FINAL EXAM NOTES

Epidemiology :  Epidemiology is the study of determinants and distribution of disease frequency within the human population.  In the 5 th century, Hippocrates suggested that the development of human disease may be dependent on an individual’s external and personal environment.  John Graunt was the first person to quantify patterns of disease  After John Graunt, William Farr was the one to setup routine compilation of numbers and causes of death.  Cholera: an acute bacterial infection of the small intestine characterized by severe diarrhea, vomiting, muscular cramps, dehydration, and depletion of electrolytes.  History of John Snow: he postulated that cholera was transmitted by polluted/contaminated water.  Components of Epidemiology: o Distribution: integral in describing disease patterns, and in the formulation of hypotheses pertaining to possible causal or preventative factors. Distribution may consist of questions about comparisons o Disease Frequency: quantification of existence or occurrence of disease o Determinants of disease: this examines social and economic environment, physical environment, and an individual’s characteristics and behaviors.  Groups of persons must be studied in order to identify and answer questions relating to etiology and prevention of disease and to allocate effort and resources to facilitate health care.  Assumptions of Epidemiology: o Majority of human disease does not occur at random o Preventative factors of human disease can be identified by studying or investigating different populations or subgroups of individuals within a population.  Quantitative science: with measured quantities and descriptive terms  Count is the number of people in the group that has the disease or the characteristic.  Ratio is the expression of relationship between 2 numbers. Proportion is a specific type of ratio  Rate on the other hand is a certain type of ratio that involves time. Prevalence and incidence  Prevalence is basically the number of cases that exist at one time.  P.R= numberof persons withthe disease total number ∈ agroup  Point prevalence: at a particular time  Period Prevalence: number of cases found within a specific time period  Incidence: number of new cases of the disease or conditions that occur during a given period  Incidence rate: Number of persons developingadisease total number at risk

 While measuring data, there is a possibility where measurements may involve some degree of error (human or systematic)  These errors affect two components of data quality: o Validity- the extent to which a machine measures the data it is intended to measure o Reliability- the extent to which a machine produces the same data with different investigators  Errors in Data Collection: o Clinical observations o Physical examination o Medical history interview o Disease reporting o Clinical diagnosis (different criteria for making same diagnosis) o Death certificates and mortality statistics o Missing information and illegible notes o Laboratory data (ingestion of certain drugs affects blood constituents) o Response to questionnaire CVD (Ch. 12)  Heart disease and cancer account for 50.1% of deaths in Canada  The actions you take today has a significant impact on your cardiovascular health in the future  CVD: are the diseases of heart and blood vessels  There are several reasons for a decline in CVD such as, advances in medical techniques, earlier and better diagnostic procedures and treatments, better emergency medical assistance programs and training of people in CPR (cardiopulmonary resuscitation)  Women’s signs and symptoms for a heart attack are not as obvious as men’s  In order to prevent CVD, one should control their high blood pressure, and reducing dietary intake of saturated fats and cholesterol. Monitoring your fat levels and cholesterol levels will help you prevent your arteries from getting clogged  The Cardiovascular system refers specifically to a network of tubes that carry blood and oxygen to all parts of the body. It includes the heart, lungs, arteries, arterioles and capillaries. It also includes venules and veins  Under normal circumstances the human body contains 6 liters of blood.  How does the heart work? o Deoxygenated blood comes to the right atrium from superior and inferior venae cava. o From the right atrium, the blood is then transferred into the right ventricle and from there is it pumped into the lung through pulmonary arteries o The blood is then oxygenated in the lungs and comes back to left atrium through the pulmonary vein

