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- 1. Chapter 1 Introduction of Pathophysiology Dr. Liu Rui (dr.liurui@Hotmail.com) Department of Physiology and Pathophysiology 1
- 2. 1. Nature and Aims of Pathophysiology Basic medicine ―→ Clinical medicine ―→ Practice ―→ Qualified doctor 2 Pathophysiology is one of basic medical sciences, which focus on sick or disordered life.
- 3. Basic medical courses normal body disordered body structure function structure function metabolism metabolism Anatomy Pathoanatomy Biology Physiology Pathophysiology Histology Biochemistry about drugs----Pharmacology Clinical medical courses Internal medicine, Surgery, Pediatrics, et al. 3
- 4. Pathophysiology is the study of the underlying mechanisms by which diseases occur and develop, and the study of the changes by diseases within the body. It provides a theoretical basis for the prevention, diagnosis and treatment. 4
- 6. Alterations in structure Disease Alterations in function Alterations in metabolism 6
- 7. Pathophysiology emphasizes the developmental process of diseases. Disruption of the body’s homeostasis; Alterations in function, metabolism Mechanisms involved. 7
- 8. 2. Content of pathophysiology Systemic and organic pathophysiology Fundamental pathological process General concept of disease Pathophysiology in diseases 8
- 9. Experimental study Reproduce disease model in animals, isolated organs and cells, and observe or perform something. Clinical study Observe directly the patient’s symptom, laboratory testing, the rules of evolution; study the treatment and prognosis. Epidemiological study Study the cause or conditional factors, risk factors, rules of development of some infective diseases 9 3. Research Methods for Pathophysiology
- 10. Summary 1. Pathophysiology is one of basic medical sciences which study the rules of origin and evolution of diseases and the underlying mechanisms --- “the physiology of disease”. 2. Pathophysiology focuses on the alterations in function and metabolism of the body and the mechanisms underlying the development of diseases. 3. Pathophysiology plays an important role in bridge linking basic medical sciences to clinical medicine. 10
- 11. Pathophysiology Physiology Different targets Normal bodySick body 11
- 13. Pathophysiology Bridge course Basic medicine Clinical medicine 13
- 14. Chapter 2 General Concepts of Diseases 14
- 15. 1. Basic Concepts 1-1 Health No diseases or infirmity. A state of complete well-being of all aspects: physical, mental, social. 15 1-2 Disease Disease is an abnormal life process caused by certain pathogenic factors, deviation from the normal status including structure, function or metabolism.
- 16. Disease is a disordered state of the body due to pathogenic agents-host interactions. 16 Homeostasis: the process that the internal environment of an organism tends to remain balanced and stable, which is required for optimum functioning. Disease can be viewed as a disturbance of homeostasis.
- 17. Manifestations of diseases: 17 1) Symptom: a subjective complaint 2) Sign: a manifestation that is noted by an observer, doctor or nurse, through physical examination, e.g. an elevated body temperature. 3) Laboratory finding: alterations found by laboratory test, X-ray examination (routine or CT), electrocardiogram (ECG), ultrasonography, magnetic resonance imaging (MRI), etc.
- 18. Sub-health There is a situation, in which the person does not show specific symptoms and signs of illness, but lives a low-quality of life both physically and mentally; this is called “sub-health”. 18
- 20. Senescence (Aging) 20 Aging is a natural, lifelong process. There is a general decline in the structure and function of the body with advancing age, resulting in a decreased reserve capacity of the various organ systems. This results in a reduction of homeostatic capabilities, making the older adult more vulnerable to stressors such as illness, surgery, medical administration, and environmental changes.
- 21. 1-4 Two very important concepts 21 1) Pathological Process A series of structural, functional and metabolic changes that appear in different diseases, e.g. fever, inflammation, edema, etc.
- 22. Pathological Process and Disease Disease Cause Site Fundamental Pathological Process Pneumonia Pneumococcus Lung Fever, inflammation, hypoxia, acid-base disturbances, shock Dysentery Dysentery bacilli Intestine Fever, inflammation, water and electrolytes disturbances, acid-base disturbances, shock Epidemic meningitis Meningococcus Meninges Fever, inflammation, DIC, shock 22
- 23. 2) Syndrome A set of signs and symptoms that occur together and are characteristics of a group of diseases or a specific disease, e.g. ARDS, AIDS etc. 23
- 24. Acute respiratory distress syndrome (ARDS) Shock, infection acute and severe lung damage pulmonary edema lung volumes and compliance↓, gas exchange impaired tachypnea, labored breathing, cyanosis, chest radiograph shows diffuse, symmetrical interstitial and alveolar infiltration. 24
- 25. 3. Etiology of Disease Etiology is a science to study the factors associated with or involved in initiation and development of diseases. According to their different roles in the development of diseases, these pathogenic factors are classified into cause of disease and conditional factors. 25
- 26. Causes of diseases are the factors that provoke or cause the particular disease. It determines the characteristics of the disease and is absolutely necessary for disease to occur. 26 Conditional factors are the factors that do not cause disease directly but rather influence the pathogenesis and the natural time course of the disease.
