Lecture 2: Concepts In Health And Disease Flashcards
Define health.
Health is a “state of complete physical, mental, and social well-being, not merely the absence of disease or infirmity”. – WHO
Different perspective for the construction of the definition health and disease …
What is physiology?
The branch of biology that studies the functional activities and its mechanisms in biological systems.
What is pathophysiology?
The study of the functional changes associated with or resulting from a disease or injury.
What is pathology?
The study of the causes and effects of diseases. It involves the diagnosis of diseases.
What is a pathogen?
An organism that can cause disease.
How are diseases classified?
Anatomical, Physiological, and Pathological.
What does an anatomical disease classification mean?
It is based on the organs that have been affected.
What does a physiological disease classification mean?
A description of a disease that affects process or a function.
For example: metabolic, digestive, or respiratory diseases.
What does a pathological disease classification mean?
It is based on the nature of the disease.
For example: neoplastic (abnormal growth) diseases, inflammatory diseases.
How many types of diseases are there? State them.
4 main types.
Deficiency
Genetic (both hereditary and non-hereditary)
Physiological
Infectious
How do deficiency diseases occur?
They are caused by a lack of essential nutrients in diets. It is commonly associated by malnutrition.
What are some illnesses that result from a deficiency disease?
• Scurvy (Vitamin C deficiency).
• Kwashiorkor (Protein deficiency).
• Anaemia (Deficiency of red cells or of haemoglobin).
• Rickets (Vitamin D deficiency, soft/weak bones).
What is a genetic disease?
A disease that occurs due to genetic mutations. It can be inherited or acquired.
What are some examples of genetic diseases?
• Down syndrome – A genetic condition where a person is born with an extra copy of chromosome 21.
• Haemophilia – An inherited disorder in which the blood does not clot due to insufficient clotting factors.
• Cystic fibrosis – Accumulation of sticky mucus in the lungs and digestive system.
• Turner syndrome – A completely or partially missing X chromosome.
• Triple X syndrome – A genetic condition where a female is born with an extra X chromosome.
What is a physiological type of disease?
A disease that occurs as a result of malfunctioning of the organs or systems of the body.
What are some examples of physiological diseases?
• Asthma
• Diabetes
• Rheumatoid arthritis (Autoimmune disorder)
• Multiple sclerosis (Myelin)
• Hypertension
What is an infectious type of disease?
A disease caused by pathogens.
What are different transmission routes for infection diseases?
• Passed from person to person.
• Transmitted by insects to humans.
• Animals to humans (Zoonosis).
What is zoonosis?
An infectious disease that can be transmitted from animals to humans.
What is an acute infection?
An infection that lasts for short time (short-term infection).
What is a chronic infection?
An infection that persists for a long time.
What is a vector?
A living organism that can transmit infectious pathogens between humans, or from animals to humans.
What is a sign?
An objective indicator of illness that others may be able to observe for example frequent sneezing, high temperature, blood pressure, but only trained health workers can associate with a particular disease.
What is a symptom?
Subjective sensations of illness in the body that only the person who is unwell can experience for example pain, blurred vision, tiredness.
What are the several types of pathogens?
• Bacteria
• Viruses
• Protozoa (Amoeba)
• Fungi
• Helminths (Parasite worm)
• Ectoparasites (Flea, lives outside the host)
•Prions
What is bacteria?
Prokaryotic single-called organism.
Can be grouped as gram positive and negative.
Different shapes.
What is the difference between gram positive bacteria and gram negative?
• Gram-negative bacteria are surrounded by a thin peptidoglycan cell wall, which itself is surrounded by an outer membrane containing lipopolysaccharide.
• Gram-positive bacteria lack an outer membrane but are surrounded by layers of peptidoglycan many times thicker than is found in the gram-negatives.
What are some examples of pathogenic bacteria? What are some diseases they cause?
• Pseudomonas aeruginosa, Streptococcus pneumoniae, Clostridium tetani.
• Tuberculosis, Meningitis, Plague, Tetanus, Pneumonia, Diarrhoea.
What are viruses? What are they made of?
Is an obligate (restricted to a particular function or mode of life) intercellular (not-infective outside the cell) parasite.
Each viral particle (virion, what it is outside) consists of a DNA or RNA.
A typical virus consists of a protective protein coat (capsid).
Some have an envelope.
Viral encoded glycoproteins (spike projections) e.g. neuramindiase and hemagglutinin expressed on influenza A viruses.
What are some viral diseases?
