Response to infection Flashcards
define the following :
the immune system, immunity, immune response, pathogen antigen and communicable disease
immune system: different types of cells that occur in most organs of the body and protect against foreign substance alien chemicals and abnormal substances
immunity: resistance to infection from invading microorganisms
Immune response: a response triggered by foreign substance or micro organisms entering the body
Pathogen: a disease causing organisms often referred to as a pathogenic organism
Antigen: any substance capable of causing the formation of antibodies when introduced into tissue
Communicable disease: a disease passed from one person into another fight infection with micro organisms called infectious or transmittable disease
in a bacteria cell define a chromosome, plasmid, flagellum, endospore, capsule, cell wall, cell membrane and pilli
chromosome: contains the genetic material
plasmid: another form of DNA
flagellum: no found in all in all bacteria but they allow for movement can be one or many
endosphore: ensures the survival of bacteria though environmental stress
capsule: formed by complex carbohydrates by some bacteria for protection
cell membrane:: similar to other cells it protects and supports the cell separating it for extracellular fluid
cell wall: composition varies often and from protien and and carbohydrates
pilli: extends from the cell membrane of the bacteria and attaches to cell surfaces
chromosome contains the genetic material of the bacteria
plasmid another form of DNA
what do the 3 lines of defense do
1st = non specific external
- external Barries and protective reflexes that prevent pathogens from entering the body/ tissue
2nd= non specific internal defences that
- acts to destroy pathogens that enter the body? tissue
- ie fever inflammatory response and macrophages
3rd= specific internal defences
-specific lymphocytes ( b cell, T cell are activated in presence of specific antigens and pathogens eg antibodies and cell mediated response
explain how viral replication occurs using HIV as an example
- HIV binds to the receptor site on the T-lymphocyte
- Uncoated RNA from the virus enters the lymphocyte
- The virus contains an enzyme that enables it to make a DNA copy of its RNA
- Host cell DNA in the nucleus DNA of HIV RNA integrates with host cell DNA
- New viral RNA is produced
- Budding of new virus particle from lymphocyte and a new HIV is able to infect other cells
describe the different methods of transmission of disease
Direct: transmission of pathogens by actual physical contact with the infectious person
Indirect: touching a object which has been touched by an infectious individual
Faecal oral: pathogens from someone’s faecal route post into someone’s mouth
Vector borne: transfer of pathogens through other animals insects or ticks
Fomite: objects or materials likely to carry infection such as clothes utensils and furniture
Transmission by contact: this can be direct or indirect by contact with the infectious person or touching an object they have touched for example skin infections and sexually transmitted disease
Contaminated food and water: pathogens in food which may result in disease
Infection by droplets: tiny droplets of moisture containing pathogenic are emitted eg when breathing eg ebola and Covid
Transfer of body fluid: when blood or other body fluids come into contact with and an infected person for example through needles
explain the process of phagocytosis
- Phagocytes move towards the bacterium
- Phagocytes change scape to completely and close the bacterium
- Lysosomes contain destructive enzymes
- Enzyme destroys bacteria
- Harmless parts are released from phagocytes
Explain how the external barriers of the body work as the first line of defence
Ear: cerumen or earwax inhibits bacterial growth by acting as a sticky trap and lysosomes are found in the earwax hairs all work as an external barrier
eyes: cleansed by tears which also contain chemical inhibiting bacterial growth called lysosomes eyelashes and eyebrows trap dust and eyelids allow for protection of the eyes
gastro intestinal tract: acidic juice or hydrochloric acid kills micro organisms and the anus mucus membrane traps micro organisms and lysosomes are present and there is less oxygen making it an anaerobic environment
uerogenital tract: acidic secretions inhibit growth of pathogens and urine flushes out any bacteria vagina has a pH of 4 to destroy bacteria and the mucus plug closes up the cervix it some parts of the menstrual cycle
skin: physical barrier which produces sweat containing lysosomes
respritory system: mucus layer traps microorganisms there are lysosomes and the cilia traps the bacteria in the throat has in the silly I off the nose and macrophages in the alveoli
Outline protective reflexes which are a part of the first line of defence
Sneezing: the stimulus to sneeze is irritation of the walls of the nasal cavity caused by fumes and dust particles which are likely carrying micro organisms the forceful expulsion allows mucus to exit the mouth
Coughing: irritation of the lower respiratory tract gives the stimulus air is forced from the lungs to remove the irritant air drives up the trachea and towards the mouth
Vomiting psychological stimuli excessive stretching of the stomach and bacterial toxins all induce vomiting constriction of muscles and the abdomen expels stomach content
Diarrhoea the irritation of the small intestine causes increased construction of the walls of the intestine’s so that the irritant is removed as quickly as possible therefore the material does not stay in the large intestine long enough to be absorbed
define what a fever is and how it works
definition: body temperature above normal range with no known cause
phagocytes enter the body other causes may also be blood clots, cancer and heat stroke
the chemical messages from the pathogen are detected by the hypothalamus
the hypothalamus will set its thermostat too 38 degrees the body will actively heat up by shivering and vasoconstriction will occur therefore the body will reach the new temperature and hot if pathogens are removed the body temperature returns to 37° if the pathogen is not removed the thermostat will be reset to even hire this is dangerous as if the body temperature reaches over 40° enzymes become denatured
how does fever effect the body
denaturing enzymes, increase tissue repair, increasing lecoyte activity
what are the steps of the inflammatory response
- damaged mast cell in connective tissue releases histamine and heparin
- histmine increase blood flow to the site of inuring injury and the vessels become leaky and brings nessasay components to the to the site
3 heparin prevents blood clots to immediate area note blood clot does form around actual damages vessels to prevent spread of infection note clot does form around the actual damaged vessels to prevent spread of infection
4 mast cells release chemicals to attract phagocyte and phagocytosis of debris and invading pathogens
5 abnormal conditions and pain occurs
6 phagocytes die (filled with dead cells debris and pus)
7 mitosis new cells repair damage
