6.3 Disease Defenses Flashcards
What is the fist line of defense?
Skin: dry - bad for bacteria & non-living - bad for viruses
Mucous: can secrete lysosomes, which can destroy cell-walls
Outline the Innate Immune System (non-specific).
1- Phagocytic white blood cells/ phagocytic leukocytes circulate in the blood
2- they move into tissues, when infected tissue releases histamine upon infection (chemotaxis).
3- Pathogen is engulfed by the phagocyte and put in a vessicle, into which lysosomes will come and digest the pathogen.
4- Sometimes, the antigens are then presented on the surface of the phagocyte/dendritic cell.
Outline the Adaptive Immune System (specific).
It’s coordinated by lymphocytes (a class of leukocytes).
The dendritic cells go to lymph nodes and activate specific helper T lymphocytes.
Helper T cells secrete cytokines -> activates the particular B cell capable of producing antibodies specific to those antigens from the dendritic cell
B cell will divide many times and differentiate into short-lived ‘plasma cells’ which produce much quicker lots of specific antibodies
A few helper T cells and B cells will turn into ‘memory cells’ for long-term immunity
What exactly do antibodies do?
Their specific shape binds perfectly to the antigens of a virus, making the virus unable to infect other cells. They also mark them for cells like macrophages to be destroyed.
What do Antibiotics do?
They target only prokaryotic cells / their metabolism, by attacking key enzymes, 70S ribosomes and the cell wall.
Why don’t antibiotics work for viruses?
Viruses don’t have a metabolism.
What is penecilin? What is the Florey Chain experiment?
Penicillin attacks cell wall components of prokaryotes!
Florey and Chain had 8 bacterial infected mice, and treated only 4 with penicillin. The treated ones survived, the other ones did not :’((((((((
What is HIV?
HIV is a virus that targets Helper T-cells, so the Adaptive Immune System gets weaker, which causes AIDS.
How does clotting work?
Coagulation Cascade:
1- Clotting factors are released from damaged cells
2- Causes platelets to get sticky & adhere to damaged region
3- Also causes vascoconstriction -> less blood flow
4) also turns prothrombin into thrombin, which catalyses the conversion of fibrinogen (soluble) into fibrin (insoluble), which are like the ropes that hold the clot
Once damaged region is healed, an enzyme is activited to dissolve the clot.
What is Coronary Thrombosis?
Walls of fat deposits in the coronaty arteries get holes because of the increased blood pressure, which are sealed by clots, which can block the blood flow, forming a thrombus.
What is the thrombus called if it is dislodged? What is the problem?
Embolus, now it could block a even smaller artery.
