Lecture 30 Flashcards
What is the immune system composed of?
Organs, cells and molecules
What is the immune system?
An organised system of organs, cells and molecules that interact together to defend the body against disease
What are some examples of diseases affected by the immune response?
Cancer, inflammatory diseases and infectious diseases
What are some examples of inflammatory diseases?
Arthritis, allergy/asthma, lupus, diabetes, Crohn’s disease/ inflammatory bowel disease, multiple sclerosis
What are some examples of infectious diseases?
HIV/ AIDS, tuberculosis, influenza and malaria
What are microbes?
Viruses, bacteria, fungi and protozoa
What are the primary organs used for?
Production of white blood cells
What are the secondary organs used for?
Sites where immune responses are initiated
What are the primary lymphoid organs?
Bone marrow and thymus
What is bone marrow the source of?
The source of stem cells that develop into cell of the innate and adaptive immune responses
What does the thymus do?
Its a “school” for white blood cells called T cells, developing T cells learn to not react to self
What are the secondary lymphoid organs?
Spleen, lymph nodes
What do lymph nodes do?
Located along the lymphatic vessels, lymph fluid from blood and tissue if filtered, the site of initiation of immune responses
What does the spleen do?
Site of initiation for immune responses against blood-borne pathogens
How many layers of defense does the immune system have?
3
What is the first layer of defense?
Chemical and physical barriers
What is the second layer of defense?
The innate ‘arm’
What is the third layer of defense?
Adaptive ‘arm’
What are the chemical and physical barriers?
Skin and mucosal surfaces, organisms can get in from cuts, things that cut the skin.
What are the two layers of skin?
Epidermis and dermis
What is the epidermis made up of?
Dead cells, keratin and phagocytic immune cells
What is the dermis made up of?
Thick layer of connective tissue, collagen and blood vessels and phagocytic immune cells.
Why is it good to have dead cells on the skin?
Any microbes or organisms get flushed away as dead skin falls off all throughout the day.
Where are dendritic cells found? and what do they do?
In the lower level of the epidermis, where they recognise bacteria for a fast responses.
What is the chemical defense of the skin?
Antimicrobial peptides e.g pores in microbial cell membranes
Lysozyme breaks down bacterial cell walls
Sebum: low pH
Salt: hypertonic
What is the mucous membrane and what is it made up of?
1-2 layers
Epithelium: tightly packed live cells, constantly renewed, mucus-producing goblet cells
What systems are the mucosal membrane cells in?
Ocular, respiratory, oral and urogenital/ rectal
What is the mucociliary escalator?
Cilia move the mucus up to the pharynx
What are other mucosal surface chemical defenses?
Stomach has low pH Gall bladder- Bile Intestine- digestive enzymes Mucus Defensins Lysozyme (tears, urine)
What are the innate defenses?
Surface barriers and internal defenses
What does the surface barriers consist of?
Skin and mucous membranes
What does the internal defenses consist of?
Phagocytes Natural killer cells Inflammation Antimicrobial proteins Fever
What are some adaptive defenses?
Humoral immunity and cellular immunity
What makes up the humoral immunity?
B cells
What makes up the cellular immunity?
T cells
How fast does the innate immunity respond?
Rapid (hours)
How fast does the adaptive immunity respond?
Slow (days to weeks)
What is the difference between innate and adaptive immunity?
- Innate immunity is already in place, its rapid, fixed, limited specificities na has no specific memory
where as: - Adaptive immunity improves during the response, its very slow, variable, highly specific and has long term specific memory
What does it mean by limited specificities in innate immunity?
Detects molecular components shared by many pathogens
What does it mean by highly specific in adaptive immunity?
Detects molecular components specific to individual pathogens
