pathology.pptx introduction to pathology

Introduction to pathology

1. INTRODUCTION TO PATHOLOGY BY – MS. ARADHANA MASIH M.Sc. NURSING

2. INTRODUCTION The word Pathology has been derived from two Greek words, i.e ., Pathos meaning Experience Or Suffering , and Logia meaning Study Of Thus a branch of medical science which diagnose disease on the basis of the laboratory analysis of body fluids (blood and urine) and tissues, by using the tools of chemistry, clinical microbiology, haematology, and molecular pathology is known as pathology.  Pathology is a medical science field that investigates the source, origin, character, and diagnosis of disease by examining surgically removed organs, tissues (samples for biopsy), body fluids, and, in certain conditions, the entire body (autopsy).

3. TYPES OF PATHOLOGY Anatomical Pathology : It is the study of large structures of body, such as bones and organs.  Cytopathology : It is the study of individual cells taken from the body.  Clinical Pathology : It is pathology as it occurs in a hospital or outpatient setting. Forensic Pathology : It is the study of dead bodies at crime scenes. Derma pathology : It is the study of diseases of skin. Hemapathology : It is the study of diseases of blood. Surgical Pathology : It is the study of tissues taken out via surgery. Neuropathology: It is the study of diseases of human nervous system. Histopathology: It is the study of human tissues. Pulmonary Pathology: It is the study of diseases of lungs. Molecular Pathology: It is the study of human tissues and fluids at molecular level. 

4. IMPORTANCE OF THE STUDY OF PATHOLOGY Understanding the Causes of Disease: Pathology knowledge will provide a nurse with the following vital information about disease etiology and pathogenesis:- A ble to comprehend illness patterns and classification. A ble to recognise the fundamental character of diseases, such as inflammatory, degenerative, hemodynamic, infectious, autoimmune, and neoplastic diseases. A ble to know the etiology and pathophysiological mechanisms underlying illness processes. Able to acquaint with several diagnostic tests and pathological report nomenclature.  2. Knowledge about Disease Progression: Pathology knowledge enables a nurse to comprehend the fundamental structural and functional changes that arise in tissues, organs, and the body as a whole: She will be able to understand the morphological changes that occur in the body during various processes of illness. She will be able to evaluate the progression of disease from its origin to its clinical manifestations, covering disease signs and symptoms. She will be able to link clinical symptoms to structural and functional pathological changes in organs caused by the illness process. She will be able to understand the pathophysiology of an illness, allowing for more effective nursing care planning.

5. Cont … 3.Early and Effective Diagnosis of Disorders: Although the clinical signs of numerous diseases may be identical, the management of these conditions might differ greatly. There are several pathological tests available, and a nurse must be well-versed in pathology to recommend the most relevant test to correctly diagnose the problem. 4.Prevention of Disease Condition: There are various standard screening tests that help a nurse to detect a disease in its early stages and hence take preventive actions accordingly. FNAC, for example is done for breast lumps. 5.Helps in Effective Management and Care of Patients: Pathology expertise assists a nurse in understanding the patient’s current health status and determining if the patient is responding to treatment by observing a range of pathological laboratory results.

6. Terminology in pathology Pathology : Scientific study of the nature of disease and its causes, processes, development, and consequences. Pathologist : A doctor who identifies diseases by studying cells and tissues under a microscope. Lesions : Characteristic alterations occurring within cells and tissues, as a result of a disease. Pathologic Changes : Changes developed as a result of a disease. These changes can be studied by examining the morphology of the diseased tissues. Idiopathic Diseases : The diseases for which the cause remains unknown.   Iatrogenic Diseases : The diseases arising as a direct consequence of the medical treatment provided. Biopsy : Removal of cells or tissues from the body for pathological examination.   Pathogenesis : Study of the progression of a disease, including the mechanism of its establishment, and thus development. Histopathology : Microscopic study of any abnormality in the tissues or organs.   Haematology : Study of blood diseases. Haematology is further divided into two branches, i.e., clinical haematology and laboratory haematology.

