Lecture 2 What is a disease Disease abnormal condition that impairs bodily functions Broad categories of diseases 1 Infectious disease 2 Genetic disease 3 Environmental disease Down syndrome pathogen mediated specific organism or combination of organisms caused by abnormalities in an individual s genetic material Ex Klinefelter s syndrome when a boy is born with 2 X chromosomes and one Y chromosome sterile have more female characteristics wide hips larger breasts cigarette smoke second hand smoke caused 34 000 heart disease deaths in 2005 2009 radon causes mutation in DNA also 2nd leading cause of lung cancer lead poisoning lead from paint in houses can affect heart kidney bones nervous system big deal for kids younger than 6 What kind of disease is cancer Infectious virus s takes control of host cells 15 20 of cancer is due to infectious disease Genetic abnormal genetic change in the cell Environmental exposure stress changes the body s tissues The scientific method Before people would observe and if they had a nice approach or if they were wealthy people would believe them After people tried to find a way to standardize a way of understanding a phenomenon Definition the scientific method attempts to explain natural occurrences of the universe by using a logical consistent systematic method of investigation initial observations and questions hypothesis and predictions experiments and data collection analysis of the data to test hypothesis discuss limitation and conclusions identify future research needs improvements further testing A theory is a well tested well documented explanation that is well supported by evidence Science is extremely dynamic and always changing the hypothesis can be revised and changed The first person to use the scientific method was Francesco Redi the meat maggot experiment Had 3 pieces of meat in 3 jars an open jar and gauze covered jar and a sealed jar Maggots appeared only where flies were able to lay eggs only flies can make more flies disproved the idea of spontaneous Conclusion generation Aristotle Living things can come from nonliving things concept known as spontaneous Early theories on Development generation Jean Baptist Van Helmont Robert Hooke mice come from dirty rags rotting grains In 1665 he was the first person to design a compound microscope started looking at cells Anton van Leeuwenhoek make a single lens microscope and observed single celled organisms father of microbiology in 1674 he was the first person to Cell theory v 1 Schleiden and Schwann kept seeing little chambers under microscope called cells and then proposed the cell theory in 1838 All life forms are made from one of more cells The cell is the basic unit of life Cells spontaneously form Spontaneous generation disapproved Heat kills cells Louis Pasteur germ theory of disease and inventing the process of pasteurization in 1859 disapproved spontaneous generation overall by confirming the Cell theory v 2 Modern cell theory Rudolph Virchow Saw that cells were dividing Cells develop from pre existing cells The cell is the structural and functional unit of all living things All known living things are made up of cells All cells come from pre existing cells by cell division All cells are basically the same in chemical composition All energy flow of life occurs within cells metabolism and biochemistry Cells contain hereditary info which is passed during cell division Germ theory of disease pathogenic theory of medicine Microorganisms are the cause of many diseases This was proven by Louis Pasteur 1860 1864 Infectious disease Disorders caused by organisms 1876 proven that a microbe caused diseases Robert Koch called Koch s postulates to show that the cause of a disease was the microbe showed that Bacillus anthracis caused anthrax and used specific criteria Factors influencing the decrease in infectious diseases in the 20 th century better nutrition better housing antibiotics safer food water immunizations improved hygiene and sanitation Decrease in host susceptibility Decrease in disease transmission Decrease in infectious diseases Factors leading to the emergence of infectious diseases Changes in demographics and behavior changes in technology and industry environmental change and land use breakdown of public health measures microbial adaptation and change international travel and commerce Life expectancy and diseases increase in host susceptibility new diseases increase in disease transmission Emerging infectious diseases Role of infections diminishes as life expectancy improves This means more people will survive to older ages Chronic degenerative diseases stroke cancer and heart disease makes up a larger proportion of deaths
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