* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Pathologic hyperplasia
Signal transduction wikipedia , lookup
Endomembrane system wikipedia , lookup
Extracellular matrix wikipedia , lookup
Cytokinesis wikipedia , lookup
Cell encapsulation wikipedia , lookup
Cell growth wikipedia , lookup
Cellular differentiation wikipedia , lookup
Cell culture wikipedia , lookup
Programmed cell death wikipedia , lookup
Tissue engineering wikipedia , lookup
By: Dr. Raham Bacha MD KMU MSc Sonology Gold Medalist (UOL) The university of Lahore Introduction to Basic Pathology Dr. Raham Bacha What is Pathology? ?? Pathology is originated, from Greek words Pathos: “suffering,” “disease,” “feeling,” and logos: saying, speech, discourse, thought, Study. Simply; it is the Study of disease. More precisely It is the “Scientific study of disease" Pathology serves as a "bridge" between the preclinical sciences (anatomy, physiology, etc.) and the courses in clinical medicine. The scientific study of the nature of disease and its; causes, processes, development and consequences. Classification: • It is divided in to: • General pathology: • The basic response of cells and tissue to abnormal stimuli. It describe the basic principles of the development of the disease. • For example basic principles of inflammation • Special pathology: • It is the specific response of tissue and organs to one or more definite stimuli. It deals with the diseases of special organs or systems. • For example inflammation of the respiratory system or urinary system. What is Disease?? ? What is the Disease? • It is taken from “Dis” mean with out and “ease” easiness. • It is the “State in which an individual exhibits an anatomical, physiological, or biochemical deviation from the normal” • Disease may be defined as: • An abnormal alteration of structure or function in any part of the body. Classification of disease • Inflammatory diseases • Hepatitis • Appendicitis • UTI and so on • Degenerative diseases • Osteoarthritis etc. • Neoplastic diseases • Lung cancer, breast cancer etc. • Traumatic diseases. • Fractures etc. Pathology focuses on 4 aspects of disease: Knowledge of etiology remains the backbone of: • Disease diagnosis • Understanding the nature of diseases • Treatment of diseases. Etiology “Study of the cause of a disease" • An etiologic agent : is the factor (bacterium, virus, etc.) responsible for lesions or a disease state. • Predisposing Causes of Disease: Factors which make an individual more susceptible to a disease (damp weather, poor ventilation, cigarette smoking, etc.) • Exciting Causes of Disease: Factors which are directly responsible for a disease (hypoxia, chemical agents…. etc.). Etiology Etiology: What is the cause? Acquired or Environmental agents: • Physical • Chemical • Nutritional • Infections • Immunological • Psychological Genetic Factors: • Abnormality in chromosome and • Genes pathogenesis The sequence events during the response of the cells or tissues to the etiologic agent, from the initial stimulus to the ultimate expression of the disease,”from the time it is initiated to its final conclusion in recovery or death” Clinical Significance: Symptoms & Signs • Clinical signs are seen only in the living individual. • “Functional evidence of disease which can be determined objectively or by the observer" (fever, tenderness, increased respiratory rate, etc.)” prognosis • Expected outcome of the disease, It is the clinician's estimate of the severity and possible result of a disease. Summary. • Etiology: Why a disease arise? • Pathogenesis: How a disease develop? • Morphological changes: How a disease present? • Clinical manifestation: What type of Signs and symptoms are present? • Prognosis: what will be likely out-comes? cytology • The study of cell is called cytology. • Mainly there are two type of cells • 1- prokaryotic cells: without nucleus and membrane bounded bodies i.e. bacteria and RBCs • 2- Eukaryotic cells: having distinct nucleus membrane bounded bodies i.e. all cells of the body other than RBCs Structure of cell • Cell has three main parts. • Cell membrane • Nucleus • Cytoplasm • Cytoplasmic organelles. Cell membrane • It is selective permeable membrane, permits some substances to pass through it while other are not. it protects the cell and maintain cell structure. • It maintain fluid and electrolytes balance. Nucleus •It is the control center of the cell. It contain DNA and is bounded nuclear membrane. Mitochondria •It is the power house of the cell. It extract energy from nutrients in the form of ATPs (adenosine triphosphate) energy packet. • RIBOSOMES: • They synthesize protein in the cell • LYSOSOMES: • Thy Provides intracellular digestive system. Which allow the cell to digest and eliminate the unwanted substance i.e. bacteria and other pathogens. Endoplasmic reticulum. •They detoxify the damaging substances to the cell. Tissue. • Aggregate of cells with similar structure and function is called tissue. • Mainly there are four types of tissues. • Epithelial, • Connective, • Nervous, • Muscle. Epithelial Tissue. • Epithelial tissue protects your body from moisture loss, bacteria, and internal injury. There are two kinds of epithelial tissues: Covering and lining epithelium • Covering epithelium cover the external body surface i.e. outer layer of the skin and other organs. • lining epithelium line the internal body surfaces i.e. lumen of the vessels and digestive tract and urinary tract etc. Terms that help us understand what kinds of tissues we are identifying: • Terms referring to the layers • Simple = one layer • Stratified = more than one layer • Pseudo-stratified = false layered (appears to be more than one layer, but only one); Terms referring to the cell shapes • ciliated = with cilia • Squamous = flat • Cuboidal = cube • Columnar = rectangular (column) • Transitional = ability to change shape Simple columnar • One layer rectangular cells present in GIT (Gastrointestinal Tract, Cervix, And Gall bladder. Ciliated Pseudo-Stratified • These are false layered cells with cilia, lining the respiratory tract. Stratified Squamous • Having multiple layers of squamous cells, it is present in skin epidermis, Lips and oral cavity, tongue, pharynx and esophagus. Transitional Stratified epithelium. • It is epithelium of multiple layers and the cells having the ability to change in shape. Chapter 2 CELL INJURY AN D ADAPTA TION. Normal Cell • Under normal circumstances cells are in steady state (regular) (homeostasis). Homeostasis mean to remain stable and regular. • The cell that constantly adjusting their structure and function to accommodate changing demands and extracellular stresses, is said to be normal cell. Adaptation • As cells encounter physiologic stresses or pathologic stimuli, they can undergo adaptation, achieving a new steady state and preserving viability and function. The principal adaptive responses are hypertrophy, hyperplasia, atrophy, and metaplasia. Injury • If the adaptive capability is exceeded or if the external stress is inherently harmful, cell injury develops. • It may either be reversible or irreversible ; • Reversible; Within certain limits, injury is reversible, and cells return to a stable baseline; • Irreversible; if the stress is severe, persistent and rapid in onset, it results in irreversible injury and death of the affected cells. Cell death • Cell death is one of the most crucial events in the evolution of disease in any tissue or organ. It results from diverse causes, including ischemia (lack of blood flow), infections, toxins, and immune reactions. Cell death also is a normal and essential process in embryogenesis, the development of organs, and the maintenance of homeostasis. The relationship among normal, adapted, reversibly injured, and dead myocardial cells Cellular Response to Stress And Injurious Stimuli. • Whether a specific form of stress induces adaptation or causes reversible or irreversible injury depends not only on the nature and severity of the stress but also on the vulnerability of the cell. several other variables, including basal cellular metabolism and blood and nutrient supply, determine cell vulnerability. CELLULAR ADAPTATIONS TO STRESS • Adaptations are reversible changes in the number, size, phenotype, metabolic activity, or functions of cells in response to changes in their environment. Physiologic adaptations usually represent responses of cells to normal stimulation by hormones or endogenous chemical mediators (e.g., the hormoneinduced enlargement of the breast and uterus during pregnancy). Pathologic adaptations are responses to stress that allow cells to modulate their structure and function and thus escape injury. Such adaptations can take several