a heart attack. The condition of a heart attack is often brought up by coronary thrombosis which is the blockage of the coronary artery.  Women in general suffer from less specific and less severe symptoms. For women symptoms of a heart diseases are vaguer and include unusual fatigue, shortness of breath and sleep disturbances  If there is a minor blockage in the heart, the heart will adapt to this by circulating the blood using the underused vessels, this system is also known as collateral circulation. This is a form of self-prevention  Following any blockage around the heart muscle, there is indeed a shortage of oxygen in that area and this is known as ischemia. Patients with ischemia often suffer more from angina pectoris. The more severe the oxygen deprivation, the more serious the pain  There are several methods of treating angina and the most critical treatment is rest. Other treatments include drugs that affect:  The supply of blood to the heart muscle  The heart’s demand for oxygen.  Pain is often relieved by nitroglycerin, a drug used to dilate veins. As a result there is less blood coming into the heart hence decreasing the workload.  Patients whose angina occurs because of the spasms of the coronary artery, are often giving calcium channel blockers. These prevent calcium atoms from passing through the coronary arteries and causing heart contractions. Beta blockers is also another drug used to prevent any overactivity by the heart. o Stroke:  Just like the heart muscle, the brain cell must have a continuous adequate supply of oxygen. A stroke occurs when the blood supply to the brain is cut off. Strokes can be cause by:  Thrombus  Embolus (a wandering clot)  Aneurysm (a weakening of the blood vessel that causes it to bulge or in severe cases, even burst)  When a stroke occurs, the brain cells die. Consequences of a stroke really depends on how long the blood supply has been cut off for and in which region. The consequences often include speech impairment, memory loss, and motor control. There are some strokes that are mild and may result in some temporary dizziness or slight weakness or numbness. These mild strokes are often called transient ischemic and often impending a major stroke. o Hypertension:  Also called as chronic high blood pressure is unique because it is a CVD itself and a risk factor for CHD and stroke. When blood pressure is chronically elevated, the workload of heart also increases, which

decreases its ability to pump blood effectively to parts of our body, resulting in heart muscle damage  High blood pressure may also damage the inner walls of the arteries  Essential Hypertension: sustained high blood pressure without any cause.  Secondary Hypertension: refers to blood pressure caused by specific factors such as kidney disease, obesity, tumors of the adrenal glands.  Blood pressure is measured in two numbers. The systolic pressure (top number) indicates the pressure in the arteries while supplying blood to the body from the heart. The diastolic pressure (bottom number) indicates pressure on the arteries when the heart is relaxing, i.e., when the blood is reentering heart’s chambers  More and more people as they age are prehypertensive, meaning that their blood pressure is above normal but not in the hypertensive range o Arrhythmia:  This is when there are irregular heartbeats. A person may complain about fast heartbeats in the absence of physical activity often known as tachycardia. On the other hand, there is bradycardia, i.e., slow heartbeats compared to normal.  This often leads the heart to go into fibrillation where the heart shows a sporadic and quivering pattern of heartbeats indicating that there is inefficient moving of blood around the heart.  Arrhythmia can be triggered by excessive caffeine or nicotine. o Congestive Heart Failure:  This is basically when the heart muscle is overworked and cannot continue the blood supplying process because of the overload.  Individuals who have had pneumonia, and other CVD in the past, often have weakened heart muscles and blood vessels.  In this condition the pumping rate of the heart decreases and the return flow of blood begins to back up, resulting in blood accumulation around the heart and around other bodily vessels. These are often treated by drugs like digitalis (increases pumping action of the heart) and a vasodilator that expands blood vessels and decreases resistance. o Congenital Heart disease:  Heart disease that is present at birth. This happens when the blood vessels around the heart do not develop normally before birth. This can be a result of many different factors such as hereditary factors, maternal diseases, or drug or alcohol intake during pregnancy. o Rheumatic Heart Disease:  This heart disease is attributed to rheumatic fever. Rheumatic fever is an inflammatory disease caused by an unresolved streptococcal

