Keeping healthy Flashcards
(105 cards)
1
Q
Microorganisms that cause disease are called
A
pathogens
2
Q
Bacterial infections cause symptoms by
A
Release of toxins
3
Q
Name some bacterial infections
A
Salmonella food poisoning; tetanus; bacterial meningitis; gonorrhea; syphillis
4
Q
Viral infections cause symptoms by
A
damage to cells as the virus takes it over to reproduce
5
Q
Name some viral infections
A
Ebola, common cold, flu, measles, chickenpox, genital herpes
6
Q
How do bacteria reproduce?
A
They divide themselves in two
7
Q
What is the type of reproduction where a cell divides itself in two called?
A
Binary fission
8
Q
What type of population growth is produced by bacteria
A
Rapid, called exponential growth as the number doubles each time they go through their reproductive cycle.
9
Q
How do viruses reproduce?
A
They need a host cell, which they enter and “hijack” to produce extra copies of themselves.
10
Q
Can viruses reproduce without host cells?
A
No
11
Q
What are our external defences against infection?
A
eg Skin; saliva; tears; stomach acid
12
Q
What is our internal defence against infection?
A
The immune system.
13
Q
What type of cells does the immune system use?
A
White blood cells
14
Q
Where are white blood cells made?
A
The bone marrow
15
Q
What do white blood cells do?
A
Some engulf and digest invading microorganisms while others produce antibodies.
16
Q
What is an antibody?
A
A protein that “fits” onto a protein (an antigen) on the invading cells surface.
17
Q
How many antigens can one antibody fit?
A
One
18
Q
Where is the antibody found?
A
On the surface of a white blood cell
19
Q
What happens when an antibody locks onto an antigen?
A
The white blood cells divides to produce multiple copies of itself. Each white blood cell produces multiple copies of the antibody.
20
Q
What do antibodies do?
A
They can destroy the invading organism; enable the white blood cells to recognise the foreign invader; cause the microorganisms to clump together, making it easier to engulf them all.
21
Q
What happens after the body has managed to fight off the invading microorganisms?
A
Memory cells remain in the bloodstream
22
Q
What do memory cells do when the microorganism that they “remember” is encountered?
A
They produce large numbers of the correct antibody very quickly.
23
Q
If you have memory cells for a specific infection you are said to be?
A
Immune
24
Q
What does a vaccine contain?
A
A safe form of the pathogen
25
What happens after vaccination?
The immune system attacks the pathogen and memory cells will remain in the bloodstream
26
What do vaccination programmes do?
They are designed to protect the target population against a specific illness.
27
Why is a new flu vaccination required every year?
The flu virus mutates rapidly, so it has new antigens on the surface and it is necessary for our immune system to create the new antibodies
28
Why are some vaccinations not repeated?
The organism concerned does not mutate much so the antibodies remain effective against the antigens on its surface
29
What is an epidemic?
A disease that is spreading rapidly
30
How does vaccination stop epidemics?
If enough people in the population are immune then there are not enough people who will catch the disease for it to spread. This is called "herd immunity". This means that even people who cannot be vaccinated are still protected as there is no one to catch the illness from.
31
Can vaccination eradicate diseases?
Yes, smallpox has been eradicated.
32
Why is it necessary to test vaccinations?
They can have side effects.
33
Are side effects always the same?
No, people have different side effects due to genetic variations.
34
Is it possible to be certain that a vaccine is safe for everyone?
No, it is not possible to test it on all genetic variations.
35
Is any medical treatment risk-free?
No, there will always be small risks, but people often perceive the risks as being greater than they are.
36
Are vaccinations safe?
Yes. (For this exam!) Millions of people have benefited.
37
What can happen as a result of vaccination?
Occasionally the person may develop a rash or a fever. Rarely, a more serious adverse reaction may take place.
38
What would happen if a vaccine caused a lot of adverse reactions?
The risks would be assessed against the benefits, and it might be withdrawn.
39
What would you call a drug to kill bacteria, viruses or fungi?
An antimicrobial.
40
What do you call a drug to kill bacteria?
Antibiotic.
41
What is the word for microorganisms no longer being affected by a drug?
Resistance
42
What are the implications of microorganisms being resistant to drugs?
Some infections are very difficult to control. This microorganisms are most likely to be found where the drugs are used frequently, eg hospitals.
43
Where would you use antimicrobials other than the drugs used to treat illness?
Cleaning products; silver nanoparticles in food containers.
44
How does resistance develop?
The antimicrobial kills off most of the microorganisms, only those most able to survive the use of it are left to breed, so the genes for resistance spread through the population.
45
Resistant microorganisms are sometimes called...
superbugs
46
How can we use antibiotics in a way that reduces resistance?
Only use the antibiotic when the infection is serious; always take the whole course of tablets so that all the microorganisms are killed.
47
Name a resistant bacteria
MRSA
48
How would a microorganism suddenly produce the ability to survive an antimicrobial
Random mutation
49
How are new drugs tested in the early stages?
On human cells, and animals.
50
How is the decision made to put a new drug through more tests?
It has to be effective and safe on human cells and animals.
51
How is a drug tested after it has been tested on cell cultures and animals?