- 27. Precipitating factors belong to conditional factors that promote the development of diseases by enhancing the roles of cause of diseases or susceptibility of the body to diseases. 27
- 28. e.g. Infection, arrhythmias, pregnancy, water- electrolytes and acid-base disturbances are precipitating factors of heart failure Tubercle bacillus is the cause of tuberculosis. Not all people who inhale the organism will suffer from pulmonary tuberculosis, which occurs in malnutrition, over fatigue and long- term depress. 28
- 29. Controlling conditional factors is easier than eliminating the causes. 29
- 30. Causes of diseases Extrinsic Factors Biological agents Physical factors Chemical factors Nutritional factors Pathogenic factors Intrinsic Factors Genetic factors Congenital factors Immunological factors Psychological factors Conditional factors Body condition (predisposing factors) Nature condition Social condition Precipitating factors of diseases 30
- 31. 3-2 Cause of Disease 1) Biological agents bacteria, viruses, 2) Physical factors: trauma and fracture, heatstroke, frostbite. 3) Chemical factors Corrosive chemicals such as strong acid and bases can destroy cells at the site of contact. Cell-injurious chemicals are often called toxic substances or poison. They induce tissue and cell damage when they enter the body through certain pathways and reach a sufficient amount. These called intoxication or poisoning. The toxic substances often act on specific cells or organs, e.g. CO poisoning. Electrical injuries Radiation injuries 31
- 32. 4) Nutritional factors Excesses: high lipids and carbohydrates diet obesity, atherosclerosis, diabetes Deficiencies: lack of certain elements in diet (1) Vitamin B: beriberi (2) Vitamin A: night blindness (3) Vitamin C: scurvy (4) Vitamin D: rickets 32
- 33. 3-2-2 Intrinsic Factors 1) Genetic factors Altered genetic material passed from parent to offspring is called genetic factors, which is classified into three groups. Genetic disorders Chromosome disorders: the defect results from numerical and structural abnormalities of chromosome. Single-gene disorders: the defect is caused by a single defective or mutant gene. Multifactorial inheritance: polygenetic disorder. 33
- 34. Common Examples of Genetic Disorders 34 Disorder Classification Genetics Huntington disease Single-gene disorder Autosomal dominant Cystic fibrosis Single-gene disorder Autosomal dominant Hypophosphatemia (vitamin D- resistant rickets) Single-gene disorder X-lined dominant Hemophilia Single-gene disorder X-lined dominant Down syndrome Chromosome disorder Trisomy 21 Turner syndrome Chromosome disorder 45, X
- 36. Inherited disease: disease caused by altered genetic material, either single gene mutation or chromosome aberrations. e.g. color blindness, Albinism, Down syndrome. 37
- 37. 38 Disorder of multifactorial inheritance result from a combination of the multiple gene variations with environmental factors. Therefore the disease on phenotype are not hereditary, but these diseases do have a genetic background (genetic susceptibility), such as congenital heart disease, cleft lip, coronary artery disease and hypertension.
