Body Defense System Flashcards
Blood cells involved in the immune system
Leukocyte:
- Neutrophils
- Eosinophils
- Basophils
- Monocytes
- B and T lymphocytes
- Plasma cells
Importance of immune system
Body defence against pathogens, infectious agents, viruses, etc.
Movement ofwhite blood cells through pores
Diapedesis: deformation of cells to pass through pores mediated by selectin
How do pores of endothelial layer change?
Size can be altered by presence of growth factors or cytokines
Chemotaxis
Movement directed by chemical concentration gradients
Granulocytes
Neutrophils
Eosinophils
Basophils
Neutrophils
Most abundant leukocyte. Neutralize infectious bodies by phagocytosis.
Eosinophils
Mobilized following parasitic infection. Release hydrolysis enzymes to weaken the parasite and release H2O2 to help detoxify inflammatory substances.
Basophils
Produce heparin. Facilitate removal of fat. Release histamine which activates inflammation and pain pathways for allergic reactions.
Two functional forms of immunity
Innate immune system
Adaptive of acquired immune system
How are infectious agents detected?
Damaged cells activate and attract phagocytic cells by releasing chemotactic factors
Innate immunity
Physical barriers and factors
Soluble compounds
Cellular component
Physical barriers
Skin
Physiological factors
Low pH or acid, increased temperature, oxygen tension
Soluble compounds
Lysozyme
Complement complex system
C reactive protein
Cytokines
Lysozyme
Enzymes that attack bacterial cell wall by cleaving molecules to disrupt integrity of cell
C reactive protien
Bind to c-peptides on bacteria to flag them for the complement system
Complement system
Compliments removal of pathogens
- Directly though activation of antibodies
- Contacting surface of pathogens
Cytokines
Biochemical messengers stimulate leukocyte activity
NK cells
Natural killer cells have no memory but is able to ducted viral proteins and target viral cells.
How to NK cells work?
Activated by interferons produced by viral cells and lymphocytes. NK cells bind to virus and release granules to form pores in the virus membrane which cause it to lyse
Phagocytic cells
Neutrophils and macrophages
Opsonization
Deposition of compounds (opsonins) on infectious agents to enhance its recognition. Multiple opsonins increase efficiency of detection.
Ex. C3B and antibody
Reticuloendothelial system
Network of neutrophils and macrophages in organs, bone marrow, spleen, and lymph node that move around in the blood stream and are attracted to foreign substances via chemotaxis
Tissues with high amounts of phagocytic cells
Skin and subcutaneous tissue Liver sinus Spleen Bone marrow Lymph node Alveoli