3.2.4 cell recognition and immune system Flashcards
(20 cards)
pathogen
microorganism which causes diseases
How do pathogens work
- colonises tissue, leading to infection
- Pathogen is transferred from host to host - transmission
What features do eyes have to protect from pathogens
- tears: antiseptic properties
- cornea and conjunctiva protective layer of tissue over eye
What features do noses have to protect from pathogens
- mucus physically stops pathogens from entering the lungs
- hairs
What features does the trachea have to protect from pathogens
- Goblet cells produce mucus to physically trap pathogens
- ciliated cells, cilia carries the mucus to the mouth, via metachronal beating
What features does skin have to protect from pathogens
- Thick stratified
- Top layer is dead cells
- keratin produced by cells near the top, waterproof + strong
- hair follicles create vulnerability, so sabaceus and sweat glands produce oils/sweat with antiseptic properties
- Blood clots, form to scab over cuts, arteries can produce clots as pressure is too high so no scab
What features does the digestive have to protect from pathogens
- Saliva antibacterial properties
- stomach HCl from peptic glands, pH 2
What features does the urethra have to protect from pathogens
area is toxic
What features does the vaginal area have to protect from pathogens
- acidic environment
- mucus
Epidemiology
- Study of diseases
- find means of preventing and controlling diseases, by finding the origins of it
- correlation doe snot mean causation
Non specific immune system definition
- Doesn’t distinguish between pathogens
- physical barriers and phagocytosis
Specific immune system definition
- distinguishes between pathogens
- T lymphocytes and B lymphocytes
Pathogens and toxins
- Pathogens release their toxins which are antigenic, similar shape to their antigens
Stages of phagocytosis
- phagocyte attaches to pathogen via attach proteins
- phagocytes contain lysozymes
- phagocyte extends its membrane and starts to engulf pathogen
- pathogen completely engulfed in the phagozone, lysozymes fuse with phagozone
- lysosymes diffuse their digestive enzymes into the phagozone to hydrolyse the pathogen
- phagocyte presents pthogens antigen on its surface, APC, sends a signal to the specific response immune system
- phagocytosis cells cause can cause inflammation, increase dilation of blood vessels so more phagocytes can enter, also increased temperature to deter pathogens
Autoimmune disorders
phagocytes dont recognise your own cells
treatment, immunosupressants
limitation of non specific response
- cant react to toxins
- cant identify infected cells8
Specific immune response
- chemical messenger from APC to T-helper cells
- T-helper cells with various antigens arrive, the complimentary antigen binds to the APC’s antigen
- When it binds chemical messenger called cytokynes illicit the b cells and cytoxic T cells with varying antigens to arrive to bind with the T helper cell, with the complimentary antigen
- Both cells reproduce via clonal expansion via mitosis
- memory cells also produced
- B cells undergo specialisation so they are able to produce antibodies and antitoxins - they are now called plasma cells
- Antibodies 3-d complimantary to pathogens antigen, they are toxic so destroy pathogen, can also agllutenate pathogens so they cant move, invade cells or reproduce and phagocytosis is more efficient
- antitoxins binds to the toxin and neutralises it
- cytoxic t cell binds to the pathogen of the APC
- it produces lytic enzymes to destory the cell membrane so water moves in via osmosis and cell explodes , the lytic enzymes also attracts phagocytes
Acitve immunity
- creates memory cells
- natural, infection
- artificail, vaccine
passive immunity
- doesnt create memory cells
- natural, antibodies transferred through breast milk or placenta
- artificial, antibiotics, tetanus injections
what are the effects of memory cells
- shortens illness time
- longer life span
- higher affinity
- reproduce at a faster rate