Measles, influenza, and polio.
What are protozoa pathogens?
Unicellular eukaryotes.
Many spend their life in arthropod host such as mosquitoes or flies.
What are some protozoan parasites and diseases?
Plasmodium spp. causing malaria infection.
Trypanosoma brucei (bugs) causing African sleeping sickness.
Leishmania spp. (sandflies) causing leishmaniasis.
What are fungi?
Any of a group of spore-producing organisms feeding on organic matter.
Eukaryotes; can be unicellular, multicellular, or syncytial (one cell with multiply nuclei).
What are fungal and cutaneous infections?
Mycoses (infections) can result due to injury or inhalation.
Cutaneous infections includes attacks on the skin, nails, or hair e.g. ring worm, athlete’s foot (tinea pedis) and jock itch.
What is candida?
Part of the normal flora of oral activity, genitalia, skin or large intestine.
What is oral candidiasis?
Thrush caused by Candida spp.
What are helminths?
Parasitic worms, eukaryotic multicellular endoparasites (live inside the host).
Grouped into roundworms (nematodes) and flatworms (Platyhelminthes including cestodes, trematodes …).
Evolved evasive strategies to prolong survival in host.
Provide the names of some types of helminths.
Trematodes (flukes), Cestodes (tapeworm), and soil-transmitted helminths.
Fasciola hepatica, Taenia saginata (found in intestines), Ascaris lumbricoides.
What are ectoparasites?
Organisms that are found on the outer surface of the host. Ectoparasites causing human diseases are arthropods; insects (6-legged arthropods) and arachnids (8-legged arthropods).
What are some examples of ectoparasites?
• Fleas – causing pulicosis
• Lice – causing pediculosis
• Tick – Lime disease, Powassan fever
• Mite – dust mite causing asthma
What are prions? How do they work?
Not organisms, they are misfolded infectious proteins. They do not contain genetic material.
What are prion diseases also known as?
Transmissible spongiform encephalopathies (TSEs).
What is the difference between a normal and a disease-causing prion?
The PrP has been shown to participate in several biological processes, including neuritogenesis, neuronal homeostasis, cell signalling, cell adhesion, and a protective role against stress.
• The normal prion protein is thought to be made up of flexible coils referred to as alpha helices; however, in the abnormally folded form, these helices are stretched out into densely packed structures called beta-sheets.
What are some commonly known prion diseases that affect humans?
• Creutzfeldt-Jakob Disease (CDJ)
• Gerstmann-Straussler-Scheinker Syndrome (GSS)
• Fatal Familial Insomnia
What are some ways infections get transmitted to humans?
• Direct person-to-person
• Indirect person-to-person
• Animal-to-human (Zoonotic infection)
• Insect-to-human
What are some examples of direct person-to-person way of transmission?
• Mother-to-child transmission
• Handshake
• Sexual contact or touch
What are some examples of indirect person-to-person way of transmission?
• Airborne transmission
• Faecal-oral
• Waterborne
• Foodborne
• Formite (inanimate objects contaminated with pathogens)
• Bloodborne
What are some examples of animal-to-human ways of transmission (zoonotic)?
• Toxoplasmosis - undercooked meat, soil, cat faeces.
• Trichinosis - infected meat.
• Rabies - disease of dogs/mammals that gets transmitted through saliva to humans (hydrophobia).
What are some examples of insect-to-human ways of transmission?
• Vector-borne diseases:
~ Malaria infection by mosquitoes
~ African sleeping sickness by Tsetse flies
~ Leishmaniasis by sandflies
What is mortality?
It refers to deaths in a population.
What is mortality rate?
Refers to how many deaths occur in a population over a given time. It is typically expressed per 1000 or 100,000 individuals.
Measures of mortality includes:
• Infant mortality rate
• Under-5 mortality rate
• Maternal mortality ratio
What is infant mortality rate?
The number of infant’s death between birth and one year of age per 1000 live births.
What is under-5 mortality rate?
The number of deaths of children under five years of age per 1000 live births.
What is maternal mortality ratio rate?
The number of female patients dying from pregnancy-related issues per 100,000 live births.
What is morbidity?
Refers to illnesses, diseases or disorders.
What does “DALYs” stand for?
Disability-Adjusted Life Years.
What does “DALYs” mean? What are they used for?
Years of Life Lost (YLL) + Years Lived With Disability (YLD).
a.k.a
Mortality + Morbidity
• Used to quantify the overall burden of disease on a population.
