Immunity and Reproduction Flashcards
(44 cards)
what are the immune responses of the body responsible for?
- defence of the body against harmful substances, such as pathogenic micro-organisms
- all elements of tissue repair
- surveillance of body cells for abnormalities of cell division
what are the two types of disease resistance?
non-specific resistance (innate immunity)
present at birth and includes defence mechanisms that provide general protection against invasion by a wide range of pathogens
immunity (adaptive immunity)
involves activation of specific lymphocytes that combat a particular pathogen or other foreign substance
what is the body system that carries out immune responses?
the lymphatic system
describe innate immunity.
refers to a wide variety of body responses that serve to protect us against invasion of a wide variety of pathogens and their toxins
we are born with this kind of immunity
two lines of defence:
- skin and mucous membranes
- internal defences
identify physical barriers and internal defences of innate immunity.
physical barriers:
- skin
- sweat
- sebaceous glands
- mucous membranes
- tears and saliva
- gastric acid
- acidic urine
- normal flora
internal defenses: immune cells or substances that treat all foreign cells in the same way - phagocytes (neutrophils, macrophages) - natural killer cells - inflammation - fever
what are neutrophils?
short-lived cells that phagocytose bacteria
what are lymphocytes?
mostly found in lymphoid tissues - specific immune response
what are monocytes?
less abundant than neutrophils but longer lived
what are eosinophils?
attack parasitic worms, involved in allergy and asthma
what are basophils?
release histamine and heparin, involved in inflammatory response, not phagocytic
define inflammation.
inflammation is a non-specific localised tissue response to tissue damage which has occurred through injury or infection.
identify the four signs and symptoms of inflammation
- redness
- heat
- swelling
- pain
what are the reasons for the signs and symptoms of inflammation?
- redness due to vasodilation
- heat due to increased blood supply
- swelling (oedema) due to increased vascular permeability and accumulation of exudate
- pain due to increased pressure on nerve endings from swelling/oedema
describe adaptive/specific immunity.
adaptive immunity is the ability of the body to defend itself against specific invading agents
adaptive immunity has both specificity and memory and is divided into 2 types:
- cell-mediated
- antibody-mediated
what are antigens?
substances recognised as foreign that provoke immune responses
usually a protein on the surface of any cell or surface of a virus
identify immune cells that recognise and remember antigens.
T Helper cells recognise a specific antigen which is often presented by antigen presenting cells - phagocytic cells such as macrophages
Cytotoxic T cells are stimulated by cytokines, recognise foreign antigens, kill virally infected and foreign cells
what is the difference in B and T cells when recognising foreign antigens?
B cells can and recognise and bind to antigens in lymph, interstitial fluid, or blood plasma
T cells can only recognise fragments of antigenic proteins that are processed and presented in a certain way
identify the B cells involved in specific immunity and their role in the process.
B lymphocytes become plasma cells which produce antibodies (humeral immunity - directed against specific antigens in body fluids
identify the T cells involved in specific immunity, and their sub-types.
T lymphocytes - for cell-mediated immunity, directed against intracellular antigens (e.g. antigens on viruses)
sub-types:
- T Helper - control humoral immune response of B cells, produce interleukins and promote cell multiplication
- T Cytotoxic - effector cells of cell mediated immunity, release lethal lytic chemicals that kill cells on contact
- T suppressor cells - damp down the immune response
explain the timeline associated with the specific immune system’s first exposure to an antigen. discuss IgM antibodies.
The primary immune response follows the first exposure to an antigen. It is a slow response that takes about 2 weeks.
During this first response, small quantities of large multivalent IgM antibodies are typically produced.
what is an IgM?
the largest antibody and the first to arrive on the scene after initial exposure to antigen. produced in the spleen.
what are IgG antibodies?
the most common type of antibody in the circulation, created an released by plasma B cells and each has two antigen binding sites.
how do IgG antibodies protect the body from infection?
- IgG-mediated binding of pathogens causes their immobilisation and binding together via agglutination. IgG coating of pathogen surfaces allows their recognition and ingestion by phagocytic immune cells leading to the elimination of the pathogen itself
- IgG activates the classical pathway of the complement system, a cascade of immune protein production that results in pathogen elimination
explain the specific immune systems response a second exposure to the same antigen.
the secondary immune response occurs on the second and all subsequent exposures to the same antigen.
rapid and efficient, which specialised memory B and T cells becoming activated and generating large quantities of antibodies of the IgG type within 2-3 days or re-exposure.
