Lecture 11; Immune system Flashcards
What is the first line of defense of the immune system?
Innate and nonspecific factors;
- Physical, chemical, and mechanical barriers
What is the second line of defense of the immune system?
Innate and non-specific factors
- Lymphatic system, inflammation, antimicrobial proteins
What is the third line of defense of the immune system?
Acquired and specific factors:
- B & T cells
What is the main physical barrier of the first line of defense?
- How does it work?
Skin
- Compacted to prevent invasion
- Contains keratin (water resistant)
What are some of the mechanical barriers of the first line of defense?
- Tears (flush away microbes)
- Urine (flush away)
- Saliva (flush away)
- Earwax (traps)
- Mucus membranes (trap)
- Cilia
How do these chemical barriers aid in the first line of defense:
- Lactoferrin (found in tears)
- Lysozyes (Found in tears, saliva, mucus)
- Lactoferrin= Sequester iron so bacteria can’t steal
- Lysozymes= Lyse bacterial cell walls
How do these chemical barriers aid the immune system:
- Lactoperoxidase (found in stomach, nose, lungs)
- Stomach acid
- Lactoperoxidase= Makes radicals toxic to microbes
- stomach acid= low pH destroys pathogens
How does this chemical barrier aid the immune system:
Microbiome
- Keeps bad microbes out
- Discerns between good/bad microbes
What are Antimicrobial peptides?
- Do microbes develop resistance to these?
Chemical barrier that destorys microbes
- no
How do Antimicrobial Peptides work?
- Stimulate immune cells
- Direct attack
- break cell wall/ target intracellular components
What is the lymphatic system?
Lymph and lymphatic vessels that collect fluids from body and filter out microbes.
- Includes organs and tissues
What are these terms:
Plasma
Interstitial fluid
- Plasma= liquid portion of blood
- ISF= Plasma that has moved into tissue
Where are the lymphatic vessels located/ how do they work?
Lymphatic vessels run parralel to bloodstream.
Collects lymph (interstitial fluid that has been taken back up by the lymphatic vessels)
What are the primary lymphoid tissue?
- What is their job?
- Thymus
- Bone marrow
- Production of immune cells (leukocytes)
What is the differences in the thymus and bone marrow?
Tissue type/job
- Thymus= organ that matures immune cells
- Bone marrow= tissue that produces immune cells
What are the secondary lymphoid tissue?
What are their jobs?
- Lymph Nodes
- Spleen
- Mucosa associated lymphoid tissue (MALT)
- Filter lymph and monitor for microbes
What are the jobs of the lymph nodes (500-700 throughout body)?
- Filter microbes out of lymph
- Multiply immune cells (swell)
What is the job of the spleen (for the lymphatic system)?
Filter microbes out of blood
What are examples of MALT?
What are their jobs?
- Tonsils, appendix, Peyer’s patch
- Clear out microbes at portals of entry
What are the variations of Leukocytes?
- Granulocytes (granules in cytoplasm)
- Agranulocytes (no granules in cytoplasm)
What is phagocytosis?
How does it work?
Form of endocytosis by immune cells.
Engulf microbe and lysosome destroys.
How do Leukocytes “chase” microbes?
Follow the microbes via chemotaxis
How are microbes engulfed during phagocytosis?
What happens to the microbe?
Placed in phagocytic vacuole and destroyed by phagosome.
Parts are expelled
What are the 4 types of granulocytes?
- Neutrophils
- Eosinophil
- Basophil
- Mast Cell
What are the jobs of neutrophils?
- Release AMPs to destroy microbes
- Phagocytose microbes
- Alert other immune cells
A low number of neutrophils indicate a ____ _____.
Viral infection
What are the jobs of Eosinophils?
- Release enzymes and antimicrobial toxins
- Target parasites and allergies
Increased numbers of these leukocytes indicate what type of infection:
- Neutrophil
- Eosinophil
- Bacterial infection
- Allergic reaction/parasitic infection
