week 1-6 theory Flashcards
Identify the Causes of Disease
Genetic: Diseases that are caused entirely by inherited or prenatally acquired genetic defects.
Multifactorial: Diseases that result from the interaction of both genetic and environmental factors.
Environmental: Diseases caused entirely by environmental factors, such as infections, toxins, and physical injury
Describe the Various Forms of Cellular Injury
- Chemical Injury:
Direct injury: Toxins directly interact with cellular components (e.g., mercuric chloride).
Indirect injury: Chemicals are converted to toxic metabolites that damage the cell (e.g., free radicals causing membrane damage). - Physical Injury:
Kinetic force: Trauma or injury caused by mechanical forces.
Thermal injury: Damage due to extreme heat (burns) or cold (frostbite). - Infective Injury: Caused by microorganisms such as bacteria, viruses, fungi, and parasites
Describe the Physiological and Pathological Role of Apoptosis
Physiological Role: Apoptosis is a form of programmed cell death that helps regulate tissue homeostasis. It eliminates damaged or unwanted cells without triggering an inflammatory response.
Pathological Role: When apoptosis is deregulated, it can contribute to various diseases, including cancer (failure to undergo apoptosis) or neurodegenerative diseases (excessive apoptosis). Apoptosis can be triggered by external factors such as radiation, toxins, and free radicals
Identify and Describe the Types of Necrosis
- Coagulative Necrosis:
Preserves the underlying tissue architecture. Common in hypoxic injuries to solid organs (e.g., heart, kidneys). - Liquefactive Necrosis:
Characterized by enzymatic digestion of dead cells, often seen in bacterial infections or ischemic infarcts in the brain. - Caseous Necrosis:
Creates a “cheesy” appearance and is most characteristic of tuberculosis.
Fat Necrosis:
Seen in acute pancreatitis, where pancreatic lipases digest fat, leading to the release of fatty acids and chalky white areas of fat saponification. - Gangrenous Necrosis:
A form of tissue death due to ischemia, often affecting soft tissues. It can be classified as dry or wet depending on the presence of infection
Define Ischemia and Infarction
Ischemia: A condition where there is impaired vascular perfusion, leading to a lack of oxygen and nutrients in tissues. This can result from conditions like thrombosis, embolism, or atherosclerosis
Infarction: Refers to tissue death (necrosis) caused by ischemia. This results when the blood supply to a part of the body is completely cut off, leading to irreversible cell death
Causes of Ischemia
Thrombosis: The formation of a solid mass of blood constituents in vessels, which can obstruct blood flow.
Embolism: A mass traveling in the bloodstream that can lodge in vessels and block blood flow.
Atheroma: Plaque formation in arteries, commonly due to atherosclerosis.
Vasculitis: Inflammation of blood vessels.
Vascular Spasm: Sudden contraction of blood vessel muscles.
Compression: External pressure on blood vessels (commonly in veins).
Hyperviscosity: Thickened blood impairing its flow, commonly due to blood disorders
Thrombosis occurs when…
Thrombosis occurs when blood clots form abnormally within a blood vessel. It can lead to infarction, embolism, or edema.
what is
Virchow’s Triad
Virchow’s Triad: Three factors that contribute to thrombus formation:
Endothelial injury.
Abnormal blood flow (stasis or turbulence).
Hypercoagulability
Signs of inflammation
Redness (rubor), heat (calor), swelling (tumor), pain (dolor), and loss of function (functio laesa).
Process of Inflammation
Vascular Phase: Increased blood flow and permeability of blood vessels.
Cellular Phase: Movement of immune cells, like neutrophils, from the blood to the tissue(
Vascular Mediators of Inflammation
Vascular mediators: Histamine, prostaglandins, and nitric oxide cause vasodilation and increased vascular permeability.
cellular Mediators of Inflammation
Cellular mediators: Neutrophils, macrophages, and lymphocytes respond to injury by migrating to the site of damage.
chemical Mediators of Inflammation
Chemical mediators: Cytokines, bradykinin, and complement proteins act to stimulate the inflammatory response
Acute inflammation
A short-term, immediate response to injury with the main goal of removing the causative agent and repairing tissue. Characterized by fluid accumulation, immune cell infiltration, and swelling.
Chronic inflammation
Prolonged inflammation resulting from persistent stimuli. It involves ongoing tissue destruction and repair processes, often leading to scarring or fibrosis. Chronic inflammation can be associated with diseases like rheumatoid arthritis or tuberculosis
Describe Oedema
Oedema is the abnormal accumulation of fluid in the interstitial spaces of tissues.
oedema cause
It is caused by:
Increased vascular permeability (e.g., inflammation).
Increased hydrostatic pressure (e.g., heart failure).
Reduced oncotic pressure (e.g., hypoalbuminemia).
Lymphatic obstruction (e.g., lymphatic damage)
what are types of Systemic Oedema
Cardiac Oedema: Caused by heart failure, leading to increased venous pressure and fluid retention, often presenting as peripheral oedema or pulmonary oedema.
Renal Oedema: Results from nephrotic syndrome, causing protein loss in the urine and hypoalbuminemia, leading to fluid accumulation.
Nutritional Oedema: Seen in malnutrition (e.g., kwashiorkor) due to low protein levels leading to decreased oncotic pressure.
Liver Failure Oedema: Due to impaired synthesis of albumin, leading to hypoalbuminemia and ascites (fluid in the abdomen)
Define different types of cell and tissue growth
Multiplicative: Increase in the number of cells.
Auxetic: Growth by an increase in cell size.
Accretionary: Growth by the accumulation of extracellular substances.
Combined: A combination of these processes occurs in various tissues.
Endocrine factors in growth disorders
Growth hormone (GH) plays a key role, released from the anterior pituitary and stimulates Insulin-like Growth Factors (IGFs). Conditions like dwarfism (due to GH deficiency) and gigantism (due to excess GH before puberty) highlight the importance of GH regulation.
Genetic factors in growth disorders
Genetic factors: Parental characteristics like height are often inherited. Conditions like achondroplasia are due to a lack of fibroblast growth factor receptors, while Down syndrome (trisomy 21) affects growth.
nutritional factors in growth disorders
Nutritional factors: Nutritional deficiencies, like those seen in kwashiorkor (protein deficiency) and marasmus (caloric deficiency), greatly impact growth.
Environmental factors in growth disorders
Environmental factors: Maternal substance abuse, birth weight, and illnesses can interfere with normal growth.
Describe normal and abnormal tissue growth:
Atrophy: A reduction in cell size or organ size due to decreased workload, aging, or poor nutrition.
Hypertrophy: Increase in cell size, usually in response to increased workload (e.g., muscle hypertrophy due to exercise).
Hyperplasia: Increase in the number of cells, often seen with hypertrophy (e.g., epithelial hyperplasia in response to hormonal stimulation).
Hypoplasia: Failure to reach normal size during development.
Metaplasia: Replacement of one differentiated cell type with another, often as a response to stress (e.g., squamous metaplasia in the lungs of smokers).
Dysplasia: Disordered growth, often precancerous, involving abnormal cell shapes and increased growth rates (e.g., in epithelial tissues).
