*Health and disease (Ch22, 23) Flashcards
1
Q
Definition of health
A
- A state of physical, mental and social well-being
2
Q
Healthy lifestyle
A
- Balanced diet
- Regular exercises
- Sufficient rest
- Good personal hygiene
- Avoidance of smoking
- Avoidance of alcohol
- Avoidance of drug abuse
3
Q
Advantages of doing regular exercise
A
- Improve the functioning of the lungs and heart
- Help reduce body weight
- Improve strength of muscles
- Improve flexibility of joints
- Reduce stress
4
Q
Infectious disease
A
- Caused by pathogenic microorganisms
- pathogen, host, environment
5
Q
Virus (organism / non-organism)
A
Organism
- Can reproduce in a cell
- Have genetic materials of controlling life processes
Not organism
- Non-cellular organisms (no cytoplasm, cell membrane, organelles)
- Cannot replicate by themselves
- No metabolism outside the host cells
6
Q
Structure of virus / Mode of reproduction of virus
A
- A protein coat enclosing nucleic acid
- Have head and tail
- Cannot reproduce by themselves
- Reproduce within host cell
- Virus is host specific
7
Q
Infectious disease caused by virus
A
- Influenza
- Hepatitus B
- Dengue fever
- Japanese encephalitis
- Common cold
- Measles
- Smallpox
- SARS
- AIDS
- COVID-19
8
Q
Bacteria
A
- Unicellular, prokaryotic
Structure
- Cell wall
- Cell membrane
- Cytoplasm
- Plasmid
- Ribosome
- Flagellum
Reproduction
- By asexual reproduction
9
Q
Infectious diseases caused by bacteria
A
- Cholera (dehydration)
- Tuberculosis
10
Q
Transmission by droplets
A
- Droplets from the respiratory tracts -> eyes
- Common cold
- Influenza
- COVID-19
- Cover the mouth during coughing or sneezing
- Wear a surgical mask
- Avoid going to crowded places
11
Q
Transmission by air
A
- Pathogens attach on dust particles
- Cover the mouth during coughing or sneezing
- Wear a surgical mask
- Avoid going to crowded places
- Keep good ventilation
12
Q
Transmission by contaminated food or water
A
- Cholera (by water / food)
- Tuberculosis (by food)
- Wash hands before taking meals / preparing food
- Cook food thoroughly
13
Q
Transmission by body fluids
A
By blood
- Hepatitis B
- AIDS
- Do not share razors, toothbrush or needles
- Screen blood before transfusion
By semen and vaginal fluid
- AIDS
- Syphilis
- Use condoms during sexual intercourse
- Have only one sexual partner
14
Q
Why antibiotics are not effective in treating viral infections?
A
- Virus does not contain cell wall / cell membrane
- Virus does not carry out protein synthesis / DNA synthesis on their own
- Antibiotics cannot act against virus
14
Q
Transmission by vectors
A
Flies / Cockroaches:
- Cholera
Mosquitoes
- Malaria
- Dengue fever
- Japanese encephalitis
- Destroy the breeding places of mosquitoes by clearance of accumulated water (impossible to clear all stagnant water)
- Directly kill mosquitoes by spraying pesticides / larvicidal oil (contaminate the environment, kill pollinating agents (bees), evolution of resistant strain)
- Prevent mosquitoes from biting by wearing long-sleeved clothing and applying mosquito repellents
15
Q
Transmission by direct contact
A
- Athlete’s foot
- Hand-foot-mouth disease
- Avoid physical contact with infected people
- Wash hands frequently
16
Q
Why children are more vulnerable to hand-foot-mouth disease?
