Memory B cells provide long-term immunity.
		e.	Immunity due to B cells is called antibody-mediated immunity.
	3.	How Antibodies Work (p. 148, Fig. 7.8)
		a.	Antibodies combine with antigens in a lock-and-key manner, producing antigen- antibody complexes.
		b.	IgG has two heavy (long) chains and two light (short) chains in a Y-shaped arrangement. Variable regions are where different antigens are bound.
	4.	How Antibodies Differ (p. 148, Table 7.1)
		Five classes of antibodies exist (see Table 7.1).
		ECOLOGY FOCUS: Pesticides: A Benefit Gone Wrong (p. 149, Fig. 7A)
		i.	Pesticides are used to kill insects, fungi, or rodents.
		ii.	Pests often become resistant to pesticides.
		iii.	Pesticides are harmful to the environment and cause cancer and illnesses in humans.
		iv.	A better approach is to breed pest-resistant crops or to use natural controls for pests. 
	5.	T Cells Become Cytotoxic, Helper, Memory, or Suppressor Cells (p. 150, Fig. 7.9)
		a.	Cytotoxic T cells attack virus-infected or cancer cells. 
		b.	T cells are responsible for cell-mediated immunity.
		c.	Helper T cells enhance the activities of other T cells and of B cells through their secretion of lymphokines.
		d.	Suppressor T cells regulate the immune response by curtailing the actions of helper T cells.
		e.	Following an illness, memory T cells persist.
	6.	Activating T Cells (p. 151, Fig. 7.10)
		T cells must be presented with an antigen by an antigen-presenting cell, usually a macrophage. 
7.4 Induced Immunity (p. 152)
	1.	Active Immunity Is Long-Lived (p. 152, Fig. 7.11)
		a.	Active immunity occurs after a person has been infected with a pathogen.
		b.	Active immunity can be induced through the use of immunization involving vaccines. 
		c.	Memory Cells Provide a State of Readiness (p. 152)
			Active immunity depends on the presence of memory B and memory T cells.
	2.	Immunization of Children (p. 153, Fig. 7.12)
		a.	Children who are not immunized according to the recommended schedule are at risk for contracting life-threatening illnesses.
		b.	Use of antibiotics has lead to the development of resistant strains.
	3.	Passive Immunity Is Short-Lived (p. 154, Fig. 7.13)
			Passive immunity results when a person receives prepared antibodies. It does not last long.
	4.	Cytokines Boost White Blood Cells (p. 154)
		a.	Cytokines (lymphokines or monokines) stimulate white blood cell production. 
		b.	Interferon (a lymphokine) may be effective in cancer treatment.
		c.	Interleukins are useful in treating chronic infectious diseases, allergies, and autoimmune diseases and in preventing organ rejection.
	5.	Monoclonal Antibodies Have Same Specificity (p. 155, Fig. 7.14)
		Plasma cells produce monoclonal antibodies that are useful for diagnosis of diseases and conditions (e.g., pregnancy) and for detecting certain types of cancer.
		HEALTH FOCUS: Allergies (p. 156, Fig. 7B)
		i.	People with allergies overproduce immunoglobulin E (IgE).
		ii.	Allergy shots can build up the amount of immunoglobulin A in the body, which interacts with the antigen before IgE can trigger histamine release.
7.5 Immunity Side Effects (p. 157)
	1.	Allergies: Overactive Immune System (p. 157)
		a.	IgE is involved in allergic reactions and is overproduced in certain individuals.
		b.	When an allergen is encountered, IgE residing on mast cells triggers the release of histamine, causing allergic reactions.
	2.	Tissue Rejection: Foreign MHC Proteins (p. 157)
		a.	Tissue and organ transplantation rejection occurs because cytotoxic T cells recognize and attack the foreign MHC antigens.
		b.	Immunosuppressive drugs help prevent tissue rejection in transplant patients but adversely affect the kidneys. 
	3.	Autoimmune Diseases: The Body Attacks Itself (p. 157)
		Autoimmune diseases, such as multiple sclerosis or rheumatoid arthritis, appear after the person has recovered from an injury or illness. No cures exist for autoimmune diseases.
7.6 Working Together (p. 157)
	The Working Together box (p. 158) illustrates the interactions between the lymphatic system and other body systems to maintain homeostasis.