skin barrier to infection - forms a tough barrier of collagen to prevent entry of pathogens, maintained by vitamin C
skin flora competes with pathogenic bacteria to prevent growth (the gut also has a flora)
blood clotting seals wounds to prevent entry of pathogens
inflammation - cells surround the site of infection to prevent the spread of disease
phagocytosis - invading microbes are engulfed and destroyed
mucous membranes - mucus and ciliated cells trap microbes and help to remove them
stomach acid - kills bacteria
lysozyme - in tears and saliva, hydrolyses the peptidoglycan in bacterial cell walls
signs of inflammation
redness
swelling
heat
pain
functions of inflammation
increases blood flow to the area
destroys the cause of infection
repairs / replaces damaged tissue
phagocytosis
pathogens entering the body are surrounded by pseudopodia
pathogens are engulfed (phagocytosed) by endocytosis (ATP)
a vacuole forms enclosing the bacteria
lysosomes fuse with the vacuole
toxic compounds (lysosomal enzymes and hydrogen peroxide) destroy the ingested pathogens
the debris from pathogen is released by exocytosis
antigens from the pathogens are presented on the surface of the macrophage
the antigens now stimulate lymphocytes
natural barriers to infection are known as non-specific immunity
pathogenic - an organism that causes damage to its host
infectious - a disease that may be transmitted from one individual to another
carrier - an infected person or other organism that shows no symptoms when infected but can transmit the disease onto another
disease reservoir - a long-term host of a pathogen ; this may be in human or another animal and may be a source of infection or disease outbreak
endemic - a disease occurring frequently, at a predictablerate, in a specific location or population
epidemic - the rapidspread of infectious disease to a large number of people in a short period of time
pandemic - an epidemic over a very wide area, crossing international boundaries and affecting a large number of people
infection - a transmissible disease often acquired by inhalation, ingestion or physical contact
vaccine - a weakened or inactive pathogen or toxin or antigen that stimulates the immune system to produce an immune response against it without causing infection
antibiotic - a substance produced by a fungus which diminishes the growth of bacteria
3 types of antimicrobials:
antiseptics used on living tissue
disinfectants used on non-living surfaces
antibiotics
antimicrobials - compounds that inhibit the growth of bacteria
antibiotic resistance - the situation in which a microorganism that has previously been susceptible to an antibiotic is no longer affected by it
antigen - a molecule that causes the immune system to produce antibodies against it
antibody - an immunoglobulin (protein) produced by the immune system in response to antigens that recognises and destroys antigens
vector - a person, animal or microbe (living organism) which carries and transmits an infectious pathogen onto another living organism
toxin - a small molecule made in cells or organisms, that causes damage to the host (toxins often affect macromolecules eg. enzymes)
antigenic type - organisms with very similar surface proteins or antigens, often subgroups or strains of a microbial species
fill in the table
A) pathogenic
B) infectious
C) carrier
D) disease reservoir
E) endemic
F) epidemic
G) pandemic
H) vaccine
I) antibiotic
J) antibiotic resistance
K) antigen
L) antibody
M) vector
N) toxin
O) antigenic type
complete the table
A) gram negative
B) gut lining
C) toxins
D) dehydration
E) water
F) water treatment
G) rehydration
H) antibiotics
I) bacteria
J) lymph nodes
K) airborne
L) antibiotics
M) variola major virus
N) fluid filled blisters
O) contact
P) vaccine
Q) virus
R) respiratory tract
S) airborne droplet infection
T) good hygiene
U) vaccine
V) protoctistan parasite
W) liver
X) fever
Y) vector
Z) anopheles mosquitos
[) prevent the vector
\) kill the parasite
]) mutates
gram negative bacteria
thinpeptidoglycan cell wall
layer of lipopolysaccharide - protects bacterial cell against lysozyme and penicillin type antibiotics
Gram staining technique - red
gram positive bacteria
thick peptidoglycan cell wall
no lipopolysaccharide layer
Gram staining technique - purple
susceptible to lysozyme and penicillin
microorganisms and parasites in the human body are only harmful if:
they secrete toxins
their population increases too much
they are transferred to an inappropriate part of the body
E. coli in the large intestine synthesise vitamin K, but in the stomach and small intestine they can cause gastro-intestinal disease
mites in the hair follicles of eyelashes eat dead cells, however, when eye make-up is not removed their population can increase and cause inflammation
entamoeba (protoctistan) graze on dead cells of gums, they can reproduce rapidly and cause gingivitis if the gums arent brushed enough
most microorganisms and parasites on or in the body contribute to general health and have a mutualistic relationship with the host