cardiovascular system. These people are often known as “hot reactors”.  Women and CVD: men suffer more heart attacks than women but women have a less chance to survive. Part of the reason is that symptoms in women are less apparent.  Premenopausal women are less likely to suffer from a heart attack unless they have other CVD risk factors or symptoms. Once a woman’s estrogen levels start dropping, the chances of a heart attack increases rapidly.  Techniques of diagnosing heart diseases: o ECG records heart’s electrical activity o Angiography: insertion of a needle-like tube into the arteries along with injecting a dye resulting in an x-ray or blockages o PET (positron emission topography)- produces three-dimensional images of the heart as blood flows through it.  Angioplasty VS Bypass surgery: o Coronary bypass surgery seemed to be the ultimate technique for treating coronary blockages. A vessel is taken from a patient’s body and it is used instead of the coronary artery in the heart. o Angioplasty on the other hand, has fewer risks and is believed to be more effective in selected cardiovascular cases. A needle-like catheter is inserted into the artery and a balloon is inflated, resulting in flattening of the fatty deposits against the wall. o Thrombolysis: this involves injecting an agent such as TPA (tissue plasminogen activator) to dissolve the clot and restore some blood flow, reducing the amount of tissues that die from lack of oxygen. Ch. 13 Infectious Disease  Pathogens: disease causing agents  Epidemic: disease outbreak that affects many people in a community or region at the same time.  Endogenous microorganisms are usually harmless in individuals with a good immune system, however, in individuals with disease or compromised functioning of immune system, these microorganisms can cause serious health issues  Exogenous microorganisms are not that used to the body and hence when they encounter the body, it often results in illness.  Virulent: strong enough to overcome host resistance and cause disease  Passive immunity is a natural occurring type of immunity that plays a role in contraction of infectious diseases. This is when the antibodies from a mother are transferred on to a fetus through placenta.  Multifactorial disease: disease caused by interaction of several factors  Heredity is another risk factor that an individual cannot control.  Sickle cell anemia: genetic disease resulting in chromosomal abnormalities commonly found among individuals of African descent  Modifiable risk factors: o Poor diet, physical inactivity o Stress, inadequate sleep

o Drug abuse o Poor personal hygiene  Non-modifiable risk factors: o Age heredity, environmental conditions  As we age, our immune system becomes less efficient in responding to these invading organisms.  In unhygienic and polluting environment, the immunological competence is often weakened  There are, however, some factors an individual can control such as dietary intake, adequate sleep, physical activity, misuse of drugs and poor personal hygiene.  Autoinoculation: transmission of a pathogen from one part of the body to another.  Pathogens are also transmitted through airborne contact and food-borne (when you eat something contaminated by microorganisms. There are also animal-borne pathogens where the infection is spread through dogs, cats, livestock and other wild animals. Along with them, there are also waterborne diseases  Bacteria: single celled organisms that can cause diseases in humans  Toxins: poisonous substances produced by certain microorganisms that cause various diseases.  Staphylococci: found normally on skin, but only causes infection when there is a break in the skin  The epidermis is the outermost layer of the skin.  Toxic shock syndrome: a potentially life-threatening bacterial infection (caused by staph) most common in menstruating women.  Streptococci: a bacterium that can cause strep throat or scarlet fever.  Pneumonia: disease of lungs caused by bacteria. This readily responds to antibiotics but can also result in respiratory failure.  Tuberculosis: a disease caused by bacterial infiltration of the respiratory system. It is transmitted by breathing infected air from a person’s cough or a sneeze.  Periodontal diseases: diseases of the tissue around the teeth. This is often the result of improper home tooth care.  Viruses: minute parasitic microbes that cause disease. A virus consists of a protein structure that contains either RNA or DNA.  Treatment of viruses are very difficult because many viruses can withstand heat, formaldehyde, and large doses of radiation. Viruses also have incubation periods, i.e., the time between exposure of disease and the appearance of the symptoms.  Slow-acting viruses: viruses with long incubation periods leading to slow progressive symptoms.  Drug treatment for viruses are limited since strong enough drugs that kill the virus cells also kill the host cells. However, when our body is exposed to viruses our body produces what is known as interferon. It is a protein substance produced by the body that aids immune system by protecting the healthy cells  Common colds are endemic. Endemic is the continued prevalence of a specific infection or disease in a specific population or area.  Influenza: a common viral disease of the respiratory tract. There are 3 varieties of flu viruses discovered to date. A B and C, with A being the most virulent and C being the least virulent.

