Health & Disease - Core B Flashcards
Define Health
A state of complete physical, mental, and social well-being, not merely the absence of disease or infirmity.
Define Disease
A disorder of structure or function in a living organism that produces specific symptoms, affecting health.
Causes of infectious diseases
Pathogens, ie.
- Bacteria (cholera, tb, strep throat)
- Virus (influenza, measles, chicken pox)
- Fungi (tinea, athletes foot)
- Parasites (tape worm, head lice)
- Protozoa (malaria, sleeping sickness)
- Prions (kuru, Creutzfeldt-Jakob Disease)
Causes for non-infectious diseases
- genetic mutations (sickle cell, cystic fibrosis)
- environmental factors (heavy metal poisoning, cancer)
- lifestyle (scurvy, obesity, heart disease)
What’s an infectious disease?
Caused by the spread of pathogens that have invaded the body - they can be transmitted between individuals.
What’s a non-infectious disease?
Not caused by pathogens, caused by malfunctions in the body and cannot be transmitted between individuals.
What’s a pathogen?
Micro-organisms that cause disease. When it invades the body, it grows and multiplies and secretes poisoning toxins which damage body tissues.
Characteristics of bacteria
Single-celled organisms that can reproduce quickly. ie. (E. coli)
Characteristics of virus
Non-living agents that require a host cell to replicate. ie. Influenza virus, HIV
Characteristics of fungi
Thrive in damp environments; can be multi- or single-celled. ie. Candida albicans causing Thrush
Characteristics of parasite
Live in or on a host and extract nutrients for survival. ie. tapeworm
Characteristics of protozoa
Single-celled organisms, often parasitic in nature. ie. Giardia species
Characteristics of prions
Misfolded proteins that cause degenerative brain diseases. ie. Creutzfeldt-Jakob Disease
What do antibiotics do?
Kill or inhibit bacterial growth (e.g., penicillin for strep throat).
What do antivirals do?
Target viruses by interfering with their replication (e.g., oseltamivir for influenza).
Antifungals
Treat fungal infection by interfering with the fungal cell membranes (e.g., fluconazole for candidiasis).
Why Don’t antibiotics Work for Viruses?
Viruses replicate within host cells, and antibiotics target bacterial structures, not host cells.
What did the soap practical show?
Showed that soap and water effectively reduce bacterial presence compared to water alone or no washing - and sanitiser with alcohol is ineffective. Found the most bacteria on classroom door handles and desks, reinforcing the need for hygiene practices.
Examples of Lifestyle for non-infectious disease
Obesity → Heart disease
Smoking → Lung cancer
Examples of genetics for non-infectious disease
Inherited conditions like Cystic Fibrosis, Huntington’s disease.
Examples of environmental factors for non-infectious disease
Pollution → Asthma
Asbestos exposure → Mesothelioma
What are the human defence mechanisms (3)
First Line: Skin, mucus, saliva, and stomach acid prevent pathogen entry. They use enzymes, act as a physical barrier, trap pathogens, or flush them out
Second Line: (immune system) White blood cells (like phagocytes), inflammation, and fever to slow down pathogen replication.
Third Line: (immune system)
B cells that produce antibodies targeting specific pathogens.
T cells that destroy infected cells or regulate immune responses.
Memory cells that “remember” pathogens for faster responses during future infections.
What’s active immunity?
Developed after exposure to a pathogen or vaccine, creating long-term memory.
What’s passive immunity?
Antibodies are introduced from an external source, rather than being made by the individual’s immune system. Temporary protection through antibodies from another source (e.g., breast milk).
Types of vaccines
Live-Attenuated Vaccines: contain weakened (attenuated) forms of the actual pathogen, which cannot cause severe disease in healthy individuals. ie. measles
Inactivated Vaccines: Contain pathogens that have been killed or inactivated.
ie. hepatitis A
Subunit: use specific parts of the pathogen (like proteins or sugars) to trigger immunity.
ie. hpv
mRNA Vaccines:
Use messenger RNA to instruct cells to produce a harmless piece of the pathogen, usually a protein, to provoke an immune response.
ie. covid vaccines (Pfizer)
How do vaccines work?
Introduce a harmless part of a pathogen to stimulate the immune system without causing disease. They are training your immune system to recognise and fight specific pathogens.
6 Vaccines on the are on the Australian immunisation schedule for children.
- Measles
- Mumps
- Rubella
- Polio
- Hepatitis B
- Whooping Cough
What’s Herd Immunity?
When 95% of the population is vaccinated, it protects those who can’t be vaccinated, because there are less people infected.
Benefits of Vaccines
- Prevents the spread of infectious diseases.
- Protects vulnerable populations.
- Reduces healthcare costs long-term.
Risks of Vaccines
- Side effects like soreness.
- Rare allergic reactions.
- Some people’s immune systems are too weak to handle the vaccine
Define Epidemic
Localised outbreak of a disease (e.g., Ebola outbreak in West Africa).
Define Pandemic
Worldwide spread of a disease (e.g. COVID-19).
Outline a recent pandemic and what is being done to control the issue
COVID-19 resulted in millions of deaths and significant disruptions to healthcare systems and economies.
Control Measures: Mass vaccination, Social distancing, mask mandates, and hand hygiene.
Ongoing Research: Studies continue to monitor variants and improve treatments.
Outline a non-infectious and what is being done to control the issue
Skin cancer is one of the most common types of cancer, with melanoma being the most serious form. Australia has one of the highest rates in the world, because of high levels of UV radiation.
Control Measures: Wearing hats, sunscreen, Regular dermatologist visits. Restrictions on tanning beds and improved workplace safety for outdoor workers.
Research: Advances in immunotherapy and targeted treatments for melanoma
Create a flow chart of what happens in the human body when pathogens enter the body
- Pathogen Enters the Body
- Through a cut, inhalation, ingestion, or other means.
⬇
- First Line of Defence (Barriers)
- Physical barriers like skin and mucus block entry.
- Chemical barriers like stomach acid, tears, or saliva kill or flush out pathogens.
- If this fails, the pathogen progresses further.
⬇
- Second Line of Defence (Innate Immune System)
- Inflammation: Increases blood flow to the area.
- Phagocytosis: White blood cells (like macrophages) engulf and destroy pathogens.
- Fever: Body temperature rises to slow pathogen growth.
- If the pathogen persists, it triggers the next line of defence.
⬇
- Third Line of Defence (Adaptive Immune System)
- T-cells recognize and attack the pathogen or infected cells.
- B-cells produce antibodies that bind to and neutralize the pathogen.
- Memory cells are created to ensure faster responses in future infections.
⬇
- Pathogen is Neutralised or Eliminated
- The immune system clears the infection.
⬇
- Healing and Recovery Begin
- Damaged tissues repair, and the immune system returns to a baseline state.
