Exam 1 Flashcards
Epidemiologic Triad
interaction between susceptible host, external agent, adn environment that bring these two together
Environmental Contamination
Can be natural: not caused by humans, fires, volcanoes
Anthropogenic: caused by humans, pollution
Climate change
more extreme weather, food and water scarcity, and emerging diseases
Eutrophication
Water body receives excessive nutrients –> overgrowth of algae –> algae die and decomposes –> lack of oxygen which kills aquatic animals.
Water quality
inorganic contaminants: Pb, Hg
organic: carbon
waterborne illness: Hep A, cholera, protozoan parasite Cryptosporidium
Bioaccumulation
accumulation of toxic chemical in the tissue
Biomagnification
a special type of bioaccumulation that occurs through the food chain
results in dramatically increasing concentrations of a toxic chemical in the bodies of animals as you go up the food chain. example: mercury
ecosystem services
functions of natural earth systems that gives human value for free
- regulating services
- provisioning services
- supporting or habitat services
- cultural services
Provisioning services
- materials benefits from ecosystems
- examples: wild caught fish, raw materials, clean freshwater, medicinal resources
cultural services
tourism, recreation, fishing hunting
Regulating services
- help keep the world climate and resources stable
- often invisible and taken for granted
- examples: maintaining quality of air, soil, or water, regulating water flow
Beavers in wetland help to restore agriculture
beaver are like ecosystem engineers (species that change biotic or abiotic materials to influence habitat)
keystone species
very important for maintaining biodiversity and ecosystem function
supporting services
- providing habitat for all organism
- maintaining biodiversity
Greenhouse effect
natural greenhouse effect: most heat escapes into space
human enhanced: less heat escapes into space because there is a lot of greehouse gases which the heat is just re emitted
Main gases: CO2, Methane CH4, Nitrous Oxide N2O, Gases that contain fluorine
CO2 and Ocean acidification
-CO2 uptake results in increase H+(proton) concentration in ocean water
increased H+ –> changes seawater chemistry and interferes with marine animals ability
Environmental Health
- examines the relationships between people and their environment
- promotes human health and healthy communities
- promotes policies and programs to reduce exposure to contaminant in air, water, soil
routes of exposure to environmental contaminants
- chemicals in the environment affect you when they are absorbed into your body
- inhalation; through respiratory system
- ingestions: through gastrointestinal tract
- dermal: through the skin
- in clinical practice: injection
Respiratory tract
- surface area of lungs is large and allows for rapid uptake and release of certain molecules
- particulate matter: smaller particles move deeper into the respiratory system
GI tract
- ingestion: the small intestine has a large surface area to faciliate nutrient absorption; chemical can also be absorbed into the body
Skin
- damaged skin (cuts, etc)
- thickness of outer layer
- skin temperature
top 10 causes of death from environment
- ischemic heart disease
- chronic respiratory disease
- cancers
- unintentional injuries
- respiratory infections
- stroke
- diarrhoeal disease
- diabetes
- malaria
- neonatal conditions
Criteria air pollutant: regulated air contaminant
- particulate matter
- ground level ozone
- carbon monoxide
- lead
- sulfur dioxide
- nitrogen dioxide
particulate matter
- less than 10 microns in diameter
- can cause: premature death, nonfatal heart attack, irregular heartbeat, asthma
- children, older adults, and people with heart or lung diseases are most susceptible to the effects
carbon monoxide
- high levels of CO dont typically occur outdoors
- elevated CO outdoors can cause problems for people who have reduced ability to get oxygenated blood to the heart
- during exercise or stress they may experience reduced oxygen to the heart and angina (a type of chest pain)
Ground level ozone
effects:
- chest pain
-coughing
- throat irritation
- airway inflammation
- reduced lung function
- damage to lung tissue
- can worsen asthma, bronchitis, emphysema
lead
- in children 0-6, lead can cause reduced IQ, learning problems, and behavioral problems
- can be stored in bones with calcium, during pregnancy
- lead can be released with calcium from mother’s bones and expose the fetus or breastfeeding infant to lead
- effects: preterm birth, low birthweight, damage to baby’s brain, kidney, and nervous system , increased risk of miscarriage and learning/ behavioral problems
- reduced IQ
sulfur dioxide
- short term SO2 exposure can make breathing difficult
- sensitive individuals include children and those with asthma
nitrogen dioxide
- can irritate respiratory pathway
- can aggravate respiratory diseases, particularly asthma
- longer exposures to NO2 may contribute to development of asthma and increase risk of respiratory infections
- sensitive individual: children, elderly, and those with asthma
Genetics
- made of DNA
- code for inherited variable traits
- Sugar phosphate backbone
- Gene –> mRNA Transcript –> protein
- ## DNA–> RNA –>Protein
Mutations
- chromosomal mutation: affecting whole or part of a chromosome
- gene mutation: changes to the bases in the DNA of one gene
- Substitution: change of one amino acid: does not affect whole reading
- Deletion: whole protein is altered.
