Post on 15-Jan-2016
PathologyConcepts of Health and Disease
Health and Society Prehistoric Times
◦ Angry god or evil spirits caused illness◦ The gods needed to be pacified to obtain a cure◦ Evil spirits driven out
Communities helped to secure health of its members◦ Health practices were based on belief systems
Modern Western Thinking◦ Originating with the Greeks
No supernatural powers affecting health
Health and Society Western Beliefs
◦ Everything that can be known can be found through studying and observing science
◦ Cortez conquering the Aztecs changed a culture’s belief in polytheism to monotheism
Diseases were thought to have been caused by emotional turmoil or grief (nervous condition)◦ Certain illnesses had a stigma attached
Leprosy, AIDS
Hippocrates◦460-377BC◦The foundation of cl inical principles and ethics for modern medicine
◦Four Humors Blood (red) from the heart = sanguine
Yel low bi le from the l iver = choleric Black bi le from the spleen = melanchol ic
Phlegm from the brain = phlegmatic
Early Scholars
384-322BC Dissection of small
animals Heart was the most
important organ◦ Center of the body ◦ Seat of emotions
Aristotle
Galen 129-199AD Physician to the Emperor of Rome
Continued to do more dissections
Started experimentations on live animals◦ Severed a pig’s spinal cord to cause paralysis
The body carried 3 kinds of blood
◦ Natural spirit from the liver◦ Vital spirit from the lungs◦ Animal spirit from the nerves
His work was considered infallible for 1400 years
Professor of Anatomy from Padua, Italy
1514-1564 Dissection of
Humans (considered horrible!)
Made much more accurate drawings and diagrams
Andreas Vesalius
1578-1657 English physician
and physiologist Established blood
circulates in a closed system impelled by a pump-like heart
William Harvey
Anton van Leeuwenhoek
1632-1723Refined the microscope lens
Robert Hooke Published Micrographia
◦ Described the plant cells in cork◦ First to describe what a cell was
Antoine Lavoisier
1743-1794 Was actually a lawyer but devoted his life to
scientific pursuits He studied Chemistry
◦ Came up with new ideas that allowed for the beginning of Biochemistry
He was beheaded during the French Revolution.
Edward Jenner
1749-1823 Conducted the first vaccination of
cowpox on a jerseymaid◦ Saved a child’s life with smallpox
1827-1912Concluded that
microbes caused wound infections
Used Carbolic acid on wounds to kill microbes
Listerine
Joseph Lister
1820-1910 Leading proponent of
sanitation Crimean War with
Napoleon◦ Had 38 nurses with her to
treat 2000 wounded and sick soldiers
◦ She and her nurses cleaned up the hospital tents
◦ Used hygiene on the soldiers and
◦ Slashed the death rate of soldiers from from 40% to 2%!!!!!!
Florence Nightingale
1822-1895 First real
Bacteriologist Studied fermentation
processes◦ Learned how to prevent
the souring of wine◦ “Pasteurization”
Dispelled the idea the “Miasma” or fumes was the cause of diseases
Louis Pasteur
Robert Koch
1843-1910 Claimed microorganisms are the cause of illnesses
Identified the organism for tuberculosis◦Discovered TB skin testing method
1845-1923 Discovered X rays
Wilhelm Rontgen
1845-1915 Bacteriologist
◦ “magic bullets” could attack diseases and leave the rest of the body undamaged
He used arsenic compound (Salvarsan) as a weapon again syphilis
Paul Ehrlich
Sir Alexander Fleming
1881-1955 In 1928 he studied the relationship between
bacteria and the mold Penicillium ◦ Penicillium had the ability to kill Staphylocci
Not until 1940 were researchers able to use the microorganism as an antibiotic Penicillin
Sir Frederick Banting and Charles Best
1921 Discovered Insulin
◦ Isolated insulin from the pancreas of a dog 1922
◦ Successfully treated a little boy with diabetes
1914-1995 Vaccine for
Poliomyelitis ◦Used inactivated
virus vs the vaccine already in use with activated virus
Jonas Salk
Watson and Crick DNA structure
DNA Molecule
Pathophysology Pathology
From the Greek for Pathos meaning Disease◦ Deals with the study of the structural and
functional changes in cells, tissues and organs of the body that cause or are caused by disease
Physiology◦ Function of the Body in the healthy state
Pathophysiology◦ Focuses on the mechanisms of the underlying
disease and provides the background for preventive as well as therapeutic health care measures and practices
Disease Any deviation from or interruption of the
normal structure or function of a part, organ, or system of the body that is manifested by a characteristic set of symptoms or signs
Etiology The causes of disease = etiologic factors
◦ Biological Agents Bacteria, viruses
◦ Physical Forces Trauma, burns, radiation
◦ Chemical Agents Poisons, alcohol
◦ Nutritional Excesses of Deficits Most diseases are multifactorial in origins
◦ Risk Factors For example, heart disease or cancer
Pathogenesis The sequence of cellular and tissue events
that takes place from the time of initial contact with an etiologic agent until the ultimate expression of a disease.
Morphology Fundamental structure or form of cells or
tissues◦ Histology
Clinical Manifestations Signs v. Symptoms
Symptom◦ A subjective complaint that is noted by the person
with a disorder Sign
◦ A manifestation that is noted by an observer
Diagnosis The designation as the the nature or cause
of a health problem Requires history and physical examination Differential Diagnosis
◦ A systematic method used to identify unknowns. This method, essentially a process of elimination
Diagnosis
Normality◦ An important factor when interpreting diagnostic test results is the
determination of whether they are normal or abnormal
Reliability◦ The extent to which an observation is repeatable
Validity◦ The extent to which a measurement tool measures what is intended to
measure
Sensitivity◦ The proportion of people with a disease who are positive for that disease
on a given test or observation
Specificity◦ The proportion of people without the disease who are negative on a
given test or observation 95% accurate v. 100%
Morbidity and Mortality Mortality
◦ Death statistics
Morbidity◦ The effects of an illness has on a person’s life
Concerned not only with the occurrence and incidence of the diseases but also the long-term impact of the disease
Risk Factors
Conditions suspected of contributing to the development of a disease
Studies to determine risk factors◦ Cross-sectional studies
Simultaneous collection of information for classification of exposure and outcome
◦ Case-control studies Compares persons known to have the outcome of
interest and those known not to have the outcome of interest
◦ Cohort studies Group of persons who were born at approximately the
same time or share some characteristics of interest◦ Longitudinal studies
A cohort is studies over a period of time
Framingham Study Framingham Massachusetts
◦ In 1948, the Framingham Heart Study embarked on an ambitious project in health research to identify the common factors that contribute to cardiovascular disease by following its development over a long period of time in a large group of participants.
5000 people between 30 and 59 years of age
Followed for 20 years Looking at coronary artery disease
Prognosis Probable outcome and prospect of recovery
from a disease
Levels of Prevention Primary
◦ Keeping disease from occurring by removing risk factors
Secondary◦ Detect disease early when it is still asymptomatic
Pap smears Tertiary
◦ Clinical interventions that prevent further deterioration or reduces the complication of a disease once it is diagnosed