 Vaccination: inoculation with killed or weakened pathogens, less dangerous antigens in order to prevent or lessen the effects of some disease.  Vaccinations contribute to acquired immunity.  Types of vaccines: o Live attenuated o Inactive vaccines o Subunit vaccines o DNA vaccines  Childhood immunization schedule: starts at about 2 months to 15 years of age  Adults: o Tetanus- every 10 years o Influenza: yearly o Meningitis: once in early adulthood o Pneumonia: once over 65 years o Hepatitis A, B – high risk, outbreak, travel  Other travel vaccines: often required in high-risk areas. (vaccines include cholera, typhoid, yellow fever and more)  Childhood vaccinations are very effective and are not linked to autism.  Sexually Transmitted infections: infectious diseases transmitted via vaginal, anal, or oral sex  Chlamydia: bacterially caused STI of the urogenital tract  Chlamydia may also result on conjunctivitis which is the serious inflammation of the eye caused by any number of pathogens or irritants  Herpes is a general term for a family of diseases characterized by sores or eruptions on the skin. It is the most common STI. Herpes Simplex -1; cold sores, fever blisters. Herpes Simplex type 2; also known as genital herpes, burning, redness blisters.  Herpes virus has a latency phase where the virus resides at base of nerve. It is, however, reactivated by stress, sun, and illness.  AIDS (Acquired Immune Deficiency Syndrome): extreme virulent STI that renders the immune system inoperative.  HIV (human immunodeficiency virus): the slow acting virus that causes AIDS.  ELISA: a blood test that detects the presence of antibodies to HIV  Western Blot: more precise test than ELISA to test the presence of HIV antibodies  Although ELISA is accurate, oftentimes it produces false positive results.  HIV virus damages cells of immune system which leads to a progressive degradation in the ability to fight infections  HIV often leads to AIDS (acquired immune deficiency syndrome) and this is a global health problem.  Modes of transmission: o Unprotected sex with infected partner o Injection drug use—contaminated needles o Blood transfusion prior to 1986 o Mother-to-baby transmission- pregnancy, birth  Once HIV/AIDS are inside the host cells, they begin to destroy helper T-cells and change the genetic structure of the cell it attacks. Our body in response, begins to produce antibodies  Symptoms include:

o Fever, headache, fatigue, enlarged lymph nodes. These symptoms usually disappear within a week or a month. This is followed by a long asymptomatic period.  In most cases, HIV leads to AIDS in about 8 to 10 years. (in adults)  During these years a person may experience a gradual deterioration of the immune system.  AIDS: because of HIV, increased bacteria, virus and fungal infections often show up. This is known as AIDS  Symptoms include cough, shortness of breath, fever, nausea, vomiting, extreme fatigue, weight loss, neurological impairments.  This also increases the risk of some cancers like Kaposi’s sarcoma, cervical, and lymphomas  Prevention strategies: o V Hand washing o Safe sex o Safe food handling o Healthy eating and exercises o Stress management and adequate sleep o No smoking, moderate alcohol, vaccination Ch. 13 - Non-infectious Diseases  Respiratory disorders: o Allergy: hypersensitive reaction to a specific antigen or allergen in the environment in which the body produces excessive antibodies o Histamines: chemical substances that dilate blood vessels, increase mucous secretions, and produce other allergy-like symptoms  Allergies become progressively worse with time as there is more exposure to allergens.  Hay Fever: a chronic respiratory disease most prevalent when ragweed and flowers bloom. Hay fever appears to have genetic component, so any changes in lifestyle may not have a huge impact. For some people, a change in atmosphere may help and in severe conditions, people usually treat themselves with injections or antihistamines  Asthma: if a person is suffering from hay fever, this may be followed by the development of another chronic respiratory disease known as Asthma. This diseases is often characterized by shortness of breath, chest tightness, difficulty breathing, and coughing spasms. Asthma attacks can also be brought on by doing moderate or vigorous physical activities, this is often known as Exercise induced asthma (EIA)  Black adults and children are more likely to suffer asthma than white adults and children. Socioeconomic level also depends, where in people with less income or poor background, often tend to suffer from asthma more than people with a high income. Finally, people who smoke and are obese are more likely to suffer from asthma.  Emotional factors such as excessive anxiety or stress can also trigger asthmatic episodes. Drugs may also be required in serious conditions  Emphysema: a respiratory disease in which the alveoli become distended or ruptured and cannot function anymore. This disease leads to people finding it hard to exhale.

