Unit 10 - Diseases and immunity Flashcards
Types of pathogens
- Bacteria
- Fungi
- Protoctists
- Viruses
Transmissible diseases
Pathogens that can be passed from one host to another
Methods of transmission
Direct contact and indirect contact
Direct contact
Exchange of body fluids e.g. blood
Indirect contact
Through air, water, food, contaminated surfaces or animals
Vector
An organism that transmits a pathogen from an infected to non-infected person
Pathogens in host
Reproduce rapidly and damage cells and organs
Mechanical Barries from pathogens
Skin, nose hair
Function of skin as a barrier
- Forms a waterproof barrier
- Microorganisms can’t get in unless skin is broken - stopped by blood clotting
Function of nose hairs as a barrier
- Trap particles that could carry pathogens
- Ciliated cells move trapped particles with mucus in the throat
Chemical barriers from pathogens
Mucus, stomach acid
Function of mucus as a barrier
- Traps bacteria and other pathogens
- Is produced in lungs & inner lining of the gut
Function of stomach acid as a barrier
Hydrochloric acid damaged or kills pathogens that could have been swallowed
Second line of defense against pathogens
White blood cells and vaccinations
White blood cells functions’ as barriers
- Phagocytes - surround and engulf pathogens and break down using enzymes
- Lymphocytes - produce antibodies, proteins that attach to antigens
Function of vaccination as a barrier
Primes the immune system so it can react to a pathogen
Controlling the spread of disease
- Clean water supply
- Good personal hygiene
- Hygienic food preparation
- Proper waste disposal
- Treatment of sewage
Antigens
- Cause the body to produce immune response
- Often are proteins but can be fats & carbs
Function of antibodies
Attach to antigens to either mark the pathogen for phagocytosis or causes the pathogen to break open and die
Relationship with antibodies and antigens
- Antibody has a specific shape for the antigen
- Each antibody is for only one antigen
Active immunity
- Gained from infection
- Antibodies react with antigen - first response
- Second response will be quicker
Memory cells
- Remain in blood after infection
- If infected again, memory cells will respond and make many antibodies
- Antibodies can destroy pathogens before illness
Vaccination
- Causes active immunity without infection
- Inject small amounts of pathogens ( dead or weakened)
- Lymphocytes respond and memory cells produced
Passive immunity
- Short-term defense against a pathogen from antibodies from someone else
- Memory cells are not produced
- Protection only lasts a few weeks or months but is immediate
- Helps people with damaged immune systems
Cholera
- Causes watery diarrhea
- Results in death & dehydration
- Comes from drinking water contaminated with human feces
- Comes from bacterium - Vibrio Cholera
Effects cholera toxin
- Bacteria goes to small intestine and produces toxin
- Intestinal cells secrete chloride ions into men of intestine
- High concentration of chloride ions causes osmotic movement of large amounts of water into intestinal lumen
- Diarrhea formed - large lost of ions and water
