Imunology And Imune System Intro Flashcards
What is the immune system composed of
Organs
Cells
Molecules
What is the immune system
An organised system of organs, cells, and molecules that interact together to defend against diseases
What are microbes in order of smallest to largest
Virus, bacteria, fungi, Protozoa
What are primary and secondary lymphoid organs
Primary: production of white blood cells
Secondary: sites where immune responses are initiated
Outline primary lymphoid organs
Bone marrow - source of stem cells that develop into cells of the “innate” and “adaptive” immune responses
Some cells move out of bone marrow to thymus
Thymus - “school” for white blood cells called T cells. Developing T cells learn not to react to self. Only 10% exit as mature T cells
Outline secondary lymphoid organs
Spleen - site of initiation for immune responses against blood-borne pathogens
Lymph nodes - located along lymphatic vessels, lymph fluid from blood and tissue is filtered, site of initiation of immune response
What are the 3 layers of the immune system
Chemical and physical barriers
Innate arm
Adaptive arm
Outline the physical barrier of the skin
Epidermis: Outer layer, Dead cells, keratin, phagocytise immune cells. Loose outer layer of skin every 2-4 weeks, constantly removing skin residing pathogens
Dermis: Thick layer of connective tissue, collagen, blood vessels, and phagocytise immune cells
Dendritic cells: large surface area, alerts immune system that something is occurring
Outline the chemical defences of the skin
Antimicrobial peptides (e.g. skin defensins - formed pores in microbial cell membranes)
Lysozyme enzyme (produced by skin): breaks down bacteria cell walls
Sebum (made by sebaceous glands): low pH (hostile environment)
Salt (from sweat): creates hypotonic cell, thus cell desiccates
Outline the mucous membrane
1-2 layers (mucus layer - traps microbes/hard to move, and epithelium)
Epithelium: tightly packed live cells, constantly renewed, mucus producing cells
Where are the mucosal membranes located
Mucosal membranes line parts of the body that lead to the outside and are exposed to the air
Ocular (eyes)
Respiratory
Oral (gastrointestinal)
Urogenital/rectal
How is mucus circulated
Beating of cilia on columnar cells
Outline the chemical defences of mucosal surfaces
Stomach - low pH
Gall bladder - bile (very toxic to most microbes)
Intestine - digestive enzymes
Mucus - trapping
Defensins - make holes in bacteria
Lysozyme (tears, urine) - breaks down bacterial cell walls
Compare and contrast skin vs mucous membrane in terms of number of cell layers, tightly packed cells, alive/dead cells
Number of layers: Skin = many, mucous membrane 1 to a few
Tightly packed cells: Skin = yes, mucous membrane = yes
Dead vs alive: Skin = dead outer, alive inner, mucous membrane = alive
Compare and contrast skin vs mucous membrane in terms of mucus present, lysozyme and defensins, sebum, Celia
Mucus: Skin = no, Mucous membrane = yes
Lysozyme and defensins: Skin: yes, mucous membrane = in some cases
Sebum: Skin = yes, mucous membrane =no
Cilia: Skin = no, mucous membrane = in trachea, uterine tubes