7. Cont … 11. Chemical Pathology : Branch of pathology including the analysis of biochemical constituents of blood, urine, semen, CSF, etc. 12. Immunology : Study of the immune system. 13. Immunopathology : Detection of abnormalities in the immune system. 14. Experimental Pathology : Study of disease processes by microscopic or molecular examination of organs, tissues, cells, or body fluids of diseased individuals. 15. Geographic Pathology : Study of differences in the distribution of frequency and the types of diseases seen within populations, in different parts of the world. 16. Medical Genetics : Branch of human genetics, dealing with the relationship between a disease and its inheritance. 17. Molecular Pathology : Detection and diagnosis of abnormalities at the level of cellular DNA. 18. Clinical Pathology : A group of practice areas in laboratory medicine concerned with diagnosing disease on the basis of body fluids analysis. 

8. CONT… 19. Cytopathology : A sub-specialty of anatomic pathology that deals with the diagnosis of diseased cells in body fluids or aspirated tissue specimens. 20. Dermatopathology : A sub-specialty of anatomic pathology that deals with skin diseases. 21. Gastrointestinal and Liver Pathology : A sub-specialty of anatomic pathology that deals with diseases in digestive tract and liver.  22. Gynaecological Pathology : A sub-specialty of anatomic pathology that deals with diseases of female genital tract (breast, uterus, fallopian tubes, ovaries, vagina, and vulva). 23. Haematopathology : A sub-specialty area of clinical pathology that deals with the diseases of blood cells, bone marrow, spleen, and lymph nodes.Pathology - 26. Neuropathology : A sub-specialty of anatomic pathology that deals with diseases of the central nervous system, muscles, and nerves. 27. Renal Pathology : A sub-specialty of anatomic pathology that deals with Diseases of kidney. 28. Surgical Pathology : A sub-specialty of anatomic pathology that deals with the evaluation of any tissue that is removed by surgical means.

9. CELL INJURY Cells maintain their normal homeostasis. As cells encounter physiologic stresses or pathologic stimuli, they can undergo adaptation, achieving a new steady state and viability. If the cellular adaptation exceeds, cell injury occurs. Most forms of diseases are initiated as a result of cell injury and subsequent loss of cellular functions. Injury is defined as an alteration in cell structure or function resulting from some stress that exceeds the ability of the cell to compensate through normal physiologic adaptive mechanisms. An injury may eventually result in a disease, if left untreated. An injury may either occur at the molecular level or at the level of cells, tissues, or organs. For example, an injury at the molecular level may result in cancer.

10. CELLULAR RESPONSE TO CELL INJURY Adaptive Changes/Cellular Adaptations: In order to survive and maintain the normal steady state “homeostasis”, the cells adjust (i.e., adapt) themselves with the changing environment (when exposed to stress) Depending on the physiological needs, which is termed as physiological adaptation. They also adjust themselves to any non-toxic pathological injury by undergoing pathological adaptation.  2. Reversible Cell Injury: This type of cellular injury occurs when the cell fails to adapt due to loss of ability to meet the demands placed on it. Initially, cellular injury may be reversible. The first function affected in reversible injury is injury is oxydative phosphorylation, resulting in the swelling of cell. But, after a certain point, irreversible cellular injury occurs because the cell loses its reparative ability. For example, irreversible myocardial damage may occur, if blood supply is not restored to the affected area of the heart in the given duration of time. Irreversible Cell Injury: This type of cellular injury occurs when mitochondria or the cell membrane have been damaged irreversibly. Some causes of this cellular injury are: Hypoxia: Most common cause, e.g., ischemia results from hypoxia. Physical Agents: Trauma, burning, and shock. Anaphylactic Reactions and Autoimmune Diseases: These immunological reactions may also cause injury.

