Option topic - Immunology and disease Flashcards
1
Q
How many cells are in the human body?
A
10 to the power of 13
2
Q
Colonies?
A
found in cells, tissue fluid, gut, skin, hair and body openings
3
Q
Microbes include?
A
fungi, Protoctista, 1000 species of bacteria
between toes, feet
genitals
4
Q
Bacteria living in the gut?
A
flora
humans carry parasites
tapeworm
lice e.g head lice / pubic lice
5
Q
Worms?
A
helminths
all these organisms cause disease + secrete toxins if the population = too high
6
Q
E.coli?
A
Estercechia coli
found in large intestine, stomach + small intestine + in faeces
contains gastro intestinal disease
have diorrhea and vomit
in small populations, synthesise vitamin K
7
Q
Mites?
A
live in hair folices of eye lashes + eat dead cells
8
Q
Enta amoeba?
A
protocistan - single celled organisms
are on gums + graze dead cells
can cause gingitivitis
9
Q
Cholera?
A
gram negatice
comma shaped
bacterium - called virus cholerae
can only reproduce inside a human host
endemic
humans - infected through contaminated food or water and become carriers, acting as reservoirs of disease
bacteria produces toxins in the small intestine which affect chloride channel proteins called CFTR gene
10
Q
Endemic?
A
exists at a low level/ population
11
Q
CFTR?
A
cystic
fibrosis
makes mucus very thick
12
Q
Cl
Na+
K+
HCO3- ?
A
not absorbed into the blood, resulting in severe watery diarrhea
causes dehydration + blood pressure falls dramatically + death can occur within hours
13
Q
Prevention?
A
good hygeine + sanitation
sewage treatment
water purificaiton
safe food handling
handwashing
vaccine = available but also provides temp protection - mutates
14
Q
Treatment?
A
replacement of water + ions - by giving patients electrolytes
can be given intravenosuly
replacement theory thin antibiotics
15
Q
electrolytes?
A
solution of water that ions that are missing in it
16
Q
Origin?
A
John snow discovered - 1854
doctor
believed that cholera = airborne but suspected it was transmitted in water
Mapped out cases of cholera in soho in london
identified the water from a pump in broadwick street as the source
when handle of water pump = removed, number of cases dropped
16
Q
Toxin?
A
small molecule that causes disease following contact or absorption
toxins affect macromolecules
( enzyme )
17
Q
Infection?
A
transmissible disease that is acquired from inhalation , ingestion or physical contact
18
Q
Carrier?
A
infected person showing no symptoms but is affecting others
19
Q
Disease reservoir?
A
long term host of a pathogen with few or no symptoms but always has the potential for disease outbreak
20
Q
TB?
A
tuberculosis
caused by a bacterium - mycobacterium tuberculosis
bacillus - rod shaped bacteria
named tb due to the tubercles or nodules of the dead, damaged cells in the lungs of people infected
tubercles may contained gas filled cavities which = identifiable on a x-ray
infection = spread by inhalation of bacteria laden droplets
in many countries, there = signs stating no spitting
TB spreads rapidly in crowded conditions such as densely populated areas ( india)
immune system of HIV and aids patients = correlated with the increase in TB cases as their immunity is compromised
21
Q
Symptoms of TB?
A
chest pain
coughing up phlegm which contains blood
swelling of lymph nodes in the neck
loss of appetite
development of a fever
22
Q
Treatment?
A
long term antibiotics
mycobacterium tuberculosis shows antibiotic resistance
23
Q
Prevention?
A
BCG vaccine - given to babies
heaf test is given to teenagers up to 11 to detect immunity
if test = negative, vaccine = delivered + provides 75 %
protection for 15 years
vaccine = less effective in adults + made from attenuated
24
Attenuated?
weakened strain
25
Strain of bacteria?
weakened strain
mycobacterium bovis
26
BCG?
Bacillus
Calmette
Guerin
people who discovered it
27
Person who is exposed to TB?
may carry anti TB antibodies which is detected by the skin test
28
Negative skin test?
have no antibodies + could be offered a vaccine
29
Small pox?
caused by a DNA containing virus
vanola major
30
Virus def?
inhaled or transmitted in saliva, if in close contacts with an affected person
31
enters small blood vessels in the mouth, skin and throat?
dispersed around the body
causes a rash + fluid filled blisters which leave scars in survivors
survivors suffer blindness + limb deformities
32
Treatment?
infected people - given fluids, drugs to control fever, antibiotic to control bacteria infections
60% of people die
33
Vaccine?
produces strong immune response
made using a live virus
( vaccina)
closely related to small pox virus
effective at preventing disease
between 1900 and 1979
500,000,000 people died of smallpox
only species that humans have deliberately got rid of
only remaining virus - in a research lab + has a high level of biosecurity
ethical debate over whether extinction - necessary
earliest evidence of smallpox - 1145 BC on a mummy but small pox emerged as a new disease 12000 years ago
34
I3 subgroups of influenza?