distinct forms i.e. Hypertrophy • Hypertrophy is an increase in the size of cells resulting in increase in the size of the organ. Hypertrophy can be physiologic or pathologic and is caused either by increased functional demand or by growth factor or hormonal stimulation. Physiologic Hypertrophy The massive physiologic enlargement of the uterus during pregnancy occurs as a consequence of estrogen stimulated smooth muscle hypertrophy and smooth muscle hyperplasia. In contrast, in response to increased demand the striated muscle cells in both the skeletal muscle and the heart can undergo only hypertrophy because adult muscle cells have a limited capacity to divide. Therefore, the chiseled physique of the avid weightlifter stems solely from the hypertrophy of individual skeletal muscles pathologic Hypertrophy • An example of pathologic cellular hypertrophy is the cardiac enlargement that occurs with hypertension or aortic valve disease. Two types of mediators are commencing hypertrophy. • Mechanical trigger, i.e. stress. • Tropic trigger. Soluble mediators stimulate intracellular protein synthesis. An adaptation to stress can progress to functionally significant cell injury if the stress is not relieved. Hyperplasia • An increase in cell number because of proliferation of differentiated cells and replacement by tissue stem cells (undifferentiated biological cells). • It may occur concurrently with hypertrophy and often in response to the same stimuli. Hyperplasia can be • PHYSIOLOGIC or • PATHOLOGIC In both situations, cellular proliferation is stimulated by growth factors that are produced by a variety of cell types. physiologic hyperplasia • There are two type of Physiologic hyperplasia • HORMONAL HYPERPLASIA • Exemplified by the proliferation of the glandular epithelium of the female breast at puberty and during pregnancy • COMPENSATORY HYPERPLASIA • In which residual tissue grows after removal or loss of part of an organ. For example, when part of a liver is resected, mitotic activity in the remaining cells begins as early as 12 hours later, eventually restoring the liver to its normal weight. Pathologic hyperplasia • pathologic hyperplasia are caused by excessive hormonal or growth factor stimulation. For example, after a normal menstrual period there is a burst of uterine epithelial proliferation that is normally tightly regulated by stimulation through pituitary hormones and ovarian estrogen and by inhibition through progesterone. However, a disturbed balance between estrogen and progesterone causes endometrial hyperplasia, which is a common cause of abnormal menstrual bleeding. • Important point is that in all of these situations, the hyperplastic process remains controlled; if the signals that initiate it reduce in strength, the hyperplasia disappears. It is this responsiveness to normal regulatory control mechanisms that distinguishes pathologic hyperplasia from cancer, in which the growth control mechanisms become deregulated or ineffective. Nevertheless, in many cases, pathologic hyperplasia constitutes a fertile soil in which cancers may eventually arise. For example, patients with hyperplasia of the endometrium are at increased risk of developing endometrial cancer Atrophy : without nourishment. • Shrinkage in the size of the cell by the loss of cell substance is known as atrophy. When a sufficient number of cells are involved, the entire tissue or organ diminishes in size, becoming atrophic. Although atrophic cells may have diminished function, they are not dead. Causes of atrophy include a decreased workload, loss of innervation, diminished blood supply, inadequate nutrition, loss of endocrine stimulation, and aging Metaplasia • Meta mean "after" or "beyond“ or “changing” • Plasia mean formation. • Metaplasia is a reversible change in which one adult cell type is replaced by another adult cell type. In this type of cellular adaptation, a cell type sensitive to a particular stress is replaced by another cell type better able to withstand the adverse environment. • Epithelial metaplasia is exemplified by the squamous change that occurs in the respiratory epithelium of habitual cigarette smokers (Fig. 1–5). The normal ciliated columnar epithelial cells of the trachea and bronchi are focally or widely replaced by stratified squamous epithelial cells. • Although the metaplastic squamous epithelium