Session 26 (KEY)
Supplemental Instruction
Iowa State University / Leader: / Ivy
Course: / AnS 214
Instructor: / Keating
Date: / 4/5/11
IMMUNE DEFENSES:
1)Fill in the diagram below with the specific defenses involved with the immune system’s intrinsic lines of defense:
2)Which of the innate defenses is the most important mechanism? Inflammation
PHAGOCYTOSIS:
1)Using the diagram to the right, list the steps of phagocytosis:
Step 1: Phagocyte adheres to pathogen; Forms pseudopods that engulfs particles
Step 2: Formation of a phagosome
Step 3:Lysosome fuses with the phagocytic vesicle, forming a phagolysosome
Step 4:Lysosomal enzymes digest the particles, leaving a residual body
2)What occurs after step 4 represented in the diagram? Exocytosis of the vesicle removes indigestible and residual material
3)What aids the adherence of the phagocyte to a pathogen?Opsonization- coating of pathogen by complement proteins or antibodies
PHAGOCYTE MOBILIZATION:
1)Name and describe the four steps for phagocyte mobilization (how does the phagocyte reach the pathogen in the first place?):
Step 1: Leukocytosis: Neutrophils enter blood from bone marrow
Step 2: Margination: Neutrophils cling to the capillary wall
Step 3: Diapedesis: Neutrophils flatten and squeeze out of capillaries
Step 4: Chemotaxis: Neutrophils follow chemical trail
OTHER INNATE RESPONSES:
1)What are the specific responses or actions taken by the following immune cells?
Natural Killer Cells: target cells without “self” cell-surface receptors
Eosinophils:target allergens, parasites
Basophils:release histamine, heparin (inflammation)
Mast Cells:induce inflammation
Dendritic Cells:antigen-presenting cell (APC)
2)What are the 3 purposes for the inflammatory response?
- Prevents the spread of damaging agents
- Disposes of cell debris and pathogens
- Sets the stage for repair
3)What are the 5 cardinal signs of acute inflammation?Redness, heat, swelling, pain, impairment of function
4)What aids the initiation of the inflammatory response?Toll-like receptors (TLR’s)- trigger release of cytokines
INTERFERONS:
1)What is the main way that interferons hinder pathogen activity?Hinders reproduction
2)Using the diagram to the right, indicate what occurs to activate an interferon and the response it invokes:
Step 1:Virus enters cell
Step 2: Interferon genes switch on
Step 3:Cell produces interferon molecules
Step 4:Interferon molecules bind to neighboring cell
Step 5: Interferon stimulates cell to turn on genes for antiviral proteins; Antiviral proteins block viral reproduction
3)What cells in the body produce these interferons?Lymphocytes, WBC’s, Fibroblasts