T2-Systems_Immunity Flashcards
(49 cards)
Body’s system that defends against foreign invaders (antigens)?
Immune system
Name some invaders
bacteria, viruses, other organisms, foreign bodies/substances, abnormal molecules and cells that develop abnormally in the body (cancerous cells)
What are bacteria, viruses, etc?
microbes
What tends to kill or damage microbes?
Antimicrobial substances (e.g. lysosomal enzymes released by immune cells)
What is a specific discrete component of an antigen that attracts immune responses?
Epitope (marked by an antibody or MHC - major histocompatibility complex)
What is a collected coordinated response of the cells and molecules of the immune system to protect against infectious disease?
Immune response
What are the two responses of the immune system?
Innate and Adaptive
What is the innate response of the immune system?
A general response; first line of defence:
- we are born with it
- rapid, early response
- always the same
- primarily reacts to microbes
- relies on phagocytes and antimicrobials
- includes external physical barries like skin/mucous membranes
- utilizes fever, inflammation, etc.
- fairly easy for microbes to adapt to it
- stimulates adaptive response
What is the first line of defense?
Skin and mucous membranes:
- sebum, mucous, hair, tears and saliva
What is the second line of defense?
AKA internal defenses
include:
- antimicrobial substances (interferons, the complement system, iron-binding proteins and antimicrobial proteins), natural killer (NK) cells, phagocytes
What is the complement system?
System that triggers adaptive response (series of cascading events)
What is the adaptive response?
A specific response; develops with exposure to organism/substance:
- slower, develops in reaction to specific attributes of invader
- works with innate processes to enhance reactivity
- attacks microbes and antigens
- generates immunologic memory - subsequent exposures lead to a more rapid response
- typically what is meant by the term “immune system”
What are the primary cells of the immune system?
B-Lymphocytes (B-cells) and T-Lymphocytes (T-cells)
What do lymphocytes do?
Act as Regulator cells (assist in controlling the orchestration of the immune response) and as Effector cells (kill/eliminate microbe or antigen)
What are accessory cells?
Phagocytes: macrophages, neutrophils, eosinophils) that break apart an invader
What are dendritic cells?
Present antigens/epitopes to killer cells
What is humoral immunity?
The immune cells and other immune material (like antibodies) that are circulating in the blood and lymph.
Where else are immune cells located?
- lymph nodes
- spleen
- skin
- mucosa
- vital organs
B-cells
- key players in humoral immunity
- very good at recognizing antigens and microbes
- produce antibodies
- when activated, they select the type of clone needed.
What is a fully mature B-cell called and what does it do?
It’s called a Plasma cell. Plasma cells produce and secrete antibodies- aka immunoglobulins (IgG, IgM, IgA, IgE and IgD)
What do antibodies do?
Bind to epitopes and either kill/neutralize the invader or present them to T-cells or macrophages.
What do some B-cells become?
Memory cells, which do not participate in the initital immune response, but stay in the body to respond quickly if a second exposure to the same antigen occurs.
IgG
“general”
- 70-80% of antibodies
- only Ig to cross placenta
- antiviral, antitoxin, antibacterial actions
- activates killer cells and complement system
IgA
“milk at IGA”
- predominant in breast milk, tears, saliva, nasal/respiratory secretions
- blocks entry of organisms to eyes, gut, respiratory and urinary tracts