has survival advantages, important protective mechanisms are lost, such as mucus secretion and ciliary clearance of particulate matter. Moreover, the influences that induce metaplastic change, if persistent, may predispose to malignant transformation of the epithelium. Summary of adaptation • Hypertrophy: increased cell and organ size, often in response to increased workload; induced by growth factors produced in response to mechanical stress or other stimuli; occurs in tissues incapable of cell division • Hyperplasia: increased cell numbers in response to hormones and other growth factors; occurs in tissues whose cells are able to divide or contain abundant tissue stem cells • Atrophy: decreased cell and organ size, as a result of decreased nutrient supply or disuse; associated with decreased synthesis of cellular building blocks and increased breakdown of cellular organelles • Metaplasia: change in phenotype of differentiated cells, often in response to chronic irritation, that makes cells better able to withstand the stress; usually induced by altered differentiation pathway of tissue stem cells; may result in reduced functions or increased propensity for malignant transformation Cell injury. • cell injury results when cells are stressed so severely that they are no longer able to adapt or when cells are exposed to inherently damaging agents or suffer from intrinsic abnormalities (e.g., in DNA or proteins) • Different injurious stimuli affect many metabolic pathways and cellular organelles. Injury may progress through a reversible stage and culminate in cell death. Reversible cell injury • In early stages or mild forms of injury the functional and morphologic changes are reversible if the damaging stimulus is removed. At this stage, although there may be significant structural and functional abnormalities, the injury has typically not progressed to severe membrane damage and nuclear dissolution Cell death/ irreversible cell injury • With continuing damage, the injury becomes irreversible, at which time the cell cannot recover and it dies. There are two types of cell death. • necrosis and apoptosis which differ in their mechanisms, morphology, and roles in disease and physiology. When damage to membranes is severe, enzymes leak out of lysosomes, enter the cytoplasm, and digest the Basic Language of Pathology etiology •The origin of a disease including the underlying causes and modifying factors. •PATHOGENESIS • The steps in the development of a disease. •HOMEOSTASIS • The maintenance of a steady state of physiologic parameters •ADAPTATION S •Achieving a new steady state to preserve viability and function. These are REVERSIBLE changes of cells in response to a change in their environment. •HYPERPLASIA •(Greek - Huper-, “Above or more" + plasis, "formation”) •An increase in cell number, which can also lead to a hypertrophic organ. • DYSPLASIA • (Greek - dys-, "difficulty" + plasis, "formation”) • An abnormality of development where cell maturation and differentiation are delayed. • HORMONAL HYPERPLASIA • One of the two forms of physiologic hyperplasia. It results in an increase in cell/organ size as a result of hormonal stimulation (i.e., uterus during pregnancy). • COMPENSATORY HYPERPLASIA • One of the two forms of physiologic hyperplasia. This is residual tissue growth after removal or loss of part of an organ. • PATHOLOGICAL HYPERPLASIA • Excessive cell replication typically caused by excessive hormonal or growth factor stimulation. This is reversible which is the main characteristic that distinguishes it from cancer. •HYPERTROPH Y • Hypertrophy (from Greek "excess" + "nourishment") is the increase in the volume of an organ or tissue due to the enlargement of its component cells. It should be distinguished from hyperplasia, in which the cells remain approximately the same size but increase in number. Although hypertrophy and hyperplasia are two distinct processes, they frequently occur together, such as in the case of the hormonally-induced proliferation and enlargement of the cells of the uterus during pregnancy. •HYPERTROPHY • An increase in the SIZE of individual cells resulting in an increase in organ size. •ATROPHY • Without nourishment; Shrinkage in the size of a cell by the loss of cell substance; the retreat of the cell to a smaller size where survival is still possible. • DISUSE ATROPHY • Atrophy as a result of a decrease in workload. • PRESSURE ATROPHY • The tissue destruction and reduction in size as a consequence of prolonged or continued pressure on a local area or group of cells. • METAPLASIA • A reversible change where one adult cell type is changed to another adult cell type. •TROPHIC TRIGGERS •Soluble mediators that stimulate cell growth. •ISCHEMIA •Hypoxia due to reduced/lack of blood flow. •PATHOLOGIC ADAPTATIONS • Cellular responses to stress that allows cells to modulate their structure and function in order to escape injury. •HYPOXIA •Oxygen deficiency from any cause (is not necessarily caused by a reduction in blood flow, i.e., in anemia). • INFARCTION • Irreversible injury resulting in cell death. • Infarction is tissue death (necrosis) caused by a local lack of oxygen, due to an obstruction of the tissue's blood supply • PHYSIOLOGICAL ADAPTATIONS • Responses of cells to normal stimulation. •NECROSIS •The premature, pathological death of cells caused by factors external to the cell or tissue; it elicits an inflammatory response. • APOPTOSIS • The cells of a multicellular organism are members of a highly organized community. The number of cells in this community is tightly regulated—not simply by controlling the rate of cell division, but also by controlling the rate of cell death. If cells are no longer needed, they commit suicide by activating an intracellular death program. This process is therefore called programmed cell death, although it is more commonly called apoptosis (from a Greek word meaning “falling off,” as leaves from a tree). •APOPTOSIS • An often physiologic form of cell death (aka, "Programmed cell death") that serves as a means of eliminating unwanted cells. May also be a pathological death after some forms of cell injury, especially DNA and protein damage. It does NOT elicit an inflammatory response. •RE- PERFUSION INJURY • When restoration of blood flow to an ischemic area results in cell death. Usually as a result of: • Reperfusion injury is the tissue damage caused when blood supply returns to the tissue after a period of ischemia or lack of oxygen. • The absence of oxygen and nutrients from blood during the ischemic period creates a condition in which the restoration of circulation results in inflammation and oxidative damage through the induction of oxidative stress rather than restoration of normal function •REVERSIBLE CELL INJURY •Injury in a cell that can be corrected, allowing the cell to return to normalcy Learning Pathology: • General Pathology • Common changes in all tissues. e.g.. Inflammation, cancer, ageing, edema, hemorrhage ….etc. • Systemic Pathology • Discussing the pathologic mechanisms in relation to various organ systems e.g. CVS, CNS, GIT…..etc. What should we Know About A Disease • Definition. • Epidemiology – Where & When. • Etiology – What is the cause? • Pathogenesis - Evolution of dis. • Morphology - Structural Changes • Functional consequences • Management • Prognosis • Prevention Cell injury and adaptation Pathology • Branch of Medicine • “suffering’ • Studies the underlying causes of diseases “etiology” • Mechanisms that result in the signs and symptoms of the patient “pathogenesis” Pathology • Bridge between basic science and clinical practice • Divisions: General Pathology Systemic Pathology The Cell How do cells react to environmental stress? • • • • • • Hypertrophy Hyperplasia Aplasia Hypoplasia Atrophy Metaplasia Hypertrophy • Increase in protein synthesis/ organelles • Increase in size of cells • Increase in organ/tissue size Hypertrophy Hyperplasia • Increase in NUMBER of cells • Increase in size of organ/tissue • Similar end result as hypertrophy • May occur with hypertrophy Hyperplasia Aplasia • Failure of cell production • Agenesis or absence of an organ:fetus • Loss of precursor cells:adults Technetium: scintigraphy Aplasia Hypoplasia • Decrease in cell production Atrophy • Decrease in mass of preexisting cells • Smaller tissue/organ • Most common causes: disuse poor nutrition lack of oxygen lack of endocrine stimulation aging injury of the nerves Atrophy Metaplasia • Replacement of one tissue by another tissue • Several forms: Squamous metaplasia Cartilaginous metaplasia osseous metaplasia myeloid metaplasia Metaplasia Barrett’s esophagus What are the causes of injury/stress? • Hypoxic cell injury • Free