- 38. Genetic predisposition (genetic susceptibility): a state of body favorable to or showing a tendency to certain diseases because of polygenetic abnormalities. 39
- 39. 2) Congenital factors Environment factors that occurred during embryonic or fetal development are called congenital factors, including the physiologic status of the mother (maternal disease) and teratogenic agents (infections or drugs taken during pregnancy), which acts on the embryo or fetus, causing abnormalities in form or function. Diseases caused by congenital factors called congenital disease. e.g. congenital syphilis. 40
- 40. 3) Immunological factors Although the immune response is a normal protective mechanism, it may cause disease while the response is deficient (immunodeficiency disease), inappropriately strong (allergy or hypersensitivity----penicillin), or misdirected (autoimmune disease----ankylosing spondylitis). 41
- 41. 4) Psychological factors Anxiety, strong or persistant psychological stimulation or stress may lead to mental illness and may be related to some disease such as hypertension, peptic ulcer(duodenal ulcer), and coronary heart disease. 42
- 42. 3-3 Conditional Factors 1) Body’s condition: age, sex, race; physical training, mental condition, fatigue, smoking, lifestyle. 2) Nature condition: weather condition and geographical environment influence some epidemical diseases. 3) Social condition: labor and hygiene conditions----occupational diseases, social life events----person’s mood and life pattern. 43
- 44. Causes of diseases Extrinsic Factors Biological agents Physical factors Chemical factors Nutritional factors Pathogenic factors Intrinsic Factors Genetic factors Congenital factors Immunological factors Psychological factors Conditional factors Body condition (predisposing factors) Nature condition Social condition Precipitating factors of diseases 45
- 45. 4. Pathogenesis of disease Pathogenesis of disease refers to the rules and mechanisms underlying the development or evolution of the diseases. 4-1 General rules for pathogenesis of disease 1) Disruption of homeostasis If homeostasis is disrupted by a variety of harmful agents, the body cannot function optimally, and illness may occur. 46
- 46. 2) Process of damage and anti-damage Damage can induce body’s anti-damage responses. The development of a disease depends on the strength of damage and anti- damage factors. Too much anti-damage process will cause new injury to the body (SIRS----MODS) 47
- 47. 3) Reversal role of cause and result The cause of the disease lead to a result, which can be another cause of the disease in the evolution process. (Cause) (Result) Chronic hypoxia erythrocyte￪ polycythemia (Cause) (Result) blood viscosity ￪ thrombus 48
- 48. Mechanical trauma Hemorrhage Cardiac output↓↓ Returned blood volume ↓ Blood pressure↓↓ Microcirculation congestion Sympathetic nerve excite Capillary open Vasoconstriction Hypoxia in tissure vicious cycle Maintain BP Heart rate ↑ Contractility ↑ beneficial cycle Recovery (Cause) (Result) (Cause) (Result) 49
- 49. 4) Correlation between systemic and local regulations Local alterations can affect the whole body through neural and humoral regulation, and the systemic functional statues can in turn affect the development of local damages via the same regulating strategies. 50
- 50. e.g. a severe furuncle congestion and edema (local) fever, chill and WBC ￪ (systemic) e.g. a recurrent furuncle may represent systemic metabolic disorder caused by diabetes. 51
- 51. 5. Outcome of Diseases 52 Recovery Death Complete recovery Incomplete recovery
- 52. 5-1 Complete recovery The alterations of the function, metabolism and structure of the body, which appeared in disease, are perfectly restored. The signs and symptoms of the disease are disappear entirely. 53
- 53. 5-2 Incomplete recovery The main symptoms are absent. Some pathological changes are still present in the body. It is brought about by the compensatory response to maintain a relatively normal life activity. --e.g. Heart disease patients 54
- 54. 5-3 Death 5-3-1 Definition: Irreversible cessation of the function of the body as a whole. Contemporary concept of death is brain death. 55
- 55. 5-3-3 Definition of brain death Prolonged irreversible cessation of all brain functions, including the brain stem. 5-3-4 Diagnosis of Death The bases for demonstrating brain death are the absence of brain stem reflexes, absence of cortical activity and demonstration of irreversibility of the state. 56
- 56. Criteria indicating brain death ◆ Irreversible coma and cerebral unresponsiveness: complete lack of cerebral response to any form of external excitation. ◆ Absence of all brain stem reflexes: It includes the absences of pupilary reflex, corneal reflex, cough reflex and swallowing reflex. ◆ Cessation of spontaneous respiration 57
- 57. ◆ Absence of any electrical activity of brain indicated by EEG (electroencephalogram) for at least 6 hours. ◆ Cessation of cerebral circulation 58
- 58. Summary 1. Disease is an abnormal life process in which the body’s homeostasis is disrupted by the interactions of certain pathogenic factor and the body. Intrinsic changes of diseases are alterations in structures, functions and metabolisms of the body. 2. A set of structural, functional and metabolic changes that occur together in different disease is called pathologic process. 60
- 59. 3. Pathologic factors include cause of disease that provoke disease and determine its characteristics and conditional factors that participate in and influence the pathogenesis of disease. Conditional factors that promote the pathogenesis of disease are called precipitating factors. 61
- 60. 4. Irreversible cessation of all brain functions, including the brain stem is called brain death. The bases for determine it are absence of cortical activity, absence of brain stem reflexes, and demonstration of irreversibility of the state. 62