o Organ and support systems develop: endoderm, ectoderm and mesoderm o Placenta, umbilical cord and amnion develops  Fetal Period: o Rapid growth and organ differentiation o Teratogen exposure  Abnormalities at birth are often present and take place in the embryonic stage/period. This causes inappropriate changes to tissues  An example of congenital abnormalities are Talipes: which is a congenital deformity of the foot where there is unilateral or bilateral deviation of the metatarsal bones. This also results from intrauterine constriction  Treatment for this condition includes: splints and casts, poinsettia method. There are also surgical options where in the anterior tibial tendon is transferred or the Achilles tendon is released  Cleft plate or Cleft lip: 1in 700 newborns, can occur on one of both sides  Because the lip and palate develop separately, an infant can either have cleft lip, cleft palate or both  Genetic and environmental: maternal hypoxia, drugs, etc.  Separation of the two sides of the lip. The separation often includes the bones of the upper jaw  Cleft palate: an opening in the roof of the mouth in which the two sides of the palate did not fuse.  Down syndrome: 21 st chromosome has 3 not 2 chromosomes o Outcomes: may result in mental disabilities (IQ b/t 20 and 60 yrs) o Walking delayed for 1+ years o Hypotonia (muscle fibers are weakened)  Klinefelter’s Syndrome: o Y sex chromosome from father combines with two X chromosome from mother (XXY) o Child is usually born with it but if often present at puberty o Risk factor: advanced maternal age o Features:  Tall, lanky build  Depression  Infertility  Intellectual difficulties  Turner’s syndrome: o Cause: complete or partial absence of one of the two X chromosomes o Appears to occur at random o Features:  Short stature  Lack of ovarian development  Webbed neck  Skeletal disorders  Hearing/vision disorders  Cystic Fibrosis: o Inherited disease that impacts the sodium channels in the body and causes respiratory and digestive problems

o Most common, fatal genetic (hereditary disorder) that affects Caucasians o In the lungs:  Build up of thick mucus that makes it difficult to clear bacteria and leads of cycles of infection and inflammation o In the digestive tract:  There is an absence of pancreatic enzymes that prevents breakdown and absorption of fat o Treatment:  Taking nutritional substances  Antibiotics  Exercise  Lung transplant  Ibuprofen for children between the ages of 5 and 13  Parkinson’s disease: o Degeneration of the dopamine producing cells in the basal ganglia o Possible causes/risk factors:  Increased age (free radicals)  Genetic predisposition (1/5 PD cases)  Chemical exposure (certain pesticides linked to the development of PD)  Neurotoxins (MPTP model) o Disease characteristics:  Bradykinesia (slowness of movement)  Tremor (shaking)  Rigidity  Postural instability  Difficulty swallowing  Dementia  Micrographia  Hypophonia o Freezing of gait:  Often occurs in confined spaces  Cause is still not backed  Muscle co-contraction  Impaired timing  Perceptual link o Treatments:  Levadopa + Carbadopa (Sinemet)  These are most effective in treating bradykinesia and rigidity  Stimulation surgery: implantation of electrodes into the basal ganglia 