immune and infection Flashcards
what is the immune system
the body protects itself from injury, harmful agents or infectious organisms through an elaborate system of networks called the host defence system
3 barriers of immune system
1- physical and chemical barriers, 2- the inflammatory response, 3- immune response
Immunity- bone marrow
found in long bones, iliac crest and sternum. Red and yellow bone marrow. Yellow is found in the shaft of the bone marrow whereas red is found at the ends. Red is responsible for producing WBC platelets and RBC
Immunity- thymus gland
develops T lymphocytes, sits in pericardial cavity, larger in children and then gets smaller in adults as immunity built up
Immunity- lymph nodes
holding areas for immune cells, this is close to blood vessel as cells are passed between them when required
Immunity- spleen
involved in RBC recycling and also stores WBC and platelets, tonsils- holding areas for immunity cells and first line of defence
what is cell mediated immune response
directed against intracellular pathogens, such as viruses, some cancer cells, and tissue transport
Cell mediated immune response- 1
involves B and T lymphocytes made in the red bone marrow, T lymphocytes are released from bone marrow, but they are immature (not in functioning form), they travel to the thymus, where components are added and they are activated, they leave as mature T cells and enter lymphatic system and are stored
Cell mediated immune response- 2
when the T cells are matured, they come out as either CD8 cells or CD4 cells, but they need each other. CD8 cells need circulating CD4 cells to combine and porduce cells that will do something about an invading organisms. this then forms killer T cells, which are good at phagocytosis
what is phagocytosis
get rid of evading pathogens/ get rid of anything that is not recognised
Cell mediated immune response- 3
CD8 T cells kill things by releasing perforin (AMC) this causes autolysis, or by releasing lymphotoxin (DNA) which effets DNA and causes death of the cell
Cell mediated immune response- 4
Drugs can be used to stop killer cells being produced to attack organ replacement, this can lead to a greater risk of other infections and diseases (immune system is compromised)
What is the memory element of the Cell mediated immune response
some natural killer cells recognise antigens quicker if they have seen them before
What is the antibody- mediated immune responses
humoral immunity- directed against extracellular pathogens, such as bacteria
the antibody- mediated immune responses- 1
this involves B lymphocytes, which are released by red bone marrow at the end of long bones and are already mature- enter straight into lymphatic system
the antibody- mediated immune responses- 2
they are made with specific§ antibodies attached to them (specific to certain antigens), they recognise specific antigens and attach to them- leads to phagocytosis
the antibody- mediated immune responses - 3
the B lymphocytes sit in the lymphatic system until they are required, the CD4 cells are required to help B cells to release antibodies when needed. B cells activated by helper T cells and mature into plasma cells, the plasma cells produce immunoglobulin that interact with specific antigens
the antibody- mediated immune responses - 4- memory element
when exposed to specific antigens, the body makes specific antibodies
what is the importance of the CD4 T cell
manages and coordinates the immune response, helper cells increase the production of T and B cells, activate CD 8 cells into killer T cells, activate B cells to mature plasma cells, act as suppressor cells, slow the immune response
Antibody actions- agulation
make foreign cells stick together preventing damage
Antibody actions- precipitation
antibody and antigen combine and become insoluble (meaning they cannot cause damage)
Antibody actions- neutralisation
when the antibodies bind to bacteria/ antigen themselves, preventing them from joining any other cells and hence, causing damage
Antibody actions- lysis
direct killing of the pathogen
Antibody actions- opsonization
antigen marks the cell meaning the cells involved with phagocytosis recognise it quickly- and destroy it
Antibody actions- compliment cascade
activation of the complement cascade- series of enzymes that cause some things to happen from different perspectives
what is an infection
it is an extension of the inflammatory and immune processes, it is a complication of the immune response
what is an infectious disease
a state of tissue destruction from the invasion of the microorganism, could be a problem with the host (e.g. seasonal or recovering from something else, or medication has reduced immunity), or the evading organisms could be strong
What is a host
individual exposed to, or contracts the infection
What is a resident flora
microorganisms that live on or within the body in a non-sterile area without causing harm, these areas include: skin, mucous membrane, bowel, rectum, vagina
how can antibiotics affect the resident flora
strong antibiotics could disrupt resident flora and can cause harmful side effect, the resident flora can protect the body without the need for antibiotics
What is a pathogen
a disease producing microorganism
Phases of acute infection- 1
pathogen gets through skin and mucous membrane, triggering an inflammatory response, this should be enough to deal with pathogens in healthy individual and weak pathogens
Phases of acute infection- 2
if immune defence is not enough or the pathogen is strong, assistants may be needed (antibiotics or fluid support), this should be enough to destroy pathogens
Phases of acute infection- 3
if immune system or treatment is inadequate (wrong antibiotics), this can lead to serious situations and patients may require organ support (could be oxygen, or drugs to support various organisms), patient is at risk of dying
examples of clinical manifestations of infection
inflammatory and immune response, pain, heat, swelling, weakness
types of pathogens
bacteria, virus, fungi protozoa (moveable organism that can invade us), rickettsia (type of parasite that is intracellular), helminths- worms, mycoplasma (extracellular organisms that are very similar characteristics as virus and bacteria
laboratory and diagnostic tests
WBC count- look for rise, serum antibody levels- look for specific antibody in a high number to see what is causing the problem (common in TB)
Cutlers- culture and grow pathogen on antibody agar jelly to diagnose infection and treatment
sensitivities
