B9: Animal physiology 5 Flashcards
Communicable diseases
These are diseases that are:
infectious (are caught)
and
caused by pathogens.
Pathogens cause disease and include:
1) viruses
2) bacteria
3) protists
4) fungi.
HIV can be passed from one person to another through
infected body fluids that contain the virus.
It can enter a person across mucous membranes or if the skin of a person is broken.
For example, the virus can be passed between people in semen or vaginal fluid so can be considered a sexually transmitted infection/disease.
However, it could be transferred in infected blood or breast milk.
prevention of infection with HIV would be by stopping the transmission of infected body fluids. This can be by:
using a condom during sexual intercourse
an HIV-infected mother bottle feeding her baby rather than breast feeding
screening blood so infected blood is not used in a blood transfusion.
people can be given …..that stop reverse transcriptase from functioning.=
anti-retroviral drugs.
less HIV with functioning reverse transcriptase, new HIV will not be made so the HIV infection can be controlled.
spread of influenza
airborne droplets of sputum
sneezed or coughed out of an infected person
inhaled by an uninfected person.
also be caught through contact.
influenza preventio
covering the mouth and nose when sneezing
or coughing or wearing a mask if infective,
and frequent hand washing to reduce potential transfer from surfaces.
influenza symptoms
runny nose, fever, sneezing, coughing and a sore throat a few days after infection but these should subside within about a week.
influenxa treatment
Vaccines - inactive virus or weakened virus
are available to groups at risk such as those with a weakened immune system. Vaccination can help to avoid pandemics.
Antiviral drugs are available to tackle influenza in some circumstances.
measles spread
direct contact such as touching an infected person.
airborne mucus droplets expelled - sneezing and coughing by an infected person
inhaled by an uninfected person.
measles symptoms
reddish blotchy rash that tends to start in the head/neck region, spreads over the face
then can cover the full surface of the skin.
a sensitivity to light.
measles treatment
can be prevented by the MMR vaccine which uses live weakened viruses for measles, mumps and rubella (German measles).
tmv spread
one plant to another by direct contact,
via an insect such as an aphid.
The virus can also remain in the soil for some time.
tmv prevention
stop viral transmission
by removing infected plants,
washing hands after touching an infected plant
through crop rotation.
tmv symptoms
cause tobacco leaves to have light and dark green areas (mosaic)
and they may become wrinkled.
tmv treatment
may also be infected with a milder strain of TMV which acts like a vaccine, preventing a more damaging strain.
Another approach is to genetically modify the tobacco plant to make it resistant to the disease.
Salmonella food poisoning spread
occur when a person ingests food contaminated with the bacterium.
The bacterium survives the low pH conditions of the stomach and reproduces in the small intestine where it causes inflammation.
Salmonella food poisoning prevention
proper food preparation such as washing hands after handling raw meat,
making sure that frozen meat is thoroughly defrosted before cooking,
and that food is thoroughly cooked.
Salmonella food poisoning treatment
Most people recover without treatment, but sometimes oral rehydration supplements are given to replace lost electrolytes.
Salmonella food poisoning symptoms
diarrhoea, vomiting and fever.
plasmodium s-causes malaria.- spread
spread by mosquitoes infected with theprotist mosquito can bite an infected human, to gain blood.
If they take in the protist, then it can be transferred to another human (or a variety of other mammals) at the next bite.
Once a human has the protist, it enters the liver where it matures.
It then moves into red blood cells where it reproduces. The red blood cells rupture, releasing the protists which then infect more red blood cells. This reproduction/release can happen in regular cycles leading to the periodic fever associated with malaria
fungal disease spread
The fungus produces large numbers of spores asexually
which disperse into the air and are then breathed in.
Symptoms include fever, cough, chest pain and breathlessness, usually in humans with a weakened immune system such as those with HIV or asthma.
Treatment uses medication such as steroids or antifungal medication. However, some strains have developed resistance to the medication.
fungal disease prevention
reducing exposure to the growing fungus,
such as regulating food storage in dry conditions which prevent fungal growth.
fungal disease symptom
fever, cough, chest pain and breathlessness,
usually in humans with a weakened immune system such as those with HIV or asthma
fungal disease treatment
medication such as steroids or antifungal medication. However, some strains have developed resistance to the medication.
preclinical tests
– do not involve testing on humans
clinical tests
– do involve testing on humans.
1) why is medicine tested on animals
to make sure safe to test on humans
2) why medicine tested on few healthy people phase 1
to make sure safe- low no. reduced risk
look for obvious side effects
3) why medicine tested on few healthy patients phase 2
to make sure works
low no. reduced risk
look for side effects
4) why medicine tested on many peope as a double- blind trial with placebo
look for less common side effetc s
double- blind to remove bia s
placebo to compare effect of medicine against placebo effect
define placebo effect
positive effect gained from taking the placebo.
If the chemical being tested does work, its positive effect should be greater than the placebo effect
Non-communicable diseases
These are diseases that:
are not infectious – they cannot be passed from one person to another
are caused by the interaction of many different factors.
Some non-communicable diseases are:
1) cardiovascular disease
2) many forms of cancer
3) some lung diseases
4) some liver diseases
5) nutrition-influenced diseases.
a) Coronary heart disease
coronary arteries are very narrow blood vessels
If any of their branches become blocked, then the heart muscle cells after the blockage will not receive oxygen and glucose and begin to carry out anaerobic respiration.
If this continues, these cells may die, leading to reduced heart function.
The blockage is usually
a fatty deposit called atheroma, or a blood clot.
Hypertension
consistently raised blood pressure (above 140/90 mmHg).
may be due to the narrowing of an artery lumen
due to atheroma or hardening of an artery
so that it cannot expand when blood flow increases.
Stroke
part of the brain is deprived of oxygen-rich and glucose-rich blood,
so brain cells die.
reason for the lack of blood is often due to narrowing and/or hardening of arteries supplying the brain tissue.
Some risk factors that can be modified:- cardiovascular
diet – consumption of foods high in fat/cholesterol increase risk of atheroma; and a high salt intake increases the risk of hypertension too little exercise obesity smoking excess alcohol intake.
Some risk factors that cannot be modified:- cardivasculae
increasing age
gender
heredity/a family history of CVD.
Statins
reduce the production of cholesterol,
which is a component of atheroma.
Build-up of atheroma can lead to blocked arteries.
Anti-coagulants
They reduce the likelihood of blood clotting
and therefore blocking an artery.
Anti-hypertensive drugs
They can cause blood vessels to relax so their lumen diameter enlarges, reducing blood pressure.
stenr
place a mesh tube into a narrowed part of a coronary artery
to increase its lumen diameter
so there is no restriction in the flow of blood to the cells it supplies.
bypass
A small section of blood vessel
is removed from another part of the body.
It is then used to re-route blood around a blockage in a coronary artery.
prostate cancer risk factors
being overweight
eating a lot of red meat or high-fat dairy products
increasing age
family history of this form of cancer
breast cancer risk factors
being overweight
increasing age
family history of this form of cancer
BRCA 1 or 2 gene mutation
colorectal cancer risk factors
being overweight
a diet low in fibre
increasing age
family history of this form of cancer
Type 2 diabetes risk
When a person eats food high in sugar, their blood glucose level will consequently rise and the pancreas responds by releasing insulin.
However, if this is done on a regular basis, their body, including muscle cells, become increasingly resistant to the insulin released.
Therefore, less insulin may be produced, leading to a persistently raised blood glucose level and the release of more glucose in the urine.
In addition to eating foods high in sugars, other risk factors for type 2 diabetes include being overweight, insufficient exercise and a family history of the disease.