A
- Weak immune system
- Poor personal hygiene
17
Q
Notes P.9
A
17
Q
Antibiotics
A
- Chemical produced by bacteria and fungi to kill / inhibit growth of other organisms
- Enables the to win the competition for resources to support their life
18
Q
Discovery and development of antibiotics
A
Hypothesis
- Mould produce substances to kill bacteria
- Mould kill bacteria
NOS
- Scientists are both collaborative and competitive in nature
19
Q
Action of antibiotics
A
Killing bacteria
- Inhibit cell wall synthesis (bacteria burst when they absorb excess water by osmosis)
- Break down cell membrane of bacteria (cell contents leak out, the cell dies)
Inhibiting growth of bacteria
- Interfere with protein synthesis (bacteria cannot function and grow)
- Interfere with DNA synthesis (cannot carry out cell division, cannot multiply)
20
Q
Broad-spectrum antibiotics
A
- Can act against different bacteria efficiently
21
Q
Group of individuals highly recommended to receive vaccination
A
- Elderly: weak immune system
- Doctor / Nurse: frequently contact with patients, high risk of being carrier of pathogens
21
Q
Indiscriminative use of antibiotics
A
- Use antibiotics to treat viral disease
- Patients stop taking antibiotics when they feel better
- Add antibiotics to animal feeds
22
Consequences of indiscriminative use of antibiotics
1. Infectious bacteria become resistant to antibiotics
Natural selection:
- Genetic variation exist among bacteria in their resistance against antibiotic
- Increase in amount of antibiotic kills non-resistant form, resistant form has higher chance to survive
- Resistant form has higher chance to reproduce
- Proportion of resistant form increases
2. Kill beneficial mutualistic bacteria
3. Allergy
4. No effective drug to tackle infectious disease
5. Productivity of disease-stricken people will reduce without effective treatment
6. Development of new antibiotics have to keep pace with mutation for resistance, demanding more resources from society
23
Solutions to alleviate the consequence of indiscriminative use of antibiotics
1. Proper use of antibiotics
- Prescribe only when necessary
- Take complete prescription (ensure all bacteria killed)
- Use narrow-spectrum antibiotic
2. Development of new drugs based on different mechanism in killing infectious bacteria
3. Short term: implement effective measures to control spread of infectious bacteria an to eliminate the sources of contamination
24
Antibiotics vs vaccination
Antibiotics
- Curative measure
- Kill pathogens
- Only for bacterial disease
Vaccination
- Preventive measure
- Stimulate development of memory cells
- For both bacterial and viral diseases
25
Explanation for efficiency of antibiotics
- The antibiotic diffuse outward from the paper disc
- The farther away from the disc, the lower is the concentration of the antibiotics
- A larger clear zone indicates that antibiotic is effective in inhibiting bacterial growth even at a lower concentration
26
Sulpha drugs
- Competitive inhibitors
- Compete with metabolite essential in reproduction of bacteria for the active site of bacterial enzyme and stop bacteria from reproduction
27
Treatment for AIDS
- HIV attacks T-lymphocytes of immune system of the body
- AIDS is difficult to treat because mutation of viruses occur rapidly, and virus take over the enzyme machinery of human cells to reproduce
- Cocktail treatment reduces the chance for HIV to develop resistance to all the drugs at the same time
28
Non- infectious disease
- Caused by lifestyle, biological factors, genetic factors, environment
29
Coronary heart disease
- Consumption of high calorie food / fatty food / food rich in cholesterol
- Excess fat / cholesterol in diet diposits of inner wall of coronary arteries
- Increases the risk of plaque formation
- Leads to narrowing of the lumen of arteries, blockage in arteries, decrease blood flow to heart muscles
- Heart muscles do not have enough oxygen and nutrients supply and die
30
Stroke
- Artery supplying blood to the brain is blocked / A blood vessel inside the brain bursts under high blood pressure
- Supply of oxygen to the brain cells reduced
- Brain cells die due to insufficient oxygen supply
31