radical injury • Chemical cell injury Hypoxic cell injury • Complete lack of oxygen/ decreased oxygen • Anoxia or hypoxia • Causes: ischemia anemia carbon monoxide poisoning decrease tissue perfusion poorly-oxygenated blood Hypoxic cell injury Early stage Hypoxic cell injury • Decrease in production of ATP • Changes in cell membrane • Cellular swelling endoplasmic reticulum mitochondria • Ribosomes disaggregate • Failure of protein synthesis • Clumping of chromatin Late stage • Cell membrane damage myelin blebs cell blebs Cell Death • Irreversible damage to the cell membranes • Calcium influx • Mitochondria calcifies • Release of cellular enzymes lab exams for AST, ALT, CKMB, LDH • Most vulnerable cells: neurons Cardiac enzymes CKMB kit Free radicals: superoxide and hydroxyl radicals • Seen in: normal metabolism oxygen toxicity ionizing radiation UV light drugs/chemicals ischemia What will neutralize free radicals? Mechanisms to detoxify free radicals • • • • • • Glutathione Catalase Superoxide dismutase Vitamin A, C, E Cysteine, selenium, ceruloplasmin Spontaneous decay Chemical Injury • Carbon tetrachloride and liver damage Morphologic patterns of cell death: NECROSIS AND APOPTOSIS • Necrosis sum of all the reactions seen in an injured tissue, leads to cell death • autolysis – cell’s enzymes • Heterolysis – extrinsic factors Types of necrosis • Coagulative necrosis • Liquefactive necrosis • • • • Caseous necrosis Gangrenous necrosis Fibrinoid necrosis Fat necrosis Coagulative necrosis • Interruption of the blood supply • Poor collateral circulation heart kidney Characteristic nuclear changes Coagulative necrosis Coagulative Necrosis Liquefactive necrosis • Interruption of blood supply • Enzymes liquefy the tissue Brain • Suppurative infections Bacteria Liquefactive necrosis Caseous necrosis • • • • Coagulative + liquefactive “cheese - like” Part of granulomatous inflammation Classic picture: Tuberculosis Caseous necrosis Gangrenous necrosis • Interuption of the blood supply to the lower extremities or bowels • 2 types: 1. Wet type: complicated by liquefactive necrosis 2. Dry type: complicated by coagulative necrosis Gangrenous necrosis types Fibrinoid necrosis • Immune-mediated vascular damage • Protein – like material in the blood vessel walls Fat necrosis • Traumatic fat necrosis: after injury Breast ENZYMATIC FAT NECROSIS: PANCREAS APOPTOSIS • • • • • “falling away from” Another cell death pattern “Programmed cell death” Removal of cells Prevents neoplastic transformation Necrosis versus apoptosis • • • • • • Gross irreversible cell injury Passive form of cell death Does not require genes, protein synthesis Marked inflammatory reaction Physiologic programmed cell removal Active form of cell death • Requires genes, proteins, energy • No inflammatory reaction Genes affecting apoptosis • Inhibits: bcl-2 • Facilitates: bax p53 Morphological features in apoptosis • • • • • • Involves small clusters of cells only No inflammatory cells Cell membrane blebs Cytoplasmic shrinkage Chromatin condensation Phagocytosis of apoptotic bodies Reversible Cellular changes • Fatty change • Hyaline change • Accumulation of exogenous pigments • Accumulation of endogenous pigments • Pathologic calcifications Fatty change • Liver, heart, kidney • Accumulation of intracellular parenchymal triglycerides -increased transport -decrease mobilization -decreased use -overproduction Fatty change: LIVER Hyaline change • Accumulation of hyaline • HYPERTENSION; DIABETES MELLITUS • “glassy” appearance Exogenous pigments • Lungs carbon silica iron dust • Lead – Plumbism • Silver - Argyria Endogenous pigments • Lipofuscin • “wear and tear” pigment • Elderly patients • Liver, heart • Brown atrophy Pathologic calcifications • Previously damages tissues “dystrophic calcification” scarred heart valves Pathologic calcifications • Hypercalcemia “metastatic calcification” Question: • A young woman was admitted due to a bacterial infection. CT scan showed an abscess in her brain. What type of necrosis would you expect to see? • A.coagulative • B.Caseous • C.Liquefactive Question: • A 15 year old girl was brought into your clinic due to painful menses. She also said that her menstrual blood flow was heavy and had clumps of blood clots and tissues.Menstruation is classified as: • A. Apoptosis • B. Coagulative Necrosis • C. Liquifactive Necrosis