Flu A
Flu B
Flu C
35
Flu B?
most prolific
influenza infects many species
: Avian and swine
birds and pigs
if new strain of flu appeals, new proteins on the virus surface +human immune system cannot provide protection
lack of immunity leads to pandemics
1918 - 1920 - spanish flu infected 500,000,0000 and killed 50,000,000
4% of world population
influenza virus contains RNA
RNA - in a single strands
36
Virion?
virus
surrounded by a phospholipid envelope which is derived from the hos cells surface membrane
envelope has 2 important proteins known as antigens, which appear has spikes in the surface of the virus
36
Haemagglutinin ( H)
has a role in the virus entering the host cell
Neuraminidase ( N)
37
Second protein?
has a role in the virus, leaving the host cells
38
Antigen def?
a molecule that causes the immune system to produce antibodies against it
39
Antigens def?
individual molecules that found on viruses, bacteria, spores or pollen grains
40
Symptoms of flu?
inhaled in droplets from coughs and sneezes
aerosol transmission
41
Treatment?
regular hand-washing
discard used tissues
influenza vaccines can be effective but the surface antigens on the virus frequently mutate so annual vaccines = required
42
Antigenic type?
different individuals of the same pathogenic species with different surface proteins generate different antibodies
43
Epidemic?
rapid spread of infectious disease to a large number of different people within a short period of time
44
Antigenic types of influenza types?
45
Antigenic drift
46
Virus Pathogenicity + reproduction?
viruses are the ultimate parasite because outside living cells - they are inert
they show none of the characteristics of life except when in a host cell where they can be replicated
47
Lytic cycle?
viruses immediately reproduce, using the host's metabolism to copy their own nucleic acid and synthesise a new coat protein
they are released in 2 ways:
1) lysis of the hosts cell
(common cold)
2) budding - in which they acquire an envelope from the hosts cell membrane
(influenza virus)
48
Lysogenic?
Viruses integrate their nucleic acid into the host cell's genome and it may remain there for many generations of the cell with no clinical affect ( no symptoms)
at a later point in time, they enter the lytic cycle + produce symptoms e.g HIV and herpes
49
Pathogenic viruses?
cell lysis
If bacteria are infected with a bacteriophage, the pressure of a new virus particle inside causes the bacteria to burst
In contrast, if animal cells are infected with a virus, there is inflammation caused by T lymphocytes or antibodies + causes Lysis
for example rhinovirus
50
Rhinovirus?
It lyses cells in the upper respiratory tract
virus - causes first one to explode
second one causes T lymphocytes to explode
51
Toxins?
virus components and their bioproducts = toxic
3 examples
measles causes chromosome fusion
herpes causes cell fusion
viral proteins inhibit RNA, DNA and protein synthesis
52
Cell transformation?
Viral DNA can integrate into the hosts chromosomes
if the DNA inserts a proto oncogene or tumour suppressor gene, the cell will undergo rapid mitosis becoming cancerous
for example HPV
human papillomavirus which causes cervical cancer by inserting the tumour suppressor gene TP53
53
Immune suppression?
Suppression of reactions causes B and T lymphocytes to mature
reduction in antibody formation
( HIV destroys T helper cells) +destroys B lymphocytes so antibodies can no longer be made
reduction of phagocytic cells
54
Antibiotics?
Alexander Fleming
there are 3 compounds that inhibit the growth of bacteria (antimicrobials)
1) antiseptics - TCP
tri chloro phenol
2) Disinfectant - bleach
Sodium Hydroxide
3) Antibiotics
55
How are they produced?
by fungi + act on bacteria but not on viruses or eukaryotic cells
they can treat a patient for a bacterial infection without harm
56
Broad spectrum antibiotics?
Ampicillin
Tetracycline
they both destroy gram positive and gram negative bacteria
57
Narrow spectrum anitibotics?
more selective
Penicillin G - kills only gram positive bacteria
58
Bactericidal def?
an antibiotic that kills bacteria by destroying the cell wall
59
Bacteriostatic def?
prevents bacterial multiplication but does not cause death
bacteria - still there
60
Bacterial cell walls?