Treatments of cardiovascular disease
1. Drugs
2. Surgery (Balloon angioplasty, coronary bypass surgery)
32
Risk factors for coronary heart disease
1. Unhealthy lifestyles
- Eating food rich in cholesterol / fat
- Smoking (Nicotine increases the chance of blocking blood vessel, causes vasoconstriction of blood vessels, carbon monoxide reduces oxygen-carrying capacity of blood)
- Lack of regular exercises
2. Biological factors
- Ageing (blood vessels become narrower and less elastic as people age)
- Gender (Male > Female)
- Family history
33
Diabetes mellitus
- High blood glucose concentration
- Presence of glucose in urine
Signs
- Excessive urine production (E1)
- High blood glucose level (Insufficient insulin to stimulate body cells / Body cells insensitive to insulin)
- Constant thirst
- Blurred vision
- Weight loss
34
Insulin-dependent diabetes (Type 1)
- Cause: little / no insulin (insulin-producing cells of pancreas destroyed by immune system)
- Risk factors: genetic factor / family history
- Occurrance: early life (5%)
- Control method: daily injection of insulin
35
Non insulin-dependent diabetes (Type 2)
- Cause: body cells insensitive to insulin
- Risk factors: obesity / lack of exercises / ageing / family history
- Occurrance: later in life (95%)
- Control method: small but frequent meals / reduce intake of food with high sugar content / eat complex carbohydrate / take regular exercise / frequent monitoring of blood glucose level / take appropriate medication of increase sensitivity of body cells to insulin
36
Mass production of insulin by recombinant DNA technology (Ch27)
- Eliminate chance of transmission of animal pathogens
- Eliminate possible allergens from animal insulin
- Eliminate possible immune response produced by patient against animal insulin
37
Formation of tumours
- When genetic control of cell division in a cell goes wrong, the uncontrolled cell division of body cells results in a mass of cells, forming a tumour
Benign tumour
- Remain within the tissue where they arise
- Grow slowly
- Cells surrounded by capsule
- Not life-threatening
Malignant tumour
- Spread to other regions (metastasis)
- Grow rapidly
- Cells not surrounded by capsule
- Life-threatening as tumour formed competes with normal tissues for nutrients and oxygen
38
Why genetic control goes wrong to form tumours?
- Gene mutation -> change in gene product -> production of unwanted protein -> leads to uncontrolled cell division
39
Treatment of cancers
- Surgery (remove localized tumour)
- Radiotherapy
- Chemotherapy (use anti-cancer drugs to kill cancer cells / inhibit their growth)
- Targeted therapy
40
Causes and prevention of cancers
1. Exposure to radiation (ultraviolet light / high-energy radiation (X-ray) change structure of genes by mutation)
- Putting on sunscreen
2. Exposure to chemicals (asbestos)
3. Exposure to pathogens
(hepatitus B virus -> liver cancer)
- Vaccination
(HPV -> cervical cancer)
- Avoid early sex, have only one sexual partner
- Cervical smear screening
- Immunization
41
Risk factors of cancer
Unhealthy lifestyles
1. Smoking
- Tar contains carcinogens
2. Alcohol abuse
3. Unhealthy diet (food may stimulate mutations)
- Red meat (eating too much red meat with little vegetables and fruits increases the chance of suffering from colorectum cancer: dietary fibre increases bulk of food to stimulate peristalsis of the gut, helps reduce time for carcinogens to stay inside the colon)
- Salted and smoked food
- Processed meat (contains carcinogenic substances)
- Deep-fried food (contains carcinogenic substances)
42
Why cancer remains one of the top killer diseases in HK
- Taking in more processed food that lacks dietary fibre
- More stressful lifestyle
- Lack physical exercise, higher chance of obesity
- Older age
- Excessive drinking
- Medical advancement -> death rate due to other diseases is lower
43
Prevention of diseases
- Breaking transmission link of pathogens (quarantine)
- Immunization programme (vaccinations induce the body to develop immunity against diseases, number of infected individuals is reduced)
- Screening programme
- Disease surveillance
- Health education
- Taking healthy lifestyles
44
Notes P.29
