AP Biology, Chapter 43
The Body's Defenses

SUMMARY
INTRODUCTION

NONSPECIFIC DEFENSES AGAINST INFECTION
	Introduction
	The skin and mucous membranes provide first-line barriers to infection
1. Contrast the readiness of the immune system with that of the body's nonspecific 
defenses.
		a. Immune system: requires priming by initial exposure to antigen
		b. Nonspecific: respond immediately to protect from all
		2. Define the roles of physical and chemical surface membrane barriers. 
			a. Physical: skin and mucous membranes keep things out
			b. Chemical
				i. Acid in skin and vagina
				ii. Stomach secretes HCl and proteases
				iii. Saliva and tears contain lysozyme
				iv. Stick mucus catches organisms
	Phagocytic cells, inflammation, and antimicrobial proteins function early in infection
		3. Contrast the roles of the nonspecific cellular defenses. [2 points]
			a. Phagocytes engulf and destroy pathogens
			b. NK cells punch virus-infected and cancerous cells
		4. Rationalize the four cardinal signs of an acute inflammatory response. 
			a. Histamine and kinins released
			b. Increased blood flow causes redness and heat
			c. Leaky blood vessels cause swelling and pain
		5. Describe the roles of chemotaxis and diapedesis in the inflammatory response.
			a. Histamines and kinins attract phagocytes and WBCs
			b. WBCs leave the capillaries at the site of inflammation for clean up
		6. How is a fever initiated and how does it aid in fighting infection? 
			a. Pyrogens are secreted by macrophages 
			b. Liver and spleen confiscate Fe and Zn, raises metabolic rate
		7. Contrast the roles of complement and interferon in nonspecific defense.
			a. Complement
				i. Proteins attach to foreign cells after activation
				ii. Cause lesions, amplifies inflammatory response, opsinizes
			b. Interferon 
				i. Released by virus-infected cells
				ii. Interferes with virus replication

HOW SPECIFIC IMMUNITY ARISES
	Introduction
		8. Describe three important aspects of the immune response. 
			a. Anitgen specific:  attacks particular pathogens
			b. Systemic: body-wide defense, not restricted to site of infection
			c. Memory: recognizes and mounts attAck on previously encountered pathogens
	Lymphocytes provide the specificity and diversity of the immune system
		9. What is the relationship between haptens and antigens. 
			a. Haptens are too small to be antigens
			b. Reaction with our proteins creates antigen
  
	Antigens interact with specific lymphocytes, including immune responses and 
	immunological memory
		10. Contrast the roles of B lymphocytes, T lymphocytes, and macrophages in specific 
		defense. 
a. B lymphocytes: humoral immunity
	b. T lymphocytes: cell-mediated immunity
		i. Cytotoxic T cells kill cancer, infected cells and attack foreign grafts
		ii. Helper T cells regulate the immune response
	c. Are phagocytes and activators of Ts and Bs
	Lymphocyte development gives rise to an immune system that distinguishes self from 
	nonself

IMMUNE RESPONSE
	Introduction
	Helper T lymphocytes function in both humoral and cell-mediated immunity: an 
	overview
		11. Define the role of macrophages in the development of cellular immunity.
			a. Phagocytosis, processing and presentation of antigens
			b. Binding to and activation of helper T

	In the cell mediated response, cytotoxic T cells counter intracellular pathogens: a 
	closer look
	In the humoral response, B cells make antibodies against extracellular pathogens: a 
	closer look
		12. Describe the cellular basis of primary and secondary humoral responses.
			a. Primary
				i. Initial antigen exposure selects a clone making antibody specific to the 
				antigen
				ii. Plasma cells die, memory cells remain
			b. Secondary
				i. Subsequent exposure activates memory cells to divide
		13. Describe mechanisms of antibody action.
			a. Neutralization: coats virus, prevents infection
			b. Agglutination: clumping of foreign cells
			c. Precipitation: clumping of soluble antigens
			d. Complement fixation
	Invertebrates have a rudimentary immune system

IMMUNITY IN HEALTH AND DISEASE
	Introduction
	Immunity can be achieved naturally or artificially
		14. Contrast the acquisitions of active and passive humoral immunity.
			a. Active: developed from B cells by natural exposure or vaccination
			b. Passive: transfer of pre-made antibody in utero or serum
	The immune system's capacity to distinguish self from nonself limits bloof transfusion 
	and tissue transplantation
	Abnormal immune function can lead to disease
		15. Describe examples of the three types of disorders of immunity.	
			a. Allergy: abnormally vigorous immune responses like to inhaled pollen
			b. Immunodeficiency: inherited as SCID or by HIV infection
			c. Autoimmune diseases: rheumatoid arthritis, myasthenia gravis
		16. Differentiate the symptoms of immediate hypersensitivity, anaphylactic shock, and 
		delayed hypersensitivity. 
			a. Inhaled: mast cells release histamine causing mucous membrane inflammation				b. Anaphylactic shock: system-wide inflammation with fluid loss
			c. Delayed hypersensitivity: contact dermititis from haptens in poison ivy, metals, 
			and the swelling from a TB test	
		17. List three possible triggers for autoimmune disease. 	
			a. Inefficient lymphocyte programming	
			b. Loose self-antigens
			c. Cross-reaction of antibodies with self-antigens
	AIDS is an immunodeficiency disease caused by a virus