The Body’s DefensesThe lymphatic System
Functions of Lymphatic System
• Help protect body from infection by disease causing agents
• Must detect a wide variety of agents, known as pathogens, from viruses to parasitic worms, and distinguish them from the organism's own healthy tissue.
• Antigen: proteins that body recognizes as foreign (pathogens, foreign cells, or cancer cells)
The boy in a bubble
• David Vetter• https://www.youtube.com/watch?v=-G_SW8LmidA
How does the body combat disease?
Specific immunity
Specific Immunity aka: acquired immunity• Direct contact with antigens and intimate a response that
marks and destroys antigens
Non-specific Immunity
NON-specific immunity (innate immunity)• cells of the innate system recognize and respond to
pathogens in a generic way, but, unlike the adaptive immune system (which is found only in vertebrates), it does not confer long-lasting or protective immunity to the host
Body’s Defenses: concept map
• Specific • Cell Mediated immunity• T cells
• Humoral immunity• B cells which stimulate
Ab production from plasma cells
• Antibodies: proteins capable of interactive with antigens
• Non-specific• Mechanical Barriers• Mucous membranes, GI, eyes,
Respiratory system, and skin
• WBC• Neutrophils Natural killer cell• monocytes• Lymphocytes• Eosinophils• basophils
• Inflammatory responses• Histamine reactions• chemical factors released by injured
cells and serves to establish a physical barrier against the spread of infection, and to promote healing of any damaged tissue following the clearance of pathogens
Blood Cells: Leukocytes
• White Blood Cells• Approximately 5,000 to
9,000 per cubic mm of blood
• Defends body from pathogens
• Divided into two types• Granular Leukocytes• Nongranular Leukocytes
Granular Leukocytes
• Neutrophils• Phagocyte; 1st to arrive at injury
site• Releases chemicals to degrade
pathogen and attract other phagocytes
• Hallmark of ACUTE infections
• 50-70% of WBC’s• Nucleus is segmented into 4-5
lobes
Granular Leukocytes
• Eosinophils• Phagocytes of antibody
marked pathogens• Mediate for allergies• Reduces inflammation• Defend against large parasites• Strong chemotaxis• Attraction to injury and infection
• 2-4% of WBC’s• Nucleus is segmented into 2
lobes• Red Granules
Granular Leukocytes
• Basophils• Functions in allergic
response by releasing histamine
• Secretes heparin• Anticoagulant
• Rare, less than 1%
• Deep blue granules• Difficult to see nucleus
Nongranular Leukocytes
Lymphocytes• Part of acquired immune
response… specific defense against bacteria and viruses
• Forms different types of cells:• T-Cells: destroys foreign cells
• B-Cells: differentiate into plasma cells which secrete specific antibodies
• NK Cells: prevent cancer
• 20-30% of WBC’s • Large round nucleus
Nongranular Leukocytes
• Monocytes• Phagocytes• Scavengers • Fixed vs. Free• Releases chemicals to
attract other WBCs and fibroblasts (scar tissue)
• 2-8% of WBC• Large, kidney bean shaped
nucleus
White Blood Cell Disorders
• Leukopenia• Low WBC (> 5,000 mm3)• May accompany:• Typhoid fever, Flu, Chicken Pox, AIDS
• Leukocytosis• High WBC• Indicates acute infection
• Leukemia• Extremely high WBC• Malignant
Practice Identifying Leukocytes
• View following cells for practice
WBC: Matching
• Match the cell types with the descriptions and microscope images
Neutrophils
40-70%Phagocytizes
primarily bacteria
Eosinophils
1-4%
Phaocytizes and destroys antigen-
antibody complexes
Basophils
0-1% Releases histamine
when stimulated
Lymphocytes
20-45%B type produces
antibodies in blood and lymp; T types
kills virus containing cells
Monocyte
4-8%
Becomes macrophage-phagocytizes bacteria and
viruses
Exit Slip: turn in as you leave
1. Pretend your friend was absent from class today. She/he asks you to explain the lesson.• On your own paper, tell him/her about your lesson today.
Be sure to relate to the learning target.
2. Include one new thing you learned.
3. Share something that you would like me to go over in class tomorrow to help you learn material/concept better.