11. ETIOLOGY The causes for cell injury (reversible or irreversible) may be categorised into two broad groups: 1. Genetic causes 2. Acquired causes GENETIC CAUSES Genetic factors responsible for cell injury are:   Developmental Defects: These defects include foetal abnormalities arising due to errors in morphogenesis. Often, defects in formation (malformation) result from teratogens, which are agents (chemical, physical, biological, and drugs) responsible for the induction of birth defects. Single Gene Defects (Mendelian Syndrome): Defects due to a single gene follow Mendelian pattern of inheritance and are known as Mendelian syndrome. Single gene defects arise from mutation in a single gene. Mutation in the germ cells leads to a change in the characteristics of the offspring. Sickle Cell Anaemia (SCA): It affects the RBCs; and involves inheritance of an abnormal gene from each parent and represents a homozygous state of abnormal Hb-S (Haemoglobin S, i.e., differs from normal adult haemoglobin A by a single amino acid substitution). The RBC changes from biconcave to crescent- or sickle-shaped. Due to this shape, they are unable to pass through the narrow blood vessels, leading to capillary wall rupture. Storage Diseases (Inborn Errors of Metabolism, IEM): These errors comprise of a group of disorders in which a single gene defect results in a clinically significant blockade in metabolic pathway.

12. CONT… 4 . Disorders with Multifactorial Inheritance: These disorders, e.g., cleft lips, diabetes mellitus, hypertension, CCF, etc. are caused by genetic and environmental factors. Colour of the hair, eyes, skin, height, intelligence, etc. also vary in normal individuals with inheritance and depend on a number of factors (multifactorial). ACQUIRED CAUSES Most of the common diseases are due to acquired causes. Depending on the agent responsible for the cause of injury to the cells, the acquired causes can be classified as: Hypoxia and Ischemia: Oxygen is the prerequisite for carrying out metabolic functions and for generation of energy by various cells of the body. Therefore, oxygen deficiency renders the cell incapable of carrying out these functions. Hypoxia results from the following factors: Reduced blood supply to the cells, i.e., ischemia.  Anaemia, carbon monoxide poisoning, cardio-respiratory insufficiency, and increased demand of tissues.  2. Physical Agents: Diseases can also be caused by: Mechanical trauma (e.g., road accidents), Thermal trauma (e.g., by heat and cold), Electricity, Radiation (e.g., ultraviolet and ionising), and Rapid changes in atmospheric pressure.

13. Cont … 3 . Chemicals and Drugs: Some important chemicals and drugs inducing cell Injury are: Chemically poisonous substances, e.g., cyanide, arsenic, mercury, etc., Strong acids and alkalis, Agents causing environmental pollution, High oxygen concentration, Societal substances, like narcotic drugs and alcohol, and abuse or therapeutic administration of drugs. 4. Microbial Agents: Bacteria, rickettsia, viruses, fungi, protozoa, metazoa , and other parasites may also cause infections. 5. Immunologic Agents: An individual’s immunity acts as a ‘double edged sword’, protecting the host from several injurious agents, while also turning out to be lethal at times, and causing injury to cells. This is evident during: i . Hypersensitivity reactions, Ii . Anaphylactic reactions, and Iii. Autoimmune diseases. 6. Nutritional Derangements: An imbalance in an individual’s nutrition may result either from an excess or a deficiency of nutrients. An overall deficiency of proteins (e.g., marasmus, kwashiorkor disease) or minerals (e.g., anaemia) or trace elements results in nutritional deficiency diseases. A common problem seen in affluent societies is consumption of nutrients in excess amounts and it results in heart diseases, obesity. Atherosclerosis, and hypertension.  7. Psychological Factors: Commonly acquired mental disorders, (e.g., depression, schizophrenia, etc.) resulting from anxiety, work overload, frustration, stress, and strain, present no distinct changes in the biochemistry or morphology of an individual. Yet, drug addiction, alcoholism, and smoking result in numerous organic diseases, e.g., lung cancer, peptic ulcer, hypertension, li ver damage, chronic bronchitis, ischemic heart disease, etc.

14. PATHOGENESIS OF CELL INJURY