Week 5

• What are the effects of external stimuli on cells?

  External stimuli may exert several effects on cells.
• What is necessary for cells and tissues to function properly?

  Cells and tissues need to maintain a steady state, known as homeostasis.
• What is cellular adaptation?

  Cellular adaptation is when a cell is between a normal state and an overstressed, injured state.
• What are the main types of cellular adaptive processes?

  • Atrophy
  • Hypertrophy
  • Hyperplasia
  • Metaplasia
• What is atrophy in cellular adaptation?

  Atrophy is a decrease in cell size and/or number, leading to organ shrinkage.
• What are some physiological causes of atrophy?

  Physiological causes of atrophy include reduction/loss of endocrine stimulation.
• What are some pathological causes of atrophy?

  Pathological causes of atrophy include denervation, vascular issues, nutritional deficiencies, disuse, and pressure.
• What is hypertrophy in cellular adaptation?

  Hypertrophy is an increase in cellular components, leading to increased cellular size and organ size.
• What are some physiological causes of hypertrophy?

  Physiological causes of hypertrophy include increased workload and hormonal stimulation.
• What are some pathological causes of hypertrophy?

  Pathological causes of hypertrophy include increased resistance and obstruction.
• What is hyperplasia in cellular adaptation?

  Hyperplasia is an increase in cellular numbers, often seen in tissues with high cell turnover.
• What are some physiological causes of hyperplasia?

  Physiological causes of hyperplasia include hormonal changes and regeneration processes.
• What are some pathological causes of hyperplasia?

  Pathological causes of hyperplasia include reactive changes in lymphoid tissue and hormonal influences.
• What is metaplasia in cellular adaptation?

  Metaplasia is the change from one cell type to another, usually seen in epithelial tissues.
• What are some physiological causes of metaplasia?

  Physiological causes of metaplasia include hormonal and chemical factors.
• What are some pathological causes of metaplasia?

  Pathological causes of metaplasia include squamous metaplasia in various epithelial tissues.
• What is Barrett's metaplasia?

  Barrett's metaplasia is the transformation of stratified squamous epithelium to intestinal epithelium in the esophagus.
• What are some causes of cellular injury?

  Causes of cellular injury include hypoxia, infection, immunological factors, genetic factors, physical factors, and chemical factors.
• What are some cellular changes that occur due to injury?

  Cellular changes due to injury include swelling of cytoplasm, clumping of nuclear chromatin, and disruption of cellular membranes.
• What defines irreversible changes in cells?

  Irreversible changes lead to cell death, marking the point of no return.
• What criteria indicate that a cell is dead?

  A cell is dead when there is loss of integrity of the plasma membrane, fragmentation into discrete bodies, or engulfment by neighboring cells.
• What are the two main types of cell death relevant to this module?

  The two main types of cell death are apoptosis and necrosis.
• What is apoptosis?

  Apoptosis is a physiological process that leads to programmed cell death.
• What are some physiological examples of apoptosis?

  Physiological examples of apoptosis include digit formation in embryogenesis and loss of endometrial cells in the menstrual cycle.
• What are some pathological examples of apoptosis?

  Pathological examples of apoptosis include tumors and atrophy due to cell loss.
• What are the key events in the apoptosis process?

  Key events in apoptosis include cytoskeletal and DNA fragmentation, cellular shrinkage, and formation of apoptotic bodies.
• What is necrosis?

  Necrosis is the death of large numbers of cells due to severe injury or disease.
• What are some causes of necrosis?

  Causes of necrosis include inadequate blood supply, bacterial infection, traumatic injury, and hyperthermia.
• What are the cellular characteristics of necrosis?

  Cells undergoing necrosis show swelling of cytoplasm and organelles, membrane blebbing, and disruption of cellular structures.
• What are the types of necrosis?

  • Coagulative
  • Liquefactive
  • Caseous
  • Gangrenous
  • Fibrinoid
  • Fat
• What is inflammation?

  Inflammation is a local response to injury characterized by redness, pain, heat, swelling, and possible loss of function.
• What is the purpose of inflammation?

  The purpose of inflammation is to localize and eliminate the injurious agent, then restore tissues to normality.
• What can cause extensive tissue damage during inflammation?

  Extensive tissue damage during inflammation can be caused by infection, hypersensitivity reactions, physical and chemical injuries, and necrosis.
• What are the key cells involved in inflammation?

  • Neutrophils: degrade debris, kill microorganisms
  • Mast cells: hypersensitivity reactions
  • Eosinophils: damp down allergic reactions
  • Monocytes & macrophages: scavenger cells
  • Lymphocytes & plasma cells: immune response
• What happens during the early response to injury in inflammation?

  The early response to injury includes increased blood flow, permeability, cell migration, and production of inflammatory mediators.
• What can unresolved inflammation lead to?

  Unresolved inflammation may cause permanent tissue damage and chronic inflammation.
• What are the characteristic features of chronic inflammation in the lung?

  Chronic inflammation in the lung features collection of chronic inflammatory cells, destruction of parenchyma, and replacement with connective tissue.
• What is acute inflammation of the lung characterized by?

  Acute inflammation of the lung is characterized by neutrophils filling the alveolar spaces and congested blood vessels.
• What is homeostasis?

  Homeostasis is the maintenance of a stable internal environment in the body.
• How do hormones influence cellular adaptation?

  Hormones can stimulate or inhibit cellular adaptation processes such as hypertrophy and hyperplasia.