Clinical trials.
52
What does a clinical trial involve?
One group of people is given the new drug, another group is given a placebo which is made to look the same.
53
During a clinical trial it becomes obvious that our new drug is saving lives of patients, those on the placebo are not surviving their illness. What can the drug company do?
The clinical trial is allowed to be abandoned and it is permitted to give all patients the new drug. It would be unethical to let people die to finish off the trial.
54
Both researcher and patient know whether they are taking the drug. This is called
open-label
55
The patient does not know whether they are taking a placebo but the researcher does. This is called
a blind trial
56
Neither patient nor researcher knows who is taking the placebo
a double blind trial.
57
Why do some trial go on for a long period of time?
Some side effects may take a long time to appear (or disappear); the drug may become less affective over time
58
What is the "blood system" really called?
The circulatory system.
59
What makes up the circulatory system?
Heart, blood vessels, blood.
60
What pumps the blood around the body?
The heart
61
In mammals, what can the heart be described as?
A double pump, half pumps to the lungs and the other half to everywhere else.
62
What happens to blood in the lungs?
The blood absorbs oxygen and loses carbon dioxide.
63
What are the blood vessels that go back to the heart?
Veins
64
What are the blood vessels that come from the heart?
Arteries.
65
Which blood vessels carry deoxygenated blood?
Veins (except pulmonary vein)
66
Which blood vessels carry oxygenated blood?
Arteries (except pulmonary artery)
67
What are capillaries?
Small blood vessels that link arteries to veins
68
How do capillaries work?
Their walls are only one cell thick to allow them to transfer substances to the bodies cells.
69
What is the structure of a vein?
A tube of elastic, muscular tissue, thinner than an artery. They contain valves to stop blood flowing back as there is low blood pressure.
70
What is the structure of arteries?
A tube of thick, elastic, muscular tissue to withstand the pressure of the blood.
71
How does the heart get oxygen?
It has its own arteries, the coronary arteries.
72
What is a heart attack?
A blockage of one or more coronary arteries, causing the death of part of the heart.
73
What is a common cause of heart attack?
Coronary arteries can become narrowed, and then blocked, by fatty deposits.
74
What is the build up of fatty deposits in the coronary arteries called?
Coronary Heart Disease (CHD)
75
What increases the risk of coronary heart disease (4 risk factors)
Smoking; poor diet; misuse of drugs including alcohol; stress
76
What is the name for a link between, for instance, the risk of a heart attack and smoking?
Correlation
77
How does exercise affect the risk of CHD?
It reduces it by strengthening the heart muscle, reducing body weight and reducing stress.
78
How would you change your diet to reduce the chance of coronary heart disease?
The diet should be low in saturated fat which lowers blood cholesterol.
79
Is coronary heart disease genetic?
No, but some people have genes that make them more prone to having it.
80
What would you call the study of the incidence of coronary heart disease within a population?
It is an epidemiological study.
81
Which countries have more coronary heart disease?
The developed countries, eg UK, USA have more heart disease than less developed countries.
82
How would you measure the heart rate?
You count the pulse in an artery running close to the surface of the body.
83
What units is the pulse rate recorded in?
Beats per minute.
84
What resting heart rate would a teenager have?
70-100bpm
85
What resting heart rate would an adult have?
50-70bpm, if fit.
86
What does blood pressure measure?
The pressure of the blood against the walls of an artery.
87
What is the implication of high blood pressure?
People with high blood pressure have an increased risk of heart disease
88
What damage does high blood pressure cause?
It damages the walls of arteries, making them more likely to have fatty deposits form, which narrows them and makes them more likely to block.
89
What is blood pressure measured in?
Millimetres of mercury (mm Hg). The first number is when the heart contracts, the second when it relaxes.
90
The maintenance of a constant internal environment by an organism is called
Homeostasis
91
Name some things that are controlled by homeostasis
pH, salt, water, sugar, temperature
92
What systems need to communicate for homeostasis?
The hormonal systems and the nervous system
93
What detects changes in the environment for homeostasis?
Receptors
94
What decides how the body will respond?
Processing centre
95
What produces the homeostatic response?
Effector
96
What happens if blood plasma is too concentrated?
Our cells will lose water by osmosis
97
What happens if blood plasma is too dilute?
Our cells absorb water by osmosis and swell. Eventually they might burst. (The brain cannot swell as the skull contains it, so the swelling brain stops blood supply, hence brain damage when people drink too much due to drugs)
98
What organ responds to changes in blood plasma concentration?
The kidneys.
99
How do the kidneys keep blood plasma concentration constant?
They remove more water if the blood plasma is too dilute, and try to conserve water when the blood plasma is becoming concentrated. They can also remove urea and salts.
100
What hormone is secreted to control the kidneys?
ADH
101
What secrets ADH?
The pituitary gland.
102
How is the secretion of ADH controlled?
Negative feedback.
103
How does ADH act on the kidney?
It reduces the amount of water lost by the kidney.
104
How does alcohol affect ADH?
Alcohol suppresses the production of ADH.
105
How does ecstasy affect ADH?
It increases ADH production, so more water is reabsorbed by the kidneys, so cells swell.
