Communicable diseases Flashcards
what is a pathogen?
disease causing organism
what are the 4 types of pathogens?
bacteria, viruses, fungi, protis
what do pathogens release?
toxins that could endanger us.
what do toxins damage?
our cells
what are the two mechanisms our immune system is divided into?
non specific defence and specific defence
what are the features of non specific defence?
the response is immediate and the same for each pathogen, barriers to entry, phagocytes
what are the features of specific defence?
response is slower and specific to each pathogen, lymphocytes
What are pathogens?
Pathogens are microorganisms that cause infectious disease.
which places in your body are susceptible to pathogen entry?
mouth (oral route, contaminated food or water), nose (inhale droplets. breathing in bacterial droplets), or urogenital openings, or through wounds or bites that breach the skin barrier.
what is a symptom
what the patient is complain of
what is a sign
something that a doctor can see
what is the universal sign of infection?
a fever or temperature
what are the human defence responses?
skin defences, the respiratory system, the digestive system
what does the skin do to defend to against pathogens entering the body?
acts as a barrier, prevents pathogens from reaching the tissues beneath the skin
produces antimicrobial secretions
healthy skin is covered with microorganisms that keep you healthy
what does the respiratory system do to defend you against pathogens entering the body?
your nose is full of hairs and produces mucus
these trap particles in the air that may contain pathogens
the trachea and bronchial secret mucus
the lining of the tubes and covered in cilia
what does the digestive system do to defend you against pathogens entering the body?
the stomach produces acid which kills many pathogens
vomiting /diarrhoea rid the body of pathogens
how does your body defend you against pathogens entering through droplet infections?
The trachea and bronchi have a ciliated epithelium. Cilia are tiny hair-like structures.
Goblet cells in the epithelium produce mucus; mucus traps smaller dust particles and microbes.
Cilia beat together to sweep mucus to the back of the throat, where it is either coughed out or swallowed.
what can you do to prevent pathogen entry/spread of droplet infections?
prevent entry:
coughing up phlegm
spitting phlegm out
prevent spread:
use a paper tissue when sneezing or coughing then put it in the bin
how does your body defend you against pathogens entering through STDs?
the acidic pH of the vagina is not favourable for the growth of most pathogens. The semen of a man is sterile
what can you do to prevent pathogen entry/spread of STDs?
prevent entry:
abstinence
physical barrier eg condom
how does your body defend you against pathogens entering through the skin?
the skin contains may layers of cells, which gives protection.
the top most layer of skin cells is dry and dead, pathogens cannot easily penetrate these dead cells.
sebaceous glands in the skin produce antimicrobial oils to kill pathogens
what can you do to prevent pathogen entry through the skin?
wash hands
wear gloves when operating on patients
how does your body defend you against pathogens entering through food and drink?
the strong acids in the stomach kill any pathogens that may have entered
what can you do to prevent pathogen entry through food and drink?
wash your hands with soap after using the toilet
before you touch or prepare food wash your hands with soap
what do scabs do that prevent pathogens from entering
scabs protect the body by forming a barrier and prevent pathogens entering the body through the site of the injury whilst the skin is healing
what do white blood cells attack?
invading pathogens
what are the 3 things a white blood cell does to defend the body against pathogens?
ingesting pathogens (phagocytes)
producing antibodies
producing antitoxins
what are the two main groups of white blood cells?
phagocytes and lymphocytes
how does ingesting microorganisms protect you against disease?
some wbc ingest pathogens digesting and destroying them, this is called phagocytes
how does producing antibodies protect you against disease?
there is a unique antibody for each pathogen which matches a unique antigen on the surface of each pathogen. once these antibodies have been produced they can be made very quickly if a pathogen enters the body again.
how does producing antitoxins protect you against disease?
antitoxins counteract the toxins released by pathogens
what does a phagocyte do?
engulf and digest pathogens (killing them), killing itself in the process.
what does a lymphocyte do?
produce antibodies and antitoxins.
antitoxins neutralise toxins
what is the first line of defence?
phagocyte
what is the second line of defence?
lymphocyte
how do phagocytes work?
a phagocyte moves towards a bacterium
the phagocyte pushes the sleeve of the cytoplasm outwards to surround the bacterium
the bacterium is now enclosed in a vacuole inside the cell.
it is then engulfed and digested
the bacterium and the phagocyte is killed.
what does a pathogen carry?
a foreign antigen
what triggers an immune response?
a pathogen carrying a foreign antigen
how do phagocytes leave the blood?
squeezing through capillaries to enter tissues that are being attacked
how does lymphocytes antibody reproduction take place?
- Lymphocytes recognise foreign antigens on the pathogens
- The lymphocyte with the matching antibody (shape of antibody matches antigen exactly) clones itself to produce an “army” of cells
- The clone of cells produces the antibody in large quantities
- The antibody binds with the antigen causing clumping of the pathogen