- Insertion: reading is also affected
Silent mutations
- mutations in introns do not affect the final mRNA
- most mutations are silent
Sex linked genetic disorders
- DNA is packaged into chromosomes
- 23rd pair of chromosomes determine gender: xx- women xy- men
- color blindness: inherited are from the X chromosome, recessive and linked trait,men are more prone
Single Nucleotide Polymorphism
- variation in one nucleotide
- originate from mutations
- more common in the population and lower correlation to phenotype
Drug metabolizing enzymes
- ## DMEs catalyze the alteration of a piece of the molecule, so can catalyze the metabolism of multiple drugs
Epigenetics
study of changes caused by activating or silencing genes without ay change in the underlying DNA sequence
DNA structure in cell nucleus
- each chromosome contains one double stranded piece of DNA that is coiled at several levels
1. DNA is wrapped around a histone protein core to form a nucleosome
2. DNA is coiled further into solenoids (each turn of solenoid has aprrox 6 nucleosomes)
3. solenoids are organized into chromatin loops
Mechanism of epigenetic modification
- consist of small molecules that are attached to existing DNA without changing the DNA sequence
- can increase/decrease gene expression
DNA methylation
- addition of methyl group directly onto DNA
- when close to a gene, often reduces gene expression
- can be reversed by removing methyl group
Histone modification
- method of epigenetic modification
- multiple types of enzymes can be involved
- increased/ decreased gene expression
Epigenetics 2
- normal epigenetic modifications do not include mutation or DNA adducts
Bisphenol A (BPA) exposure
- most of the population has detectable BPA in urine
- exposure is primarily through diet
- heat can increase leaching of BPA from packaging
- ## Associated with –> increased risk of miscarriage and gestational diabetes … DNA damage to sperm/ reduced male fertility
Impact of epigenetics
- ## some modification change throughout life in response to environment or behavior
Cancer
- unregulated cell proliferation
- lack of differentiation of cells
Cellular kinetics
- generation time: time needed for a quiescent cell to complete once cell division cycle to produce 2 daughter cells
- malignant cells may have short generation time and often have smaller percentage of cells in G0 phase
type of mutations that can lead to cancer
- mutations in key genes can lead to cancer: proto-oncogene (normal cell growth) ; mutation in her may cause it to become oncogene (causes growth of cancer cells)
- mutation of tumor suppressor gene leading to inactivation: tumor suppressor genes make tumor suppressor protein that help cell growth, mutation can cause uncontrolled cell growth
- mutation in DNA repair genes can impair ability of cell to repair DNA
Carcinogenesis: multistage process
- Initiation
- mutation in a somatic cell
- irreversible genetic alterations to DNA - Promotion
- tumor promotion: tumors are stimulated to grow, does not involve mutagenesis - Progression
- conversion of benign preneoplastic lesions into neoplastic cancer
Function of the immune system
- protect from pathogens
- differentiate between self and non self
- homeostasis
part of the immune system
- lymph nodes
- respiratory system
- skin
- spleen
- white blood cells
- stomach and intestine
Lymphatic system
- thymus
- spleen
- liver
-bone marrow
- lymphatic system
types of immunity
- Innate
- body’s first line of defense against infection
- anatomic barrier (skin)
- present from birth
- rapid
- non specific - Adaptive
- cell mediated
- humoral mediated
- system that need to be trained/ exposed
- slower than innate
- involves development of immunologic memory
- respond to antigens of specific pathogens
two types of adaptive immunity
- cell mediated immunity
- primarily involves T cells/ lymphocytes (derived from bone marrow
- detects its a virus through viral peptide - Humoral (antibody mediated) immunity
- production of antibody
- when B cells encounter pathogen, they recognize parts of the antigen on the surface as being foreign (non self)
- B cells binds to antigen which triggers the cell to divide and develop into plasma cells( make antibodies that are specific for antigen) and long lived memory B cells (produce faster, stronger response to future exposures)
Type of T cells
- cytotoxic t cells: destroy infected host cells
- helper t cells: increase antibody production by plasma cells; increases phagocytosis
- long lived memory T cells: produced after initial antigen exposure; mobilize fast if future exposure to same antigen
antibody functions
- antibody: proteins secreted into plasma to help eliminate foreign organism (y shaped)
- neutralize bacterial toxins
- neutralize viruses before they infect cells
- attach to bacteria promoting phagocytosis
- activate components involved in inflammatory response
active immunity
- after exposure to a foreign organism, immune cells produce antibodies and memory cells
- can be acquired due to infection with organism
- acquired due to vaccination
- memory cells are formed –> long termed protection
passive immunity
- involves the transfer of pre formed antibodies to an individual
- no memory cells formed –> short term protection
- ex: injection of an individual with preformed antibodies
autoimmune diseases
- autoimmunity: when tolerance ( immune system’s appropriate non response to “self” )fails and body develops autoantibodies to won tissues or self antigens
acute vs chronic inflammation
acute
- outcome: healing
- short term
- not age related
chronic
- persistent, non resolving
- outcome: collateral damage
- age related
circadian rhythms
- physical, mental, behaviorals changes that occurs
- cyclical
- governed by light/ dark
- biological clock: control these cyclic responses, composed of protein
- major clock: suprachiasmastic nucleus
- located in the brain and synchronizes the circadian rhythms
- receives direct input from light
- control production of melatonin
Inflammation
- body’s response to injury, infection, and certain environmental exposures
- part of innate , non specific, rapid early response, increased blood flow
- purpose: neutralize/ destroys foreign particles of the body, limit damages tissue, prevent spread of infection or damage to other tissue
- symptoms, acute inflammation: warmth, redness, throbbing pain, localized swelling, short term
- symptoms, chronic inflammation: often invisible, can last for years,
- associated with increased risk of chronic diseases
insufficient sleep
associated with
- increased risk of obesity
- decrease in leptin (hormone that helps you feel full
- increase in ghrelin ( hormone that stimulates appetite
- stroke
- depression
sleep hygiene
- go to bed at the same time
- avoid caffeine and nicotine 4-6 hr before bed
- create a routine
- dont look at bright screen for 2-3 hr before sleep
effect of light color
- blue wavelength during day: boost mood, attention, reaction time
- blue wavelength during night: powerful suppressor of melatonin
- Red light: weakest suppressor of melatonin ( best for night lights)
- exposure to bright light during day boost alertness, mood, and helps with sleep at night
insomnia
- trouble going to sleep, staying asleep or getting good quality of sleep
- chronic insomnia: trouble sleeping at least 3 night per week for more than 3 month
