lecture 30 - intro to immunology Flashcards
What are the overall components of the immune system that defend the body against disease?
Organs, cells, antibodies
What is the name for a microbe that causes disease?
Pathogen
What are primary lymphoid organs?
Organs that produce white blood cells/lymphocytes
What are the two primary lymphoid organs?
Bone marrow, thymus
What is the function of bone marrow?
Source of stem cells that develop into cells of the innate and adaptive immune responses.
What is the function of the thymus?
Produces T cells (T lymphocytes) and ‘teach’ them what to react to and how. They learn not to react to self in order to prevent auto-immunity.
What are secondary lymphoid organs?
Sites where immune responses are initiated
What are the two secondary lymphoid organs?
Spleen, lymph nodes
What is the function of the spleen?
Site of initiation of white blood cell immune responses to blood-borne pathogens. Filters blood to remove old cells.
What are lymph nodes?
Nodes along lymphatic vessels where lymph fluid from blood and tissue is filtered. Site of initiation of immune responses.
What are the two key layers of the skin?
Epidermis, dermis
What is the structure of the epidermis?
Contains dead cells, keratin, and phagocytic cells. It is constantly being renewed.
What is the dermis?
A thick layer of connective tissue, collagen, blood vessels and phagocytic immune cells.
What are the chemical defences of the skin?
Antimicrobial peptides, lysozyme, sebum, salt
What is the functions of antimicrobial peptides, e.g. defensins?
Form pores/holes in microbial cell membranes
What is the function of lysozyme?
Sits in skin and breaks down bacterial cell walls.
What is the function of sebum?
An oily secretion that gives the skin a low pH, making it hostile to bacteria.
How does salt defend the skin from pathogens?
It makes the skin hypertonic, desiccating bacteria.
How many layers of cells do mucous membranes have?
1-2 layers
What is the structure of mucous membranes?
They have an epithelium: layer of tightly packed live cells and mucous producing goblet cells.
Do mucous membranes produce sebum?
No
What parts of the body do mucous membranes line?
Parts that lead to the outside and are exposed to air - ocular, respiratory, oral and urogenital/rectal
What structure lines the respiratory tract and traps particles?
Musociliary escalator
What is the function of the musociliary escalator?
Lines the respiratory tract and is responsible for trapping particles in mucus and propelling them up and out of the lungs via cilia.
How do cilia move mucus up the pharynx in the musociliary escalator?
They beat in tandem.
What two mucous membranes have cilia?
Respiratory tract and uterine tubes
What are examples of chemical defences of mucosal membranes?
low pH, bile (gall bladder), digestive enzymes (intestine), mucus, defensins, lysozyme (tears, urine)
What are the two systems of immune system defence?
Innate and adaptive immunity
What are the characteristics of innate immunity?
Already in place, rapid, fixed, limited specificities, no specific memory
What surface barriers are employed by the body’s innate immune defences?
Skin, mucous membranes
What are the internal defences of the innate immune system (5)?
Phagocytes, natural killer cells, inflammation, antimicrobial proteins, fever
What are the characteristics of the adaptive immune response?
Improves during the response, slow, highly specific, long term specific memory
What make up the humoral immunity component of adaptive defences?
B cells
What make up the cellular immunity component of adaptive defences?
T cells (B cells come under humeral category)
What is the difference between humoral and cellular adaptive immunity?
Humoral immunity involves antibodies (produced by B cells) to combat extracellular pathogens/toxins, while cellular involves the attack of intracellular pathogens via T cell action and apoptosis.
