The Immune System Flashcards
(41 cards)
What is immunity
Bosdy’s ability to protect itself from
itself (abnormal growth/death of cells)
Bacteria, viruses and disease-causing entities
What are the key feature so the immune system that allows this identification?
Specificity and memory
- self vs non self
- targeted response to specific invaders
What are the three main function?
1) recognize and remove abnormal cells Growth and development go wrong 2) Remove dead and damaged cells Digest dead/dying cells 3) Protect from disease causing invaders Protect from pathogens
What happens when things go wrong?
1) Incorrect immune response Cannot distinguish self from non self Autoimmune disease 2) Overactive Response is out of proportion (allergies) 3)Lack of response Some components fail to function Immunodeficiency disease -Primary (inherited genetic disorder) -Acquired (result of infection(AIDS) or drug side effect)
What are pathogens?
Disease-causing invaders
Microorganisms such as:
-Bacteria, viruses, fungi, 1 celled organisms
-larger pathogens such as pararsites
-any exogenous molecule that can initiate immune response
what are the most common pathogens?
Bacteria and viruses
parasites
What is the difference between bacteria and viruses?
Different immune response Common Bacteria (non-self) Staph, strep, E.coli, listeria, salmonella Common Virus (take over cell) Cold, flu, chickenpox, HPV, HIV
Bacteria
Cells. surrounded by cell wall
Can survive without host
Killed by antibiotics
Viruses
Not cells. Nucleic acid core with protein coat
Parasitic. Require host
Cannot be killed with antibiotics
What are the two anatomical components of the immune system?
Lymphoid tissue -primary: thymus and bone marrow -secondary: spleen(monitors blood) and lymph (encapsulated), Tonsils and GALT (unencapsulated and diffuse) Immune Cells - White blood cells/leukocytes
What are some examples of immune cell function and morphology?
Granulocytes (granules in the cytoplasm)
-Basophils, eosinophils, neutrophils
Phagocytes (ingest target cells)
-Eosinophils, neutrophils, macrophages, monocytes
Cytotoxic cells (kill target)
-Eosinphils, and some lymphocytes
Antigen presenting cells (APC) (present fragments of foreign proteins)
-Macrophages, monocytes, B lymphocytes, dentritic cells
What are the body’s 2 lines of defense
1) Barriers - Physical (skin and mucous)
- Chemical (stomach acid)
2) Immune Reponse
What are the four basic steps of immune response?
1) detect and identify
2) Communicate with other immune cells
3) Recruit assistance and coordinated response
4) Destroy/suppress the invaders
What is innate immunity and what is acquired immunity?
Innate immunity
-Second line of defense
-Non-specific (inflammation)
Acquired (adaptive) Immunity
-Specific immune response
- Cell mediated: immune cell binds to target
- Humoral mediated: antibodies are secreted and bind to target
What happens in the Innate Immune response?
Leukocytes recognize unique features of pathogens
-Pathogen associated molecular pattern (PAMP)
Phagocytes are attracted by chemical/ signals (chemotaxin)
Leukocytes secrete cytokines to attract additional leukocytes
a) pathogens bind to phagocytes
b) Bacteria must be coated in antibody for recognition and ingestion
c)Antigen-presenting macrophages display fragments
What are Natural Killers(NK)?
Recognize virus infected cells and induce apoptosis
Can attack tumor cells
Secrete antiviral cytokines (interferons) that interfere replication
What are three important roles of the inflammatory response when fighting infection?
1) attract immune cells
2) Create physical barrier
3) promote tissue repair
When is the inflammatory response initiated?
When the macrophages release cytokines:
- attract other immune cells
- increase capillary permeability
- cause a fever
What are chemicals of the innate immune response?
Acute phase proteins act as opsonin that coat pathogens and enhance inflammatory response (C-reactive protein)
Histamine acts as:
- Vasodilator
- Brochoconstrictor
Interleukins
- Leukocyte secrete cytokines to activate leukocytes
Bradykinin
- Stimuates pain and vasodilator
Complement proteins
- Act as opsonin, chemotaxins and membrane attack complex
What do complement proteins do?
Insert themselves into membrane of pathogen to create pores
H2O and ions enter pores of attack complex (cause apoptosis)
What happens in the innate immune response?
Recognize pathogen and react specfically
Mediated by lymphocytes
Overlaps the innate immune response (lymphocytes are attracted by cytokines)
What are the two categories acquired immune system?
Active immunity
-exposed to pathogens and creates own antibodies
-occurs naturally during invasion or artificially through vaccine
Passive Immunity
-Antibodies made by another person or animal
What are lymphocytes?
Primary cell in acquired immunity
Has a membrane receptor for a specific ligand
Clones identical receptors to respond to specific pathogen
What is clonal expansion?
when the lymphocytes are exposed to antigens which activates clones and stimulates division