Peptidoglycan ( miurein)
forms part of a bacterial cell wall
its made of polysaccharide and short chain amino acids
Transpeptidase cross links the polysaccharide to the amino acid sidechain
giving:
strength
shape
and allows resistance to bursting
61
Gram positive?
have a thick layer of murein which makes up 90% of the cell wall
62
Murein?
there are pores in the murein which close during the decolourisation of the staining process so the dye - crystal violet is retained in the cell
staining the cell violet
63
Safranin?
used as a counterstain + turns the violet cells purple
Murein is accessible to molecules outside the cell so it is susceptible to attack by penicillin and lysozyme
64
Gram negative?
thin layer of murein
only 10% in the cell wall
it is surrounded by a layer of lipoprotein and lipopolysaccharide
these lipid molecules - disrupted by the decolourisation stage of gram staining
the crystal violet stain leaks out of the cell
leaving them unstained
safranin - the counter stain
turns the gram negative cells red
lipid layer protects the murein
from antimicrobial agents such as penicillin
65
Penicillin?
released from the fungus
penicillium notatum
fungus produces penicillin when under stress or its growth = inhibited
originally - penicillin was massed produced from penicillium mutatum but now produced from penicillium chrysogenum
Fungus = grown aerobically in an industrial fermenter and then purified
the first available penicillin = penicillin G which had t be injected not ingested because stomach acid broke it down
Penicillin V can be taken orally and works by disrupting the bacterial cell wall
66
Penicillin?
Penicillin diffuses through the cell wall of gram positive bacteria
penicillin enters gram negative bacteria through the surface membrane molecules called porins
67
Enzyme DD transpeptidase?
catalyses the condensation reaction that makes crosslinks between amino acid side chains and peptidoglycan molecules
68
What is it sometimes called?
PBP
Penicillin
binding
protein
can act as an enzyme inhibitor
69
Pencillin?
hydrolyses the cell wall, preventing cross links from being formed, making it weaker, so water enters via osmosis
Pressure potential increases + the cell lyses
70
Tetracyclin?
originates from the fungus
Streptomyces - which is a broad spectrum antibiotic
acting against gram positive and gram negative
Used against bacterial infections such as acne chlamydia + anthrax
could be effective against plasmodium
many bacteria are now resistant to tetracyclin
71
How does it work?
inhibit protein synthesis + is diffused and pumped into the bacterial cell
It binds to the small subunit of the ribosome and blocks tRNA attachment so amino acids cannot be added to the chain
Tetracycline is bacteriostatic - prevents bacterial multiplication
72
Antibiotic resistance def?
a situation where a microorganism that has previously been susceptible to an antibiotic is no longer effective by it
73
How long has antibiotics been used?
for thousands of years
74
How did they use it for a treatment?
including the use of mouldy bread for wound infections in ancient greece
75
Allowing animals to stay free from infection what do farmers use?
antibiotics to prevent rather than treat disease
76
Antibiotics in the environment?
kill susceptible individuals
but any that have a mutation that makes them resistant will survive
this means they have a selective advantage
in the presence of antibiotics
they reproduce passing on the allele for antibiotic resistance and build a resistant population
( Darwin's theory of natural selection)
77
2 types of Antibiotic resistant alleles?
1) every time bacterial DNA replicates
a mutation causing resistance may arise
bacteria divide rapidly when conditions are suitable
so they have a high mutation rate
2) bacteria may acquire plasmids that carry an allele for resistance from their environment
Plasmids replicate inside the bacteria and are passed onto daughter cells when the bacterium replicates
78
Penicillin resistance?
they secrete beta lactamase which is an enzyme that degrades penicillin
they alter the PBP so penicillin cannot bind during protein synthesis
They reduce penicillin entry by having smaller porins
79
Tetracycline resistance?
they pump tetracycline out of the cell
they dislodge tetracycline if it binds
they prevent tetracycline attaching to a ribosome
80
Antibiotic resistant diseases?
Leprosy
TB
Gonorrhea
MRSA ( Methicillin resistant staphylococcus aureus)- resistant to penicillin and all derivatives of penicillin including vancomycin
81
What is vancomycin?
an antibiotic used as a last resort to treat highly resistant infections
82
What does the Immune system do?
enables the body to resist disease
Physical barriers protect against the entry of pathogens
( cilia )
skin
mucus
acid
moisture
83
How does it work?
the body is invaded by thousands of microorganisms every day
yet humans remain healthy as the body detects foreign nonself antigens from the self antigens of their own tissues
84
2 types of immune system?
innate
adaptive
85
Innate?
A group of natural barriers which resist infection
86
Skin?
covers the external surface of the body expect at openings such as mouth, eyes, nose and genitals
Secondary proteins
Keratin in epidermal cells makes the skin waterproof
Collagen in the dermis
( middle layer of skin) is maintained by vitamin C which makes the skin tough
87
Skin flora?
Microbiota
made of bacteria + fungi
which outcompete pathogenic strains
they cannot be washed off
so regular washing is an important way of resisting infection
88
Inhalation?
