6.3/11.1 - Immune System Flashcards
Skin
physical barrier as primary defense, protects from entry of pathpgens, chemical and physical damage
- Sebaceous glands secrete sebum to maintain skin moisture and prevents growth of bacteria/fungi due to low pH
- Mucous membranes: softer type of skin that secretes mucus
made of glycoproteins and lyzosymes as a physical barrier trapping bacteria and harmful particles to be swallowed or expelled
Blood clotting
process that transforms blood into a semi-solid to prevent blood lost and drop in BP
- platelets aggregate at the site of cut as a plug and releasing clotting factors
- clotting factors signals production of thrombin (enzyme) to convert fibrinogen to insoluble fibrin
- fibrin forms a mesh trapping platelets and blood cells forming a gel
- exposure to air forms scab
Non specific immunity
defence active upon infection where all foreign pathogens are targeted by phagocytes (white blood cells) that engulf pathogens by endocytosis and digest them with lysozyme in lyzosomes
specific immunity (+ affect of antibodies)
defense response through the production of antibodies that target specific antigens in the presence of a pathogen
Antibodies bind to specific antigens on pathogens to fight the pathogen
- opsonization makes pathogens more recognizable to phagocytes
- neutralization of viruses and toxins prevents them from affecting/ attaching to host cell
- activation of a complement is a group of proteins that digests pathogen cell wall allowing entrance of water and ions until it bursts
- agglutination sticks pathogens together to be easily engulfed by phagocytes
- more easily recognizable to phagocytes
process:
- foreign pathogen digested by macrophage
- macrophage displays pathogen antigen
- helper T-cell bind to antigen and are activated
- t-cells activate b-lymphocytes that produce the specific antibody to divide by mitosis producing clones
- some become plasma lymphocytes that are specialized to produce large amounts of the antibody
- some become memory b-cells for rapid production of plasma cells in the case of a secondary infection by the same pathogen
immunity and vaccines
when memory cells countering a specific antigen persists for a rapid immune response in the case of a second encounter
- Passive immunity when antibodies are obtained by an external source (placenta, breast milk)
- Active immunity wehn antibodies are produced from exposure to infection (vaccine, disease)
Vaccines inject dead, weakened or part of a pathogen to trigger a primary immune response with the production of antibodies without causing disease to establish immunity.
antibiotics, antibacterial, antibiotic resistance, antiviral
antibiotic: chemical that inhibits growth of microorganisms
antibacterial antibiotic: inhibit the processes of prokaryotic cells (replication, transcription, translation) killing them without harming the eukaryotic cells
antibiotic resistance when bacteria develop strains that resist antibiotics and prevail through natural selection
viruses: are non-living and depend on the processes of a host-cell making it difficult to inhibit processes without host cell
antiviral: drugs with enzymes that control virus without harming host cell
Histamine
histamine is a chemical that is released by mast cells when there is an infection causing the dilation of blood vessels.
- immune components leak out of blood vessels
- non specific and specific immunity
- allergy symptoms (inflammation anaphylaxis)
Monoclonal antibodies
production of large amounts of a purified antibody deriving from the clones from one cell
- mice injected with antigen that wanted antibody targets
- specific immune system produces antibody
- b-cells from spleen are removed
- b-cells are fused with hybridoma (tumour cell)
- b-cell with desired antibody is identified and cloned
coronary thrombosis (causes+consequences)
formation of blood clot in coronary arteries which supply oxygenated blood to the heart
causes:
- atherosclerosis -> rupturing of atheroma
- smoking
- low exercise, obesity
- high cholesterol
- low BP
consequences:
- lack of oxygen and glucose to heart
- irregular contractions
- fibrillation
- death
Florey and Chase’s test of penicillin
Experiment:
- Fungus penicillium was cultured to stimulate production of penicillin which killed bacteria on agar plates
- Injected penicillin in mice infected with pneumonia (non treated mice died)
- Human test on man with a life-threatening infection (condition improved, but died because there was insufficient penicillin)
- 5 other patients with life-threatening infections were treated and cured (1 died from related issues, though infection was cured)
In accord:
Lots of research and testing on animals (mice) to observe its effectiveness and possible risks. However, relatively quickly, and not extensive research with human cells.
Test of effectiveness on infected individuals against a control group (this was only done with mice)
Tested a small group of affected individuals who were in critical condition anyways
Purification of penicillin for use in humans
Breach:
Penicillin was not tested on a group of healthy human volunteers to assess possible negative side effects (slowly increasing dosage)
Blind testing with placebos was not used, ill individuals were tested immediately with high doses. (they were close to death regardless)
No consideration for subject health profile (allergies, at-risk individuals)
HIV
human immunodeficiency virus destroyes helper t-cells preventing the production of antibodies for immune response over time
- passed through blood to blood transaction (sex, needles, transfusion)
- leads to AIDS (autoimmune deficiency syndrome) when multiple infections exist together due to compromised immune system
Pregnancy test
HCG in urine when pregnant released by embryo
- free dyed antibodies bind to HCG
- immobile antibodies bind to free dyed antibodies on one strip (strip always dyed)
- immobile antibodies bind to HCG (dyed) on second strip (strip visible if pregnant)
ABO blood groups
A has H antigen with acetylgalactoseamine addition producing antibodies for A
B has H antigen with galactose addition producing antibodies for A
AB has H antigen with both producing no antibodies
o has H antigen without any addition producing antibodies for A and B
