microorganisms in relation to human health: chapter 4
superbugs = strains of bacteria, viruses, parasites and fungi that are resistant to most of the antibiotics and other medications commonly used to treat the infections they cause.
→ are mutants who after frequent contact with antibiotics for example changed their DNA → become insensitive to the antibiotic → break it down or render it harmless
example: MRSA
immune system
non-specific defense = the body’s first line of defense against diseases. They are not directed against a particular pathogen.
skin = a barrier with the outside world → protects the body in 3 ways of parasat=ic microorganisms
The stratum corneum = the outermost layer of the epidermis
The sebaceous and sweat glands secrete acidic and antibacterial substances
Body’s bacteria compete with foreign bacteria
mucous membrane
epidermis of body cavities is much thinner than the other skin but is also in direct contact with the outside world →mucous glands protect it →create a thin layer of mucus to prevent access to the underlying tissue
white blood cells and cell signaling
Macrophages = specialised cells that are involved in the detection, phagocytosis and destruction of bacteria and other harmful organisms
phagocytosis = The process by which a phagocyte (a type of white blood cell) surrounds and destroys foreign substances (such as bacteria) and removes dead cells.
example:
1. Bacteria penetrate the skin via a wound
2. Macrophages leave the capillaries to attack the bacteria 3. Macrophages phagocyte the bacteria and digest them
Natural killer cells/ NK-cells = a special type of white blood cells that produce perforin that open and drain infected body cells
perforin = a protein, released by killer cells of the immune system, which destroys targeted cells by creating lesions like pores in their membranes.
Signaling molecules → secreted by infected cells → 2 important functions
attract macrophages and activate NK-cells
warn other cells to create a protein → prevent multiplication of microorganim
specific defense = consists of mechanisms and agents that target specific antigens
characteristics
The detection of antigens
antigen = a specific molecule (a protein) found in the cell membrane of all cells of any organism (including in the protein coat of a virus)
via antigens → immunesystem can recognise foreign cells and viruses = T- and B-lymphocytes → recognise antigen
cell membrane lymphocytes have receptor molecules →ability to bind to the antigen = key-lock-principle
building memory
after an infection → body produces memory lymphocytes → new infection with same microorganism → faster detection → faster reaction of immunesystem → no sickness → immunity gained
functions of T-cells or T-lymphocytes
have membrane receptors to recognise infected cells → bind with it → perforate cell → cell dies
T-cells keep on multiplying upon contact → some turn into memory T-cells
T-cells produce signaling molecules → stimulate B-lymphocyte production
functions of B-cells or B-lymphocytes
recognise antigens → produce antibodies → bind with antigen → create antigen antibody complex →macrophages clean it up
B-cells keep on multiplying upon contact → some turn into memory B-cells
How to keep or increase your resistance?
get enough sleep
excercise regularly
have a balanced diet
avoid smoking, drugs and excessive alcohol consumption
be cautious with the use of medicines
active immunisation → vaccines
injection of dead or weakened pathogens → encourage the body to make memory cells and antibodies
passive immunisation → serum therapy
injection of anitiserum → presence of antibodies → patient doesn’t produce them → no production of memory cells
superbugs = strains of bacteria, viruses, parasites and fungi that are resistant to most of the antibiotics and other medications commonly used to treat the infections they cause.
→ are mutants who after frequent contact with antibiotics for example changed their DNA → become insensitive to the antibiotic → break it down or render it harmless
example: MRSA
immune system
non-specific defense = the body’s first line of defense against diseases. They are not directed against a particular pathogen.
skin = a barrier with the outside world → protects the body in 3 ways of parasat=ic microorganisms
The stratum corneum = the outermost layer of the epidermis
The sebaceous and sweat glands secrete acidic and antibacterial substances
Body’s bacteria compete with foreign bacteria
mucous membrane
epidermis of body cavities is much thinner than the other skin but is also in direct contact with the outside world →mucous glands protect it →create a thin layer of mucus to prevent access to the underlying tissue
white blood cells and cell signaling
Macrophages = specialised cells that are involved in the detection, phagocytosis and destruction of bacteria and other harmful organisms
phagocytosis = The process by which a phagocyte (a type of white blood cell) surrounds and destroys foreign substances (such as bacteria) and removes dead cells.
example:
1. Bacteria penetrate the skin via a wound
2. Macrophages leave the capillaries to attack the bacteria 3. Macrophages phagocyte the bacteria and digest them
Natural killer cells/ NK-cells = a special type of white blood cells that produce perforin that open and drain infected body cells
perforin = a protein, released by killer cells of the immune system, which destroys targeted cells by creating lesions like pores in their membranes.
Signaling molecules → secreted by infected cells → 2 important functions
attract macrophages and activate NK-cells
warn other cells to create a protein → prevent multiplication of microorganim
specific defense = consists of mechanisms and agents that target specific antigens
characteristics
The detection of antigens
antigen = a specific molecule (a protein) found in the cell membrane of all cells of any organism (including in the protein coat of a virus)
via antigens → immunesystem can recognise foreign cells and viruses = T- and B-lymphocytes → recognise antigen
cell membrane lymphocytes have receptor molecules →ability to bind to the antigen = key-lock-principle
building memory
after an infection → body produces memory lymphocytes → new infection with same microorganism → faster detection → faster reaction of immunesystem → no sickness → immunity gained
functions of T-cells or T-lymphocytes
have membrane receptors to recognise infected cells → bind with it → perforate cell → cell dies
T-cells keep on multiplying upon contact → some turn into memory T-cells
T-cells produce signaling molecules → stimulate B-lymphocyte production
functions of B-cells or B-lymphocytes
recognise antigens → produce antibodies → bind with antigen → create antigen antibody complex →macrophages clean it up
B-cells keep on multiplying upon contact → some turn into memory B-cells
How to keep or increase your resistance?
get enough sleep
excercise regularly
have a balanced diet
avoid smoking, drugs and excessive alcohol consumption
be cautious with the use of medicines
active immunisation → vaccines
injection of dead or weakened pathogens → encourage the body to make memory cells and antibodies
passive immunisation → serum therapy
injection of anitiserum → presence of antibodies → patient doesn’t produce them → no production of memory cells