Inhaled air contains microorganism and spores
which are trapped by mucus and cilia of the epidermal cells lining respiratory passages
this forces them to the opening of the oesophagus
where they are swallowed and die in acid
If the skin barrier is breached and capillaries are broken, blood clots preventing the entry of microbes
89
Inflammation?
increases blood flow to the infection site of infection brings phagocytic cells
Broken capillaries heal
+ temperature rises
to kill microbes
90
Bloodstream?
if microbes enter
phagocytic cells including macrophages and neutrophils engulf and digest them
91
Enzymes?
tears
mucus
and saliva all contain lysozyme which hydrolyses peptidoglycan in bacterial cell walls and kills them
92
Acid?
Stomach acid ( HCl)
pH 1
kills microbes that are ingested in food and drink
93
Adaptative def?
Body produces a specific response to each antigen so the body is continually adaptive
Lymphocytes provide the response and are generated from stem cells in the bone marrow
94
Adaptive response?
Humoral response
Cell mediated response
95
Humoral?
this results in the production of antibodies
96
Antibody def?
An immunoglobulin produced by the body in response to a foreign antigen
B lymphocytes mature in the spleen and lymph nodes
the Receptors on the cell respond to a foreign protein in the bloodstream
they begin to divide, making plasma cells
which release antibodies
a second cell known as a memory cell
remains dormant in the circulation
+ divides to form B lymphocytes if the same antigen is encountered again
97
Antibodies?
Y shaped
glycoprotein molecules
called amino globulines
they have a quaternary structure where each molecule is made of 4 polypeptide chains that are held together by
disulphide bridges
the variable portions of the antibody are specific to each antigen
an antigen molecule binds to an antibody and each antibody combined to 2 antigen molecules
When an antigen joins to an antibody, they agglutinate
98
Cell meditated response?
99
2 types of
100
T lymphocytes?
have receptors on their cell membrane which respond to their antigens, causing them to divide, forming T memory cells which remain dormant in the circulation and divide if the same antigen is encountered
divide to produce T killer cells ( cytotoxic T cells )
they kill pathogenic cells by lysing them ( making them explode) to produce T helper cells which release chemicals called cytokines
101
Cytokines?
they stimulate phagocytic cells such as macrophages or neutrophils to engulf pathogens and digest them
they cause B and T lymphocytes to undergo the process of clonal expansion
(divide repeatedly to form genetically identical cells)
B lymphocytes begin antibody production
102
Primary immune response?
on exposure to an antigen
there is a short latent period where macrophages engulf the foreign antigen or cell or virus and incorporate the antigens into their own cell membrane
This is known as antigen presentation
this triggers T helper cells to detect the antigens and respond by secreting cytokines
B plasma cells secrete antibodies for at least 3 weeks until the symptoms of the infection subside
103
Secondary immune response?
relies on memory cells and may protect against an identical antigen decades after exposure
on reexposure, even a minute quantity of the antigen causes the memory cells to undergo clonal expansion but at a faster rate than the primary response
antibodies are produced more quickly and are a hundred times more concentrated than the primary response
they remain at high concentration in the circulation for longer and no symptoms develop
104
Active immunity?
the body makes its own antibodies stimulated by either an infection or a vaccination
longer lasting because response produces memory cells
105
Vaccination?
cells mediated and humoral response are initiated even when no harmful pathogen is present
vaccines can be of 4 types
106
4 types of vaccines?
107
Passive immunity?
the body receives antibodies produced from another individual
from mother to foetus across the placenta
from mother to baby in breast milk
Antibody injections can be given when rapid resistance is needed such as when someone is bitten by an animal infected with rabies
or a wound where the risk of tetanus is high
in people with HIV or aids
they do not make enough antibodies so cannot protect themselves against pathogens
injected antibodies are short lived because of the body's immune response as they are recognised as foreign and no memory cells are made
108
Vaccination?
The latin for cow is vacca
Edward Jenner was the first to vaccinate against smallpox using cowpox which is the less dangerous pathogen
109
Effectiveness of the vaccine?
different vaccines
require different schedules
HPV only given one
meningitis given 3 doses
Influenza annually
110
Antigens?
highly immunogenic so a single dose of a vaccine would initiate a strong response it would rapidly make a large number of antibody molecules specific to an antigen
111
Vaccinia Virus?
a close relative of variola major ( smallpox ) which is used to make the
smallpox vaccine
there should be only 1 antigenic type of a pathogen
Rubella - virus that causes german measles
all rubella viruses have the same antigens so only one vaccine is needed
flu virus has many
serotypes which means it can undergo genetic recombination and mutation
the memory cells that are initially reproduced may no longer produce the correct antibody
112
Ethics?
against
not medically advised because they are immunocompromised
if a spleen is being removed
chemotherapy
aids
HIV
old age
Choice
religious objections
mistrust in pharmaceutical companies
a preference for natural or alternative medicine
113
114
115
